Radio-News-1952-08-R

1 R I & AUGUST TELEVISION 1952 354 NEWS In Canada 40a

IN THIS ISSUE

1ICROWAVES FOR THE "HAM"

JNIVERSAL DESIGN CURVES

'CDR TONE- CONTROL CIRCUITS

TELEVISION PICTURE TUBE REPLACEMENT GUIDE

t "Data- Print" No. 41

THE "DIALAUDIO" SYSTEM

SERVICING PICTURE TUBES

MULTI- SIGNAL GENERATOR

UNIQUE TV SIGNAL TRA PROBE

IMPROVED SPEECH CLIPPER

CINEMAGNETIC RECORDING See Page 401

www.americanradiohistory.com Specialized racks like these are used tc life -test RCA Kinescopes.

The Million - Dollar Test Equipment that pays off in better picture tubes

AT RCA's picture tube plants, duction lines and subjected to rigor- ance that only top -quality RCA constant vigilance over quality is ous life tests in racks such as those Kinescopes leave the factory. In this maintained with specialized test shown. Any deviation from pre- way, RCA closely guards its own equipment valued at well over one scribed quality standards is promptly reputation ... and yours as well. million dollars. This huge invest- noted and corrected at the source. In ment is one reason why RCA picture addition, a portion of these samples With RCA Receiving Tubes, tubes are the best you and your cus- is given an extended life test equiva- as well as RCA Kinescopes, TOP -QUALITY tomers can use. CONTROL lent to years of actual service in the makes the difference. In one phase of the quality -control home. program, random samples of picture RCA's constant vigilance at all tubes are taken directly from the pro- stages of manufacture is your assur-

TMKS. ïì RADIO CORPORATION of AMERICA ELECTRON TUBES HARRISON, N. J.

www.americanradiohistory.com / Will Show You How io LEARN RADIOTELEVISION SERVICING OR COMMUNICATIONS by Prwcfíeingin Spare Trine

YOU PRACTICE RADIO YOU PRACTICE RADIO SERVICING COMMUNICATIONS 1 ou build the modern Radio I send you all the parts to build shown below as part of my Transmitter shown below as Servicing Course. I send you part of my new speaker, tubes, chassis, trans- Communications former, loop antenna, every- Course. Conduct thing you see pictured and actual procedure of EVERYTHING you need to Broadcast Opera- build this modern Radio Re- tors, practice in- ceiver. Use it to make teresting experi- many tests, get ments, learn how practical ex- to actually put perience. a transmitter on the air.

(O'$' 9 e> °e 01 tt tot tpuPo n "i""P MDd áuNXa1 PJ e o11so Pe Poe 474 a: ¡c I TRAINED THESE MEN "After gorduetine, worked "While learning, I Will Train You at Home for servic- made $5 to $10 a ingshop. Now Chief week in spare time. Engineer of three Now have a,profit- Police Radio Sta- ble spare time tiona."-S. W. DIN -hop." MANY WIDDIE, Jackson. - L. ARN- with KITS OF PARTS I SEND ville, Illinois. OLD, Pontiac,, Mich. s "I accepted a posi- "Rave my own Do you want good a tion as Radio and shop. Am author- pay, a job with bright Many Soon Make S10 A Week Extra in Spare Time Television Techni- ized serviceman for future and security ? Would you like a profit- Keep your job while training at home. Hun- . five manufacturers cian was pro- able shop of your own ? The fast growing, dreds I've successful RADIO- moted to manager of and do servicing for prosperous RADIO trained are Television Service 7 dealers. " -P. MIL- -TELEVISION industry TELEVISION TECHNICIA NS. Learn Radio - and Installation." LER, Maumee, O. is making these opportunities for you. Radio Television principles from illustrated lessons. L. HAUGER, San- alone is bigger than ever. 90 million home Bruno, California. "When I enrolled, Get PRACTICAL EXPERIENCE experi- had no idea it would and auto Radios, 3100 Broadcasting Stations, menting with circuits common to Radio and "Four years - ago. a be no easy to learn. expanding use of Aviation and Police Radio, Television. Many students make $5, $10 a bookkeeper on a Have equipped my Micro -Wave Relay, Two -Way Radio hand -to -mouth sal- shop out of spare for buses, week extra fixing neighbors' Radios in spare ary, am now a Ra- time earnings. I taxis, etc., are making opportunities for dio Engineer time. Special Booklets start teaching you the ABC am clearing about Servicing and Communications Technicians day you enroll. network." - N. H. $40 to $60 a month." and FCC -Licensed Operators. WARD, Ridgefield. A _4s; J. D. KNIGHT, Denison, Tex. Park, New Jersey. Send Now for 2 Books FREE -Mail Coupon Television is TODAY'S Good Job Maker Send for my FREE DOUBLE OFFER. Get In 1946 only 6,000 TV sets sold. In 1950 over actual Servicing lesson. Also get my 64 -page 5,000,000. By 1954, 25,000,000 TV sets will book, "How to Be a Success in Radio -Tele- be in use, according to estimates. Over 100 vision." Read what my graduates are doing, TV Stations are operating in 35 states. earning. Send coupon in envelope or paste on Authorities predict there will be 1,000 TV postal. J. E. SMITH, President, Dept. 2HE, Stations. This means new jobs, more jobs, National Radio Institute, Washington 9, D. C. good pay for qualified men. OUR 39TH YEAR. Good kraohi-FREE MR. J. E. SMITH. President, Dept. 2HE National Radio Institute, Washington 9, D. C. Mail me FREE Lesson and 64 -page book. (No salesman will call. Please write plainly.)

NAME AGE ADDRESS A TESTED WAY TO BETTER CITY ZONE STATE PAY...MAIL Approved COUPON NOW fora Training-a -.a. Under G. I. Bill RADIO & TELEVISION NEWS 1, published monthly by the Ziff -Davis Publishing Company at 185 N. Wabash Ave.., Chicago 1, Ill. Entered as second -class matter. July 21, 1 ode, at the Post (flic. Chicago, Ill., under the act of March 3, 1870. Authorized by Post Office Department, Ottawa, Canada. as second-class matter. SUBSCRIPTION RATES: Radio c Television News-one year, U. S. and Possessions, Pan -American countries. and Canada $4.00; all other foreign countries $5.00: Radio -Electronic Engineering Edition -one year, U. S. and Possessions. Pan -American countries. and Canada $6.00: all other foreign countries $7.00. Postmaster- Please return undelivered copies under form 3589 to 64 E. Lake St., Chicago 1. Ill. 3

www.americanradiohistory.com Editor OLIVER READ, D.Sc., DLitt.

Managing Editor RADIO& WM. A. STOCKLIN, B.S. Juif inoo e Technical Editor TELE VISION radio - television - electronics H. S. RENNE, M.S. NEWS Average Paid Circulation over 200,000 Associate Editor Reg. U.R. Pat. Off. BECKER HAROLD Radio News Trademark Reg. U. S. Pat Office Television News Trademark Reg. U.S. Pat. Office.

Service Editor CHARLES TEPF ER

Assistant Editor P. B. HOEFER CONTENTS AUGUST, 1952 Television Consultant WALTER H. BUCHSBAUM Microwaves for the "Ham" Samuel freedman, W6YUG 31 Short -Wave Editor KENNETH R. BOORD Audio Goes Mobile 35

Staff Artist Servicing Picture Tubes John B. Ledbetter 36 FRANK SAYLES Electronic Growth in the Pacific Southwest S. K. Painter 38 Draftsmen A. A. GANS, W2TSP The R.C.O. -A Remote Control Oscillator John F. Clemens, W9ERN 40 J. A. GOLANEK Universal Design Curves for Tone -Control Circuits (Part 2) M. B. Knight 42 Advertising Manager The Multi -Signal Generator Louis E. Garner, Jr. 44 L. L. OSTEN Cinemagnetic Recording A. C. Blaney 46 Midwest Adv. Manager JOHN A. RONAN, JR. Unique Sound Alarm for Deaf Persons H. G. Davis, Jr., M.D. 48 Western Adv. Manager The TV Picture Tube Walter Buchsbaum 50 JOHN E. PAYNE Television Picture Tube Replacement Guide -Data -Print 4 (Insert) 51 Color Art Editor HERMAN R. BOLLIN Constant K Type High -Pass Filter Design Seizo Yamasita 54 An Improved Speech Clipper L. C. Watkins, Jr., W5JXO 55

A Unique TV Signal Tracing Probe E. G. Louis 58 Mac's Radio Service Shop John T. Frye 60 The "Dialaudio" System Budd Meyer 61 Industrial Electronics Ed Bukstein 64 Convert Your Signal Generator into a Grid -dip Oscillator Hartland B. Smith, W8VVD 66 WCEMA -IRE West Coast Meet Ralph L. Power 80

What Is Eidophor? 94 Radio -TV Service Industry News 134

DEPARTMENTS COVER PHOTO: Robert Mitchum, star of the Wald -Krasna production "The Lusty Men," on location. RCA's portable magnetic recorder -reproducer For the Record The Editor 8 What's New in Radio 76 equipment was used in this filming. (Ektachrome by J. Dale Healy Spot Radio News I b Manufacturers' Literature 88 and Alex Kahle) Within the Industry 24 Reel Review 98 Chairman of the Board and Publisher WILLIAM B. ZIFF Short -Wave K. R. Boord 65 New TV Products 118 President Technical Books 124 B. G. DAVIS

Secretary Treasurer G. E. CARNEY Vice -Presidents OAK H. J. MORGANROTH VOLUME 48 NUMBER 2 Production Director Member Audit Bureau of LYNN PHILLIPS, JR. Circulations Advertising Director

H. G. STRONG Editorial and [aeeutive Offices. Madison Ave., New York 17, N. Y. to Dept.. 84 E. Circulation Director SUBSCRIPTION SERVICE: communications 8g366 addressed Lake Chicago , Ill. Subscriberseshouldsubscriptionsaow t least two weeks change oflraddress. BRANCH advised retain should OFFICES CONTRIBUTIONS: Office must accompaniedhby etunrnspastage, Contributions wiContributionsl b l ndletl to the ONew York rEditoriall d to whatever adapta- CHICAGO (I) sortable care, but this magazine assumes no responsibility for their safety. Any copy accepted is subject revisions are necessary to meet the requirements of this publication. Payment covers all author's. contributor's, 785 N. Wabash, AN 3.5200 tions and in accepted be tint rates upon ad- and contestant's rights, will part of the material apurchaseä LOS ANGELES (I 4) Allnphoton and be conslideretl 815 S. Hill St., Tucker 9213 Copyright 1952 by Ziff -Davis Publishing Company. All rights reserved. RADIO S TELEVISION NEWS

www.americanradiohistory.com TELEVISION RADIO- ELECTRONICS:

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A REPORT ON H III//PHOR-FI'l'. PLF,:ISF. NOTE!

THE long- awaited and much -touted ticularly on the long shots, the skin CBS Eidophor color TV projection tones varied between tan and near system (see page 94) made its initial white. A short boxing skit with two bow in New York City, Wednesday, professional heavyweights served to June 25 at a closed preview. We had show the dramatic effects possible with looked forward for many months to the any color system. Here was realism at opportunity to compare the new CBS its best! projection system with that demon- Other notations include "shirt color strated last fall by RCA. We had an- (lavender) on head." This refers to a ticipated at least a comparable qual- dramatic skit which included the prin- "LITTLE GIANT" ity of color projection and had even cipal actor dressed in a lavender sport hoped that we might see major (or shirt. This lavender color also ap- even minor) improvements over those peared on the actor's face (uninten- TV systems which we had viewed on pre- tionally) directly below the hair -line vious occasions. and was quite noticeable. lightning arresters Such was not the result and the From a technical viewpoint, we were telecast, being transmitted via closed attempting to identify a peculiar trav- circuit, was under way less than a eling white spot that slowly made its minute before we found ourself reach- way from left to right across the ing for a pencil to make suitable obser- screen. It looked like two inverted millions sold! vation notes. kidney beans. There were additional Our first note was that the produc- weird effects that appeared on the tion appeared quite fuzzy and that lower right of the screen and these because they there was a distinct multiple ghost -like appeared to be reflections being picked have proved effect on the right side of the emcee. up by part of the lens system, either from cameras or through the projec- their worth in Vertical colored stripes .remained on the left side of the screen during the tion medium. Our final notation refers safety and sales! entire half-hour show and, except for to the "stroboscopic effect" during any occasional close -ups, the registration fast movement. It was particularly no. AT105 $1.25 list was far inferior to that seen at the noticeable as a dancer with a whirling RCA demonstration. skirt concluded her routine. Individual no. AT105S $1.50 list Our next note was favorable. The vertical color bars replaced the pat- (with strap) color renditions of red and blue were terns on the skirt and were very con- excellent, especially on a close -up. The spicuous. This illusion would be most only times that we considered over-all bewildering to the layman. reproduction to be acceptable was dur- All in all, and in fairness to the ing the many close -ups, but here again Eidophor system, it should be men- there was a noticeable effect in the tioned that according to the develop- changing from tan to light flesh color ers, "the medium is not as yet per- of the performers. Continuing our no- fected." We heartily agree with that tations, we find an underscored refer- statement. ence "colors fade out on left." The Following our notations, we went to effect was that not only did the over- the extremities of the theater to wit- all production lose its sharpness, but ness the color from approximately 100 became washed out progressively to- feet. We attempted to analyze the wards the left -hand side of the screen. effect from the standpoint of the aver- write for Form No. 84 One of the outstanding qualities of age movie -goer and came to the con- the RCA system, which we well re- clusion that the Eidophor system, as J F D Mfg. Co. member, was that costume jewelry or demonstrated, would in no way com- other gold colors were startlingly true. pare favorably with our accepted Y. Brooklyn 4, N. With, the Eidophor system, gold ap- standards for Technicolor movies and is concerned, BEnsonhurst 6 -9200 pears as a faded yellow, at least at this as far as the TV medium particular demonstration. we are more convinced than ever be- world's largest An excellently produced choreo- fore that the public, if given the op- with the chorines portunity, would certainly choose the of TV graphic sequence manufacturer dressed in vivid colors was very star- system which the FCC did not see fit antennas & accessories tling in its realism. However, and par- to wait for O.R. NEWS 8 RADIO & TELEVISION

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As above, but In counter -type calibrating crystals (not supplied) for local blue enameled steel case. Size, 17y3 'x 1885 x 6". channels. Also provides horizontal sweep Shpg. wt., 32 lbs. 84 -186. Net $168.00 voltage (phasing control). Standby switch. blue Model 539A. Lab model: measures mutual con- In Hammertex steel case, 14 x 16% x ductance In mlcromhos: vernier adjustment. Du- 7'. Less crystals. For 105 -125 v., 50 -60 cycles. Shpg. wt., 35 lbs. rable leatherette case. For 110.130 volts, 50 -60 84 -139. Net $219.00 cycle AC'. Size, 16% X 18% x 7%'. Shoe. wt.. Model 630. TV voltage calibrator. 39 lbs. 84 -180. Net Permits exact peak -to -peak voltage measurements $271.50 - regardless of waveform. Size, 11 ( x 8% x 6'. For 110 -120 volts, 50-60 cycles. Wt., 15 lbs. 84 -176. Net $87.50 Model 292X Microvolt Signal Generator. Covers 125 kc to 110 mc and 150 -220 me, on fundamentals, with 1.0% Model No. accuracy. Size: 14 x 163. x 7'. With cables and 1000 kc 600A Tube Tester crystal. For 105 -125 v., 50-60 Cr. AC. Shpg. wt.. 36 lbs. 84-145. .Vet S266.00 Dynamic Mutual Conductance tester for highly accurate radio servicing, and New Model 670 5" Oscilloscope for lab and industrial applications. For the service technician. Direct -coupled, Testa for gas content; reads in mi- P -P amplifiers for vertical and horizontal cromhos; applies separate voltage to deflection provide perfect square wave re- each element; easily detects weak sponse on low frequency signals. Vertical tubes. Triple -scale meter has ranges amplifier has useable response beyond 2 mc. of 0- 3000 -6000- 15,000 micromhos and Horizontal amplifier response from 0 to 100 REPLACE -?-GOOD. Replaceable kc. Sensitivity: vertical amplifier, 10 milli- roll chart gives setup data at a glance. volts rms per inch; horizontal amplifier, 70 Leatherette -covered case. Size: 16% x millivolts rms per inch. Input impedance: 7% x 11 % ". For 110-130 volts, 50 -60 vertical amplifier, 2.2 meg and 30 mmf; cycles AC. Shpg. wt., 21 lbs. horizontal amplifier, 1 meg and 35 mmf. 84 -185. Net $155.00 Recurrent linear sweep from 3 to 50,000 cps Modell 605. As above, but has built -In VOM. A compact, low -cost portable tube and and fixed sweeps at 30 and 7,875 cps. De- set tester. Shpg. wt., 27 lbs. $4 -189. Net S167.60 modulator for viewing modulation on RF Cathode Ray Tube T Adapter. For use with tube testers above: permits signals. Line phasing control. Internal 60 checking of all present TV picture tubes without removing tube from set. Shpg. wt., cycle or external Z -axis modulation. Ham - 1 Ib. 84 -184. Net ... $9.90 mertex blue case, 12% x 9%i x 18'. Complete with 5UP1 CRT,, tubes and instructions. For 105 -125 volts, 50 -70 cycles AC. Shpg. wt., 35 lbs. Model No. 680 VHF -UHF Marker Generator 84 -160. Net $199.98 Model 640 5" Oscilloscope. Professional quality. Response: 0 -4.5 mc (down only 3 db). A new RF signal and marker generator. For Vertical -l0 my /Inch (low sens. pos. 2.5 my /inch): horizontal -50 my /Inch full gain, aligning VHF and 20 v /inch direct. Size: 14 x l l j x 19'. For 105 -125 v., 60 cycles. Shpg. wt., 45 lbs. UHF TV front ends. Provides 84 -179. crystal calibrated markers from 53 mc Net $355.00 -89 and Model 34 Probe. For above scopes; extends RF range to 500 mc. Shpg. wt., 1 y5 lbs. 174 -217 mc on fundamentals and from 522 -651 84 -138, Net mc and 696 -868 mc on harmonics. A magic eye 59.88 o insures accurate calibration. Choice of 3 calibrating crystals is provided by front panel Model 209A Electronic VOM switch (a 2.5 mc crystal is supplied). RF output, Lab -size instrument. Zero- center scale for .15 v. Portable steel case. 11% x 9 x 6'. For fast discriminator alignment. Measures AC 110 -130 v. 50 -60 cycle AC. With tubes. Shpg. rms and peak -to -peak volts directly from 30 wt., 18 lbs. 84 -188. Net $129.50 cycles to 300 megacycles. 42 ranges: AC -DC volts, 0- 3 -12 -30 -120- 300 -1200; DC current, 0- 3- 12 -30- 120 -300 -1200 ma; resistance, .1 ohm to Model 650 Videometer 10,000 megs in 8 ranges; capacity, 0- 10,000 mmf and 0 -1000 mfd (7 ranges); A specialized signal generator for quickly inductance, 50 mh to 100 henries; db, -20 to localizing any TV trouble. Fundamental -25 in 3 ranges; AC peak -to -peak volts, output on all 12 channels. Can be externally 0- 3- 12-30- 120 -300. Input impedances: DC, video modulated on all channels. Crystal - 12 mega; AC, 12 megs and 6 mmf. 9' meter controlled circuit generates 60 -900- 15,750 has easy -to -read scales. Separate jack for 1200 volt AC range. Case is blue cycle and 315 kc video pulses- produces Hammertex; I6% x 134 x 7'. With tubes, high- frequency probe, leads. For horizontal and vertical bar patterns individ- 105 -125 v., 60 cycle AC. Wt., 25 lbs. 84 -136. Net $132.50 ually, or together; also dot pattern. Pulses Model PR30A Probe. High voltage DC probe for use with above. Extends range to also available externally; metered in peak - 30,0(10 volts DC. With 4 -foot cable and connector. Shpg. wt., 1% lbs. to -peak. Has 1 to 100,000 microvolt cal- 84 -149. Net 511.90 ibrated attenuator. Has video amplifier with Model 450 VOM.- Lightweight, portable general -purpose VOM: 5' meter: high sensitiv- 180° phase control, for use as ity: 20.000 ohms /volt on DC; 5000 ohms /volt on AC. Only 8% x x 2%3'. Shpg. wt.. substitution amplifier. Sawtooth outputs for 41bs. 84 -182. Net substitution in TV set. Reads AC line voltage. Blue Hammertex case, 13 x $46.50 Model 215 VTVM. A professional unit of high accuracy. Reads RMS and peak -to -peak 16 x 7 ". With test leads, output cable, and instructions. For 105 -125 volts. AC volts 50-60 cycles. (7 ranges each), and DC volts: 0 -1.5, 3- 12 -30- 120 -300-1200. 5' meter. 8% x Shpg. wt., 40 lbs. 84 -183 Net $310.90 5% x 454'. Shpg. wt., 8 lbs. 84 -181. 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FREQUENCY RESPONSE Vertical Amplifier DC- -0 to 400 kc, +0, -20 %, not more than 50% down at 700 kc. AC- -10 cycles to 400 kc, +0, -20 %, not more than 50% down at 700 kc. Probe- -2 cycles to 400 kc, +0, -20 %, not more than 50% down at 700 kc. of gain or attenuator setting. PRECISION Response independent Horizontal Amplifier DC- -0 to 400 kc, +0, -20 %, not more than 50% at 700 kc. AC- -10 cycles to 400 kc. +0, -20 %, not more than 50% down at 700 kc. Response independent of gain or attenuator setting SENSITIVITY THAT Vertical AC -10 mv. rms/inch DC -28 mv. dc/inch Horizontal AC -15 mv. rms/inch DC -42 mv. dc /inch Probe 130 mv. rms /inch Deflection Plates Direct Reliable General Electric Instruments Vertical 22 volts rms /inch Horizontal 25 volts rms/inch Offer Extreme Versatility in Lab and SWEEP Industrial Applications Range-Triggered or recurrent -2 cycles to 30 kc (may be extended downwards by adding external capacity across panel jacks). Sync- ±Internal, Cline and -Ext. (requires -.3 volts peak to peak for ex- STABILITY is the keynote of the ST-2B all - ternal sync). Sweep Expansion -At least 4 times tube diameter. purpose scope, shown in the picture above. PHASE SHIFT -Negligible phase shift between amplifiers from 0 to 300 kc. Designed to permit a choice of short, medium BLANKING -Z -axis blanking requires 20 volts peak to blank. or long persistence CR tubes, the unit incor- vertical and CALIBRATION -Seven voltages available by selector switch: porates identical direct coupled .1, .3, 1, 10, 30, 100 and 300 volts peak to peak ±15 %. horizontal amplifiers. Filaments and screens DIRECT CONNECTIONS TO DEFLECTION PLATES -Avail able through first amplifier stages are regulated. Ver- capacitors -internal positioning circuits still function. on the tical selector switch allows choice of probe, RANGE-0° to 40° C. AMBIENT TEMPERATURE calibration, AC or DC inputs. POWER REQUIREMENTS- 105-125 volts, 50/60 cycles power consumption approxi lately 120 watts. (By a simple wiring change, may be operated from the board against 4 conventional -250 volt line.) Across 210 scopes, the General Electric ST -2B tests superior in 11 different characteristics.

Type ST -2A -For gener- Type ST -2C -A 5 -inch scope particularly use- al purpose use in labor- ful where wide fre- atories. Excellent wide quency response plus frequency response for portability are required. TV receiver circuit Ideal for maintenance work and industrial of microwave installa- testing. Special features tions and TV stations. include a DC vertical Low capacity input amplifier to adapt the probe Z -axis input equipment to a wide ... range of applications. . calibration volt- .. can ages provided de- Deflection pattern ... to several flection plates avail - be expanded able...hard times the diameter of tube sweep. 5 -inch tube.

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TV Channel Sweep Generator Type ST -11A - Covers all 12 VHF television channels and is designed primarily for TV receiver production line testing. Simple to operate: one front-panel control selects the sweep range and markers simultaneously. On-off switch and side -band control switch are also on the front panel. Separate crystal for each TV channel ... picture and audio carrier markers available simultaneously. This instrument combines the characteristics of General Electric's ST-4A Variable Permea- bility Sweep Generator and ST -5A Crystal Con- trolled Marker Generator.

CHECK OFF THE FREE BULLETINS THAT YOU NEED General Electric Company, Section ST -2A Scope Type ST -I2A 982 TypeBulletin X52-127 Diode Checker Electronics Park, Syracuse, New York Bulletin ECL-3 'lease me ST -28 Scope send without charge the bulletins checked at left. Bulletin ECL -4 Type Type ST -4A Sweep Generator NAME Type ST -2C Scope Bulletin X52-147 Bulletin X52 -014 COMPANY OR TITLE ST -11A Type ST -5A TypeChannel Sweep Marker Generator ADDRESS Bulletin ECL -1 Bulletin X52-128 CITY STATE GENERAL ELECTRIC ir,M,ral. I9.:1 13

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ECONOMICAL * Presenting latest information on the Radio Industry. By RADIO & TELEVISION NEWS' MOBILE WASHINGTON EDITOR

TELEVISION, since its inception a permitted more assignments. "As a AMPLIFIERS topic of teeming interest, has sparked, matter of fact," Sterling added, "un- by with the appearance of that famous less we reduce separations substan- sixth report on allocations, the most tially, the number of additional assign- fiery debates on record, not only within ments that we would pick up by industry circles, but also within the reduced separations would be few... . official family of Commissioners in And if we did take such action, we Washington. Even those who have would be employing separations below been quite docile have begun hammer- those necessary to insure interference - ing away. free service." Such a move, he noted In a pounding effort to support the would roar us back to the ice age. government's decision and its plan, vet- Hitting at the allegations that the eran radioman and FCC Commissioner, Commission has been arbitrary and ca- George Sterling, told members of the pricious in refusing to add a third or Maryland -DC Radio and TV Broad- fourth very -high channel to one of the caster's Association, meeting in Ocean larger cities, Sterling asked his audi- City, Maryland, that it seems as if ence if they heard about . . . "those some of the critics of the decision have persons who live far away from larger relayed a frightening impression that cities, those persons who would receive Newcomb mobile amplifiers are carefully built for the freeze -lift program was based on interference rather than service be- the rugged conditions of mobile use and to de- a . "conglomeration of master gim- cause of the addition of this third or liver consistently the top quality performance you micks dreamed up by a bunch of dia- fourth channel for a large city ?" He bolical whose pointed out that grade B service, upon expect from any bureaucrats main pur- Newcomb amplifier. Dollar for pose in life was to do damage to the which sparsely settled and rural areas dollar they give you more good service, more television broadcasters and viewers." depend, would be destroyed, if the convenient operational features and more all Emphasizing that such a distressing giant metropolitan center received the around, long -time satisfaction. view was unwarranted, Sterling asked additional grade A service, so boldly his to a closer look requested. The Commissioner felt that MODEL E -25MP delivers 25 watts from either 6 volt listeners take at these opinions and determine for them- only if the interests of the smaller cit- battery or 117 A.C. It has a standby switch, sep- selves if there is ". . . any justification ies and those residing in outlying areas arate power and phono switches and inputs for 2 for the belief that the majority's deci- were disregarded at this time, could mikes and 1 phono. Heavy duty plugs. 2000 volt sion was spawned by Satan himself or mileage separations be reduced. How- hermetically sealed buffer condenser. Phase cor- five or six of the fallen Angels." ever, he added ... "this does not mean rection capacitator for phono motor. Declaring that he was quite per- that the Commission cannot at a fu- plexed by the criticism that the Com- ture date make changes in the table, MODEL E is the some amplifier -25M without phono mission did not make adequate provi- when television is started and we have top. sion for the interests of the smaller more engineering data.... We might MODEL E -10M is a rugged, low cost, 10 watt unit cities, the FCC's technical expert said very well some day reduce the mileage also for either battery or A.C. power. Has standby that if there was any aspect of the separations.... We shall learn more as new stations are activated.... But switch, inputs for 1 mike, 1 decision which should not be criticized, phono. Special mount- propagation data does not ing simplifies installation and it was the Commission's recognition of the existing removal. the small cities. To support this com- permit a reduction in separations at ment, the record was described, and it this time." Se «dazAd" was pointed out that 1274 cities now Striking away at those who declared utAttOta a have one or more assignments, with that the safety factor was a "mum- 892 having one channel, while 176 have bo -jumbo created to justify wider sep- toda! a couple of assignments. "I think it is arations" the Commissioner declared clear," Sterling said, "that adequate that this ... "is far from the truth." provision has been made for potential Describing the safety factor as a means local television service." Comparing of insurance to prevent interference, the TV plan with AM broadcasting pro- with the service information now avail- visions, the Commissioner added that able, Sterling said that regardless of 1359 cities have one or more stations, which licensing procedure is used, a and of this number 971 have but one safety factor would have to be in- station and 199 but two stations. The cluded to determine separations. "The present decision, it was noted, per- data which currently exists must be mits cities without assignments in the the basis of any plan, whether it be table to come in at any time to obtain the Commission's or one proposed by an assignment. our critics," the FCC rep said. Con- NEWCOMB Commenting on the critics' views tinuing his blast, Sterling added: "Our that the separations between the very- critics are faced with the same prob- AUDIO PRODUCTS CO. high stations were too wide, the Com- lem of the completeness of the engi- for Dept. F, 6824 Lexington Ave., Hollywood 38, Calif. missioner said the wider separations neering data, and it is no answer I6 'RADIO & TELEVISION NEWS

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www.americanradiohistory.com them to state only that the Commission admits its ignorance of the ultimate in engineering facts. Manifestly, our critics can only rely on the very self -same CRYSTAL HEADPHONES facts." Reviewing the so- called disparity be- CRYSTAL MICROPHONES tween very -high and ultra -high coverage, the Commissioner indicated that he felt that eventually this problem will be minimized. "One thing is certain," he said, "u.h.f. will, in general, i provide a TV service free from the for every us effects of several forms of interference tew that plague v.h.f. frequencies. . . . I sincerely believe that u.h.f. will be a success. Despite all of the criticisms, and what might almost be termed a campaign of terror to scare people away from u.h.f., some of our most prominent and experienced AM broadcasters are reportedly ready to seek u.h.f. assignments in many cities." Drawing a parallel between the early lack of interest in TV and the present reluctance on the part of some to accept the higher frequencies, Sterling BA -109 MICROPHONE -Superior micro- BA -106 MICROPHONE -Unexcelled in its said that ... "those entrepreneurs who phone for public address, home record- price range. Particularly useful for P.A. ing and amateur applications. List systems and home recording. List price, were willing to risk their capital in price $22.50 $19.75 order to bring a new medium of corn - munication to the public are now very successful, and are reaping the benefits of their courage and faith.... Let us BA -116 MICROPHONE hope that all who are not yet in tele- Rugged ... uniform vision heed the lesson to be learned response. Unexcelled in its price range. from those who could have afforded to Particularly suitable enter television early but did not." VM -1 VIBROMIKE- Useful for many for home recording BL -2 LAPEL MICROPHONE -Only 11/2"" types of direct contact pickup. Appli- and industrial paging x 2 t/ ". Virtually flat response. Can cable to musical instruments and in- applications. List also be used in hand or as instrument ELSEWHERE, allocation decision dis- dustrial uses. . List price .. $19.50 price . . . . $14.75 pickup. List price $25.00 senter Commissioner Robert Jones continued his stinging tirade against the ruling, painting bleak outlooks for TV. In- Pittsburgh, before a combined session of the Radio and Television Club and Advertising Club, he said that it might be five years before the "Steel City" would get its second TV station. Jones' attack so disturbed the city's mayor that he asked for appointments with House Speaker Sam Rayburn and Commissioner Frieda Hennock, hoping that discussions with them might provide a solution to the problem. The ,AY/' Commissioner's words irked and simply scared many too, who felt that his MODEL A HEADPHONES BA -303 HUSHATONE* outbursts would delay issuance of au- Fullest response available Miniature extension thorization, by lending support to the from medium priced speaker for under -pillow headphones. Useful for use. Hermetically sealed. modification briefs now being prepared many studio, amateur Can be dipped into dis- for the examiners and courts. and industrial applica- BA -206 CRYSTAL HEADPHONES - Highest infecting solution. List tions. List price, $12.00 fidelity with exceptional bass response. Suit- price $9 75 able for all studio and amateur uses. List MEMBERS OF CONGRESS also price $28.00 displayed an active interest in the These highest quality crystal headphones are allocations, seeking to secure funds for also available in single headphone and lorgnette models. more examiners who can approve Lorgnette and Single Phone authorizations. Aroused by the fact Models also available in the A series. that it will be impossible to process the flood of applications that are ex- All Brush crystal products feature the famous Brush DIMORPH* pected, unless the examining staff is crystal drive element. Brush crystal products are leaders in expanded, twelve members of the Sen- their fields because for many years Brush laboratories have ate Interstate and Foreign Commerce specialized in research, development and applications of Committee petitioned the appropria- Piezoelectric crystal materials. T. M. Reg. tion subcommittee to secure at least $800,000 for . . . "salaries and other Piezoelectric Crystals and Ceramics expenses necessary for the employment Magnetic Recording Equipment of 20 examiner teams to be used exclusively for processing and hearing Acoustic Devices television applications during the fiscal THE Vuta Ultrasonics year ending 1953." DEVELOPMENT COMPANY Industrial & Research Instruments The Senators told their colleagues 3405 Perkins Avenue Cleveland 14, Ohio (Continued on page 103) I 8 RADIO & TELEVISION NEWS

www.americanradiohistory.com NOW you can build a Collins AM -FM tuner from the Pre -Fab units shown below !

COMPLETE VERSATILITY is the byword in this ECONOMY: The very finest in tuner design is offered new tuner design. Through the addition of the you at exceptionally low prices. Collins quality is your AM circuit, the Collins tuner will meet all require- assurance of a fine product that will work to your comments for home music systems and installations plete satisfaction. You cannot duplicate this tuner in its where a fine tuner is required. completed form at twice the price!

3 Ways to purchase ( 1. As an AM tuner kit 2. As an FM tuner kit COLLINS Tuner ... 1 3. As an AM -FM tuner kit

AM Tuning Unit FM Tuning Unit $15.25 The Collins FM -AM Pre -Fob Tuner Kit As ,t Looks (Includes After You Ass °mb'. It (To 'a' Kit Cost $69.00) IF and Audio Amplifier) $19.25

e0;6411.:,. t r 111

tu ning E ye i FM IF Amplifier K t $ 9.75 Availblea $2.85 UC -2 Universal Chassis Kit $14.75 ALL PRE -FAB UNITS ARE ASSEMBLED,WIRED, TESTED, AND ALIGNED AT FACTORY. PRICES SHOWN INCLUDE TUBES.

The FM tuning unit employs a 6.I6 duct: triode RF amplifier, 6AG5 converter, and 6C4 oscillator. Permeability tuned, stable, MAIL ORDER COUPON and drift -free. High sensitivity of between 6 and 10 microvolts. Cimensions: 7 1/4"x4 %T ". The IF amplifier for FM uses 6 tubes: TODAY ¿8A6, (4) 6AU6, and 6A15 discriminator. High gain, wide band ! response for highest fidelity reception Frequency response of FM section, plus or minus 2 DB, 20 to 20,000 cycles. Distortion r 'ess thon 1/2 of 1%. Dimensions: 1 1 TAe "x2 t/= ". TO: COLLINS AUDIO PRODUCTS CO. INC. The AM tuning unit utilizes a super -het circuit employing three P.O. Box 368, Westfield, N.J. tubes: 613E6 converter, 6BA6 IF amplifier, and 6AT6 detector Extremely high sensitivity and selectivity is accomplished through Enclosed Find Check L. Money Order For the use of new, high gain iron -core transformers. Carefu: alignment provides widest response available from this type of circuit AM Tuning Ur it If builder desires, triode amplifier section of 6AT6 tube may be used as first audio stage. FM Tuning Un t UC -2 Chassis Kit Chassis Kit includes all necessary parts. Nothing else to buy FM IF Amplifier M -1 Tuning Eye Kit Instruction Manual included with detailed, step -by -step procedure, pictures and schematic diagrams. Chassis measures 8 "x17 "x NAME_ 21/2". Overall, the tuner, when cssembled, measures 8 "x17 "x6" ADDRESS

CITY_ STATE

August, 1932 t 9

www.americanradiohistory.com Radio -relay station at Evanston, Wyoming

atcher for lonesome places

Many of the Bell System's 107 radio keeps moisture out of the wave - stations connecting New York and guide. At intervals the testman puts San Francisco by microwave radio - the system through its paces to be relay stand on hills and mountains sure it is on guard. far from towns. Day after day, the Sometimes the testman can cor- apparatus does its duty; no man rect a trouble condition through need be there to watch it. But when remote control, or the station may trouble threatens, an alarm system cure itself-for example, by switch- developed by Bell Telephone Lab- ing in an emergency power supply. oratories alerts a testman in a town Sometimes the trouble can await the perhaps a hundred miles away. next visit of a maintenance man - A bell rings. The testman sends sometimes he is dispatched at once. a signal which asks what is wrong. This is one of the newest examples A pattern of lights gives the answer of the way Bell Laboratories adds -a power interruption, an over- value to your telephone system by heated tube, a blown fuse, a drop reducing maintenance costs and inin pressure of the dry air which creasing reliability.

BELL TELEPHONE LABORATORIES Alarm- receiving bay in town. Lights on a chart report on 42 separate conditions affecting service. Telephone is to communicate with maintenance crews. Eleven IMPROVING TELEPHONE SERVICE FOR AMERICA PROVIDES CAREERS FOR CREATIVE MEN IN SCIENTIFIC AND TECHNICAL FIELDS. alarm centers across the country cover all 107 radio - relay stations. Stations too far off the beaten trail for wire connections signal by very high frequency radio. 20 RADIO si; TELEVISION NEWS

www.americanradiohistory.com Learn RADIO TELEVISION -New Package Unit Plan -PAY AS YOU LEARN

NO MONTHLY PAYMENT CONTRACT TO SIGN! /Send You 18 816 A'ITS TRAIN IN 10 MONTHS LESS OF RADIO- At Home in Your Spare Time TELEVISION Now . be ready for Radio- Television's big pay opportuni- ` EQUIPMENT ties in a few short MONTHS! Frank L. Sprayberry's completely new 'Package' training unit plan prepares you in just 10 MONTHS . or even less! Equally important, there is NO monthly payment contract to sign . thus NO RISK to you! This is America's finest, most complete, practical training -gets you ready to handle any practical job in the booming Radio - Television industry. In just 10 months you may start your own profitable Radio -Television shop ... or accept a good paying lob in this fascinating expanding field at work you've always wanted to do. Mr. Sprayberry has trained hundreds of successful Radio -Television technicians -and stands ready to train you in less than one year, even if you have no previous experience. You learn by DOING . . actually working with your hands with equipment of special design to illustrate basichheory instead of relying on books alone. VALUABLE EQUIPMENT INCLUDED WITH TRAINING The new Sprayberry "package" plan includes many big kits of genuine. professional Radio-Television equipment. While training you actually perform over 300 demonstrations, experiments and construction projects. In addition, you build a powerful 6-tube standard and short wave radio set, a multi -range test meter, a signal generator, signal tracer, many other projects. All equipment is yours to keep . . you have practically everything you need to set up your own service shop. The interesting Sprayberry book -bound lessons and other training materials . . . all are yours to keep.

Approved for EARN EXTRA MONEY WHILE YOU LEARN! All your 10 months of training is AT YOUR HOME in spare hours. Keep Veterans Wader on with your present job and income while learning ... and earn EXTRA CASH in addition. With each training "package" unit, you receive extra the G.I. Bill plans and ideas for spare time Radio -Television jobs. Many students pay for their entire training this way. You get priceless practical experience and earn generous service fees from grateful customers. Just one more reason why the Sprayberry new 10 MONTH -OR -LESS training plan is the best Radio -Television training in America today. If you expect to be in the armed forces later, there isi no better preparation than good Radio -Tele- vision training.

FREE TELEVIS ONABOOKS I want you to have ALL the facts about my new t0- MONTH Radio - Television Training without cost! Act now! Rush the coupon for my -three big Radio -Television books: "How to Make Money in Radio-Television," PLUS my new illustrated Tele- vision Bulletin PLUS an actual sample Sprayberry Lesson -all FREE with my compliments. No obligation and no salesman will call on you. Send the coupon in an envelope or paste on back of post card. I will rush all three books at once!

SPRAYBERRY ACADEMY OF RADIO Dept. 25 -M, Ill North Canal St., Chicago 6, III.

SPRAYBERRY ACADEMY OF RADIO, Dept. 25 -M 111 North Canal St., Chicago 6, Ill. Please rush to me all information on your 10 -MONTH Radio -Tele- 1 vision Training Plan. 1 understand this does not obligate me and that no salesman will call upon me.

Nome Age

Address

Men already in Radio who seek a short inten- IF YOU ARE sive 100% TELEVISION Training with City Zone State FULL EQUIPMENT Please check Below About Your Experience EXPERIENCED IN RADIO INCLUDED are invited to check and mail the coupon at the right Are You Experienced? No Experience 1

August, 1952 21

www.americanradiohistory.com RADIO -TV SERVICE Get this important NEW

22 13 1nlO & TELEVISION NEWS

www.americanradiohistory.com E N GI N EERS! CENTRALAB catalog!

Hundreds of new components pictured and described with exact specifications and details for faster, more profitable servicing!

Centralab's Catalog 28 will keep you up-so-date on anteed Centralab parts, you're sure to get better, safer latest developments in the fast -changing radio and TV servicing ... satisfied customers. servicing market. It's a complete, 32 -page index to Don't delay! Ask your distributor for your copy

Centralab's line of parts . . . filled with essential now. Or clip the coupon and send to Centralab. information and features about this superior line. You'll get your copy of the Centralab catalog in the You'll want your copy because when you use guar- next mail.

NEW CATALOG INCLUDES ALL THIS...

A new, expanded line of switches, including a CRL "Blue- Shaft" Volume Controls - newest complete line of miniature sizes. developments for TV -AM -FM service. Factory assembled, tested and guaranteed. More value, greater Ceramic Capacitors most complete line in - flexibility. industry. Includes higher voltages and wider capacity ranges not previously shown, plus new items exclusive New kit packages -for volume controls, switches with CRL. and capacitors. Handy and convenient. Centralab Printed Electronic Circuits -the com- Famous CRL steatite insulators -the best ceramic plete line from small resistor plates to complete insulators anywhere - and the only packaged line! speech amplifiers ... in new, still smaller sizes.

A Division of Globe -Union Inc. Milwaukee 1, Wis. 9 CENTRALAB, A Division of Globe -Union Inc. 910 E. Keefe Avenue, Milwaukee 1, Wisconsin i Please send me my copy of the new Centralab Catalog No. 28 at We will appreciate it if you tell us - name of principal distribu- once and without charge. tor you do business with -

Name._ Name Address

City State ._....__ ...... _._.._...._ Address Company _....Check One: My Own Work For City. State_ _..._...._

August, 1952 23

www.americanradiohistory.com M. J. McNICHOLAS has been advanced The school, which originally started to the post of manager of the special as a one -man organization, now has apparatus division expanded until it includes both resi- of Andrea Radio dent and home -study curricula. During Corporation, Long the war, the school prepared programs Island City manu- for training thousands of Army, Navy, facturer of televi- and Coast Guard radio technicians. The sion receivers. extension courses are now being used Mr. McNicholas by government agencies and a large joined the company number of private industries. in May of 1951 and * * * has been assisting OLIN INDUSTRIES, INC. has acquired AUTO RADIO in the procurement and expediting of RAMSET FASTENERS, INC. of Cleveland, government contracts. Prior to his as- Ohio. The new subsidiary will con- sociation with Andrea, he was purchas- tinue operation under its present man- ing agent for North American Philips, agement as one division of the parent )VIBRATORS; Inc. with headquarters at Mount Ver- company's Arms and Ammunition Di- non, New York. vision . . . ETRACO MANUFACTURING l ave eena`xcc * * COMPANY has announced a change in VICTOR MUCHER, president of Clarostat its corporate name and will henceforth sac% Sfretwed Mfg. Co., and Austin C. Lescarboura, be known as HINDLE TRANSFORMER advertising counsel, were recently hon- COMPANY. The firm manufactures ored by Clarostat officials and sales transformers and wire and cable as- reps at a banquet held to pay tribute semblies at its plant in Flemington, to the former shipping clerk who be- New Jersey . . . CONSOLIDATED ENGI- came president of the multimillion NEERING CORPORATION of Pasadena, dollar corporation and the former California has announced the forma- science magazine editor who now heads tion of a new corporation, CEC INSTRU- his own advertising agency catering to MENTS, INC., which will function as a the radio -electronic industry. subsidiary organization to handle sales Both men received the company's and service work on instruments man- traditional 25 -year gold wrist watches ufactured by the parent firm. and testimonial scrolls as tokens of ap- * * * preciation for their quarter- century NEWELL J. CORWIN has been appointed service to the organization. manager of the General Electric Com- * * * pany's Scranton, FREDERICK PALMER has been named Pennsylvania, tube president of the newly- formed San works. Diego County Electronic Association, The Scranton Incorporated. Works was pur- ,,,,L-' by 1 , Other officers named to serve with chased recently Mr. Palmer are : Upton Hildebrand, the Tube Depart- A COMPLETE LINE vice -president; William E. Stout, sec- ment from the com- VIBRATORS . OF .. 1 retary; and C. J. Mahoney, treasurer. pany's Electric Sink i Directors of the Association include: and Cabinet Depart- Designed for Use in Standard Vibrator - John R. Dorsen, John Miner, George N. ment and will continue under the di- Operated Auto Radio Receivers. Built ¡ Cocoronis, Sonny Kahn, and Thomas rection of Neil C. Mulcock, present with Precision Construction, featuring works manager, until the change in Ceramic Stack Spacers for Longer :: :: O. Crawford. Lasting Life. Backed by more than The Association, with a growing manufacturing operations has been 2G years of experience in Vibrator membership of over one hundred elec- completed. Design, Development, and tronic technicians, has been formed to Mr. Corwin has been associated with Manufacturing. establish, promote, and maintain the G -E since 1937. He is an engineering highest standards of ethical business graduate from Rensselaer Polytechnic practice and service among Association Institute. Prior to joining G -E, he was members and to render service to the associated with the Boonville, New York, Power and Light Commission, MODELS public. * * * and Barker and Wheeler, a New York V/NEW NEW DESIGNS CAPITOL RADIO ENGINEERING INSTI- City engineering firm. * * * TUTE of Washington, D. C. recently V NEW LITERATURE celebrated its 25th anniversary in the THE REPRESENTATIVES" of Radio Parts radio and electronics field with a se- Manufacturers, 'Inc. recently named a "t." Ealtery tl,minators, DC -AC Inverters new slate of national officers at its an- Au o Radio Vibrators ries of special events. of Anniver- nual national delegates' and general S« roes ;Wes os ws[te Pictosr The highlight the Silver sary program was a banquet held at members' meeting held in Chicago. B. Neely Los Angeles AMERICAN TELEVISION t RADIO CO. the Mayflower Hotel in Washington. Norman of the Russ Quality Pseduet4 Succ ,'931 George Bailey, executive secretary of Chapter was named president; Inc., Diethert (Chicagoland) was named SAINT PAUL I, MINNESOTA -U.S.A. the Institute of Radio Engineers, and president of the ARRL, was the first vice -president; Wally B. Swank principal speaker at this commemora- (Empire State) is the new second vice - tive affair. president; Dean A. Lewis (California) 24 RADIO TELEVISION NEWS

www.americanradiohistory.com 6 -color displays that prospects can't pass by!

úbes

Striking Ann Blyth and June Havoc streamers! tit/

and te,e, `.sion radioorefunivycu You can double your fall service NERE" S Wan Rcu'iu r service business with this We use SYt\'ANIÁ 4 sets of mailers with NEW SYLVANIA CAMPAIGN postage already Two gorgeous movie stars, Ann with your name, address and attached! Radio Blyth and June Havoc, feature phone number. All of the mailing announcements! their personal endorsements of pieces have stamps already at- your service in this brand new tached. You pay NO POSTAGE! Sylvania advertising campaign Radio spot announcements, and for service dealers. On life -like reminder stickers for your cus- window displays and streamers, tomers' sets round out this sure they recommend you just the business -attracting kit! way they will in the big Sylvania And all you pay is just 2 cents ads in Collier's, Life, Look, and per prospect per month for the The Saturday Evening Post, mailers. All the rest is absolutely which will appear this Fall. FREE ... even the postage on In addition, the Sylvania Cam- the mailers! Call your Sylvania paign offers you four sets of Distributor today, or mail the personalized mailings imprinted coupon below. r__ Sylvania Electric Products Inc. Dept. R- 2308, Emporium, Penna.

Please send me full detaills on Sylvania's big Fall Campaign for Radio -TV Service Dealers.

SYLVÁNIA Name Street

RADIO TUBES; PICTURE TUBES; ELECTRONIC PRODUCTS; ELECTRONIC TEST EQUIPMENT; FLUORESCENT TUBES, City Zone State FIXTURES, SIGN TUBING. WIRING DEVICES; LIGHT BULBS; PHOTOLAMPS; TELEVISION SETS J :1uo:uc1. 1932 25

www.americanradiohistory.com will serve as third vice -president; James P. Kay (Missouri Valley) is the new secretary; while Royal J. Higgin (Chicagoland) will serve as treasurer.

JOSEPH S. WRIGHT has been appointed assistant general counsel for Zenith Radio Corporation of Chicago. Mr. Wright has been an attorney with the Federal Trade Commission since 1936 and since 1947 has been the Commission's assistant general counsel and chief of its compliance division Prior to 1947, he served variously as an attorney- examiner, reviewing attorney, special legal assistant to the chairman, and trial attorney. From 1942 to 1945 he was on active duty with the U. S. Navy, attaining the rank of lieu- tenant- commander before his discharge. a a SYLVANIA ELECTRIC PRODUCTS INC. has leased 20,000 square feet of warehouse and office space in a new building in Seattle, Washington, that will serve as the company's headquarters for sales and service operations in the Pacific Northwest. The new building is located at 3466 East Marginal Way, Seattle . . . ELECTRONIC SUPPLY COR- PORATION has moved to new and larger quarters at 41 -08 Greenpoint Avenue, Long Island City, N. Y. The new location provides over 4000 sq. ft. of floor space to house the firm's distribution activities . . . A new plant for the manufacture of "Speed Nut fasteners The highest praise of technical critics in Canada has been opened by DO- MINION FASTENERS, LIMITED of Hamil- ton, Ontario. The plant will supply now goes to T w ¡ n Performers Canadian industry with more than 100 million units annually MOTOROLA differ- ... Astatic's "Twin CAC" Turnover You can see the great INC. has opened a new West Coast service department at 811 Captures, as No Other ence as readily as you can hear it. parts and Cartridge South B Street in San Mateo, Califor- Turnover Cartridge Can, the The radical design principle com- nia ... CONRAC. INC., manufacturers Full Glory of the Finest Music bines two complete CAC car - of custom -built television receiving a new sales and to back, sets, etc., has opened on Records. +ridge assemblies, back display room at 7264 Melrose Avenue on a common plate. No chance in Hollywood, California . . . GERBER SALES CO. of Boston, Mass. has opened 1 aboratory test if or interaction! For the for needle a new Connecticut office in the First simply listen to it. On all high fi- first time in a turnover cartridge, National Bank Building. 42 Church . . . The SHEL- delity counts, for brilliance of tone, the ideal output and response Street, in New Haven DON ELECTRIC DIVISION of ALLIED for smoothness of response, for characteristics for EACH side can ELECTRIC PRODUCTS INC. has acquired frequency range, by any standard be established, independently, in new branch office and warehousing facilities at 2724 Leonis Boulevard in the reproducing unit! . . . you, too, will recognize one such record Los Angeles. The new quarters pro- unmatched excellence of Astatic's Why not write for complete de- vide 21,000 square feet of air- condi- . . . MOTOROLA INC. has new tioned space new "Twin CAC," turnover pickup tails of this sensational leased certain manufacturing facilities cartridge, the Model CAC -D -J. Astatic product? from STROMBERG- CARLSON CO., LTD. in Toronto Canada and has formed a new subsidiary, MOTOROLA CANADA, The single needle Astatic LTD. which will manufacture and sell CAC -J has been acclaimed television receivers as well as a com- the perfect cartridge for mi- home and portable radios crogroove records by many plete line of impartial experts. Model ,CORPORATION for the Canadian market . . . H -B IN- N E A r,` 0 1 4 1 CAC-78J designates the sin- - .C.0 N U STRUMENT COMPANY is in production gle needle 78 RPM version. i in its newly- acquired plant at Ameri- can and Bristol Streets in Philadelphia. Y. Cable Address: ASTATIC, New York EXPORT DEPARTMENT: 401 Broadway, New York 13, N. (Continued on page 85) Astatic Crystal Devices manufactured under Brush Development Co. patents -ISION NEWS 26 RADIO d: TILES

www.americanradiohistory.com FUTURE How new TV stations are expected to cover the notion. PRESENT -Chart shows extent of current coverage. Cash in on this

... for good -pay jobs in TV SERVICING

YES, thousands of opportunities are choose-installation and troubleshooting of neers and experienced instructors-pioneers and going begging right now for good -pay TV receivers in homes ... bench technician in leaders in radio, television and electronic de- radio -TV service shops . .. inspector, tester, re- velopments. jobs in TV Servicing. pairman, field serviceman for TV receiver man- RCA Institutes home study course The lifting of the "freeze"on new television sta- ufacturers, distributors and dealers ... testing planned to your needs tion5 clears the way for the expansion of the and servicing with electronic instrument manu- industry for 2,053 new stations, in 1,291 com- facturers and companies with military contracts You keep your present job. In your spare time, munities in the United States, its territories and for electronic equipment ... civilian serviceman you study at home. You learn "How- to- do -it" possessions. There are only 108 stations tele- with U. S. Military Bases ... your own TV techniques with "How -it-works" information in casting now. service shop -and many more. easy -to -study lessons prepared in ten units. Cost This is your golden opportunity to get all set of RCA Home Study Course in Television Serv- RCA Institutes home study course icing has been cut to a minimum -as a service for a good job that can mean employment se- trains you in your spare time curity and a bright future for years to come. It's to the industry. You pay for the course on a "pay -as -you- learn" unit a great opportunity that can lead you, as a If you are associated with the radio-electronics lesson basis. You re- trained and experienced TV Serviceman, into industry, with no experience in TV servicing, ceive an RCA Institutes certificate upon completion of the course. The RCA Institutes establishing a profitable business of your own. the addition of the RCA Institutes Home Study Home Study Course in Television Servicing is approved Course in TV Servicing to your present experi- Big TV Technicians by leading servicemen's associations. shortage of ence will quickly qualify you to step out and creates opportunities -NOW grasp the good jobs now open in television. Don't pass up this lifetime opportunity for financial security and a bright future in TV. Industry experts have estimated over 130,000 The RCA Institutes course gives you a sound experienced TV technicians will be needed for knowledge of television fundamentals ... in- SEND FOR FREE BOOKLET the installation, trouble -shooting and repairing tensive practical instruction on the proper of television receivers in use by 1955. There are maintenance and servicing of TV receiver cir- Mail the coupon -today. Get complete information on fewer than 50,000 fully trained TV service tech- cuits teaches you the "short cuts" on TV the RCA INSTITUTES Home Study Course in Tele- ... vision Servicing. Booklet gives you a general outline of nicians available today. What an opportunity installation and troubleshooting. Learn TV this creates for you! the course by units. See how this practical home study servicing (based on actual experience of hun- course trains you quickly, easily. Mail coupon in en- Here are some of the good -pay jobs you can dreds of skilled technicians) from RCA engi- velope or paste on postal card.

RCA Institutes conducts a resident school in New York City offering day and evening courses in Radio and TV Servicing, Radio Code and Radio Operating. Radio Broadcasting, Advanced Tech- nology. Write for free catalog on resident courses. Ï

RCA INSTITUTES, INC., Home Study Department RN -852 350 West Fourth Street, New York 14, N. Y. Without obligation on my part, please send me copy of booklet "RCA INSTITUTES Home Study Course in TELEVISION SERVICING." (No salesman will call.)

Name RCA INSTITUTES, (pleese print) INC. Address A SERVICE OF RADIO CORPORATION of AMERICA 350 WEST FOURTH STREET, NEW YORKI4, N. Y City lone State 1uguvt. 1452 27

www.americanradiohistory.com r Arl,rert iai no COMMON SENSE about easy tv servicing

Each contains full data for manufacturers' receivers produced during a certain period. your servicing job easier (The latest, T. V. 9, recently published, Make covers October 1951 through February 1952.) Each manual has over 2,000 (8-1/2" x 11 ") pages in permanent binder, with an than you ever thought possible index covering the contents of all manuals. for shop use and get this vital informa- Rider manuals are perfect Here is how you can reference. Price -$24 each. Complete Servicing Facts tion. Insist on Rider Servicing Data. For 22 permanent years Rider Servicing Data has been the Method Proved only publishing source for the complete servicing facts: Exactly as issued by the -Files Success manufacturer who made the set. Una- Rider T.V. Tek Outstanding bridged facts ... everything is here to make your diagnosis and repair EASY. You get (Packs now cover Tens of thousands of service techni- page after page of troubleshooting test pat- cians throughout the country have terns . large, easy -to- follow complete 2,200 models) fast, easy, profita- schematics ... circuit explanations ... stage learned this key to by stage alignment curves ... clear, en- A typical T.V. Tek-File pack is shown ble servicing: They insist on having larged chassis views ... all circuit changes below. In Rider Tek -File packs you buy For example: complete Rider servicing data for whatever the complete servicing facts for every . and much, much more. Rider tv servicing data has shown 'scope receivers you want ... when you want it. receiver they repair! They know that waveforms in tv receivers ever since the first You buy according to your needs with the by having the complete story ... and tv receiver was made! assurance of getting the complete servicing facts for every repair. Notice that each pack only by having the complete story ... consists of handy, standard file folders for can they spot trouble quickly and do easy use. Only $2 each pack. an easy, permanent servicing job. To meet your individual Here's an example: On Philco models needs, Rider Servicing 52-P- 1810,52 -P- 1812,52- P- 1840,52- P -1842, 52 -P -1844, 52 -P -1882, 52 -P- Data comes in two forms 2110, 52 -P -2142, codes 122 and 123, both with these im- the manufacturer released 32 pages ... (8 -1/2 x 11" ) of official service data. portant, new features: (That is what we published in Rider TV Manual Vol. 9 and in Rider TV Manufacturers' Pack 22.) Tek -File Trouble Cures These models were made in a variety of production runs; using three differ- These 3" x 5" standard index cards called its own Rider Handies contain vital manufacturer - ent chassis ... each with issued permanent trouble cures plus produc- schematic. These chassis are identical tion changes. Each Handy is identified with in many. respects ... but the vital a manufacturer and a receiver model. With a real Rider Handies you save countless hours of differences can make servicing diagnosis and repair time . because headache. For instance, three types Handies contain the data you must have to FREE Tek-File indexes cov- repairs on many manufac- Rider T.V. of power transformers are used. Each make permanent ering the contents of all published packs turers' models. (Rider Handies information he doesn't have has different electrical constants - Tek -File packs, and are at your jobber's. If appears in Rider TV them, write us. and a different part number. In the Rider TV Manuals beginning with Vol. 9.) C2 deflection chassis, the power transformer has one high voltage winding of 635 volts, center -tapped, Guaranteed Replacement DON'T BE SWITCHED! and four low voltage windings: one Rider Tek-File is DEFINITELY NOT the 6.8 volts and one 6.4 Parts Listings same as any other publisher's service. If 5 volts, two your jobber doesn't carry them, DON'T BE volts. In the CPI deflection chassis, Beginning with Rider T.V. Manual 10 and SWITCHED. Write us direct ... we'll sell the power transformer has one high Rider T.V. Tek -File Pack 57, replacement you. (Please include your jobber's name.) of 635 volts, center parts listings are included. All the replace- voltage winding ment parts listed in Rider tv servicing data tapped, but only three low voltage meet the physical and electrical performance windings: one 5 volts, one 6.8 volts ratings of the original equipment! TRY A PACK and one 6.4 volts. In the F2 chassis, Prove to yourself that Rider Tek -File makes the power transformer has one high tv servicing easy. Buy one pack for the next voltage winding of 675 volts, center - receiver you service. If you don't agree it's Rider T.V. Manuals better than anything you ever used, return tapped, and four low voltage wind- the pack to us within seven days .. , we'll ings: one 5 volts, two 6.8 volts and Vols. 1 to 9 send you a full refund. one 6.4 volts. (covering more than Suppose you were the service tech- 4,200 models) Rider Radio Manuals. Vols. 1 nician faced with one of these re- to 22. Contain complete, factory -issued, ceivers. A single schematic showing official AM, FM radio servicing data ... just one of these chassis and one of plus auto radios, record changers, tuners these power transformers certainly and recorders. would not be coverage for all production runs. If you were lucky, the OUT SOON ! single schematic might happen to receiver you had before Rider RADIO Tek -Files! Same style as T.V. match the Tek -Files. Now, get your complete radio you. But -and it's a very big but - servicing data this easy economical package you might also be unlucky and be way. Ask your jobber. faced with a receiver not described by the schematic! This is only one ex- John F. Rider Publisher, Inc., 480 ample in thousands of why you need Canal St., New York 13, New York. complete, factory -prepared and fac- West Coast Office: 4216 -20 W. Jeffer- tory- issued data for every set you son Blvd., Los Angeles, California. service. TELEVISION NEWS 28 RADIO di

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CATALOG IMP -1 describes Pyramid's new line of molded plastic tubular capacitors. "IMPS" are rugged - impervious to moisture and withstand a temperature of 100° C.

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CATALOG PG -1 lists miniature Glasseal capacitors. These tubular units perform at tempera tures ranging from -55° C. to -125° C.

CATALOG J-7 is a 32 -page compilation of paper, electrolytic, oil -paper and metallized paper capacitors. Complete data on eighteen different types, including construction variations, sizes and prices are listed.

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30 RADIO R TELEVISION NEWS

www.americanradiohistory.com MICROWAVES for the "HAM"

Fig. I. A 6V6 tube mounted in a wave guide and cavity system for generating microwaves with a conventional receiving tube.

B.- SAMUEL FREEDMAN w1:1' l't: SINCE May 1945 the Federal Com- The growing problem of TI'1 will eventually force munications Commission has reserved seven bands of microwave hams to" more upstairs" into the microwave bands. frequencies for the exclusive use of hams. Ideally located between 420 and 22,000 mc., this allocation provides ferent type of TV receiver and the ter, crystal receivers, monstrous an- over 2,000,000 kilocycles of spectrum problem of interference becomes criti- tennas, and wireless telegraphy. He as compared to the 16,000 kilocycles cal. was forced to operate in the band from now used for approximately 99 per- The public's investment in televi- 1500 kc. upward with equipment recent of all ham transmissions. sion receivers now aggregates three quiring the use of vacuum tubes and It is now seven years since these billion dollars as compared to the ap- careful attention to impedance match- bands were assigned to the hams yet, proximately thirty million dollars ing. with the exception of the 420 -450 mc. which hams have tied up in their In a matter of months this enforced band, activity in these bands is negli- equipment. Thus the hams' stake in move resulted in several important de- gible. This state of affairs is incon- radio gear has been exceeded a hun- velopments. The move led to the dis- sistent with the ham's traditional role dredfold by the public's investment in covery of the Kennelly- Heaviside layer, as a "radio pioneer." home receivers. In terms of the num- reliable determination of sky wave The fact that 15,000,000 television ber of households affected (or in votes skip phenomena, and the establish- receivers are now in the hands of the at election time), the relationship is ment of the advantages of short -wave public with more to come as new sta- even more top- heavy. At the present operation. tions bring larger areas of the country time there are over 200 times more The ham was delighted to discover within the fold will provide a power- television households than there are that with a fraction of the power ful impetus in "kicking the amateurs ham radio homes. Even the ham often needed on the lower frequencies he upstairs." If there is to be any lasting finds himself in the unenviable posi- could communicate world -wide -even peace and harmony between the mil- tion of having his ham equipment in- to the antipodes. Even a small re- lions of televiewers and the thousands terfere with his own television recep- ceiving tube, such as the now -obsolete of amateurs, the only real solution lies tion! A showdown is in the making at UV201A, was sufficient to serve as a in a voluntary, or perhaps involuntary, the present time and eventually the transmitter to reach all the way to exodus of radio hams to the high fre- ham will wind up in the microwave Australia. The range of communica- quency, or microwave, side of the tele- region and, in the opinion of the au- tion jumped from the usual hundred vision frequency bands. thor, when this happens it will be the miles or less to distances circling the Ham transmissions on the present greatest "blessing in disguise" ever globe. Furthermore the ham could popular amateur bands will continue vouchsafed the radio art. make his contacts by voice or radio- to cause interference in nearby re- The situation is even more critical telephony instead of code or radio- ceivers with the attendant protests than it was in 1922 when radio broad- telegraphy. from irate TV fans. Although it is casting developed virtually overnight Today a similar situation exists ex- technically and theoretically possible into a hydra -headed monster of gigan- cept that now the amateur will move to eliminate such interference, it is tic proportions. At that time, ama- to a much higher and more spacious sometimes financially unfeasible to teur radio had to move up in the radio spectrum. He can achieve efficiencies do so. The mere fact that one ama- spectrum and operate on the high fre- in circuitry never before possible since teur station can operate in a certain quency side of radio broadcasting. This he can dispense with lumped or spe- area without causing interference in enforced move made the ham's equip- cially- provided inductances, condens- nearby television receivers is no guar- ment and techniques obsolete and un- ers, and even resistors with their antee that the equipment will con- suitable. Specifically he had to discon- losses. He can develop and control the tinue free from TVI. All the ham has tinue operations on frequencies of 1500 electric and magnetic fields through to do is change frequencies or equip- kc. and lower where he had employed distributed inductance, capacitance, ment or for a neighbor to buy a dif- a spark coil or rotary spark transmit- and impedance by means of the physi- August, 1952 31

www.americanradiohistory.com It is estimated that most of the li- .24 MEDIUM FREQUENCIES TOTAL KC. 1800 -1825 kc. 25 kc. censed amateur radio activity in the ATTENUATION VS FREQUENCY FOR 1875 -1925 kc. 50 kc. United States is concentrated in the rx I /2"X .050" COPPER WAVE -GUIDE .22 1975 -2000 kc. 25 kc... 100 high frequency band, representing a FOR THE 7E0 MODE. HIGH FREQUENCIES total of only 3570 kc. out of the total 20 3500 -4000 Ito. 500 kc. 7000 -7300 Ica. 300 kc. 2,256,670 kc. assigned to hams. They, 14,000- 14,350 kc. 350 kc. 21.000- 21,450 kc. 450 kc. plus the bulk of the rest of the hams I8 26,960- 27,230 kc. 270 kc. operating on the 50 -54 mc. and 144 -148 28,000- 29,700 kc. 1700 kc... 3,570 mc. bands, are the source of the TVI. 16 VERY -HIGH FREQUENCIES The hams have congregated into 11,670 50,000 -54,000 kc. 4000 kc. a 144,000 -148,000 kc. 4000 kc. kc. of the amateur spectrum subject . 14 220,000 -225,000 kc. 5000 Ice. 13,000 to TVI whi:e doing little to equip ó ULTRA -HIGH FREQUENCIES themselves and engage in operations 420 -450 mc. 30,000 kc. . 12 ç 1215 -1300 mc. 85,000 kc. on the balance of the 2,245,000 kc. as- 2300 -2450 mc. 150,000 ke... 265,000 signed to them. They are jammed into wz I-.10 SUPER-HIGH FREQUENCIES less than one -half of one per -cent of 3300 -3500 mc. 200,000 kc. the spectrum and are ignoring the 5650 -5925 me. 275,000 kc. 08 10,000 -10,500 mc. 500,000 kc. more than 991/2 per -cent of the spec- 21,000- 22,000 mc. ....1,000,000 kc...1,975,000 trum in which TVI would be virtually .06 Total Spectrum 2 256,670 nonexistent. Microwaves have been generally rec- .04 Table 1. Currently authorized ham bands. ognized to be the frequencies between 300 and 3000 mc. (known as ultra -high 02 place without his participation. He frequencies) and between 3000 and 6500 8500 10500 12500 can ultimately save the taxpayers un- 30,000 mc. (known as super -high fre- FREQUENCY- MCS. / SEC. told sums which are now going into quencies). The FCC has allocated 9.8 microwave research and development. per -cent of all ultra -high frequencies Fig. 2. Graph of attenuation vs frequency In the past decade it has been demon- and over 7.3 per -cent of all super-high for a 1 x ' 2 inch wave guide suitable for 10.000 to 10.530 mc. ham band operation. strated that professional microwave frequencies for the exclusive use of activities have been unable to keep hams. On a non -exclusive basis, the cal arrangement of simple metallic microwaves simple and inexpensive amateurs may also use all frequencies shapes. enough to encourage their widespread above 30,000,000 kc. on to infinity or On microwaves, the amateur will usage. Only the radio amateur is in a cosmic rays, including the bands again be recognized as one of the na- position to substitute empirical (cut - known as "infrared," "light," "ultra- tion's most valuable sources of orig- and -try) methods for the calculated violet," "x- rays," "gamma rays," and inal research and experimentation in- complex and planned procedures of beyond. stead of a mere nuisance as he has government and industry. There are now become in the opinion of millions relevant discoveries yet to be made Microwave Techniques of televiewers. On microwaves, where which can best be made by a free ex- Basically, the difference between mi- amateur radio now more properly be- change of information and experiences crowave operation and transmissions longs, hams by their very number and by amateurs operating largely "with- at the lower frequencies is a matter of geographical distribution will open a out rhyme or reason" techniques. equipment. In the case of microwave new era in amateur radio. They will The radio amateur today has a large operation there is no need for specially - quickly overtake the billions of dollars' number of frequencies in which he is provided transformers, coils, condens- worth of professional microwave de- free to operate. These frequency ers, or resistors. As shown in Fig. 3, velopment that has thus far taken bands are listed in Table 1. all of these components are replaced by positions taken along a closed or Fig. 3. How coils and condensers, alone or as series or parallel circuits, can be elim- shorted pipe (called a wave guide). In inated by moving along a quarter wavelength within any over -all half wavelength. practice, this pipe is usually rectangular with its wide dimension exceeding _ - - oatE°' - - a half wavelength. Fig. 4 is a photo- J`SOP`'Nl / / graph of a commercially - available \ k945° 90 135' 180 `225`\ 315° 360°or0 i ?70 model and an improvised unit made of screen wire. The home -built unit can I a/ I 3A1 a/I 8'I ,...4,-- Ti 1 I 4 foil or any con- I other 4I I 2 9/,\I be made out of i V(OPENI non -conductive material as CF, I I _ ductive or

C-tisNORT , -- -I I , long as the inner surface is a good con-

I ductor. If a simple can is used instead I

I I is called a "cavity." I of a pipe, the unit I I I I 1 1 I I frequencies which have elec- t I Only the I tric and magnetic field distributions I SHORTED LINE that fit inside of such a can or cavity

I I I I I I I I will exist in same. Thus, it is a fre- _1_ J_ o` _1_ _1_ quency controlling element that r e- °1 T T °) -1- places quartz crystals on the lower

1 I I I O I frequencies. For the amateur fre- Z min 1 ..., I I I I I quencies, the cavities can have a "Q" a b a d e f p h i on the order of 10,000 or more. 1 I I I I I I On the frequencies that the radio

I I I I I I I I I amateur best understands (frequen-

I I I I I I j I I cies below 450 mc.), he has been con-

I OPEN LINE I I j I veying energy by means of conductors 1 .1- i I I I I such as circuit wiring. On the micro-

I I I I I I I wave frequencies, he conveys the cur- I _L [TI rent by means of electric and magnetic within the wave 2 max. T T T V field displacements C. guide. In other words, microwaves i are characterized by the displacement CIRCUIT EQUIVALENT! technique while conventional frequen- :t2 RADIO & TELEVISION NEWS

www.americanradiohistory.com cies use conduction or the cumbersome electric power line technique. On microwaves, the phenomenon of space radio propagation is extended to the passage of energy within the equipment itself and the transmission line system. The method by which this takes place is shown in Fig. 5. One side of the wave guide pipe (Fig. 4) simulates the ionosphere while the opposite side simulates the earth. Fig. 5 shows a several- hundred -foot medium frequency broadcasting tower used for sky wave transmissions by reflections between the ionosphere and the earth. Fig. 5A shows a rectangular pipe (arti- ficial or fabricated wave guide) which replaces "Nature's wave guide" and performs the same function. In Fig. 5A the pipe is less than a half wavelength or at cut -off. Energy will not proceed down the pipe and attenuation is maximum. Fig. 5B shows what happens if the wave guide is wider than a half wavelength. Energy will propagate down the wave guide. Fig. 5C shows what happens if the wave guide is made even wider. Energy will be propagated even better with less at- Fig. 4. Commercial vs homemade wave guide for the 3300 -3500 mc. band. This tenuation or losses. In order to keep 3 "xl1 /z" wave guide has a power handling capacity of nearly 3,200.000 watts. this explanation simple it is desirable that the dimension of the guide not ap- feet long before the energy would be REFLECTING CATERS proach or exceed a full wavelength. If attenuated 50 per -cent. By selecting ABOVE THE EARTH the guide is wider than a full wave- an appropriate size wave guide, mini- length, the energy divides itself and mum attenuation can be obtained for becomes similar to two wave guide any frequency. This same concept pipes. Two energy patterns or modes holds true even on low frequencies ex- would then exist side by side. In ad- cept that at 4000 kc., for example, the dition, the narrow side of the rectan- wave guide pipe would have to be sub- gular wave guide would accommodate stantially greater than a half wave- a pattern. The narrow side walls func- length, or 123 feet in width. It is only tion to keep the other two walls prop- because of the shorter wavelengths erly spaced. They also determine how which make possible convenient physi- much power can be handled by the cal dimensions that it is possible to wave guide. The wave guide of Fig. 4 take advantage of microwave tech- Fig. S. Nature's wave guide on low frequen- can handle up to 3,200,000 watts of niques that would be impossible or un- cies vs fabricated wave guides on micro- power without breakdown or flashover. feasible to employ on lower frequen- waves. Wave guide is shown at cutoff, Fig. 2 is a graph of the performance cies. The technique would otherwise above cut -off, and at even higher values. of a wave guide suitable for the 10,000 function on any wavelength as long as to 10,500 mc. amateur microwave band. physical dimensions and associated Fig. 6. Cutaway view of reflex klystron. The rectangular pipe has an inside costs are not prohibitive. The amount The negatively biased repeller atop the dimension of .9" x .4 ". Part A in Fig. of power which such a wave guide can tube turns the electrons back to the positively grids. A cavity circuit is 5 corresponds to 6562 me. on the graph handle depends upon the height of biased guide. wave set up between pairs of grids. A tube of of Fig. 2. Part B in Fig. 5 might the For the guide of similar type can be used at 3300 -3500 mc. correspond to 7500 mc. on the graph Fig. 2, the power handling capacity is of Fig. 2. Part C might correspond to 235,000 watts. The smallest size wave 10,500 mc. on the graph of Fig. 2. At guide, such as the one required for 13,123 mc., two modes of energy will 21,000 to 22,000 mc., will still exceed form, changing this particular energy 60,000 watts power handling capacity. designation from "cut -off frequency of Since communication at microwave transverse electric mode 1,0" to "cut- frequencies can be carried on with a off frequency of transverse electric fraction of a watt power (even micro - mode 2,0." watts) there need be no concern that It is preferable to operate in the dom- the user might, in any way, exceed inant or first mode for reasons of sim- the power handling capacity of a wave plicity. It is feasible, and research has guide. been conducted along these lines, to use To further appreciate wave guide several modes, each a separate channel phenomena, one need but recall what of communication. If the wave guide happens to an auto radio receiver when is two wavelengths in width, there the car is driven through an under- would be four modes of energy. If it is pass. The underpass is, in reality, a three and one -half wavelengths in wave guide. Since the broadcast might width, there would be seven modes of be 1000 kc. (300 meter wavelength), energy, etc. Fig. 2 also shows the at- such an aperture or wave guide would tenuation in decibels -per -foot for a have to exceed 500 feet in diameter in particular size wave guide. In this order for the signals to go through. case, in the 10,000 mc. amateur micro- Police radios and two -way vehicular wave band, it is less than .035 db -per- systems have no difficulty in commu- foot. The wave guide could be over 28 nicating in such a wave guide since August, 1952 33

www.americanradiohistory.com range from as little as a half inch on can be adjusted external to the guide. 22,000 mc. to as much as 14 inches on The photograph also shows an elabo- 1200 mc. rate wave guide attenuator consisting There are many other methods of of a carbon- coated resistor that can handling microwave energy of which be inserted into or withdrawn from the "G string" and the "helical coil" the wave guide. A gauge is used to in- are particularly interesting examples. dicate how much attenuation is being In the case of the helical coil, the co- inserted. axial inner conductor connection is ex- Other means of providing micro- tended into a coil which serves as a wave energy include: wave guide. With the "G string," the 1. Tubes having very close inter- coaxial connector inner connection ex- electrode spacings while maintaining tends as a straight wire while the co- low orders of interelectrode capaci- axial connector outer connection flares tance by their geometrical design. out into a horn which focuses the 2. By using conventional tubes with energy onto this straight wire. the transit time between cathode and Tubes for Producing Microwaves plate equal to more than a period of oscillation in order to maintain proper There are several tube types or tube phase relations even though the tran- techniques for generating microwaves. sit time is too long with respect to the Where one can be purchased at sur- same period or cycle of oscillation. It plus, a reflex klystron is a useful can be corrected for a subsequent pe- means of generating microwave fre- riod. The electron transit time may quencies. Fig. 6 is a cross -section view take two or more periods of time to of a type which is approximately cor- reach the plate from the cathode but rect for the 3300 -3500 mc. amateur it must arrive at the plate during the band. It has a cathode, a pair of grids, correct part of the period. This is ac- and a repeller. A repeller is equiva- complished by means of suitable volt- lent to a plate but is biased negatively ages. Fig. 7. A reflex klystron tube with instead of positively. The grids oper- 3. By use of its output coupled into a wave guide a spark gap within a ate at a high positive potential. A cav- shielded wave guide. A spark gap gen- as required for operation in the 10,- ity connects 000 to 10,500 megacycle ham band. to the grid extremities to erates the frequency spectrum while form a tuned circuit. If modulation or the wave guide plumbing enclosing or audio is impressed on the repeller volt- connected to it SHIELDED CABINET permits only the mi- Ics 7K age, the tube will serve as an FM crowaves to propagate. AUDIO OUTPUT of 250V transmitter. In its simplest form, a microwave NAVE- 16FBG V2 7K GUIDE Fig. 7 shows how a reflex klystron t I transmitter is merely a signal source PASSI Cc 005 tube is coupled to the wave guide. Rr The which may be a tube or a spark gap 83 output electrode extends into the wave and a wave guide pipe. The outer end guide as if it were a quarter -wave of the pipe will squirt energy into grounded antenna, in low frequency space from the end of such a wave applications. Energy IK then propagates guide. If a horn extends from that r down the wave guide. An I adjusting end, the energy may be concentrated 5MEQI screw tunes the cavity contained with- L *sic_1 I or directed as desired. The beam may - ---- in the tube itself. Such a tube and be sharpened or broadened by chang- wave guide is nearly correct for the ing the length and angle of the flared 10,000 to 10,500 mc. amateur micro- horn. Fig. 8. Circuit of one -tube microwave wave band. The simplest microwave receiver is receiver using conventional -type tube. Fig. 1 shows a conventional tube en- a silicon or other type of receiving closed within a wave guide cavity. In crystal connected to a pair of head- their operating wavelength is substan- this application only the tube frequen- phones. A more elaborate receiver tially shorter and will fit inside such cies which can exist for that size mi- may consist of a crystal detector fol- boundaries. The wavelengths involved crowave plumbing are available and lowed by several stages of audio or for the amateur microwave bands utilizable. The grid and plate leads video amplification. Still more elaborate is a crystal mixer stage in which Fig. 9. One -tube microwave receiver using single 6F8G tube. The horn unit the crystal output is mixed with a comprises the antenna and transmission line when placed over the tube. local oscillator (which may be the transmitting tube) to yield an i.f. frequency which is then handled by a superheterodyne circuit similar to the one used on the lower frequencies. Fig. 8 is the schematic of a one -tube microwave receiver used by the author in his laboratory experiments. The same tube serves as a combination r.f. amplifier, detector, first audio amplifier, as well as providing for possible a.v.c. connections. Fig. 9 shows how this receiver appears, complete with its antenna system made of brass foil. The horn and wave guide section slips over the tube with a coaxial tuning plunger connecting to the grid of the first half of the Type 6F8G tube. The antenna system comprises an electromagnetic horn, tapering to a round wave guide. The coaxial plunger, consisting of a movable short, permits ad- (Continued on page 131) 34 RADIO .c TELEVISION NEWS

www.americanradiohistory.com AUDIO GOES MOBILE

Over -all view of Electro -Voice s "Audio CaraVan " mobile MOBILE -a sound DEMONSTRATION studio and demonstration unit. UNIT

6UGNANAN WC, GAA

BELIEVING that high -quality audio equipment By making a eomphte line of need only be heard to be sold, Electro- Voice, Inc. high quality of Buchanan, Michigan has developed a unique mobile demonstrator which will tour the country and bring audio equipment accessible to the customer a flexible assortment of audio gear to the small -town listener as well as the urban music lover. one firnt hopes to stimulate its sales. Designed to permit the customer to make his own "com- parative listening tests," the "Audio CaraVan" has been set up to simulate rooms in a home or studio. Approxima- voiced their approval of the idea of taking the merchandise tely 1850 cubic feet of space is available in the 12,000 pound, to the customer. This wholehearted 38 -foot endorsement of the trailer which is pulled by a Chevrolet cab-over- scheme presages its enthusiastic acceptance by dealers engine tractor. throughout the country. Inside the "CaraVan" is displayed the company's line of Should the idea go over as expected, cabinets, the company plans speakers, and speaker systems -all fed by broad- to equip several more such trailers in order to cut down cast- quality recording equipment such as Ampex and the time required to cover Magnecord the country. Dealers will be tape recording and playback units, and Rek -O- invited to visit the "CaraVan" and, if they wish, bring Kut turntables equipped with E -V phono cartridges. All of along their prospective customers who this will be allowed to equipment is hooked into a console switching control test various combinations of the equipment that is dis- system which enables the customer to make his own lis- played within the mobile unit. tening comparison tests. The "CaraVan" may be headed your In way-so look for the addition to these purely audio items, the "CaraVan" distinctively- designed trailer unit in your community. When also carries a display of the company's television boosters it reaches your town, stop and distribution in and look around. You will systems. be more than welcome to try out the equipment in various The new "CaraVan" made its debut at the Parts Show combinations until you find the audio units that best suit held in Chicago in May. During the Show thousands of your needs. persons visited this unusual display- room -on- wheels and HU A customer selects audio equipment by means of control console. Over -all view of trailer showing assortment of audio equipment.

August, 1952 35

www.americanradiohistory.com WHAT would you do if restric- tions suddenly were placed on picture tubes ? This is a TUBES serious enough question at the present time, but it assumes even more serious proportions when you consider the rising popularity of large- screen receiv- By ers and the possibility of shortages in B. LEDBETTER the near future. Obviously, the only .IOIIN course to follow would be the replace- Eng., WKRC, WKRC-TV ment of inoperative picture tubes as your supply allows and the disregard- hints on extending the life of TV ing of all other picture -tube troubles Some useful until the situation has been improved. tube In many cases, a defective picture picture tubes and improring performance. tube can be serviced or returned to normal by one of several simple opera- and soot on the picture tube face and tions. These are important to you inside of the safety glass. stow because their successful employ- REMEDY 1: Substitute a new pic- ment not only will extend the present ture tube. If a new tube is handy, this life of the tube but will ease replace- may save time by either clearing the ment problems later. These methods old tube from suspicion or positively will be covered in detail in this ar- identifying it as the defective unit. ticle. Picture tube troubles usually REMEDY 2: Readjust the ion trap are limited to one of the following: or try a new one. The original trap of 1. DEFECT: Loss Of Brilliance. A may be misadjusted as a result gradual drop is normal (brightness Fig. 1. Correct positioning of ion trap tampering or accidental jarring, or the usually drops off rapidly during the to give maximum brightness on the tube. magnet may be partially demagnetized first 500 hours of use, then tapers off either from an accidental blow or from exponentially from then on). These high -voltage power supply (i.e., weak having been placed near an a.c. or changes are usually not too noticeable tubes, defective filter condensers or strong d.c. field. Be sure the new ion because the customer automatically second anode resistor, leaky terminal trap is a duplicate type (single and compensates by adjusting the bright- strip, etc.), low brightness can be double -magnet traps are not inter- ness control. caused by (1) a weak picture tube, changeable), and see that the identify- CAUSE: Barring possible troubles in (2) weak or misadjusted ion trap mag- ing arrow or colored dot on the magnet the horizontal output circuit or in the net, or (3) a heavy collection of dust faces toward the bell or front of the picture tube. Ion Trap Adjustment: Set the bright- Fig. 2. Neck shadow normal and or rounded corners, as ness control slightly above shown here, require slide the ion trap magnet slowly back that the focus and de- and forth, at the same time rotating flection coils must be it slightly from side to side. Adjust checked once again. for maximum brightness. Next, adjust the focus control for sharpest scanning lines and increase the brightness as far as possible before "blooming" or loss of focus occurs. Readjust the magnet carefully at this point for maximum brightness. Note: On some picture tubes, two different positions of the magnet will give maximum brightness. The correct position is the one nearest the picture tube base (approximately over the gun flags. See Fig. 1). If neck shadow or rounded corners (Fig. 2) appear while adjusting, you may have to readjust the focus and deflection coils and recheck the centering adjustments. REMEDY 3: Clean the picture tube. This is the most obvious but is often overlooked. (It has been estimated that in a typical industrial city enough soot can be collected in 6 months or Fig. 3. Condition such less to reduce the brightness by more as this indicates a than 50 per- cent!). Use mild soap and weak or low emission water, or regular glass cleaner. Clean tube. Correcting this the rubber mask with carbon tetra- fault requires the use of a new picture tube. chloride. 36 RADIO dir TELEVISION NEWS

www.americanradiohistory.com NEW YORK

Fig. 4. Grid -cathode or heater -cathode short in TV picture tube may produce this extremely "contrasty' effect. Fig. S. I' a metal -cone picire ttte has been 2. DEFECT: `Blooming "; increase magne-iz, a condition in picture size, loss of focus when suci as siov -n here re- brightness is increased. sulta. Th: ube must CAUSES: Defective second anode be demanne ized. See resistor; weak high -voltage rectifier; text or .nstr.cticns. defective horizontal output transformer, or high- voltage Fig. E Anther case cl other troubles. meta is the cone tutte mag- Very seldom picture tube at netization. The serv- fault in this instance. icing procsdn-e out- REMEDY: Check out the high -volt- lined for Fig. i ap- age supply as usual. Particularly, re- plies in -his case. place the second anode resistor. 3. DEFECT: Flicker; varying brightness, or intermittent picture (raster may or may not disappear). CAUSE 1: Intermittent or poorly - Fig. 7. Hum in picture soldered connections on the picture causes curved a dis- tube socket or base pins. torted raster edges as REMEDY: Sweat out the old solder shown here and in and resolder all base pins and socket Fig. 8. Try replacing the TV picture tube. connections. Use a very hot iron and a good grade of solder. CAUSE 2: Intermittent grid- cathode or cathode -heater leakage or short. REMEDY: Substitute a new tube. If leakage or short is indicated, use one of the methods described under Defect No. 5. 4. DEFECT: Ion. Spot. CAUSE: Incorrectly- adjusted ion trap (allows heavy ions to bombard screen in concentrated force). REMEDY: If the picture is tube Fig. E. Anat . e >am- covered in the customer's warranty. ple at hunt in tie pi- contact his dealer or distributor for tu-e tube. Replaze the adjustment. (Customers should be tube first tefo-e chec:t- advised to call you or their dealer the inq the paver applies. moment a discoloration or ion burn appears.) An ion trap adjustment may keep the spot from spreading, even if the tube is out of warranty and replacement is not desired immediately. Note 1: On some receivers, the beam will remain in a concentrated spot for some time after the set has been turned off. On tubes like the 16JP4, W this may eventually discolor or burn the screen. Advise your customer (if this occurs) to turn the brightness Fig. 9. When the pic- full on immediately after the set has ture inverts or gees been turned off. (This aids in drain- negative when bright- ing the charge of the high -voltage ness control is cd- condensers.) If this trouble is too se- venced. several tulses rious, you must be checked. In might try a non -inductive this illustration the pic- bleeder resistor (2 megohms or higher) ture is on the verge of across the high -voltage output filter inverting. See text or condenser. (Continued on page 125) method of correction. August, 1952 :17

www.americanradiohistory.com ELECTRONIC GROWTH in the PACIFIC SOUTHWEST

THE growth of electronics in the New store of Radio Specialties Company showing Pacific Southwest has been at a center island sample boards, RCA murals above faster rate than in any other sec- test equipment displays, and the indirect light- the center of island displays. tion of the country. When the West ing fixtures in Coast Electronics Manufacturers' As- sociation was founded in 1943, the area was producing electronic equipment at the rate of approximately $25,000,000 . K. PAINTER a year. Production increased ten -fold Pres., Radio Specialties Co., Los Angeles by the end of World War II and is currently at the rate of a half -billion dollars a year. The meteoric rise of the Pacific Southwest as an According to a survey made by the electronics center has stimulated the growth of Department of Labor, there are more people employed in military and com- specialised distributor warehouses and stores. mercial electronics manufacturing in the Los Angeles area than there are in other electronic applications ever since 1931, when programs were scheduled Chicago. A recent report by the U. S. the birth of "wireless." Its many en- one hour per day, six days a week. Navy estimated that approximately gineering schools, such as Cal -Tech, With motion picture studios concen- 50,000 persons are employed in South- Stanford, California, UCLA, and USC, trated in Southern California, it was to ern California by electronic prime con- have been leaders in electronic re- be expected that some of the finest tractors and component manufactur- search. The radio handbooks of F. E. sound research would originate and ers. More than 6,700,000 square feet Terman of Stanford University are audio equipment would be developed is devoted to electronic work alone. used throughout the world. Even the in this area. Moreover, an entertain- California has been important in the first regular telecasts in the U. S. ment center so important could not research and development of radio and originated from Los Angeles, circa help but create a need for outstanding recording studios and television program sources. With the advent of commercial telecasting, many predicted that motion picture studios would soon be out of business. It is interesting to note, The "Audio Shop" at therefore, that more films are now Radio Specialties. made for television than are made for Note semi -circular dis- theater viewing. Many of the smaller plays on which TV motion picture studios devote their en- chassis are resting. of kine- These displays can be tire facilities to the production lifted out to leave scoped programs which are shipped one continuous shelf throughout the world. of the same height. The number of television transmitters in Los Angeles is the same as for the combined New York -New Jersey metropolitan area and considerably more than those of any other cen- tralized location. Seven transmitters are located a short distance from Los Angeles on Mt. Wilson (at an elevation of approximately 6000 feet). This excellent location permits the transmitting of a signal which is picked up reg- 38 RADIO L TELEVISION NEWS

www.americanradiohistory.com The test equipment display. The molding along the back drop Close -up of one of center island display boards with its glass cov- has electrical outlets spaced at intervals of 12 inches. ered samples. Record changer display is shown in background. ularly in fringe areas as far away as The aircraft industry has become this need, have met the new competi- 225 miles. more and more closely associated with tion by establishing Los Angeles ware- The importance of the television re- electronics. A number of aircraft and houses to service their distributors ceiving field in the Los Angeles area is air parts firms now are concerned al- and manufacturing customers more attested by its rating as second in the most exclusively with the electronics quickly. nation, New York City being the only involved in guided missiles, radar, and To help meet the demand for an on- area with a greater number of sets in communications equipment. the -spot source of supply, Radio Spe- use. On May 1, 1952, according to the Major prime military awards to Cal- cialties Company, a twenty -year -old Electric League, there were 1,252,184 ifornia in the fiscal year ended June 30, electronics parts distributing company, television receivers in the Los Angeles 1951, amounted to $3,899,450,000 or 13.2 has recently opened a unique type of signal area, or 7.5 per -cent of the total per -cent of the total for the United wholesale display store and enlarged number in the United States. In the States. California had the second and redesigned parts warehousing fa- calendar year 1951, 437,172 sets or 8.6 largest total for any state. The im- cilities. per -cent of the U. S. total were shipped portance of aircraft in the Southern Probably the most unusual feature to California. These sets were han- California industrial picture is evi- of this new outlet is that it' is a parts dled by the approximately 1800 tele- denced by the fact that aircraft ac- store without an apparent small parts vision retail stores in addition to the counts for 27.6 per -cent of all manu- stock and that with its contemporary other outlets which retailed TV in facturing employment in Los Angeles. design has a singularly uncluttered addition to other merchandise. The exceptional diversity of elec- look. There is only one sample each To electronics, as found in other tronics in the Los Angeles area has of the basic small parts in each line metropolitan centers, is added the fast - given rise to a new local industry of on display. These items are shown on growing aircraft industry. California electronic parts manufacturers; fabri- sample boards with the warehouse had 32 per -cent of the total employ- cators of antennas, masts, lead -in wire, stock accessible but out -of- sight. ment of the U. S. aircraft industry by and other accessories; television in- As one of the largest distributors of the end of 1951. Aircraft and allied stallation firms; and radio and tele- RCA industrial tubes in the nation, activities currently involve more than vision schools. More and more Eastern Radio Specialties Company has long 185,000 persons in California, an in- manufacturers, taking note of the supplied a large part of the replace- crease of 110 per -cent over the pre - growth of demand and of the local ment needs of the television and broad - Korea level. firms which have sprung up to meet (Continued on page 122) Sample boards act as facades for the stock bins behind counter. These boards, which are indirectly lighted for easy parts selection, help hide the warehoused stock while selling parts. Wall -type sample boards and the record player-changer display. Construction is of combed plywood in a "free form" design.

August, 1952 39

www.americanradiohistory.com The R.C.O.A Remote Control

By JOHN F. CLEMENS R HERN Oscillator

Details on a unit which permits the transmitter frequency to be varied by means of a compact eontrol box which is Connected to the oscillator tube through coaxial cables.

HE variable frequency oscillator is becoming increasingly popular T among mobile station operators. To obtain the full benefit of the v.f.o. the frequency control dial must be located in such a way so as to permit convenient manipulation by the driver. At the same time, most mobile transmitters are located in the trunk compartment where the equipment may be easily mounted and at the same time not snag the XYL's stockings. tiny frequency control box (right) em- Over -all view of exciter and control box. The Various stratagems have been may be installed remote from the oscillator and exciter unit shown at the left. ployed in separating the v.f.o. and the remaining stages of the transmitter or mechanical remote control devices fects on the oscillator frequency, the and the inductance of the cable may have been devised. Very often the re- usual design criterion being that the be disregarded. sulting layout is a disheartening array capacity should be as large as possible The benefit of grounding the com- of interconnecting cables and complex up to the limiting point where the cir- mon junction of the bypass condensers coupling circuits. cuit ceases to oscillate, although good is now evident since the shield of each A new circuit, originated for remote stability is obtainable well before cable is at ground potential. The ca- control of an oscillator, promises a reaching this limit. bles may be moved about freely, either number of advantages. The control In the most popular version of the together or separately, without af- box itself need be only large enough to series -tuned oscillator, the plate, or fecting the oscillator frequency. house the oscillator coil and tuning screen, if a pentode is used, is operated An experimental transmitter r.f. condenser so that under -dash mount- at ground potential. This connection section incorporating the r.c.o. is ing of the control is no problem. The places the cathode and common junc- shown in the photographs. This unit frequency control circuits could be tion of the large shunt capacities at a was constructed to test the workabil- easily installed in the regular switch potential above ground for r.f. In de- ity of the r.c.o. idea and is not neces- control box found in most mobile veloping the r.c.o. circuit, the ground sarily recommended as the optimum installations. The heat generating ele- point has been moved to the cathode layout, although circuit elements have ments, tubes and resistors, are com- of the tube. This means that one been varied to obtain the best operat- pletely isolated from the frequency terminal of each of the large shunt ca- ing conditions. box so that frequency stability pacities is grounded. It is now a sim- A 6AG5 is used as a pentode oscilla- control first tested in is not affected by temperature changes ple step to substitute a length of tor- doubler. A 6J6 was in the transmitter. Only two coax ca- coaxial cable for each of the bypass the circuit, using the first triode sec- control box condensers, utilizing the internal cation as oscillator and the second sec- bles connect between the was and the transmitter and the length of pacitance of the cable. The capacity tion as frequency doubler. It the interconnecting cable is not criti- of 50 -ohm cable is approximately 28 found that the 6AG5 was considerably µµfd. per foot so that in a length of more efficient than the 6J6 and since cal. and The remote control oscillator or cable suitable for connection between an interstage coupling resistor the dashboard and the trunk compart- condenser are not necessary in the r.c.o. is designed around the very pop- the ular series -tuned oscillator circuit. ment, a shunt capacity is obtained 6AG5 due to the electron coupling, by a high which is adequate for operation of the pentode circuit has more advantages. This circuit is characterized was chosen as the degree of isolation between the oscil- oscillator in the 7 mc. band. On the A second 6AG5 tank cir- lower frequency bands additional fixed second doubler to 28 mc. after compari- lator tube and the oscillator of a 6J6 cuit. This isolation is achieved by the capacity may be shunted across each son with a 6C4 and one -half bypass capacities cable or the cable length may be ex- showed the superiority of the 6AG5. relatively large of the oscillator shunting the grid- cathode and plate - tended. At 7 mc. the cables are still The 14 mc. plate tank is not electrically "short," meaning that the and the 28 mc. tank of the multiplier cathode circuits. This capacity circuits with very critical, having only second order ef- capacity can be considered as lumped are both broadband 40 It t11110 & TELEVISION NEWS

www.americanradiohistory.com low tuning capacity, using slug -tuned coils. The 2E26 stage is incomplete as shown since the plate circuit is mounted on a separate sub -chassis with the output coupling circuit. The rectified grid current of the 2E26 has been used as a criterion of oscillator and doubler performance throughout the tests. With a plate voltage of 275 on the circuit, grid current to the 2E26 was 5 ma. maximum with both 6AG5 plate tanks peaked at 29 mc. The grid current did not drop below 4 ma. when the r.c.o. was tuned over the entire 28 mc. phone band, 28.5 -29.7 mc. Total plate and screen current to the two 6AG5's was 26 ma. at 29 mc., rising to 28 ma. at both ends of the tuning range. Al- though some decrease in the 2E26 grid current is to be expected when plate voltage is applied, the grid current obtained is almost twice the rated requirements, so that adequate excita- tion is assured. The tuning condenser shown in the development model has a capacity of 50 µµfd. which is larger than necessary to cover the 28 mc. phone band. A 15 µµfd. variable condenser, shunted Frequency control box contains just a series coil and condenser tuning circuit. by a 30 µµfd. fixed ceramic condenser, will bandspread the 28 mc. phone band over the entire scale. The slug -tuned cs oscillator grid coil may be adjusted to the proper frequency after the control box is installed. The shaft of the RFC tuning condenser is not grounded and SZEo' an insulated shaft coupling must LI Li I-4-6 therefore be used. The rotor of the R tuning condenser should be connected to the lead to the coax center conduc- R2 CI CIRO tor rather than the junction of coil and CONTROL condenser, since the former is at a BOX lower r.f. potential. A double- bearing tuning condenser is highly recom- RI, R3- 68,000 ohm, 1/2 w. res. slug -tuned form R2, R4, R3- 10,000 ohm, t/Z w. res. 4-15 t. #24 en. closewound on ;/s" dia. mended for greatest mechanical sta- C, -50 µµfd. var. cond. (see text) slug -tuned form bility. C2-30 µµfd. ceramic cond. RFC -1 or 2.5 mhy. choke The Cs, C.,-.005 pfd. ceramic cond. M -0 -10 ma. d.c. meter interconnecting cables used in C, -100 µpfd. ceramic cond. 2-6AG5 tubes obtaining all the above data were each L,, L2-40 t. i30 en. closewour.d on 3/8" dia. 1 -2E26 tube ten feet long. RG -29/U, 50 -ohm cable was used. Cable lengths up to 13 feet Diagram of remote contro' exciter. The "B-1,-" supply (indicated by arrow at right were tested with similar results. If of diagram) is 275 volts which is obtained from the transmitter's power supply. longer lengths are required, a 72 -ohm coax cable may be used since its ca- Underchassis view of exciter oscillator. Shielding and heat isolation diffi- pacity per foot is lower. Operation culties are eliminated since frequency control elements are physically separated. with cable lengths up to 20 feet with the oscillator on 7 mc. should be possible with 72 -ohm cable. On lower frequencies the cables may be propor- tionately longer. As a general rule, the capacity shunting each cable circuit should be approximately 300 µµfd. at 7 mc., twice this value at 3.5 mc., etc. For very short cables having insuf- ficient internal capacity, the difference may be made up with fixed condensers shunted across the cable circuits. Another obvious application of the r.c.o. is frequency control of a rack - mounted transmitter and v,f.o. from an operating table. The elimination of frequency drift troubles due to the absence of heat in the tuned circuit compartment, plus the compactness and simplicity of the control unit make this system attractive. August, 1952 I

www.americanradiohistory.com UNIVERSAL DESIGN CURVES

for Tone - Control Circuits

Pari 2. Design dula on turo circuits uhit11 may I. B. KNIGHT be used to proridc rariablc ba]s lona control. RCA Victor Division Harrison. N. J. ation of the ability of a circuit to ful- pedance is avoided. On the other hand, THIS is the second article in the fill specific design requirements. They R. cannot be excessively large, or the current series on practical RC also indicate the preferred potentiom- value of the potentiometer R becomes tone -control circuits. These ar- eter taper and facilitate the choice of impractically large. ticles describe simple circuit arrange- component values. The universal design curves for this ments suitable for particular types of The first article of this series and circuit are shown in Figs. 3, 5, 6, and tone control and include frequency - the author's article in the November 9. The zero db reference level repre- response curves obtained with each 1951 issue presented universal design sents the output at frequencies high circuit. The curves permit rapid evalu- curves for three treble tone -control enough so that the output is unaffected circuits which are also useful for fixed by the adjustment of the tone control. bass compensation. This article will As was mentioned in the November cover two circuits designed for vari- 1951 article, a boosting circuit should able bass tone control. not be designed for more boost than is required because the boost is obtained Variable Ilass- Iloosling Circuit at the expense of gain. The loss of gain A circuit which will accomplish for the middle and high frequencies variable bass boosting is shown in Fig. caused by this circuit may be deter- 1 and the equivalent circuit used for mined from the curves and is equal to analysis is shown in Fig. 2. In many the highest value of boost on the designs, the resistor R. will be so large curves when R equals infinity. compared to the source impedance of As an example of the use of these the tube and its plate load resistor curves, let us set up some design ob- 1/ (1 /rp- 1-1 /R,.) that, for practical pur- jectives and see if we can meet them. Fig. 1. Circuit for providing variable bass poses, the resistance R, may be con- Suppose we would like to use a triode boosting. Fig. 2 is the equivalent circuit. sidered to be equal to R3. This for V, and want as much gain from relationship will usually be true if the the amplifier stage as can be reason- tube V, is a medium -mu triode. If V, ably obtained. We shall seek a tone is a its plate resistance, rp, is control capable 15 db of boost Ri+R3r pentode, of about Rö so high compared to the plate load re- so that 3 db of boost occurs at 500 sistor, RP, that r may be neglected, but cycles. The curves of Fig. 6 show that will be and 15 db of boost can be with a R2 R, not usually negligible obtained W 1 R, will equal R. plus R. ratio of R, /R: equal to 5. In the There are two advantages in making interest of obtaining the maximum R. and R. relatively large in value. possible gain from the amplifier, the First, a smaller coupling condenser is potentiometer should be as large as a required for good low- frequency re- practicable, say one megohm. Next, the sponse. Second, the danger of distor- value of R. may be determined. Ex- Fig. 2. The equivalent circuit for Fig. 1. tion in V, because of small load im- amination of the curves reveals that

Fig. 3. Curves for Figs. 2 and 4 when R /R_ is equal to 1. Fig. 4. Bass boost circuit which gives 14 db at 50 cps. 10 1IM..N11=11l1Ittttttttt.iiiñi iiii .d1M-..1MEOW M..III.0.11111...111 ..111111 .111..11 . 11 R% M00 -awn .O1I .n-"11=MMIIIMINI1 s . .\\111w'M111 _.11 -111E NI 1iiiii1l 1..111..1...\m._mam..tB1: 11 YCJ:1 ..1111I1 =ammo.111 111 MME111 .-:-.714111 o .111--- 11\-

1 1A \ b *AUDIO TAPER, ARROW INDICATES CLOCKWISE ROTATION 2TTFCR2

12 RADIO .1i TELEVISION NEWS

www.americanradiohistory.com IMILUMMINI IM I1I 25 ==11M1..II _.1II1.MMIMI..1I1 M1.MM1IM.a.II MEs=----IIMIR111141111M..II-=-'MM.I1 M..IM11Il . MMMIM ..1II MM.EIMM11 20 iiiiiiiSiiiiilMERMEN IMMIMMI 1I om(m\..11 MIIMMIEMINIMMINEENEIIMla..11 IM.11I1 .MMIM.III\...1IM..iiiiil\\.\\I11l'iewm\v11II NEI.IIIIMM...I1...nMMEM..0 woMIM11lI\IM111 2 15 .e --.ESIM.a.II ..11I. e \ 1.I l dM..- MMI..1 miu..dlIMINEI.\+Il ` .I117M.Ilmm...... rIMSCII..II MINIM..I11..M.\1 III NEMEI..I1rS' .M.111 MIMMM\ \1 ML-71111M\1..I1 NI..II OIMMMMI.1\I twala..III®mmo....milmI MMIIM.V .111 MMIMIM.11 Miiiii.V ...III ENC.O.Ill.I11a..I11 NNEE..Ill . =M.. MIMI.111MIIIWII; 11.111MMMI..III II d M..I II.MI.MI11 M.Em.IM.111 MIrM.1l M.M 5 .o.. m.=momm\.-"' II ...III IENINEI1f1 MINIM.N.:1411111M!.IIIM.MIIIM. .I MEN 11..IIII Iswe .IlMIIIM111II1NS. -.MEIM w0iqlom..I= -'..I11 MMn MIM.I \.II I o Mla.11m..I11\ì-.IIM..III- _--._ .1 1.0 10 1.0 10 21TFCR2 21TFCR2

Fig. 5. Curves for Figs. 2 and 4 when R, /R_ is equal to 2. Fig. 6. Curves for Figs. 2 and 4 when R, /R, is equal, to 5. slightly more than 15 db boost can be find this impedance, we first calculate obtained with the ratio of R /R2 equal R0, the effective parallel value of the lo 100. If the ratio is 50, however, only grid resistor, R the plate load re- about one -half db of boost is sacrificed, sistor, R,,, and the plate resistance, r, and we shall see that it is easier to ob- of the tube. As stated in the previous tain the desired gain if the values of articles, we have found a formula R. and R2 are made as large as possible. which may be used to calculate Ro Using the ratio of R /RR2 equal to 50, the directly with fair accuracy. It should value of R2 will be 20,000 ohms. Then, be remembered that this formula is because the ratio of R, /R2 is 5, the empirical and applies only to triodes value of R, is 100,000 ohms. Now the operated in accordance with the values choice of a tube for V, can be made. We given in the "Resistance- Coupled Am- would expect to obtain the most gain plifier Charts." from a high -mu triode, so let us select Fig. 7. Circuit for variable bass attenuation. one section of a 12AX7 and use the R, = .17 µ Rk 5000 (ohms) circuit values from the `Resistance - + Coupled Amplifier Charts" found in = .17 (100) (1300) + 5000 tube handbooks. The value of the grid R. = 27,100 ohms resistor Ro to be used with these charts is equal to the impedance of the tone - Then, using the formula for Ro, control network at high frequencies (or with R adjusted to zero). Using the R, - 1 constants selected above, this value of impedance is approximately 100,000 D RpRe ohms. Examination of the "Resistance - Coupled Amplifier Charts" shows that We can rearrange the terms to solve 100,000 ohms is a good choice for the for the source impedance of the tube plate load resistor, R. The cathode re- and its plate load resistor. Fig. E. The equivalent circuit foT Fig. 7 sistor, Rk, should be 1200 ohms, the assuming the same value of impedance. nearest RTMA value to the value of 1 1 1300 ohms given in the chart. The mu 1 1 1 1 1 _ 37,00(1 (dim,: of the tube, obtained from the tube R. R. 2.69X 10-5 data, is 100. In order to determine the rp + Rp value of R2 we must find the equivalent 1 The value for R. is R, minus the source source impedance of the tube and its 1 impedance value determined by the plate load resistor, 1 /(1 /rp+1 /R). To 27,1ttlt (Continued on page 93)

Fig. 9. Curves for Figs. 2 and 4 when R /R, is equal to 10. Fig. 10. Curves for Figs. 7 and 8 for two circuit values. 25 MM1111.I..1EMM..I M..1EMMA. 5 ....111 Lv111I11.1MM.111PEIMMINIIMIMIEMEN I11111111 '::'1MM!1n íiMMQI1I::':II Nolii=11I.M.1.. M11 wu .mm.MI...I 20 11M1M111 l/I .. \:ZIVI.III..II\\.II.M..1 NW MU .M.I .--_-_/..I1Ì Iiii7.!11...III MN s .r. _:.1./l!%I..I11 i/ 11 . M1It1 M1I1 .11 .MIP.r:ii'INIMM.III SAI' IMMt.Z.1Mh:111MM11I-I1i\7..1I ..aIMM I/.I ï4....I1 ...I1 EMINEEMEIN.TMINENEENIImim'.IMOR\\..II Illa'ou J..%Id MM.111.\\M.II REIM 11./I1e w 10 IMSME.ISI M.I.`101111 MI.iMj. 1111I.111 mmows.. 7.O OSMI1.111 ENE M..1I11 \11I11 M..III M11/1.1111111/41M111 Q 111111.11InMINvZ,WíiEN.I111 M.MMIll i:7 \.'! I I I EM. ..II .MMMi1r-.1 rlMII/M1 5 waeI1-sl..\. 11 Ei111.111 > __...I.,.IM.1I.-_ .6 . M.II1 ...1...I1...11II MIMI ..M..:\.11 _MIA.r: A mM.1.11 .uL.11Ì _ o .1n ..1II \l\,MMI\_ _.a_. -20 .i,Miriii `t.0 10 .1 I.0 IO 100 21TFCR2 21TFCR ul;nst, 1952 43

www.americanradiohistory.com The MULTI- SIGNAL GENERATOR By LOUIS E. GARNER. 1R.

saw -tooth signal appearing across C. Thus, only a pure saw -tooth is available at the output terminal of the chassis. To obtain a 60 -cycle square -wave signal, a portion of the voltage available across one -half of the high -voltage secondary winding is applied through coupling condenser C, to a series -diode clipper circuit. C, and R. act as a voltage divider to reduce this Fig. 1. Over -all view of the "Multi-Signal Generator." The entire unit measures high voltage slightly. At the same 7!/z" x 5" but provides 60 -cycle sine -wave, sawtooth, and square -wave signals. time, however, R, acts as part of the clipper circuit. Construction details on a combination power supply, The series diode clipper has been previously described by the author square -ware and sau- -loallt generator for home use. (RADIO & TELEVISION NEWS, March, 1950, "Wide Frequency Range Square - TEACHERS, lab technicians, and tional parts needed can generally be Wave Clipper ") but a brief review of home experimenters often need fitted easily on any available power its operation may be appropriate here. a d.c. and filament power source supply chassis. The flashlight cell, E, acts to place a small bias on the cathodes of the to supply experimental circuits. This Circuit Dem.riptiun need is generally met by having a dual -diode tube, V,,, so that this tube small power supply chassis available. Reference to the schematic diagram is normally conducting. As long as the experiment- of Fig. 2 shows that a conventional the amplitude of any applied signal In addition, however, voltage, er often requires a signal of a particu- d.c. power supply circuit is employed. does not exceed the battery lar waveshape, either to check the V. is connected as a full -wave rectifier, the diode acts simply as a closed cir- or to check the with filtering provided by choke CH, cuit, permitting any signal appearing operation of a circuit, modifica- response of a filter or attenuator cir- and electrolytic filter condensers C, across R. to appear, without cuit to signals other than sine waves. and C:,. Bleeder resistor R, provides a tion, across one, of slight degree of voltage regulation. When the negative peak of the ap- Where the need is a continuing the the financial resources of the experi- The 6.3 volt winding of the power plied signal is sufficient to drive menter large, this need can be filled transformer is used to supply filament plate of the left -hand diode section genera- voltage to the clipper tube, V,, and negative with respect to its cathode, by appropriate special signal conducting tors. also acts as the sine -wave signal this half of the tube stops source. Since the filament current re- and acts as an open circuit, thus clip- On the other hand, where the need negative for special signal waveshapes is not quirements of V, are small, this wind- ping the remainder of the power supply ing may also serve to supply filament peak. continuous, an ordinary peak of chassis may be modified, by adding voltage to external circuits. Similarly, when the positive parts, to A neon -bulb relaxation oscillator is the applied signal is sufficient to make only a few readily available right -hand diode a saw - used to supply a saw -tooth signal. the cathode of the supply a square -wave signal, with respect to its tooth signal, and a sine -wave signal, Condenser C, is charged s 1 owl y section positive through resistor R. As soon as the plate, this half of the tube stops con- in addition to acting as a source of d.c. an open circuit, voltage. charge across C, reaches the firing ducting and acts as clipping the remainder of the positive small chassis shown in Fig. 1 potential of V, (a neon bulb), the gas The peak. (only 71/z" x 5 ") supplies "B plus" (350 in this tube ionizes and acts as a practical short -circuit across C., discharg- Either condition will occur when volts at 40 ma.), a 60 -cycle sine -wave the voltage may also be used as a ing this condenser until the voltage is the applied signal exceeds signal (which E. volt, 2.5 amp. filament supply), no longer sufficient to sustain ioniza- of battery 6.3 Since the sine -wave signal applied a 60 -cycle square -wave signal, and a tion. V, then stops conducting and C, starts to charge again, with the action through C, greatly exceeds the bat- 60 -cycle saw -tooth signal. The cost of clipping is ob- necessary to sup- repeating itself at a rate dependent tery voltage, excellent the additional parts and an almost perfect square ply these special signal waveshapes upon the supply voltage and upon the tained time -constant of R, -C,. By making wave appears across R,. over the cost of the power supply com- thus serves to was two dol- R, variable, the output frequency of The entire chassis ponents alone less than simultaneously, a "B" voltage, lars. Only about an hour's additional the saw -tooth signal may be varied to supply, suit the individual experimenter. a square -wave signal (Fig. 3A), a sine - wiring time was required. 3B), and a saw- not wish to C, acts as a blocking condenser to wave signal (Fig. Where the builder does signal (Fig. 3C). assemble a special chassis, the addi- eliminate the d.c. component of the tooth TELEVISION NEWS 44 'RADIO &

www.americanradiohistory.com Since r.f. or other high frequency in circuit, ZSP signals are not present the 5V wiring and layout is not at all critical. TI VI It is only necessary to take reasonable 2 +1C3 care and follow conventional wiring techniques. Ri A word of caution, however. The battery should either be mounted below chassis or, if mounted above chassis, should be located well away from R3 the rectifier tube and power trans- 63v 117V GND former. This is to insure that the heat A.0 of these two components will not ad- R,-50,000 ohm, 5 w. wirewound res. CH1 -10 hy., 40 ma. filter choke versely affect the life of the flashlight R2-8.2 megohm, 1/2 w. res. E -1.5 r. flashlight battery Ra, R42 R5-47,000 ohm. 1 w. res. T1-Power trans. 350.0 -350 v. @ 40 ma.; 6.3 cell. C,-.01 pfd., 600 v. cond. v. ek 3 amps.; 5 v. @ 2 amps. (4 -tube re- Parts values are not at all critical C2, Ca -10/10 pfd., 450 v. upright elec. cond. ceiver type) variation from the C,-.02 pfd., 600 v. cond. V, -5Y3 tube and considerable C6 -.1 pfd., 600 v. cond. V2- -NE -51 neon bulb values given in the parts list are per- S,- S.p.s.t. slide sw. Vg-6AL5 rube missible. This is especially true as far of the "Multi -Signal Generator." Except for C all the as components are Fig. 2. Circuit diagram the power supply special parts required are shown to the right of the dotted line in the schematic. concerned. A much heavier power transformer may be used; almost any suitable rectifier tube may be employed for V,; a much larger filter choke or filter condensers may be sub- stituted. In fact, if the builder pre- fers, the simple power supply circuit shown may be replaced with a complex voltage -regulated circuit, incorporating regulator and control tubes as well as the rectifier. V, may be either an NE -2 or an NE -51. Other neon bulbs may be sub- stituted by varying the sizes of R, and C4. Fig. 3. Output of unit. (A) square -wave, (B) sine -wave. and (C) saw -tooth signals. The 6AL5 used for V. may be replaced, without circuit modification, buffer amplifier between the saw - square -wave output terminal and the by a twin- triode tube, diode connected tooth output terminal of this unit and experimental circuit. The size to use (grids and cathodes tied together), or the test circuit. If desired, this ampli- will be determined by the impedance by other twin -diode tubes, such as the fier may be powered by the "Multi - of the circuit to which the square - 6H6. Signal Generator" itself. wave signal is applied. For high im- If a square -wave signal of greater Secondly, a d.c. component appears pedance circuits, a .5 pfd. condenser amplitude is desired, substitute a 41/2 with the square -wave signal across will generally give satisfactory re- volt bias battery for E. If a control R,. While this component is small in sults. For low impedance circuits, it over amplitude is desired, use a 50,000 amplitude, it may cause trouble if an may prove necessary to go to 2 pfd. or ohm pot. in place of R. attempt is made to connect the even higher if good waveshape is to As can be seen by reference to the square -wave output terminal directly be preserved. under -chassis view (Fig. 4), the addi- to the grid of an amplifier tube. Thus, These limitations are not serious, of tional parts required occupy very when d.c. cannot be tolerated in the course, and do not affect the operation little space, even on the small chassis experimental circuit, connect an ordi- of the "Multi -Signal Generator" in used by the author. Where space is nary paper condenser between the most of its applications. -J- at a premium, however, these components may be mounted in a small Fig. 4. Under chassis view of the "Multi- Signal Generator" showing parts layout. metal utility box, which, in turn, may be connected to the power supply chassis through a multi- conductor cable. Except for C,, all the special parts required are shown to the right of the dotted line in Fig. 2. The applications of the "Multi - Signal Generator" are many and varied, but a detailed listing would be out of place here. Each experimenter or reader can best tell, from his own experience, where such a piece of equipment would fit in his home or shop laboratory. Several important points should be remembered when connecting this piece of equipment to other apparatus for tests, however. First, the saw -tooth signal source is a high -impedance source. Thus, if loaded too greatly, the waveshape and amplitude may suffer considerably. Where it is mandatory that the output saw -tooth signal be used in a low - impedance circuit, interpose a simple August, 1952 15

www.americanradiohistory.com CINEMAGNETIC RECORDING

By A. C. BLANEY Manager, Film Recording Engr. Radio Corporation of America Fig. 1. The mixer amplifier which is part of RCA's PM -64 sound re- New tape techniques, adapted to movie work, cording system for movie work. presage substantial savings and efficient eilnn processing for Hollywood studios.

ANEW and useful tool for making motion pictures was first public- ly presented to the film industry in May, 1948 by the Radio Corporation of America at the Society of Motion lems would develop in the operation cording had served the film industry Picture and Television Engineers' con- of this new tool. It was therefore de- quite well for many years. vention in Santa Monica. This new cided to explore this new medium by Those who were willing to experi- tool was magnetic sound recording. first adapting photographic recorders, ment soon found that magnetic record- The art of magnetic recording had then in operation, to handle the per- ing could be made to pay dividends. shown steady improvement for more forated magnetic film. This gave the First, the greater volume range of the than a decade. Recording on 14 inch film industry the opportunity to ex- magnetic film was found to be quite magnetic tape and wire had advanced periment with the new medium with a useful in the original recordings where to a degree which permitted its use in minimum investment in equipment. In wide variations in sound level exist. many commercial applications. All of retrospect, this proved to be a wise and Quite often a recording was found to these previous methods, however, did conservative decision. be entirely satisfactory when recorded not provide the exact synchronism re- Although it was realized from the on magnetic film although when required by the motion picture industry. first that magnetic recording would corded on photographic film the level While there was no question regard- enable motion picture producers to ex- proved to be too low and therefore too ing the quality that could be obtained tend the volume range and the fre- close to the noise level. The photo- by recording on magnetic materials, quency range of their original sound graphic films depended upon the trans- RCA film recording engineers realized recordings, it was necessary that the mission of light for the reproduction of through their close association with new sound recording technique show sound and therefore were subject to Hollywood that many practical prob- other advantages. Photographic re- noise due to handling which picks up dirt and causes scratches on the film. system shown in use on movie location. Magnetic films were found to be com- Fig. 2. The portable RCA sound recording paratively free from this type of problem. Again, the handling of magnetic film could all be done in daylight which proved a distinct advantage for the operator. Still another advantage of the magnetic medium was that it could be played back concurrently with the recording and the operator was assured that he had a record of the sound. While it was possible to listen to the modulated light in the photographic process and gain some assurance that recording was satisfactory, still it was not as positive as playing back the signal from the film. All of these advantages added up to faster operation and more assurance that a satisfactory record had been made of the sound at the time the recording was made. Here we may ask why the industry has not changed over more rapidly to use magnetic films for all of their 46 RADIO Rz TELEVISION NEWS

www.americanradiohistory.com sound recording work. Aside from the resistance to changeover in equipment, the new recording technique does offer several new problems for solution. One of these is the problem of identification. Photographic films carry footage numbers and each "take" or scene is identified by some visible characters on the original negative. It follows, therefore, that any and all prints made from this original carry the same identification marks. At the present state of the art, copies of magnetic recordings must be made by the re -recording process. The identification must therefore be done manually which requires more time and expense. Another,rather serious problem with magnetic recording is that of editing. Film editors have been accustomed to working with visible soundtracks and depend on this extensively for accurate cutting. Magnetic soundtracks are not visible (although they can be made visible) and thus add to the time required by the editor to do his work. Splicing also has been a problem. En- open. gineers and technicians in the film in- Fig. 3. Front view of RCA's Model PM -64 magnetic sound recording unit, with cover dustry are finding ways and means of overcoming all of these problems and recorder is equivalent in time to 1000 no doubt as the state of the art grows feet of picture film such as would nor- and there is time to develop the spe- mally be used in the motion picture cialized equipment for handling mag- camera. This reduction in speed has netic film, this new medium will re- not only cut the film cost for the sound place photographic recording at least also the track in half but has permitted C! up to the release negative point, with development of a smaller, more porta- rr111rrrrSE(Srtr conventional photographic prints dis- ble recorder. This is important where tributed to the exhibitors. the equipment must be taken on loca- At the present time, Hollywood is tion. The use of 171/2 mm. film reduces making most original recordings on film costs to approximately one -fourth magnetic film. The "OK" magnetic of that required if the normal 35 mm. rrrrrrrrrarrrrrrr rr takes are then re- recorded on a photo- film were used at the normal speed of graphic track which is then edited in 90 feet -per -minute. Magnetic film has the conventional manner. .In some the further advantage that the sound- the transfer is made to a direct cases track can be erased and used over 13 positive which eliminates the necessity again. for a negative -to- positive printing op- -64 re- The complete RCA PM sound magnetic tape types used eration. Some studios are using this cording system consists of a mixer am- The five different in conjunction with an antici- for film recording. (A) 16 mm. striped mag- process plifier, the recorder -reproducer, and (B) 16 mm. patory noise reduction system for netic- photographic raw stock; the power supply. This equipment is full-coated; (C) 171/z mm. full- coated; (D) which RCA recently won a citation (Continued on page 116) 35 mm. full -coated; and (E) 35 mm. striped. from the Academy of Motion Picture Arts and Sciences. This system makes provision for minimizing the introduc- Fig. 4. Rear view of the recorder with the door open to show component layout. tion of extraneous noise, thus achiev- ing clearer and truer reproduction of speech, music, and other wanted sound. Quite recently RCA has developed a new high -quality portable magnetic recorder- reproducer especially for original recordings whether in the studio or on location. This equipment is pictured on the front cover with Robert Mitchum as part of RKO Radio's location unit filming "The Lusty Men" in the ranch country north of Hollywood. The Wald -Krasna Production stars Susan Hayward, Mitchum, and Arthur Kennedy and was directed -by Nicholas Ray. This sound system is expected to greatly change the recording picture and provide many studios with the means for low cost magnetic sound recording. This recorder handles 171/2 mm. film at 45 feet -per- minute. This "half" speed provides ample frequency range for the motion picture industry with a safe margin, since 500 feet of film at 45 feet -per- minute in the sound August, 1952 17

www.americanradiohistory.com UNIQUE SOUND ALARM for DEAF PERSONS

B. II. G. DAN IS. JR.. M.D.

Top chassis view of a volt. The basic circuit is shown in practical signalling de- Fig. 1A. For use as a device vice for a deaf person. actuated by a negative pulse, the voltage on the grid 1 of V, is set by R2 at a value greater \ than that on the grid of V,. Plate current flowing in R, then keeps the grid Although designed to aid a deaf mother in caring of V2 biased to cut -off so that the voltage at the plate of V2 is nearly that for her child. this visual signal has many uses. of the high voltage supply. A negative pulse applied to the grid of V, gives it a negative reference to the voltage THE device to be described solved peak. Obviously a relay directly op- applied to the grid of V, and increases an interesting, but not unique erated could not be relied upon to do the current through RA, allowing V2 problem. While it is simple in this consistently. However, the Schmitt suddenly to conduct, thereby producing conception, certain definite limitations switch often used to trigger a synchro- a negative pulse at its plate. The re- in operation and original cost made it scope sweep is capable of resolving verse process occurs when the grid difficult to execute. So it is thought these small differences. It can be ar- voltage of V, rises again. This switch that the special circuits utilized might ranged to operate on positive or nega- has two stable limiting conditions de- warrant description for their individual tive pulses differing by less than 0.5 pendent on the voltage on V, and may usefulness, not limited to this single be used to actuate a relay if the input application. Fig. 1. (A) Simplified circuit of Schmitt pulse is of sufficient duration. The The problem was to notify a deaf switch. (B) Simplified circuit of relay amount of voltage required to change switch. (C) Block mother when her infant cried. The de- diagram of the alarm. the condition of operation depends on vice had to be sensitive, relatively in- the difference in voltages applied to expensive, compact, and entirely auto- R4 8+ the grids of the two tubes. PULSE matic. Since the patient's hearing at OUTPUT Using the Schmitt circuit solved the R3 the point of minimum loss (512 cps) vI z noise -vs- signal problem, but its output would not was 90 db below normal, an ordinary CONTROL actuate a relay when op- amplifier and speaker would not work. VOLTAGE erated directly from the signal ampli- 1 fier. This Something to actuate a warning light is due to the fact that speech had to be devised. . (and a baby's howling) is a series of The simplest solution seemed to be relatively short bursts. Since the a microphone pickup placed near the Schmitt switch works very rapidly, child, operating an ordinary speech keying on and off with each burst, it amplifier, the output of which was rec- (A) would not remain conducting for the tified and used to cause conduction in finite time required to close the relay. a tube biased beyond plate- current cut- Also it was necessary to hold the light off, thus actuating a plate circuit relay. on a short while after keying. This was impractical because of the To give a pulse of sufficient duration extraneous a.c. pickup in the high im- to close the relay and prevent instan- V2 BIASED opening, pedance microphone line. This volt- BEYOND taneous the discriminator out- age, plus that developed by ambient CLT -OFF put pulse is used to key a "one shot" noise in the room, was not sufficient to multivibrator with a relatively long trip the relay, but was enough to pre- time constant. The basic circuit ar- vent fallout once the relay was ac- ranged for negative pulse keying is tuated. Use of a low impedance mi- shown in Fig. 1B. A positive -going crophone and shielded input trans- relatively square pulse may be had former was precluded in this special IBI from the cathode of V2 provided the loading does not appreciably alter the case because of cost. MIC. SCMMI" ONE LAMP NOISE PU 5M0T' RE AY operating condition of V2. It was im- Measurement demonstrated that the AMP. HEIGHLSET MULTI- SWITCH -40 instrument had to discriminate be- DISCRIM. BIB. possible to operate the relay directly Inv. TO from the multivibrator so another tween a noise and noise -plus -signal tCt RELAY voltage, differing by about one volt CONTACTS Schmitt switch, direct -coupled to the 48 RADIO .0 TELEVISION NEWS

www.americanradiohistory.com OUTPUT R,6 29 Raa 501

LI C12 c1 TO IITN _ Z7 s1_aV R19 R20 0254 R27 R33 C 1' T CI R4 V2 M ve v9 6SN7 v7a 65N7 vTe 6AC R3 R37 16AC1 LAMS

Ci0 136 822 P23 829 RJ3 039 040 C2 Tr CHI 00 504 cii c20 Ca, Co -.1 ad., 400 v. cond. C4, C10, ad., 150 v. elec. cond. P3 C21- 80/40/30 T C6, C11, C14, CEO, C22-.006 ad., 400 v. cond. R v. 3 1 -L C7-1 µfd., 400 cond. Cl,, C13 -.5/.5 pfd., 400 v. cond. TO OUTPUT PLUG C1 -3 ad., 400 v. paper cond. VIA RELAY T21 C13-4 Aid., 400 v. elec. cond. C15, C20-40/40 ad., 500 v. elec. cond. R R11, R2.- 10.000 ohm, 1/2 w. res. R.., R,0 -10 000 ohm, 2 w. res. T1 -Power trans. 350.0 -350 v. @ 80 ma.; 6.3 R,-500,000 ohm, 1/2 w. wirewound res. RI; R32. R0,- 47,000 ohm, 1/2 w. res. V. @ 4 amps.; S v. @ 2 amps. R0, R12 -2.2 megohm, I/2 w. res. R24, R3,- 120,000 ohm, 1/2 w. res. CH,-6 hy. @ 80 ma., 200 ohm filter choke R4, R1, R15 -1 megohm, 1/2 w. res. R2- 100,000 ohm, 1/2 w. res. RL,-4 ma. plate circuit relay R0, R0 -1200 ohm, 1/2 w. res. ROO- 500,000 ohm, 1/2 w. res. S,- S.p.s.t. sw. R.-3300 ohm, 1/2 w. res. Reo, R33-22,000 ohm, 1 w. res. F1-3 amp. line fuse R - 510,000 ohm, 1/2 w. res. R,1-p390,000 ohm, 1 w. res. V1 -6J7 tube R15, R17, Re0-500,000 ohm pot Ras, R37. R43- 33,000 ohm, 1 w. res. .170-6S.17 tube R14 -6800 ohm, 1/2 w. res. R,0- 100,000 ohm pot V3-6SR7 tube R,- 220,000 ohm, 1/2 w. res. R42 -75 ohm, 2 w. wirewound res. V4, V5, YR. V0 -64C7 tube R 5000 ohm, 1/2 w. res. Cl, CC. C,,, C,-20/20/20/20 ad., 450 v. elec. V3-6J5 tube R,,,. R_,,, R_5, R41- 47.000 ohm, I w. res. cond. V -6SN7 tube R21. R,4 -1500 ohm, 1 w. res. C.-1000 pfd.. 5 v. elec. cond. V,I,-5W4 tube

Fig. 2. Complete circuit diagram and parts list for a sound alarm unit which is designed to provide a visual warning signal. cathode of the multivibrator, is used switch triggers, thus the degree of dis- determining when the switch will as a relay switch. In this case V, of crimination between noise and signal. change from one regime to another the switch is biased to cut -off and a R24 and the pulse amplifier, V6, control and close the relay. relay inserted in its plate circuit. Since the height of the trigger signal to VT,. The circuit may seem complex for so the resting current here may be as The potentiometer, Rab, couples the simple a job, but does fulfill the re- near zero as desired, there is no prob- multivibrator to the second switch cir- quirements of stability and reliability lem of relay fallout not occurring when cuit, Vs and V,, and also controls the which the many simpler circuits which the unstable regime of the multivibra- steady -state bias on the grid of VR, thus were tried could not do. tor has been completed. Fig. 1C shows the block diagram of Under chassis view. Standard and readily -available are used throughout. the unit. It can be seen that the timing parts of the whole sequence of events depends on the duration of the unstable portion of the multivibrator's cycle and that it will automatically reset and be ready for another stimulus at the end of this period. The input to the multi - vibrator and its output to the relay - actuating switch circuit must be adjusted to give a positive switching action, yet not be so great as to cause these circuits to draw grid current and block them for undesirably long periods. Fig. 2 shows the circuit of the complete instrument. V,, V2, and Va comprise a simple, high gain amplifier. Ex- tended range of response is actually undesirable in this application, since low rumbles (street noises) and very high -pitched sounds should not actuate the relay. The inverse feedback over V, and V,, therefore, is not for the purpose of range extension, but to reduce internal noise and stabilize gain. R. is a standard gain control and is used to adjust the sensitivity of the instrument. The output of this amplifier triggers the first switch circuit, V4 and V6, whose output is tapped off RO and used to trigger the multivibrator VT. R,, controls the voltage at which the August. 1952 49

www.americanradiohistory.com THE

PICTURE TUBE

By WALTER BUCHSBAUM Television Consultant, RADIO & TELEVISION NEWS Points to remember when replacing your picture tubes. Article covers basic tube types, their characteristics, and data on substitution.

found only in a few experimental receivers use this type of picture tube. Metal picture tubes, like the RCA 17 -inch ceivers. The most common type is the Ranging from 7 -inch round to 30 -inch unit shown above, combine a large face 7 -inch all -glass and the 8 -inch metal - round, these tubes all have several fea- with light weight for ease of handling. shell tubes used widely in portable TV tures in common. All sockets are of the sets. All of these tubes use less than 12 -pin type and almost all socket con- 8 kv. second anode voltage and none nections are identical and interchange- THE picture tube is the heart of require an ion trap. Before replacing able. Some of the latest electrostatic the television receiver, not only an electrostatic picture tube with a focus tubes utilize Pin 6 which is un- because it is the most bulky and different number, be sure that socket used on other types. On all tubes Pins expensive item, but because it pro- connections and voltages are correct. 1 and 12 are the filaments, 2 is the grid, duces the desired end result -the Some use a 12 -pin and others a 14 -pin 11 the cathode, and 10 is the first picture. Since the early days of TV the socket. anode. Thus it is possible to inter- improvement in picture tubes has been Projection picture tubes: The 3NP4 change tube sockets without much the greatest concern of the industry, is used in the so- called "folded Schmidt difficulty. The second common feature since bigger and better pictures depend System" of projection TV manu- is that they all need a deflection yoke. on the tube. Thus we have seen the factured by North American Philips Different deflection yokes, however, 5 -or 7-inch round tubes of 1946 evolve Co. Careful handling because of the are required for different deflection as today's 20 -and 30 -inch round and fragility and the critical adjustment of angles and this is a particularly impor- rectangular picture tubes. Just how the optical system is the major factor tant consideration when converting to extensive this development has been is when replacing this tube. The tube re- a larger picture tube. Larger screens evidenced by the long list of picture quires a special socket and is mag- require wider deflection angles and tubes given on the "Data- Print" in this netically focused and deflected. Both this, in turn, calls for a different de- month's issue. Although there is con- focus coil and deflection yoke are flection yoke and more sweep power, siderable variation between tubes, cer- specially made for this tube alone. The especially in the horizontal section. tain basic features permit us to group other projection tube is the 5TP4, used More powerful focus coils are also used them and classify them. The purpose in practically all other projection -type on many of the larger tubes. This is of this article is to acquaint the techni- receivers. The focus is electrostatic indicated on the "Data- Print" by an cian with the great variety of available and requires a high voltage at the tube asterisk which means that an RTMA picture tubes and the use of each type socket which often causes arcing and #109 type (470 ohms) must be used inin replacement and conversion work. breakdowns. A special deflection yoke stead of the standard RTMA # 106 Three main classifications can be is also required for the 5TP4. (264 ohms). It is also important to made immediately : electrostatic de- Magnetic deflection, di r e c t view have the correct anode voltages, focus flection, projection types, and mag- types: The vast majority of TV re- (Continued on page 139) netic deflection direct view tubes. We shall discuss them in this order. Electrostatic deflection tubes: These tubes use deflection plates mounted in- COMING IN NEXT MONTH'S ISSUE -"DATA- PRINT" NO. 5 side the tube to sweep the beam vertically and horizontally. Focusing is eTelevision Conversion Guide" also done electrostatically. The largest This "Guide," when used with this month's "Data- Print," will pro- electrostatic deflection tube used in vide pertinent information and circuit data for the rapid conver- commercial sets is the 10HP4 although sion of small- screen television receivers to large- screen operation. we list a 20AP4 which uses electrostatic deflection. This latter tube is 50 RADIO & TELEVISION NEWS

www.americanradiohistory.com M A K E S H I F T

R E P L A C E M E N 7S

-r reduce picture quality

Replacements with Raytheon Television Tubes assure picture quality

Remember! Raytheon Picture Tubes with Corona Inhibitor give constant picture clarity what aver the weather.

RAYTHEON MANUFACTURING COMPANY Receiving Tube Division Newton, Mass., Chicago, III., Atlanta, Ga., Los Angeles, Calif. c` cellenee C leCillyJ2C

RECEIVING AND PICTURE TUBES RELIABLE SUBMINIATURE AND MINIATURE TUBES GERMANIUM DIODES AND TRANSISTORS RADIAC TUBES MICROWAVE TUBES

www.americanradiohistory.com E REPLACEMENT GIIIDB

DEFLECTION ANODE H V sE FACE LENGTH TYPE ANGLE ION ANODE e.V. p comedian le ),./ FOCUS' MISC TYTDPE SHAPE ENVELOPE (tortes) DEFLECTION Ideereesl TRAP roeeertiee Ih s.1 FOCUS' MISC

e Cavity 14 Automatic Filterglas 7SP4 Red. Glass 191 Magnetic 70diag. Single Cavity 12 Automatic Cyl. foci e Cavity 14 Automatic 7TP4 Red. Metal 191 Magnetic 70diag. Single Rim 14 EOto500v. Etched f ace

e Cavity 13 E -60to 350 v. Filterglass 7ÚP4 Rect. Glass 191/4 Magnetic 70diog. Single Cavity 12 M95ma.' Cyl.fao 7VP4 Red. Glass 191e Magnetic 70diag. Single Cavity 14 E -S0 to -300v. Cyl.fao de Rim 12 M90ma.* Filterglau 7yP4 Red. Glaze 193(6 Magnetic 70diag. Single Cavity 12 M90ma. Cyl.fac e Etched fan 9AP4 sie Cavity 12 M 110 ma.* 9AP4A Filtergk us sie Cavity 14 M115 ma.* 9AP4B Round Metal 2111 Magnetic 66 Single Rim 16 M140ma. Etched I ace ie Cavity 12 M 115 ma.* 9AP4C Filtergk SS Filterglass,i 9AP4D Etched I ace 9BP4A Round Glass 211/2 Magnetic 66 Single Cavity 14 M110ma. sle Rim 12 M 100 ma.* Filterglass 9DP4 le Etched face Round Glass 211/2 Magnetic 66 Double Cavity 13 M 140 ma. 9DP4A Filtergk SS le Ball 13 M 145 ma.* 9EP4 Rect. Glass 211/4 Magnetic 70diag. Double Cavity 14 M100ma." Filtergk ss,t Filterglass 9FP4 Round Glass 22 Magnetic 66 Double Cavity 14 M 100ma.* Etched 000 le Rim 12 M 100 ma.* 9GP4 Round Gloss 211/4 Magnetic 60 Single Cavity 14 M 100ma.* Filtergll ist Etched face 91P4 Rect. Glass 211/4 Magnetic 70diag. Single Cavity 12 M95ma.' Filtergk ss,' Etched face 9014 Rect. Glass 2118 Magnetic 70diag. Single Cavity 12 E -50 to + 350 v. Filtergk ss

sie Cavity 12 M110 ma. Filterglass OAP4 Round Glass 27'ße Elec. --- None - -- 8 E4kv. Disconti nued,2 2 OBP4 Round Glass 28'oá Magnetic 54 None Cap 15 M 135 ma. Disconti nued, I sie Cavity 11 M115 ma. Filterglass 2 OCP4 ) Filterglass 2 OCP4ARect. Glass 21'8 Magnetic 70diog. Single Cavity 12 M95 ma.* Filtergll SS le Cavity 14 M 105 ma.' Filterglass 2 OCP4C ) Etched I ace,-1 2 ODP4 C 'le Cavity 12 M110 ma.* Red. Glass 213-4 Magnetic 70diag. Single Cavity 12 M95ma.* Filterglass 2 ODP4A) Filtergll ss 2 OFP4 Filtergis ssi 1 sie Cavity 12 M110 ma.* Red. Glass 21 Magnetic 70 diag. Single Cavity 12 E kv. Filterglc ss Filterglass 2 OFP4A J sie Cavity 11 M 130 ma. Filterglass 2 OGP4 Red. Glass 213.4 Magnetic 70diag. Single Cavity 12 E2 -3 kv. Filterglc ss >le Cavity 12 M100ma.* Filterg lass 2 OHP4 ' I

E 2 OHP4A Red . Glass 21' 8 Magnetic 70diag. Single Cavity 12 -50 to 270 v. Filterglc is sie Cavity 12 M 110 ma.* I Filterg lass 2 OHP4B 1 le Cavity 12 M 110 ma.' Filterg lass 2 0114 Red. Glass 218 Magnetic 70 diag. Single Cavity 13 Automatic le Cavity 12 M 100 ma.' F i lterg lass, 1 2 01P4A Filterglc le Cavity 12 M 110 ma.' Filterglasst 2 OMP4 Rect. Glass 22'a Magnetic 70diag. Single Cavity 14 E -50 to 350 v. Filterglc

sie Cavity 12 M110 ma.* Single Rim 14 M 105 ma.* Etched I ace Filterglass !IAP4 Rect. Metal 22'4 Magnetic 70diag. '.IDP4 Rect. Metal 225a Magnetic 70diog. Single Rim 16 E2 -3kv. Etched ace ble Cavity 12 M 100 ma.' Filterglass,l 21EP4 le Cavity 12 M 100 ma." Filterglass 21 EP4A Rect. Gloss 23 Magnetic 70 diag. Single Cavity 16 M 95 ma.* Cyl. foc e ale Cavity 12 M110ma.* Filterg lass 21EP48 Cyl. foc e le Cavity 12 M 100 ma.* Filterglass, 21FP4 ) S Rect. Glass 23 Magnetic 70 diag. Single Cavity 14 E -50 to 350 v. Cyl. foc e Filterglass, l 21FP4A) Filterglass 21GP4 Rect. Metal 225a Magnetic 70diag. Single Rim 18 Automatic Filtergl, ass le Cavity 12 M 100 ma.' Filterglass 21KP4 1 S Glass 223a Magnetic 70 diag. Single Cavity 14 Automatic Rect. Cyl. fac e Etched face, I 21KP4Ar Etched face 21MP4 Rect. Metal 225e Magnetic 70 diag. Single Rim 14 E -50 to 350 v. Etched) ace le Rim 12 M 95 ma.' Filterglass 22AP4 I Round Metal 23le Magnetic 70 Single Rim 14 M 105 ma.* Filterglass 22AP4A( Filtergk SS le Cavity 12 E 2-3 kv. Filterg lass 24AP4 I 16 M100ma.* Round Metal 24'a Magnetic 70 Single Rim filtergli le Rim 12 E 2-3 kv. Etched face 24AP4A` E -50 to 1 270 v. Filterglc le Cavity 14 E -50to 270v Filterglass 24BP4 Round Metal 24'iá Magnetic 70 Single Rim 14 ia Cavity 14 M 95 ma.' Filterglass 90 Rim 15 E -60 to 300 v. le Cavity 14 Selfocus Filterglass '7AP4 Rect. Metal 2131 Magnetic diag. Single Filtergll Filterglc Cyl. face 3 OBP4 Round Metal 23'2 Magnetic 90 Single Rim 27 M95 ma.' e Cavity 14 E -50 to 270 v Cyl. face 'Requ,re RTMA 5109 focus coil (470 ohms) or equ'volent. e Cavity 14 M 110 ma.* Cyl. foce :M Magnetic locus E Electrostatic focus Zero focus Filterglass e Cavity 14 Tube requires use of a 1000 yytd condenser between 2nd anode lead and chassis ground. E- 100to 100v Filterglass All cylindrical faced rubes have Filterglass.

5e ing for grounding of the second anode require the use of u- a 1000ypfd. condenser between the second anode terminal Sr- or lead and chassis ground. h Tubes having cylindrical faces may require a change Dn or modification of the tube mask to allow the tube to fit RRDIOa snugly into the frame. This should be investigated before 1te making a replacement. TELEVISION ie- In the 50 to 60 degree deflection angle group, a differ - NEWS Ny ence in deflection requirements up to about 5 degrees Fi can be tolerated. In going from 60 to 70 degree deflection DATA -PRINT #4 of tubes, however, new deflection yokes are necessary. The is deflection angle for rectangular tubes represents the di- Copyright 19521 agonal deflection; for round tubes, the deflection along El- the diameter is given.

www.americanradiohistory.com TELEVISION PICTURE TUH

DEFLECTION DEFLECTION TOBE FECE LENGTH TYPE ANGLE ION ANODE B.T. TOBE FACE LENGTH TYPE ANGLE IONS' TYPE SHAPE ENVELOPE (inches) DEFLECTION (degrees) TRAP connection I h FOCUS MISC. TYPE SHAPE ENVELOPE (Indies DEFLECTION (degrees) TRAl 3KP4 Round Glass 11% Elec. - -- None - -- 2 E450v. 1 16ABP4 Rect. Glass 18'4 Magnetic 70 ding. Sing. 3NP4 Round Glass 10 Magnetic - -- None Ball 24 M120 ma. Projectic n I6ACP4 Round Glass 20's Magnetic 60 Sing! 5TP4 Round Glass 12'8 Magnetic - -- None Cavity 27 E 4.9 kv. Projectic 16AEP4 Rect. Glass 18'ía Magnetic 70 diag. Sing' 16AP4 7AP4 55 Round Glass 13'8 Magnetic None - -- 3.5 E600v. 1 16AP4A Round Metal 224 Magnetic 53 Doul 7CP4 Rcund Glass 13'8 Magnetic 57 None -- 6 E 1.1 kv. 16AP4B 7DP4 Rcund Class 143 %e Magnetic 50 Double Cavity 6 E 1.4 kv. 16CP4 Round G ass 21'r Magnetic 52 Doul 7EP4 Round Glass 15''2 Elec. - -- None - -- 2.5 E650 v. 16CP4A Round G ass 22's Magnetic 53 Doul 7GP4 Round Glass 1 14'8 Elec. -- None - -- 3 E 1 kv. 16DP4 7HP4 Round Glass 13 ?a Magnetic 50 None Ball 6 M -- Round Giess 21 Magnetic 60 Sing 16DP4A 7 JP4 Round Glass 14'8 Ele:. - -- None - -- 6 E 1 kv. 16EP4 8AP4 Round Metal 1458 Magnetic 54 Single Rim 9 M 112 ma. 16EP4A Round Metal 20 Magnetic 60 Doul 8AP4A Filtergla ss 16EP4B Sing- 8BP4 Round Glass 16's Elec. - -- None - -- 6 E2kv. 16FP4 Rourd Glass 20'.S Magnetic 62 Sing 9AP4 Round Glass 21% Magnet c None Cap 6 E 1.2 kv. - -- 16GP4 IOBP4 16GP4A Round Glass I7,,e Magnetic 50 Double Cavity 10 M130 ma. Round Metal 17's Magnetic 70 Sing IOBP4A Filtergla SS 16GP4B IOCP4 Round Glass 17% Magnetic 90 None Ball 10 M 150 ma. 16GP4C

10DP4 Round Glass 18 Magnetic 90 None Cavity 10 E 2.9 kv. t 16HP4 Round Gloss 21% Magnetic 60 Doul 10EP4 Round Glass 18 Magnetic 50 Double Cavity 9 M132ma. 16HP4A( OFP4 16JP4 Round Glass 18 Magnetic 50 None Cavity 10 M 115 ma. Round Glass 21'4 Magnetic 60 Doul OFP4A Filtergla ss 16JP4A IOGP4 Found Glass 18'8 Elec. - -- None - 5 E 1.5 kv. Discontil oued 16KP4 -- Rec. Glass 19'e Magnetic 70 ding. Sing_ 'OHP4 Found Glass 1958 Elec. - -- None - -- 5 E 1.5 kv. Discontii oued 16KP4A1 OMP4 Ì No 2nd grid 16LP4 Pound Glass 173u Magnetic 52 Double Cavity 10 M 150 ma. 1 Round Glass 224 Magnetic 52 Doul OMP4A) Filtergla ss 16LP4A 1 16MP4 12AP4 Round Glass 25'íe E ued Rot. nd Glass 22'8 Nagnetic 60 Dour Magnetic 50 None Cap 7 1.5 kv. Discontii 16MP4Aj 12CP4 Round Glass 18% Magnetic Double Cap 7 M No 1st a node, 50 -- 160P4 Red. Glass 19% Magnetic 70 ding. Doe 12JP4 Round Glass 18 Magnetic 50 None Ball 12 M 146 mo. 16RP4 Red. Glass 19't Magnetic 70 ding. Dour 2KP4 Round Glass 18 Magnetic 54 None Cavity 12 M 135 ma. 165P4 j 12KP4A.112KP4A11 Filtergla SS Round Glass 17'4 Magnetic 70 Doc' 16SP4A ( 12LP4 Round Glass 19'-8 Magnetic 57 Double Cavity 12 M 125 ma. 16TP4 Rest. Glass 18)i Magnetic 70 ding. Siny 12LP4A } Filtergla SS 16UP4 Rest. Glass 18sá Magnetic 70 ding. Sing 12QP4 Round Glass 17% Magnetic 55 Single Ball 10 M 135 ma. 16VP4 Ro and Glass 17': Magnetic 70 Sing_ 12QP4A Filtergla ss, 16WP4 11034 Round Glass 17'2 Magnetic 55 Single Cavity 10 M 135 ma. Repl. for 120P4. Ro ,nd Glass 18'2 Magnetic 70 Dou, )6WP4A1 2RP4 Round Glass 18 Magnetic 56 Single Ball 10 M 135 ma. 16XP4 Re_t. Glass 19'8 Magnetic 70 diag. Dou 2TP4 Round Glass 19'8 Magnetic 54 Double Cavity 10 M 110 ma. 16YP4 Round Glass 17'u Magnetic 70 Sing 2UP4 ) Double )6ZP4 Round Glass 22% Magnetic 52 Doul 2UP4A ¡( Round Meal 19 Magnetic 54 Double Rim 10 M120 ma, Filtergla 2UP4B) Single Etched fl ce 17AP4 Rect. Glass 19 Magnetic 70 ding. Sing 2VP4 1781,4 I Round Gloss 18% Magnetic 55 Double Cavity 10 M 150 ma. No 2nd grid,'' 2VP4A 17BP4A Filtergla Ss Rect. Glass 19% Magnetic 70diag. Sing_ 2WP4 Round Glcss 17% Magnetic 55 Single Special 12 M 110 ma. Cyl. face 17BP4B 2YP4 Round Glass 185e Magnetic 54 Single Cavity 12 Automatic 17BP4C 17CP4 Rect. Metal 19 Magnetic 70 ding. Sing 4AP4 Round Glass 24'4 Elec. - -- None - -- B E4kv. Discontir ued 17CP4A 4BP4 Red. Glass 16'8 Magretic 70diag. Doub e Cavity 10 M 110 ma.* Filtergla 17FP4 Rect. Glass 1958 Magnetic 70 ding. Sing 4CP4 Rect. Glass 17, a Magnetic 70diag. Single Cavity 12 M 115 ma.* Filterglar I7FP4A f 4DP4 Red. Glass 17''a Magnetic 70diag. Double Cavity 11 M100 ma.* Filtergla. s 17GP4 Rect. Metal 18'2 Magnetic 70 ding. Sing 4EP4 Rect. Glass 16'2 Magnetic 70diag. Single Cavity 12 M110ma.* Filtergla, 17HP4 Rect. Glass 19'8 Magnetic 70 ding. Sing 4FP4 Rect. Glass 16'2 Magnetic 70diag. Single Cavity 12 M115 ma.* Filterglas 17JP4 Rect. Glass 19'4 Magnetic 70 ding. Sing 4CP4 i Filtergla, 17KP4 Rtd. Glass 19'4 Magnetic 70 diag. Sing Rect. Glass 17'é Magnetic 70diag. Single Cavity 12 E2.5kv. 4GP4A) Filtergla S 17LP4 Rad. Glass 194 Magnetic 70 ding. Sing 5AP4 Round Glass 201a Magnetic 57 None Ball 12 M 160 ma. i. 17LP4A ) 5CP4 Round Glass 21'8 Magnetic 50 Double Cavity 12 M 110 ma. 17QP4 Rad. Glass 19'4 Magnetic 70 diag. Singl

5DP4 Round Glass 20r8 Magnetic 57 Single Cavity 13 M 145 ma. i 17RP4 Ì R_ct. Glass 19'4 Magnetic 70 diag. Singl 1014P4 Round Glass 20'8 Magnetic 57 Single Ball 13 M145 ma. Repl. for 5DP4, 17RP4A

Replacement of picture tubes in television receivers (as nel tube falls. Then, within that group, compare the tul opposed to conversion) ordinarily involves the substitution to be replaced with the others as regards each of the chi of the same type number tube for a defective original. In acteristics given for the tubes. if all electrical charactt many cases, this is not possible because the same tube istics of two tubes match, a difference in over -all len

type may not be available or desirable. Under such con- may be tolerated depending upon the space available 1 ditions, the correct replacement of a picture tube depends the chassis and in the cabinet. upon finding a tube whose physical and electrical charac- For example, tha 121P4 is a perfect replacement for teristics match, as closely as possible, those of the tube to 120P4A. The difference of 1/8 inch in over -all length k be replaced. In replacement, the only physical character- tween the tubes can obviously be accommodated by al istics that must be checked are the over -all length of the cabinet. However, the 16LP4 or 16LP4A is a perfect elect tube and the face diameter or diagonal. The flare dimen- cal replacement for the 16CP4 except for a difference sions do not vary greatly for tubes of equivalent face size. 314 of an inch in length. Some cabinets may accept t To find the correct replacement for any tube type, first, difference, others may not. find the size group on the above chart in which the origi- Those glass tubes which do not have an external coy

www.americanradiohistory.com CONSTANT K TYPE HIGH -PASS FILTER DESIGN By SEIZO YAMASITA The constants of a "T" or °epi" type constant K high -pass filter may be determined rapidly with acceptable accuracy with the aid of this chart.

IN DESIGNING an electrical filter, it is customary From the chart (Fig. 2) it is possible to determine to determine the constants of the elements to a L and C if f, and R are known. For example, the fairly high degree of accuracy. However, the damp- chart shows that a filter with a cut-off frequency ing characteristic of the constant K type filter is of 10,000 cycles and an image impedance of 600 ohms not sharp, so that calculations to an accuracy of would call for L = 4.8 mh. and C = 0.014 pfd. better than a few per -cent are seldom required, and effective use can be made of charts to determine inductance and capacitance.

Fig. 1 shows both the "T" and "pi" types of constant K high -pass filter. In this figure: L - R/41rf, C 1/47rf,R (A) st(B) = where f, is the cut-off frequency and R is the image Fig. 1. (A) "T" type and (B) "pi" impedance. type constant K high -pass filter.

Fig. 2 10MH.

I fd OH I fd 1H 001 fd 100MH. IOOyyfd. IOK11 . _.IMM =I ~..owl am No : sum r,..4 -. .__-.._.NNW= =./.: :,.-_-.s:4-474\RI \\ mt/PA,.-...-_- _. . NI./I/ 1 :41_\Rs%I\I./I pfd. SMEWP.:11111 RAMP :111M7%/II.V.\II./I! :!_\(,: MAIM x \ II WWIIN'I:nG//WKW4WdNII:Ì//'ATAX.4,WILMMIì!G/./WZMIVIMASINNI'Ii: :I_\ SÌ// M_M W\\i:Gii/1 MIM!\\%ÍM/1 DRMAM\\i%'//ii/,Í MIM S.V\\i:G Ìi,/ 1010\\`P.%1:';%I:M11\\`: v;.-.,- v- r1'VI`.Ì/\\':i:ÌÌI\!1::Ì.-- ...- _...... ríi/ ...... 1. 1 ...í ...,...... ,1...... 1' .:.í ...:1. 1/ ä:b'...... :._.1 1 I I I 1\ -Fe/ri/rN1211111, . 1111 WI/ _2.111 k9,I 2111111v Ng1 /P\;1 1Im 4.1 . p.4 ' /P,1 %1'_í,/ . % 1 4. .; I Kn. / / i / °%' ' ' IOpfd. re.Nl:10.,MMMArrKM1ít,í___Ì%` Ì\Ïi M.:1N._M1111&%%%ì2I\GVÌ 02r 14.MINMFAÌ¡V_%. iO:.fa:11111i2Eioii !`"WaMÌÌIIS2PAMMTae'Ii 1120/:47411MNPIéS%N/W:WiMMMÌ!1%M/'ÌÏÏ M:M!:WW. i:"//ÌM1 M1M\\i:% i.I.1-:O i://.Ì:.1-I D1'//.Ì.1I,1 I_i/i1/_=ííIiliI_i..1v, vrv \ r, \ir.\ r, !-.rv , !\\.r\if.. `ì. , .. I ...... _.1 j I ì1-._:.._.._1 11-.... I `-.._....1.: 11 11I //. \ í4 . 11\ ... . \ .--. . \ - / ,.,.,.,II...I /"o...111I ,-- 'i I I 0,!1.--, 1 I I .- I , /._,...... s///.r_...1.1.-\ - - --...1,1.:.; 1 ,s///._.Í,` -'I'I/I'I IiI - .I ; 1 :íI / :`:1,.;i I \11- iiI1 ¡ 1- %:!.!I.'1I!!::%:!I'1/1!'::%!i! . . : . / . : . . loon .- _ , _. . . .. , :. ... _- _ . . . .. :. :. .-. . . .. : . .. - - -. , ...... m . . 11.7.44"6:4-4. 100pfd. :V.I/. ,ir' :\\ri0:: . iirGCK_\=iirE \\iri': -.\._ fs\ A..:IMMIiÌ G/..C.4I.11/W:l.WÍi.dl/.:S4'Ii_I/// r0:.I - ii%K ; . ' Ì:u,1. i. Ìdß1i! ' %.1I! i.. ÌI..i . I\1.!.!I.fl..\r. .\\ ir . r \ I.\\.!'.!.1_. .\\ r r \ _ \.!.!r..I.._\\ . r \\.!.!I.!.1.\\ -.-r . . 1 I 1 I I I . `1 ì1 i1 ,1'1 i1 .1 .,'1 tf ,'1y ,'1 !. N . I, .- . Ì--, I !.:- '1 Ì-., I i1 "-j`.,! '/ Ì--, I -.. ..,//_ o, 11.. I/.1_ ....,..11. .. ._. .._,...:.,`...... 1. //._:...... `1 1.. /- I 4 \ /- I \ -I I \ . - /'I 1 -IÌ!' IIÌ ¡ i11,I Ì! IiI Ii1/ 10A AL 'i\1!::;!í //11%:: /'11%:_.i!/'1 1 KC. í 10KC. 100KC. 1001) !

www.americanradiohistory.com An Improved SPEECH CLIPPER

Fig. 1. Front panel view of clipper. The unit indicates clipping level directly in decibels by means of flashing neon lamps.

By Although designed for the ham. this unit may also L. C. WATHINS, JR. wSJXo he used by couud,uen in connection with p.a. systems.

I,REMODULATION speech clip- wave. A square wave is found to have filter system is the loss in the aver- ping and filtering has become an only odd harmonics, being composed age power of the clipped wave as it accepted and proven method of of an infinite number of sine -wave goes through the filter. Let us assume obtaining increased sideband power components of different frequencies a filter cut -off frequency of 3000 cps from phone transmitters. The theory and amplitudes. and examine the clipped waveform at and benefits have been discussed so fre- In order to preserve a square -wave the filter output terminals. Assuming quently that space will not be devoted signal through an audio system, the 200 cps as the fundamental frequency, to a detailed summarization here. A system must have (1) flat amplitude then the fundamental and the 3rd review of the more pertinent articles response and, (2) uniform time delay, through the 15th harmonics lie within will be helpful to those persons inter- so that the frequency components will the filter passband. The output wave -, ested. I' 2 3. 4. 5 retain the same alignment relative to form will be very square and will con- The disappointing results often ob- one another that they had originally. tain high average power. At a funda- tained when clipping is attempted may Any filter arrangement that provides mental frequency of 400 cps, only the usually be traced to one or more of the a sharp cut -off, of which the common 3rd, 5th, and 7th harmonics lie within following situations : (1) Overmodula- m- derived filter is an example, does the passband. The output waveform is tion due to phase shift in the filter that not exhibit a linear phase -shift charac- still quite square. With a 600 cps fun- is necessary to use after the clipper, teristic. The phase shift increases damental, the 3rd and 5th harmonics and phase shift in the audio circuits rapidly as the filter cut -off frequency are passed, and the square waveshape following the clipper -filter. (2) Skimpy is approached. This gives rise to a has deteriorated considerably. Finally, or improper modulator design. (3) The realignment of the frequency com- with a 1000 cps fundamental, only the use of an excessive amount of speech ponents present in the clipped wave, 3rd harmonic is passed, and the aver- clipping, usually due to the lack of an such that the new peak amplitude at age power has suffered a large reduc- accurate method of determining how the filter output is greater than that tion. At frequencies higher than 1000 many decibels of clipping are in use at of the fundamental. In other words, cps, only the fundamental components any given instant. (4) Failure to elimi- full advantage cannot be taken of the are passed and show up as sine waves, nate noise and hum voltages from original reduction in the waveform with their usual contribution to the the low -level speech stages ahead of peak factor that clipping accomplished, average power of the total waveform. the clipper. (5' The use of clipping, in since it is mandatory that the trans- The end result is to cause the voice excess of a very few decibels, when the mitter not be overmodulated. frequencies lower than about 600 cps. transmission path is subject to selec- Some relief may be afforded by us- to modulate the transmitter with a tive fading conditions. ing a constant -k filter section after greater average power than the higher Most of these problems have obvious the clipper instead of the m- derived frequencies. This often results in the solutions. Perhaps not so obvious is type. The constant -k filter exhibits a excessive "boominess" of some signals the fact that phase shift accounts for much improved phase -shift character- from a clipper -filter rig, especially a major part of the unsatisfactory re- istic for the purpose at hand, although if the voice characteristics of the sults which are sometimes noted. it does not cut off as sharply as the operator tend to be on the "bass -y" The voice, as far as the instantane- m- derived filter. More important, it side. In any case, frequencies below ous conditions are concerned, can be gives better attenuation at frequencies about 200 cps should be attenuated in considered as various sine -wave com- farther out from cut -off. In addition, the speech amplifier stages ahead of binations and even -order harmonics. A the rather gradual attenuation charac- the clipper, and the operator with an sine wave clipped 10.5 db has a shape teristic seems to afford a greater ele- unusually bass voice should carry the factor of 0.9, which is nearly as great ment of voice "naturalness. "G attenuation as high in frequency as is as the 1.0 shape factor of a square One other situation inherent in the necessary to avoid excessive "boomi- August, 1952 55

www.americanradiohistory.com REF. S16 C11 R18 C4 R12 J2 11 J4 6AU6 VI 6AU6 5 V2 a CH2 FILTER OUT d R19 2 JI RI V J3 C12 C13 á - OUT R4 R5 e FILTER IN JS 7 ,Jj R20 R2 Si IN CI C2 o

TI 6X4 V6 NE-51 FI R26 2 R34 T 441. 2 de Il 67 6AU6 V5 4.4 V4 1 6AK6 CHI VAG C16

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HUM BAL. i5 db R43 1111}113 R33

R40

w. res. ± 5% and CIE C_, -10/20 Add., 450 v. can -type elec. R1, R8- 47,000 ohm, 1/2 w. res. R3e -1730 ohm, 1/2 (1800 in cond. R2, Rll, Rio, R13-1 megohm, 1/2 w. res. 43,000 ohms parallel) t/2 w. res. ± 5% (2400 and S0 µtd., 150 v. can -type elec. cond. R3 -510 ohm, 1/2 w. res. Ray -2320 ohm, C,Ir w. res. 68,000 ohms in parallel) C2, -10 ltfd., 450 v. can -type elec. cond. R4, Ris, R18-- 200,000 ohm, 1/2 v. metallized -paper R5-100,000 ohm, I w. res., low- noise, metallic - R,,, Ras, Rae, R,7, R,,, R30- 50,000 ohm res. in C22, C2é-.05 pfd., 600 film type (Continental Carbon Type X-1) NE -51 neon panel assembly (Dialco Series cond. (Aerovox Type P82 "Aerolite ") R,I- 100,000 ohm pot. 95408, clear plastic cap) T, -Power trans. 250 -0 -250 v. @ 60 ma.; 6.3 2 w. res. V. @ 2 amps.; S v. ® 2 amps. (unused) R -1100 ohm, 1/2 w. res. R40- 120,000 ohm, ohm, w. res. R41- 18,000 ohm, 2 w. res. (Chicago Transformer #PV -60) Rn- 560,000 1/2 w. trans., pri. imp. 10,000 ohms, R10, 220,000 ohm, 1/2 w. res. R,2- 10,000 ohm, 20 w. wirewound res. T2-10 mod. R2- sec. imp. 10,000 ohms (Merit Type A -3008) R14 -470 ohm, 1 w. res. R43- 10,000 ohm wirewound pot. (screwdriver adjustment) CH -13 hy., 65 ma. filter choke. 500 ohms R15- 22,000 ohm, 1 w. res. -1365) 22,000 ohm, 2 W. res. R44-100 ohm wirewound pot. (screwdriver d.c. res. (Chicago Transformer #R R10- reactor, hum -bucking type (Thor- 15,000 ohm, 2 W. res. adjustment) CH.,-22 hy. R,- darson Type T20074) Ron -1000 ohm pot. R45 -22 ohm, 2 w. res. C,, C14- 20/20/20 pfd., 25 v. can -type elec. 11, 15- Microphone connector R..1 -1000 ohm, 1/2 w. res. Ce, type banana test jack R22-130,000 ohm, 1/2 w. res. cond. 13, 12, 14- Insulated R24- 250,000 ohm pot. ( screwdriver adjust- C2, Ce, C,5-.25 pfd., 400 v. metallized -paper S,- S.p.d.t. toggle sw. ment) cond. ( Aerovox Type P82 "Aerolite") F, -1 amp. fuse and holder I w. res. Cs, C7, C10- 10/10/10 pfd., 450 v. can -type PL1 -6.3 v., .15 amp. pilot light, used in neon 82-510 ohm, with ohm res. re- R28- 470,000 ohm, 1/2 W. res. elec. cond. panel assembly 50,000 10 w. wirewound res. C4 -.002 pfd., 500 v. mica cond. placed by piece of solid wire (Dialco Series R2-5000 ohm, plastic cap) R28 -1870 ohm, 1/2 w. res. ± 5% (2000 and CE -.005 pfd., 500 v. mica cond. 95408, green C, pfd., 25 v. tubular elec. cond. 6 -Type NE -51 neon lamps 30,000 ohms in parallel) Co, -50 tube R,, -1630 ohm, Vi w. res. ± 5% (1800 and C11 -.5 pfd., 400 v. metallized -paper cond. V,. V2, V,, V4 -6AU6 18,000 ohms in parallel) (Aerovox Type P82 "Aerolite") V5 -6AK6 tube v. mica tube R80-1300 ohm, 1/2 w. res. ± 5% C42, C18-265 µpfd., 500 cond. V8-6X4 v. metallized -paper cond. V 75/0A3 tube R -1150 ohm, 1/2 w. res. ± 5% (1200 and C18 -.01 pfd., 600 -VR 27.000 ohms in parallel) ( Aerovox Type P82 "Aerolite ")

Fig. 2. Complete schematic diagram and parts list for the clipper. The unit is entirely self -powered. ness." The lower audio frequencies add to be an adaptation of a standard and ping level and is one of the front panel very little to the signal intelligibility well -proven handbook circuit. V, and controls. and may be easily attenuated by the V2 are merely linear voltage amplifiers, The filter, made up of CA_, CIT, and use of smaller- than -normal coupling and V, is the overdriven amplifier Co, is of the constant -k type with a condensers in the amplifier stages pre- wherein the clipping actually occurs. cut -off frequency such that the output ceding the clipper. A clipper system should be quite linear signal voltage is down 3 db at 3000 The clipper described in this article up to the point where clipping takes cps, with reference to the output volt- was designed as a complete unit so place in order to introduce the least age at 1000 cps. A major stumbling that it could be connected to the input amount of distortion into the signal. block has been removed by designing jack of nearly any existing speech am- The degenerative feedback network the filter so that a readily available plifier. It incorporates a clipping in- from the plate of V, back to the pre- choke of accurately known characteris- dicator circuit to enable the operator ceding stage makes the amplifier- tics could be used. It is the 22 hy. re- to know accurately at all times the clipper considerably more linear than actor of hum -bucking construction peak clipping level directly in decibels. any of the series- or shunt -clipper made by Thordarson for use in dual compact, con- diode systems on which the author has tone -control circuits. If the specified The unit is quite will structed of readily available com- made measurements. components are used, the reader ponents, and requires no elaborate Resistor R. is a low- noise, metallic - be able to duplicate the filter success- calibration procedure. A special effort film type and results in a substantial fully without recourse to elaborate test was made to reduce noise and hum reduction in noise voltage output at equipment. voltages the output terminals to a the signal amplification values neces- The filter is terminated in its design at Ria. The very low value. The circuit constants sary to obtain 10 -15 db of clipping. The impedance of 200,000 ohms by a passband lower right corner of the photograph of output -level potentiometer, Rae, forms have been chosen to permit to limit the of approximately 200 cps to 3000 cps. Fig. 5 will reveal that the author used a voltage divider with R. two 50,000 ohm resistors in series to maximum output voltage available at /Tipper- Filter Circuit make up R,, since they were already J. to about 80 millivolts, more than to the schematic diagram, on hand in the desired type. sufficient to drive the usual speech am- Reference plifier. About 20 volts of signal out- Fig. 2, will show the clipper amplifier Potentiometer Re controls the clip- NEWS 56 RADIO TELEVISION

www.americanradiohistory.com put is available at the top end of the resistor R, Banana jacks J_ and J. are for calibration purposes, to be explained later. J, may be omitted, as it was included in the unit pictured to permit the convenient oscilloscopic examination of the -filter output waveform during a group demonstration of the unit. Clipping Indicator Circuit The indicating circuit is a simple linear amplifier consisting of a voltage amplifier stage, V,, and a power amplifier stage, V. The power amplifier and its output transformer, T2, must be capable of handling a watt or so of power to provide a distortion -free signal with which to operate the six NE -51 neon indicating lamps. The lamps, when lighted, consume a small amount of power and also tend to vary the load impedance somewhat, as presented to the secondary of T2. Inverse feedback around V, helps to stabilize the power stage against load variations and also lowers the distortion Fig. 3. Top chassis view of the speech clipper showing recommended parts layout. content of its output signal. T2 is a small and inexpensive modulation the regulated positive bias voltage ap- ence signal voltage at the grid of V. transformer, set up for a one -to -one plied to the six neon lamps. The bias will just cause clipping to commence, turns ratio. is adjusted so that the lamps normally then any desired number of decibels of Resistors R. through R29 are current - are just on the verge of firing, result- clipping may be determined by allow- limiting resistors for the neon lamps ing in a much smaller amplitude of ing the V_ grid signal to increase by and are already provided in the neon audio signal voltage needed to trigger the proper multiplying factor. A ratio panel assembly sockets. The values of them. Condenser C. provides a low im- of 1.3 :1 will provide about 2 db of clip- resistors R., through R. are such as to pedance path to ground for the audio ping, and a ratio of 5.6:1 will provide cause the neon lamps to flash with the voltage, without short -circuiting the 15 db of clipping. desired decibel relationship in accord- bias voltage. The condenser should be These figures indicate that a large in- ance with the amplitude of the voltage large, at least 50 µfds. crease in the amplifier gain is necessary across the secondary of T2. The 4 db An audio signal applied to the grid ahead of the clipper to produce sub- lamp is connected across 81.3 per -cent of V, is amplified linearly, and so on stantial amounts of clipping. Even an of the total voltage divider resistance; through V2 and V3 unless the signal is inch or two of variation in the speak- the 6 db lamp at 65 per -cent; the 8 db increased enough so that V:, begins to ing distance from the microphone, or a lamp at 52 per -cent; the 10 db lamp clip. After clipping commences, the slight variation in the voice level, will at 40.5 per -cent; and the 15 db lamp signal at the grid of V2 will continue change the clipping level by several at 23.2 per -cent of the total resistance. to rise linearly, as the clipping level decibels. A truthful indicating circuit The NE -51 bias control. R43, varies control is advanced. If a certain refer- should possess no operational inertia and should be activated by the in- Fig. 4. Top -rear view of chassis. The neon lamp voltage divider resistors are stantaneous voice peaks, instead of the soldered directly to the lamp socket terminals as shown in the photograph. average voice level. The indicating amplifier is linear in operation, so all that is necessary is to adjust Re for a 2 db clipping level, then adjust R24 until the 2 db lamp just lights. Further increases in the setting of R. will produce Corresponding increases in the output of V6, and the remaining lamps will light, one after another, in the proper decibel relationship. This unit was designed for a maximum normal clipping level of 10 db, as it is doubtful whether clipping much in excess of this figure is practical. Acoustic background in the operating location may even then prove annoying. Another important factor that should be emphasized is that the voice quality is still very acceptable at the 10 db figure. Hum voltage in the output is reduced practically to the vanishing point by using a hum -balancing potentiometer across the power transformer 6.3 volt heater winding, and by placing about 35 volts of positive bias on the tube heaters. The brilliance of the 6.3 volt pilot lamp is reduced by a series voltage-dropping resistor, R46, to provide (Continued on page 129) August, 1952 57

www.americanradiohistory.com A UNIQUE TV SIGNAL TRACING PROBE

By E. G. LOUIS

SIGNAL tracing, as a servicing technique, probably offers the Fig. 1. Over -all view of probe which can be most rapid and accurate method used with both medium and high -gain scopes. for definitely isolating distortion, hum, or weak operation to a specific stage. Unit permits detection of r.f. and i.f. signals and Unfortunately, this valuable technique has, in the past, been somewhat diffi- has a stage of direct- coupled wide -band amplification. cult to apply to TV receivers due to the comparatively low signal levels and R. acting as the diode load re- really useful in tracking down the is important present in the video i.f. stages. The sistors. The probe condenser C, is kept source bf distortion, it difficulties stem primarily from the low nn value to minimize loading and that the probe itself introduce no dis- video signal. fact that many service type cathode - detuning when the probe is used to tortion of the ray oscilloscopes do not have sufficient check signals in tuned i.f. stages. R4 and C. together act as a decou- gain in the vertical amplifier to permit A demodulated signal appears across pling filter, preventing or minimizing direct observation of a detected TV R2 having both a.c. and d.c. compo- any effects due to power supply cou- signal unless the signal level is quite nents. The d.c. component serves as pling. This permits the power supply high. a bias voltage for the direct -coupled of either the TV receiver or the CRO To difficulties, amplifier following the detector. Note to be used for operating the probe. ( A overcome these the may be used if probe shown in Fig. 1 and diagrammed that the grid of the triode amplifier is separate power supply connected directly to R2. available, of course.) in Fig. 2 was designed. This probe use probe not only permits of an r.f. or An amplified video signal appears If the builder plans to the detection AM or FM re- i.f. signal, but also provides a stage of across the amplifier load resistor R, primarily for servicing d'rect- coupled wide-band amplification. and this is applied to the input of the ceivers where extreme bandwidth of vertical amplifier of a cathode -ray the amplifier is not important, R. may Although designed originally for TV with servicing, the probe may be readily oscilloscope. R. has purposely been be made several times larger, a adapted for use in signal tracing AM kept low in value to minimize the ef- resulting increase in stage gain. fects distributed capacity the and FM receivers. of and Construction Mints In actual servicing tests, the probe input capacity of the CRO, thus as- shown in Fig. 1 was used with both suring good bandwidth and an accu- If a metal, plastic, or fiber tube is medium and high -gain oscilloscopes. rate reproduction of the video signal. available, the probe may be assembled It was found that the video signal For the signal tracing technique to be in it, using conventional construction could be detected and observed up to techniques. An old electrolytic "can" the output of the TV front -end when Fig. 2. Complete schematic diagram of the may also be used. local TV stations were being received. TV probe which uses a twin- triode tube. However, it has been the author's Thus, it is possible to make gain and expérience that when a tube is needed, quality tests of individual stages in the r one can seldom be found even at the I 12AT7 OUTPUT TO local radio wholesalers. And electro- entire i.f. strip. Since the scope, alone, SCOPE may be used to observe signals fol- lytic condensers seem to suddenly ac- lowing the video second detector and a quire a new lease on life if a defective in the sweep and sync circuits, the ad- SHIELDED one is needed. Therefore, an effort PROBE T CASE was made to design the probe so that dition of this probe to the tools of the W (SEE TEXT) . construction could be undertaken with service shop or laboratory permits the PI sR2 technician to observe and study signals B+ parts which are almost always avail- GROUND 6.3V. A.0 able in the service shop or in an ex- present in any section of the TV re- CLIP COMMON box." The probe ceiver. The advantages in servicing _ "SHIELDED. perimenter's "junk are obvious. L J CABLE shown in Fig. 1 was the result. RI, R2- 27,000 ohm, 1/2 w. res. Fig. 4 is an "exploded" view of the Circuit Description R, 10,000 ohm, 1/2 w. res. probe, showing the essential features R4- 15.000 ohm, 1/2 w. res. Referring to Fig. 2, a twin- triode C, -10 Auld. ceramic cond. of construction. The only machine C2 -.005 ufd. disc ceramic cond. is a single drilled hole tube is used. One -half of the tube is V, -12ÁT7 or 12ÁU7 tube work necessary connected as a diode detector with Ri in the side of the i.f. can for the power 58 RADIO & TELEVISION NEWS

www.americanradiohistory.com cable and signal lead. The hole in the end of the i.f. can is already present - this is where the coil or trimmer condenser was mounted. TV The probe "point" is a 21/2" length Iyt 2nd 3rd ah VIDEO TO VIDEO FRONT-ENO A VIDEO I.E VIDEO VIDEO .- I.E of #12 tinned bus bar, with the end B G I.F. D VIDEO I.F. E 2nd DET. AMPLIFIER pointed and a piece of spaghetti tubing slipped over its length (see Fig. 1). Fig. 3. Block diagram of the video i.f. stages of a conventional The end of the power supply cable television receiver. may be terminated in several ways, de- from 5000 to 8000 cps may be used to pending on the power supply to be em- observe the line signal. Adjust the GROUND CLIP ployed. If an experimental supply is vertical gain control until the observed to be used, terminate the cable in spade video signal is of the desired amplitude. FLEXIBLE lugs, so LEAD that easy connections may he "Sync" SOLDER and "'Fine Frequency" con- LUG OLE FOR POWER CORD made to a screw -type terminal strip. AND SIGNAL LEAD trols should be adjusted for a stable TUBE SHIELD D R ++ ` The power supply of the TV receiver pattern. 3 HOLE FOR 1 being PROBE serviced may be used to supply With the set operating normally, the the probe; in this case, terminate the observed video signal ( using approx- OMM'MixuATURE I.E. CAN power leads in alligator clips for ease 9 -PIN MINIATURE TUBE imately 20 cps sweep in scope) will ap- SHIELD -BASE SOCKET in making connections in the receiver. pear somewhat Since the power as shown in Fig. 5A. required by the A hazy band representing the sync probe is small, the scope itself can Fig. 4. "Exploded" view of probe showing easily furnish pulses should be clearly visible at the the most important construction features. the necessary filament top of the video signal (1 in Fig. 5A), and "B" voltages. In this case, ter- while the lower edge of the video sig- 120 minate the power cable in while -cycle hum is generally a power nal will be uneven' and in plug and mount an appropriate socket ragged (2 caused by the last two defects. Fig. 5A). If a test pattern or fixed When the probe is used to check the on the scope. signal The signal is being transmitted, the video video signal directly in the i.f. stages, lead should be terminated pattern will be fixed in a between pulses. hum is readily apparent as a ripple spade lug for ease of connection A program, to the scope vertical on the other hand, will superimposed on the video signal as input binding post. give a video signal in which pat- shown This lead may be shielded if necessary the in Fig. 5B. Where the field sig- to keep tern between pulses is constantly shift- nal is observed, 60 -cycle hum will pro- hum and noise pickup to a ing in form and shading. minimum, but a low- capacity coaxial duce one complete cycle for each To measure stage gain check the "cycle" of video signal, while 120 -cycle cable should be used - to minimize high relative amplitude of frequency loss. If the scope power the input and hum will cause twice as many ripples output signals of a single stage, di- in the supply is used for probe, a signal. the sep- viding the output level by the input Checking arate ground connection to the scope is each i.f. stage individually not necessary. level. permits rapid isolation of the stage at Otherwise, provide As an example, suppose was ground bonding between the scope and it de- which hum is introduced. Components the TV receiver. sired to check the gain of the 2nd in that stage may be checked using video i.f. stage of a TV receiver (Fig. conventional techniques. The "B plus" may be any value from 3). First, touch the probe 150 volts to 250 volts. If greater volt- to point B Open bypass or filter condensers may and adjust the vertical gain control of be easily identified by using the probe ages are available, use a resistance the scope for voltage divider to obtain the necessary a small deflection (two to check for the presence of a video operating voltage. squares on the scope graph scale would signal at the bypassed point. As an be satisfactory). Now, without touch- example, a screen -grid bypass con- Applications ing the vertical gain control of the denser may be checked by touching the scope, Once transfer the probe to the plate probe point to the screen -grid terminal the construction and wiring is of the i.f. stage completed and checked, the builder (point C). Check the of the tube. The presence of a video amount of deflection obtained and di- signal at this point indicates an open should connect the probe to a power vide by the deflection source and CRO,, not only to check its obtained in the or partially open bypass condenser. operation, but previous test. Open condensers in the i.f. stages also to gain familiarity If 22 with its use and limitations. squares of deflection are ob- may cause regeneration and oscilla- tained when checking the signal In Fig. 3 are shown, in block diagram am- tion, distortion, and other complaints. plitude at point C, with 2 form, the video i.f. stages of a typical squares of Individual stage oscillation is read- deflection obtained at point B, the gain ily identified by checking the video TV receiver. Other portions of the re- of 2nd ceiver, including the power supply, the video i.f. stage is 11. signal at each point in the TV receiver been Hum in the video i.f. stages may be i.f. strip, starting at the front -end and have omitted for purposes of caused by clarity. The points at which the probe stray coupling, an open grid working towards the video 2nd de- may be used for checking circuit, heater -to- cathode leakage, or tector stage. the video defective bypass or filter signal are indicated as A, B, C, D, and condensers. Distortion in the video i.f. stages may Sixty -cycle hum is usually caused by cause a number of complaints, ranging E. After the video 2nd detector, the one of first scope may be used without the probe the three defects listed, (Continued on page 84) for checking signal quality. To probe, Fig. 5. (A) "Normal" video signal as seen on scope. (B) 60 -cycle hum appears as a use the connect the flex- ripple superimposed ible ground lead to a convenient chassis on video signal. (C) Flattened or clipped signal. See text. point and touch the probe end to the grid or plate terminal of the stage to be checked. Check the input to the stage by touching the grid, the output by touching the plate. A local TV station should be tuned in and controls on the TV receiver adjusted for normal operation. The scope controls should be adjusted for a linear sweep, using internal sync. A sweep frequency of from 20 to 30 cps may be used to observe the field signal, while a sweep August, 1952 59

www.americanradiohistory.com them really do have a sound grasp of both theory and practice; but practically none of them have the kind of Mac's RADIO equipment needed to do design engineering work. Modern service equipment is good, but it makes no pretense of equaling laboratory equipment; yet without such precision instruments it is impossible to measure the exact SERVICE SHOP effects of a particular circuit change. By JOHN T. FRYE When a technician is working without the original performance data and when he has only service instruments for doing his measuring, it is very, very easy for him to cure one particular o fault but to produce two other faults in the process. You and I have seen some cases of that come into the shop. "So -o -o," Mac went on, "I think the technician will do well to follow the advice of the old adage : 'Let the cob- bler stick to his last.' I know it is a great temptation to him to display his knowledge and ability by completely reworking a television receiver, and by doing so he can often build up a cheap local reputation for himself as an electronic wizard who knows 'more about a TV set than the men who built it'; but no matter what the layman believes, there is often a great and im- DOG DAY DISCUSSIONS portant difference between changing a set and improving it, especially when August afternoon heat was lar chassis that will result in bringing accurate equipment for checking the hot and oppressive, but both men up the sound without, in any way, im- complete results of any change is THEin Mac's Radio Service Shop were pairing the picture." lacking. too busy to notice it. Barney was "Thirty operations! Whew! That "Personally, I am content to follow fussing away at a little a.c. -d.c. chassis must take a lot of time and cost the the manufacturer's recommendations on the service bench, and behind him customer a lot of dough." with regard to changing the original his boss was checking out a TV set "On the contrary, and that is why I design. If I spot what I believe is a that had just been returned to its like the conversion job. All of the weakness or shortcoming in that de- cabinet. Mac kept switching the re- time-consuming cutting- and -trying and sign, I do not hesitate to call it to the ceiver from one weak signal to another de- bugging has been done by the engi- set -maker's attention and ask for ad- and listening intently to the sound as neers. The technician has only to fol- vice in correcting it. Invariably I re- the snow came and went on the low the action -by- action instructions ceive a courteous answer that usually screen. which are so clearly prepared that he includes specific instructions for "Now that," he finally said as he can do this at a gallop. The complete straightening out the trouble. I have stepped away from the set, "is my idea rewiring job can be done in a couple of confidence in those suggestions because of a really successful fringe -area con- hours at the outside, and another half - I know they have been worked out by version job." hour is ample for the required realign- men who make design their business, "Let's not break our arm patting ment. The important thing, though, is who know the receiver as they know ourselves on the back, shall we Bar- how well it works. Notice that right the backs of their hands, and who have ney suggested sarcastically as he now the picture is so snowy you can thousands of dollars worth of precision looked up from the receiver that was hardly make it out, yet the sound is equipment for checking every move very obviously giving him a hard time. clear and strong. Before, on a signal they make." "What's so good about that particular that weak, all you would be getting "Yeah, but aren't you afraid that conversion ?" from the speaker would be a loud roar. people will say the guy who cooks up "The fact that it was really en- When the customer gets this set back, his own changes is a better electronics gineered in the laboratory of the he is going to have to quit calling it his man than you are ?" manufacturer who built the set. This 'Pantomime Special.' " Mac's eyes twinkled in a grin as he receiver was a good performer in the "What kind of changes did you answered, "That won't seem so im- strong -signal area for which it was make, anyway ?" portant when you get a little older. I designed, but the intercarrier sound "Put in two new traps; changed the don't want to be known as a good 'elec- became very weak and buzzy when the loading resistors across the i.f. trans- tronics man.' I just want to be a first - set was used out here in this ultra - formers; cut the first i.f. tube off the class technician whose primary job it fringe location. When the manu- a.g.c. bus; put a new sound i.f. trans- is to see that radio and television sets facturer began getting complaints of former in place of the former induct- keep playing as well as they did the noisy sound in fringe areas, he did not ance- capacity coupling arrangement; day they left the factory. Maybe the take the easy way out of explaining and then realigned the video and sound frustrated -engineer type of technician that the receiver was not intended for i.f. channels and reset all traps." feels apologetic about being 'just a fringe -area use; instead he set his en- "I gather you are not 'very enthu- technician,' but I don't. I think the gineers to the task of seeing what siastic about technicians working out service problems I solve require just as could be done to help technicians clear their own methods of souping up sets much intelligence and knowledge of up this condition in the field. for fringe -area reception." practical theory as do the design prob- "The result is a kit that comes with "If by 'souping up' you mean mak- lems worked on by the engineer, but all needed parts and is complete with ing unauthorized circuit changes or the schooling, technique, and equip- detailed diagrams, drawings, and step - radical changes in alignment, you are ment that each of us uses is different. by -step instructions for performing right. It is not that I question the It is like the difference between the some thirty operations on this particu- technicians' knowledge, for many of ( Continued on page 126) 60 RADIO & TELEVISION NEWS

www.americanradiohistory.com Telephone dial is used as u simple remote control to permit the selective switching of audio inputs.

telephone -type dial and a rotary step wipers, 110 volt d.c. coil for use with switch to accomplish rapid and posi- selenium rectifier power supply; Type tive switching with a minimum of com- 1C "off- normal" and 1C interrupter ponents. In combination with a pilot spring contacts. It seems as though lamp panel it is not a difficult task to telephone system engineers have a lex- Pilot light assembly. See Chassis A in route the desired program material to icon of their own because when trans- Fig. 1 for data on how this is set up. the amplifier or the output of the am- lated into terms used by radio engi- By plifier to any speaker or combination neers it becomes a 4 -pole, 10- position BUDD MEYER of speakers throughout a home. It is switch with 2 shorting and 2 non - Audio Consultant also possible to control this routing re- shorting contacts. The 1C designa- motely by running wires to the dial tion indicates single -pole, double -throw ONE of the great problems in- chassis located at a convenient point. switches. volved in the design and in- The dial chassis with associated push- To explain the function of the "installation of custom high fidel- button switches used in this system was terrupter" and "off- normal" springs it ity equipment is that of switching the designed so that it could be removed in is necessary to describe briefly the op- various inputs. Most of the commer- its entirety from the mounting panel eration of the switch. The switch is cially available amplifiers and preamps and used remotely. indirectly driven, i.e., it is stepped have provision for five inputs, namely: As will be noted from Fig. 1, the sys- when the power is removed from the FM and AM radio, tape recorder out- tem is designed around a type 44 ro- coil after a momentary application of put, records, and TV. There are, of tary step switch manufactured by power. Application of the power pulls course, many variations, but the afore- Automatic Electric Co. Technical a pawl from a toothed wheel which mentioned sources of program material specifications for the switch used in stores energy in a driving spring, and are the ones usually provided. this particular design include: 4 level, also releases a detent. Interruption of There have been many instances 10 bank, 2 bridging and 2 non- bridging power allows the drive spring to drive where the average consumer has become quite confused by the great num- Over -all view showing main telephone dial panel and the audio amplifier. ber of controls and switches incorporated in some custom installations. The unit described herein, although desig :, 3d for a particular installation, has the advantage of great flexibility. The same basic components can be used not only to switch various sources of program material into the amplifier but can be used to switch various speaker combinations and, in many cases, provide power to the various units comprising the complete installation. Although the author designed this particular equipment to handle the audio equipment which made up his "home entertainment center," this same "Dialaudio" system can be adapted to operate a wide variety of units. It can be used by dealers to tie -in various pieces of audio equipment for demonstration purposes, etc., and can even be employed in miniature train operation and other similar applications. The "Dialaudio" system utilizes a

August, 1932 li I

www.americanradiohistory.com the pawl forward, engaging the toothed wheel and driving it forward one step until the detent stops its forward motion. This action positions the movable contacts (brushes) on one of the stationary contacts. The relay rotates in one direction only and all contacts are traversed in one -third of a revolution. The brush assembly incorporates an indicator wheel which has cams spaced 10x3 7! 120 degrees apart. When the brushes are not engaging any of the contacts (Pos. 11), the cam closes the contact on the "off-normal" springs. "Off -normal" means that the brushes are resting on any one of the contacts. The "off- normal" contacts are actuated RL2 A E-- LEVE LEVEL every one -third revolution. The inter- 0 C 8 o- rupter contacts are so arranged physi- _: cally that when the relay coil is energized an armature actuates the switch lever which opens a contact on the in- 56 SS ON terrupter assembly, thereby providing (ON RLI) r,u RLI E sa the power interruption needed to step the switch. ;17 Is The five inputs for this particular l'a 53 system : Position from PLI are 1- Output J dynamic noise suppressor (for 78 rpm S2 records) ; Position 2- Output from FM CHASSIS B tuner; Position 3 -Tape playba2k and monitor; Position 4- Output from pre - CHASSIS A SR2 -250 ma. selenium rectifier 8 volt pilot lamps amp- equalizer for LP records; and Po- -3 w., 120 CHASSIS D CHASSIS B R -700 ohm, 2 w. res. sition 5- Output from TV audio strip 52, 5,-S .p.s.t. push -button sw. C -.034 ofd., 400 v. cond. for recording. These inputs are fed 5,- Telephone dial (Automatic Electric No. RL, -Relay coil on rotary stepping sw. (Auto- ÁK14) (normally -open contacts) matic Electric No. 44) into Positions 1 through 5 on level A of PL, -3 w., 120 volt pilot lamp RL_- D.p.d.t. relay, 110 v. d.c. coil (Potter & the rotary switch. Positions 6 through CHASSIS C AND Cl Brumfield No KR11D) 10 are paralleled with 1 through 5 1 -22 ohm, 1 w. res. 5, -3 -pole, d.t. rotary sw. 1 -22 ohm, 2 w. res. S5-Interrupter sw. on RL, (author used part of when recording. Level C is used to 1 -800 ohm. 10 w. wirewound res. original s.p.d.t. sw.) power the relay for recording. Level 1 -40/40 µfd., 150 v. dual elec. cond. S0- "Off -normal' sw. on RL, (author used 1 -40 Aid., 150 v. elec. cond. part of original s.p.d.t. sw.) D is used to provide pilot light indi- SR, -75 ma. selenium rectifier J -Phono jack cation. Level B is used to "home" the relay. Fig. 1. Schematic of "'Dialaudio" system. Although author built Chassis C and Cl "Homing" is another word peculiar separately, it is possible to build both into a single unit. Jack J, goes to tape re- to telephone system engineers. By corder for recording, J, goes to disc reco_ der, and J, goes to the main amplifier. "homing" is meant the rapid return to normal position, i.e., when brushes are not resting on any of the contacts and therefore no signal is being fed into the amplifier. It will be noted that Top view of the main telephone dial panel showing the position of Chassis D. Level B is wired so that when switch S. is closed, the rotary switch drive magnet circuit is completed to ground through all the contacts on that level and through the interrupter springs. This provides the power interruption needed to step the switch. This feature is extremely useful when using the dial as it provides a definite starting point for the dialing, eliminating the necessity for counting how many steps to advance the step switch in order to stop on the desired position. By skip- ping a contact on Level B it is possible to have the brushes come to rest on a predetermined contact by merely press- ing the "homing" switch S. Although the contacts will carry 3 amperes when at rest, it is not advisable to exceed 11.5 watts while they are in motion. The system herein described was designed around a particular installation which was complicated by the fact that it was necessary to provide a means of automatically monitoring the tape while recording, a feature which made the use of an additional relay mandatory. Switch S, provides a means of 62 ß.1I111/ TELEVISION NEWS

www.americanradiohistory.com routing the signal to either the tape or disc recorder and giving an indication on the pilot panel. It also serves as routing switch for the monitor signal from the tape unit. Fig. 1 also shows the power supplies used for the entire system. It had been originally planned to use one supply for the step -switch, the record relay, and the pilot lights. However, as the step -switch draws approximately 180 ma. during operation, the voltage drop across the filter circuit resistor was too high to insure positive record relay operation. In addition to the filtering action of the 800 ohm resistor, it also serves to drop the voltage for the record relay and pilot lights to 125 volts. In the "record" position with two lights and the record relay actuated, the total current is 56 ma. Both supplies can, of course, be mounted on the same chassis but provision should be made for adequate ventilation. The chassis used to mount the dial Over -all view of part of the home sound also contains push- buttons S2 and Sa for author's reproduction system. The "Dialaudio" selector system may be seen in the lower single stepping and "homing." A meter right hand corner. case for a 2" meter just fills the bill as all the large holes are already punched. input is shorted. At the completion of For other types of mounting, the dial the return motion these contacts open, dimensions are given in Fig. 2. It is thereby removing the ground and per- not necessary to use the dial, as the mitting the program material to be fed relay may be single- stepped using just into the amplifier. an s.p.s.t. push- button switch. The dial A pilot light has been incorporated is a type AK14, also manufactured by on the dial chassis to show when the Automatic Electric. The number dialed step -switch is in the "home" position. indicates the number of steps the relay This feature is desirable when the dial brushes will move. For example, if chassis is used at a position remote the brushes are on contact 2 and it is from the pilot light panel. By making desired that they rest on contact 7, it the connection at point "X" a semi- is necessary to dial 5. permanent one, this pilot light can be The dial assembly proper has an ad- used to indicate any predetermined ditional s.p.d.t. switch. As supplied by setting of the step switch. the manufacturer this switch has two On the levels which contain the of the contacts tied together by a bridging brushes (Levels A and B) wi l metal link. In order to eliminate "key be found twelve contacts. Contact 11 clicks" when the dial is executing its is the one used to connect the level return motion, this link was removed (pole) to the external circuit. Con- and a shielded wire run from the am- tact 12 (not shown in Fig. 1) on Level plifier input to the center lug of the A is used to ground the amplifier input switch. Another wire is run from the when the step- switch is in the "home" normally open contact to ground. Now position. If this contact is not grounded when any number is dialed a cam the amplifier input will be open and closes the contacts and the amplifier (Continued on page 100) Fig. 2. Mechanical drawing of dial assembly.

Bottom view of the subassembly, designated as Chassis D. Over -all view of power supply chassis, C and Cl (Fig. 1).

August, 1952 63

www.americanradiohistory.com made variable to permit control of the timing interval. When a wide range of timing intervals is desired, several ndustria different values of condensers and a selector switch may be employed. Fig. 2 shows a circuit diagram of a time delay circuit in which the discharge time of a condenser is utilized. When the switch is closed, the condenser is charged to the potential of the battery. This charge makes the By grid of the tube negative, so that no plate current flows and the relay is l;n ItIFKST1:1\ open. The timing interval is initiated Vocational Institute by opening the switch. Under these Northwestern conditions, the condenser begins to discharge through the resistor connected to across it. As the condenser discharges, Process and sequence timers hare helped IBIroi'P the potential on the grid becomes less the quality of a 1aril'ly of manufactured products. and less negative. After an interval of time, this negative potential has de- creased to the point at which the tube THE success of innumerable man - conducts current and the relay closes. ufacturing and processing oper- The duration of the timing interval is ations depends, to a large extent, dependent upon the values of C and R. on accuracy of timing. In welding, The circuits of Figs. 1 and 2 both electronic heat treating, x -ray expo- require a d.c. source of power. In the sure, etc., the quality of results is di- interest of simplicity and compactness, rectly related to precise control of the SI a timing circuit which will operate di- time during which the product is sub- rectly from the a.c. power lines is de- jected to the influence of the machine. sirable. A circuit which fulfills this Many mechanical timing devices in- requirement is shown in Fig. 3. When volving motor -driven gears and cams the switch is open and the upper power have been evolved and used, but none line is negative, electrons flow in the with the same degree of success as circuit as shown by the arrows. Here, electronic timers. Mechanical timers the grid- cathode circuit of the tube is exhibit many shortcomings. They are acting as a diode, and the resultant slow and inaccurate, Fig. 2. A time delay circuit which utilizes charges condenser. comparatively the discharge time of a condenser. As the current the and since they employ many moving condenser discharges through R, the grid To initiate the time delay, the parts; vibration, wear, and breakdown becomes less and less negative, the plate switch is closed. The tube is now cut are common. In timing devices, as in current increases, and the relay closes. off because the charge of the condenser so many other types of apparatus, elec- makes its grid negative. However, as tronics stands out as the superior voltage divider across the d.c. supply. the condenser discharges through the method. That portion of the voltage which ap- resistor connected across it, the grid Most electronic timers operate by pears across R3 is applied as bias to the becomes less negative. After an in- virtue of the fact that when a voltage cathode of the tube. This bias is suf- terval of time determined by the val- is applied to a resistor and a con- ficient to produce cut -off, so that no ues of R and C, the negative potential denser in series, a finite and calculable plate current flows and the relay is on the grid has diminished to the point open. The timing interval is initiated at which the tube conducts and the by opening switch 1. At this time, C, relay closes. begins to charge through R2 from the To prevent the relay from opening d.c. supply. The positive terminal of during the alternations when the plate the supply attracts electrons from the of the tube is negative, a condenser is upper plate of the condenser. At the connected across its winding. This same time, the negative terminal of condenser charges when the tube con- the supply repels electrons to the lower ducts and discharges through the relay plate of the condenser. Since the (Continued on page 139) upper plate of the condenser loses electrons, it, and the grid of the tube Fig. 3. A time delay circuit designed to which is connected to it, become in- operate directly from the a.c. power line. creasingly positive. After an interval The grid-cathode circuit acts as a diode of time, the positive potential on the to charge the condenser. When switch is sufficient to overcome closed. the condenser discharges, the grid grid becomes relay closes. the cut -off bias on the cathode. At becomes less negative, and this time, the tube conducts plate cur- Fig. 1. Basic type of time delay circuit. closes. As the condenser charges, it drives the rent and the relay grid of the tube increasingly positive The timing interval is therefore the until the relay in the circuit closes. length of time which elapses between opening of the switch and closing of time elapses before the condenser be- the relay. The duration of this in- comes fully charged. In some of its terval depends upon the values of C, variations, the electronic timer in- and R. A larger condenser will re- A. C. volves an initially charged condenser quire more time to charge, and a which is subsequently discharged in larger resistor will slow down the the required length of time. charging rate. Consequently, increasing the value of either C, or R1 will Time Delay Circuits increase the timing interval. Con- A basic type of time delay circuit is versely, decreasing C, or R, will result shown in Fig. 1. R2 and R3 form a in a shorter time delay. R, is usually 64 RADIO Ai TELEVISION NEWS

www.americanradiohistory.com SHORT -WAVE

7000-11140,001--%\ Compiled by KENNETH It. 1111111111 r101W IN THE first DX Contest of the QRM from VOA, Tangier. (Engberg, British Somaliland- VQ6MI, Radio United 49'ers Radio Society, top Sweden) Is heard in Eastern USA. Somali, 7.125, Hargeisa, 1 kw., is on the winners included Gary Rinton, Le- Bolivia -CP38, 9.497A, La Paz, opens air 0815 -1215, according to a letter Roy, New York, first with 1386 po'n's; 0555 with "Onward, Christian Sol- from station officials. ( Radio Sweden) Robert Green, Ridgetown, O n t a r i o, diers" and identifies in S p a n i s h. Bulgaria -Radio Sofia, 7.671, 6.070, Canada, 1287; James R. Pickering, (Stark, Texas) Radio Sweden lists noted with news 1500. (Engberg, Swe- Highstown, N. J., 1024. (Boice, Conn.) schedule for this one as Sundays 0655- den) Also with news 1600. (Pearce, s s * 0815. 1100 -2100, weekdays 0555 -0730, England) Heard on 7.671 at 2340 in This Month's Schedules 0930 -1245. 1755 -2115 (closing time is Bulgarian. (Cox, Dela.) Albania Tirana, 6.560 and only approximate). Canary Islands- Tenerife, 7.515, -Radio 1600. 7.850, has programs in French 1345- Brazil -PRL5, 11.950, Rio de Ja- noted at fair level from (Eng- 1400 and in English 1615 -1630. (Radio neiro, noted Saturdays around 1630- berg, Sweden) Sweden) Heard by Pearce. England. 1700 with English "literary" program, Cape Verde Island -Praia is noted Algeria Algerie now then continuing in Portuguese. (Kary, on 7.110A signing off 1700 in Portu- -Radio op- by erates on 7.280 instead of 6.145. (ISWC, Pa.) Heard in Sweden at 1500 in Portu- guese. (Engberg, Sweden) Heard London) guese and English. (Engberg) Ferguson, N. C., from 1630 tune -in. Anglo- Egyptian Sudan -Radio Om- PSF, 14.687, is noted transmitting Leaves air with "A Portuguesa." durman noted 1225 with news in Ara- prior to scheduled 1730 sign -on; an- Ceylon -Radio Ceylon, 15.120, noted Y.) Re- bic on 9.737, 7.385A. (Pearce, England) nounces "Agencia Nacional;" at 1730 opening 2045. (Bellington, N. Angola- CR6RB, 9.165, Benguela, has news in Portuguese which is relays BBC news 2100. has weak level in Sweden 1330 -1400; layed by all Brazilian commercial sta- Chile- CE1515, 15.150, noted recent- often has nice musical session. (Eng- tions. (Kary, Pa.) Radio Sweden says ly ending dance music with English an- berg) Noted closing 1400 weekdays PRS4, Radio Cultura da Sao Paulo, has nouncements 1825; continued in Span- with "A Portuguesa" but runs to been heard on 2.470 at 1930 -2030. ish. (Niblack, Ind.) Has nice signal after 1430 Sundays. (Pearce, England) Radio Inconfidencia, Belo Horizonte, evenings to 2330 closedown. 11.862, in Newfoundland is now using approximately 15.190; China -WRH lists summer schedule Luanda, noted Service as around 1430-1530. (Peddle) Closes weak signal in Sweden from 1500. for Radio Peking's Overseas 1730. (Engberg) "Brazil Calling" (English) 6.100, 1530 -1630, 0330 -0500, 0800 -0830; Officials of Radio Diamang, CR6RG, now appears to be aired (at least 9.040, 0400 -0430, 0800 -0830; 10.260, Dundo, recently reported of recep- weekdays) on 11.825 around 1935 -1955. 1530 -1600, 0330 -0500, 0800 -0830; 11.690, that 0730- tion reports received, about 40 per -cent and on 9.565 around 2005 -2025. 1530 -1600, 1730- 2100, 0400 -0700, 1730 0400- have been from Sweden; about 20 per- British Guiana -ZFY, 5.980A, 1030; 15,060, 1530 -1600, -2100, 0800 -0830; cent from Britain, and about 10 per- Georgetown, noted at good l e v e l 1030; 15.170, 0330 -0430, cent from Australia. (Radio Australia) around 2100. (Cox, Dela.) 7.500, 0330 -0400. 0800 -0830; English at 1730 -1800 on 11.69. 15.06; 0400 -0430 on Radio Clube de Huila, Sa da Band - 6.100. 9.040, 10.260. 11.690. 15.060, eira 10.050, noted closing 1530; bad (Note: Unless otherwise indicated. all time is expressed in American EST: add 5 hours for 15.170; 0830 -0900 on 11.690, 15.060. CWQRM. ( Pearce, England) G('T. "News" refers to newscasts in the English Peking fairly good Argentina-LRU, 15.29, noted with language. In order to avoid confusion. the .I4 Dilg. Calif., notes English 2300 -0100 sign -off. (Bishop, hour clock has been used in designating the times late mornings (EST) on 10.200 (this of broadcasts. The hours from midnight until 10.260, 11.690, Ohio) By this time the English session noon are shown as 0000 to 1200 while from 1 one is not announced), p.m to midnight are shown as 1300 to 2400.1 9.03A also has a 1730-2030 probably will be on 9.69 in- The symbol "V" following a listed frequency 15.060V; the channel of 17.720. indicates ..varying." The station may operate fairly good signal at times. stead either above or below the frequency given. "4" 108) Radio Splendid, 9.315A, noted at means frequency is approximate. (Continued on page strong level 2245 with Latin American Programs of the Danish State Radio originate in Radio House in Copenhagen. This music. (Niblack, Ind.) and foreign programs. Australia -Radio Australia now has modem building provides excellent facilities for both domestic a session for Central Europe 1300 -1500 on 11.760, 9.580. Austria -BDN, 9.617, S a 1 z b u r noted 0455. (Pearce, England) Azores- CSA92, 11.090, Ponta Del- gada, still noted in Portuguese 1400- 1500. (Kary, Pa.) Belgian Congo -OTC2. 9.767, now lists QRA as Belgian National Broad- casting Service, P.O. Box 505, Leopold- ville. Belgian Congo; sent fine QSL card. (Harris, Ind.) Recently announced over the air that the station will be moved soon to Brussels, Bel- gium. Radio Congo Belge, Leopoldville, now uses 11.720 around 1400 -1600; has August. 1952 63

www.americanradiohistory.com Convert Your Signal Generator into AtA t Grid -dip Oscillator

HARTLAND II. SMITH, R aN 'I D Fig. 1. Three units must be added to the panel of your signal generator if it is to be used as a grid -dip oscillator. Jack J. labeled "Probe," is in the upper left -hand corner. S. the circuit being checked. One satisfac- link switch, is just below and to the right of L. J, or J tory way of accomplishing this is to depending on the type of indicator used, mounts on the right use link coupling. side of the panel above and to the left of the pilot light. A probe coil, as shown in the photograph of Fig. 3, is energized by r.f. fed to it through J, in Fig. 2, from Add a useful piece of equipment to your test bench links wound around the cold ends of the SG -6's coils. Before winding the at small cost and a nominal expenditure of time. links, be sure to apply a layer of Scotch electrical tape or some other suitable insulation to the coil forms to reduce WITHIN recent years a great the process can also be applied to ear- the possibility of short circuits. Then many hams and service tech- lier models of the same make or to wind on the prescribed number of turns nicians have learned what a similar generators produced by other and apply enough coil dope or cement useful piece of equipment a grid -dip manufacturers. to hold the links in place. oscillator can be. Unfortunately, most Most grid -dip oscillators use coils The proper link is selected by switch of the oscillators which have been de- which plug into a socket on the out- Si and connected to output jack J,. The scribed in radio magazines or sold in side of the case. This arrangement regular output cable test lead plugs kit form cover only the high frequen- makes it relatively easy to couple the into J, and carries r.f. from the oscilla- cy ham bands and TV channels. Thus, oscillator to a circuit under test. Since tor to the probe coil. In most cases if one is interested in checking i.f. coils the coils of the SG -6 are mounted in- the probe shown in Fig. 3 can be em- and other low frequency components, side the case, some additional means ployed. However, the alligator clips he has to build a special unit, just for must be provided for transferring r.f. on the signal generator's test lead this purpose. from the oscillator to the resonant cable make it a simple matter to Despite the circuit simplicity of a change to a coil of different size or grid -dip oscillator, construction and Fig. 2. Circuit showing how links are cou- shape for use in hard -to -reach spots. calibration is a rather time -consuming pled to J, by means of the rotary switch. S,. There are two types of indicator task. Because of this, a lot of radio- which may be employed with the con- men keep putting off the project, verted signal generator. A vacuum - thereby depriving themselves of a very CI tube voltmeter can be used to meas- worthwhile instrument. Many of these ure grid bias as shown in Fig. 4A, or fellows, unknown to themselves, al- the grid current may be measured by ready possess a device which, with the SI inserting a meter in series with the addition of three or four inexpensive grid leak to ground as in Fig. 4B. parts, can be easily converted into a Between 160 kc. and 20 mc., the grid calibrated, bandswitching grid -dip os- bias averages 5 volts and the grid cur- cillator capable of tuning from 160 kc. rent is in the neighborhood of 200 to 50 mc. The basic unit is an r.f. sig- microamperes. From 20 mc. to 50 mc. bias is about 114 volts and the grid nal generator, several inexpensive ver- C, -250 µµtd. mica cond. (see text) the sions of which are now on the market. J, -Open circuit jack current 50 microamperes. The bias is S, -S.p. 5-pos. rotary sw. sufficient to provide plenty of defíec- One of these instruments can be LA-16 t. #28 en. wire. (Link on coil A -160- changed into a grid -dip oscillator in 500 kc.) tton on the low voltage range of a Ls -10 t. #28 en. wire. (Link on coil B -500- vacuum -tube voltmeter. If you own jig time. What is more, the conversion 1600 kc.) has little or no effect on the genera- Le -7 t. #28 en. wire. (Link on coil C -1.6. one of these instruments, I would sug- perform its primary job 5.5 mc.) gest that you use it for an indicator. tor's ability to Ln -5 t. #28 en. wire. (Link on coil D-5.5- of receiver alignment. Although the 18 mc.) Nevertheless, measuring the grid cur- LE--1 t. #20 hookup wire. (Link on coil E- rent will prove quite satisfactory if a changes to be described were made in 18-50 mc.) a Heath Model SG -6 signal generator, 0 -500 microammeter is employed. A 66 RADIO .1i TELEVISION NEWS

www.americanradiohistory.com 0 -1 milliammeter can be used in a pinch, but because of low grid current it will be rather difficult to read when the unit is operated between 20 mc. and 50 mc. There are those who may wonder about the advisability of adding links to the SG -6 because of the effect which they may have on the inductance of the coils in the signal generator. Ac- tually, there is only a slight shift in inductance and what frequency change does take place can be fairly well corn - pensated by readjustment of the calibrating trimmer in parallel with the main tuning condenser. On the author's particular signal generator, with the links in place, the average accuracy of the dial readings is within .75%. The highest error Fig. 3. Over -all view of probe coil. The unit consists of 6 turns of No. 14 enamel is only about 2.2%, while many points wire, 13/s" in diameter. After the turns are cemented together, the coil is ce- are within .5% or better. These checks mented to the end of a wooden handle. The leads are fastened to soldering lugs were made with switch S, set on band mounted on the handle by means of 6 -32 machine screws. Alligator clips on signal "A" (160 kc. - 500 kc.), and with the generator's output test lead attach to the lugs and energize the coil with r.f. test lead plugged into the regular r.f. output jack. For greatest accuracy, R.F. OSCILLATOR R F OSCILLATOR S, should always be left in position 6C4 ,- 6C4 "A" when the SG -6 is operated as a 150 150 signal generator. Accuracy of the instrument when used as a grid -dip oscillator will depend upon how tightly 27 360 the probe coil is coupled to the circuit 360 J3 being tested. The least amount of coupling will produce the most nearly correct dial reading. .11MIP When a grid -dip oscillator is constructed, a portion of the circuit some- (A) (B) times resonates at one particular fre- R1 -2.2 megohm, 1/4 w. res. quency and whenever the oscillator is l.. -Tip jack ro ft v.t.v.m. d.c. prod tuned past this frequency, a pro- 1:,- Closed circuit jack nounced dip in grid current occurs. Fig. The unwanted dip can prove quite an- 4. Wiring changes for two versions of the grid -dip oscillator. (A) Circuit for use in conjunction with a v.t.v.m. The d.c. prod of the voltmeter should be noying if it happens to fall in a range plugged into L and the meter's ground lead clipped to the signal generator's metal where you expect to do very much test- handle. (B) Added parts and wiring are shown in heavy lines, deletions are ing. The only resonance of this nature dotted. If a microammeter indicator is employed, it is plugged into J. of the circuit. which showed up in the SG -6 landed right smack in the middle of the 10 used in place of a v.t.v.m., it should be dip. If no dip can be found on one meter band. The distributed capacity plugged into 4. Couple the probe coil band, change to another, making cer- of the test lead was tuning the link on closely to any resonant circuit you wish tain that both S, and the bandswitch the 20 mc. to 50 mc. coil. The purpose to test and tune the signal generator are always on the same frequency of condenser C,, placed in series with until the indicator shows a pronounced range. LE, is to raise the unwanted resonance to around 40 mc., a test frequency Fig. 5. A layer of "Scotch" electrical tape is put over the ground ends of the which is not often used. The lower the oscillator coils before the links are wound, thus preventing shorts between units. capacity of C,, the higher will be the frequency of the spurious dip. C, cannot be made too small, though, or it will reduce the sensitivity of the oscillator on the 20 -50 mc. range. 250 µpfd. appears to be the most practical value. The panel of the SG -6 is so filled with controls that there is little room for mounting the required jacks and switch. While the placement of these items might not please an esthete, I am convinced that the advantage of having a grid dip oscillator on hand far outweighs the slight panel un- balance resulting from the necessary additions. After the conversion has been completed, plug the test lead into link jack, J,, and attach the alligator clips to the probe coil. Clip the ground lead from the vacuum -tube voltmeter to the metal handle on the case of the SG -6 and plug the d.c. prod into J2. If a microammeter dip indicator is to be August, 1932 67

www.americanradiohistory.com or the capacitance of the circuit under test is known the value of the other component may be calculated by means of the following formulas. If C is known : L = 25,330/CF2 or if L is known : C = 25,330/LF2 where L is the inductance in microhenrys, C is the capacitance in micromicrofarads, and F' is the frequency at which dip occurs. If mathematical computations are as distasteful to you as they are to me, you can obtain painless solutions to these formulas by using either a "Shure Reactance Slide Rule" or an "Allied Rapid R.F. Resonance and Coil Wind- ing Calculator." In conclusion, it would be well to again point out that this circuit can be added to almost any signal generator and is not confined to the Heath unit alone. The author happened to have the Heath Model SG -6 on his test bench so the circuit was worked out using the Heath circuit and panel layout as the model. For your particular signal generator, a few alterations will be required. Fig. 6. Converted signal generator. Output test lead is plugged into J, and its The slight investment in time and alligator clips are attached to probe coil. The d.c. probe of v.t.v.m., used as a parts required for the conversion will dip indicator, is plugged into 12. Ground lead is clipped to handle of generator. begin to pay off the moment construction has been completed. Until there When resonance is finally encoun- mental range and for its third har- is an all -wave grid -dip oscillator avail- tered, move the probe coil away until monic. Since a grid -dip oscillator only able on your work bench you'll never the dip is barely perceptible. The dial functions on the fundamental, the top realize how much time can be saved reading of the signal generator will frequency of the SG -6 when used as a when ancient trial and error methods then closely approximate the resonant grid-dip oscillator is restricted to 50 of resonance checking are tossed into frequency of the circuit being tested. mc., even though the dial reads to 150 the wastebasket. Besides, the ability In most cases the accuracy of the dial mc. to check values of unmarked conden- will be adequate. However, if you de- The principal use of a grid -dip oscil- sers, i.f. coils, etc., is an added dividend sire a more exact check, tune in the lator is in finding the resonant fre- which must not be discounted. Con- signal from the oscillator on an ac- quencies of tuned circuits. In addition, vert your signal generator and I am curately- calibrated, all -wave receiver. if the value of either the inductance certain you'll be pleased with the re- The highest frequency band of the sults. Allied Radio Corp., 833 II'. Jackson Blvd.. SG -6 is calibrated for both its funda- Chicago. Ill. 39 -995 . 35c po.ctp,,id. -

Fig. 7. Schematic diagram of the Heath Model SG -6 signal generator. Points "A" and "B" correspond to Figs. 4A and 4B. The probe coils shown in Fig. 2 are air- coupled to the band coils shown on right -hand side of diagram as "Band A," "Band B," etc.

A.F. OSCILLATOR-AMPLIFIER R OSCILLATOR MODULATION SWITCH SHOWN IN EXT. POSITION A OUT ATTENUATOR SWITCH SHOWN IN "LO" POSITION BANDSWITCH SHOWN IN "E. BAND POSITION

A F IN

01 MODULATION FRONT 390K SWITCH DECK

47 ATTENUATOR SWITCH R.F. OUT o V n7V. ae.

68 u1.%DIO .1i TELEVISION NEWS

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www.americanradiohistory.com The Heathkit 0 -7 Oscilloscope with its 10 tube lineup (including CR tube) and carefully engineered circuit using highest quality components is truly the most outstanding scope value on the market today. The "spot shape" (astigmatism) control working in conjunction with the focus control assures clear, sharp focusing . extended sweep range and faster retrace time permits the study of high frequencies . . . step - attenuated frequency-compensated cathode follower vertical input contributes to the excellent frequency response of the vertical channel ....03V RMS per inch vertical sensitivity makes weak input signals easy to study . . . push -pull operation of both vertical and horizontal deflection plates reduces pattern distortion . specially designed extra -wide CR tube mounting bracket places vertical cascade amplifier, vertical phase splitter, and defle:- tion amplifiers near base reduce of CR tube to distributed wiring capacity New "spot shape" control for spot adjustment - to give and increase high frequency response. really sharp focusing. Ideal for TV servicing steep wavefronts encountered in TV work are - A total of ten tubes including CR tube and five miniatures. easily handled. Fine for production line testing rugged quality com- - Cascaded vertical amplifiers followed by phase splitter and ponents can stand up under continuous hour -after -hour use. Excellent for balanced push -pull deflection amplifiers. laboratories electrical performance comparable to scopes costing 4 and - Greatly reduced retrace time. 5 times as much. Step attenuated - frequency compensated - cathode fol- You'll like the complete instructions showing all details for easily build- lower vertical input. ing the kit - includes pictorials, step -by -step construction procedure, num- New mounting of phase splitter and deflection amplifier erous sketches, schematic, circuit description. All necessary components in- tubes near tube base. cluded transformer, cabinet, all tubes (including CR tube), completely CR - Increased frequency response - useful to 5 Mc. punched and formed chassis - nothing else to buy. Tremendous sensitivity .03V RMS per inch Vertical - .6V RMS per inch Horizontal.

MODEL eefttlZez" ELECTRONIC SWITCH KIT S -2 SHIPPING WT. The companion piece to a scope - Feed two different signals into the you can observe both signals 11 LBS. switch, connect its output to a scope, and - each as an individual trace. Gain of each input is easily set (gain A and gain B controls), the switching frequency is simple to adjust (coarse and fine .19;0 frequency controls), and the traces can be superimposed for comparison or separated for individual study (position contol). The kit is complete with tubes, switches, cabinet, power transformer and all other parts, plus a clear detailed construction manual. AUDIO FREQUENCY METER INTERMODULATION AF -1 '114. iical SHIPPING WT. instrument for 15 LBS. frequencies from determining KIT Set the 20 too ANALYZER selector switch to KC. feed the propertr f signal into the input testing of nals - and read the termi- Intetmodulation meter frequency from the - completely simple audio equipment d and yet dependable to operate, t y imorerapidly results. being audio Quality more engineers and meter Simpson 200 microampere way idetdeter- has two plainly as the best 0 -300). marked scales plifiers,characteristics conjunction These scales read mine sys- with the in audio ammp tor switch, seven position selec- etc. give full tems, networks, -1 100, 300, scale readings of Heathkit MODEL IM 1000, 3000, The i of 18 LBS. and 100,000 10,000, 30,000, suppliesInterchoice a SHIPPING WT. for cycles. Convenient Analyzer cox. fast and easy readings. ranges two high frequencies For greatest - accuracy, the a cycles (60 of ranges is maintained 1 -3 -10 ratio one low frequency has and each range and or 4:1 ratios 950 A signal voltage an individual calibrating cycles). Both 1:1 be into anywherean between control. frequencies can by means of a the instrument and 2 and 300V can of low to high ratios are easily set will not in signal be fed directly IM testing, and the An output affect the meter reading. voltage between these set up for with critical (the unit In addition, limits control and at the desiredI level will read the frequency inputput wave se lthe mixed siiignal section wave input), cy of either sine control supplies ohms.The Analyzer The tube wave or square of two thousand is feedingng complement consists haan oinput impedance and proper filer the amplifier and clipper, of a 6SJ7 amplifier input level control directly rectifier, 6116 meter pulse and clipper, 6V6 has to read power supply and OD3 /VR150 rectifier, 6X5 cale ranges and Woo. Built-in Construction voltage regulator. power supply neof 30°íy +volltages the instrument. is simple, and ranges for operating quality components all necessary are used throughout. furnishesfurni YOU SAVE BY ORDERING DIRECT FROM MANUFACTURER -USE ORDER BLANK ON LAST PAGE

Exr01I AGENT ROCKE INTERNATIONAL COP. li E. 40Th ST. 111W YORK CITY (16) ?tie H: EAWT H C O IV& PAgoV Y V. CAW : Ar{nN. .. BENTON HARBOR 15, MICHIGAN u RADIO .` TELEVISION NEWS

www.americanradiohistory.com MODEL VS-A SHIPPING WT. 7 LBS.

Designed to take up a minimum of space, yet designed to be the most important and useful instrument on your workbench. Really handsome looking -note the rounded edges on front panel and rear cover. New compact size has cabinet dimensions of only 41/8" deep x 411 4r" wide x 7 vt;" high. Tremendous coverage - will read from 1/2V to 1000V AC, 1/2V to 1000V DC, .1 to over 1 billion ohms res stance, and Db. Meter scale has zero -set mark for FM alignment - all ses les clearly marked for easy and fast readings and Db scale is in red for easy identification. Simple to operate. Ohms adjust and zero adjust ccntrcls located on front panel along with selector and range switches. Selector switch has four positions: AC, DC -, DC+ and Ohms to set up the instrument for type New styling, - formed case for beauty. of reading desired. DC- position allows negative voltages to be taken New truly compact size. Cabinet 41 /e" deep by 4- 71/16" without. reversing test prods. AC and DC voltage ranges are full scale 3V wide by 7 -3/8" high. - 10V - 30V - 100V - 300V - 1000V and resistance ranges are RX1, Quality 200 microamp meter. X10, X100, X1000, X10M, X1 Megohm. Convenient ranges for fast and New ohms battery holding clamp and spring clip - assur- accurate readings. ance of good electrical contact. Strictly highest quality components used throughout Highest quality precision resistors in multiplier circuit. - 1% precision resistors in multiplier circuit, 200 Calibrates on both AC and DC for maximum accuracy. Simpson microampere meter movement, sturdy cabinet, excellent positive detent smooth acting switches, etc. New Terrific coverage - reads from 1/2V to 1000V AC, 1/2V to 1000V DC, and .1 to over I billion ohms resistance. miniature tube used in meter balancing circuit and new battery holding Large, clearly marked meter scales indicate ohms, AC clamp and spring clip assure good contact to ohms string of resistors. Volts, DC Volts, and DB - has zero set mark for FM Kit comes complete - and the instruction manual with its step -by -step alignment. instructions, pictorials, figures, and schematic makes assembly a pleasure.

V DC ff'CC{tGLKG¿`' CRrlc',Lr 30,000 P R O B E K I T R F PROBE KIT For taking readings up to 30,000 V DC when Extends range of Heathkit VTVM to used with the Heathkit VTVM ( or any stand- 250 MC i- 10 %. Designed for taking ard 11 megohm VTVM). Comes with two RF measurements. All parts furnished color molded plastic probe body and all parts. including probe housing and crystal Shipping Wt. 2 lbs. diode detector. Shipping $550 Weight 1 lb. $550

SQUARE WAVE vóLr`A. C. VACUUM ''eaeáe VOLTMETER TUBE: GENERATOR KIT Now as a Square Wave can afford,- Heathkit at KIT The Heathkit an - a price excellent those AC VTVM. anyone Generator is an sensitive AC Makes frequency source enthusiasts, measurements Psíby square wave required by features you mentors. The and with won't nota-t ingmg kit laboratories, to be without. Especially for. Ten rangeskit men have been wide range of the consisting look- ble is the 100 .or IgeS of full scale cycles to RMS assure , 3,' 10, 30, 100, instrument -10 easy and 300 volts continuously variable. Ten ranges more accurate kilocycles it use- Ternfrom ges on DB provide readings. wide range makes to for, measurements This wide band +52 DB. ful for television and I DB from Frequency well as audio MODEL SQ -1 The 20 cycles responseres amplifier work as ingenious to 50 KC. The output im- 14 LBS. multiplied circuitry incorporates experimentation. SHIP. WT. resistors pre is low, and the output amplifier stages for accuracy, - pedance variable using two voltage is continuously bridge miniature tubes, volts. Because 50 Simpson rectifier meter between 0 and 20 41 i meter with 200 circuit, quality stage cann See and microampere a multivibrator terminals external wiring. move - calibrated, to an A high of parts accurately can be used for synchronization degreelayout for easy MODEL 7 panel provides for g of inverse AV on the front a stability feedback SHIP. it be desired. a clipping and Extremelyfl and linearity. WT 5 source should seep Y tom LBS. gu ge, iaatscathode stage. pTThe power x 4- 11 -16" pact, cabinet size The follow rtoe output designed / wake stage,ann, and a full wave rectifier cabinet x h s/th high,high. squaring and utilizes Piece makes Newlyanion is transformer operatedope to the VTVM the 5 0 supply LC filtering. companion withw 2 sections of priced square wave generator, tube range, a good, wide For be beat. SQ -1 just can't - the YOU SAVE BY ORDERING DIRECT FROM MANUFACTURE -USE ORDER BLANK ON LAST PAGE

EXPORI. AGENT

ROUE INTERNATIONAL CORP. 11 E. anti, ST. NEW YORK CITY (16) . rr r R ) u . . BENTON HARBOR 15, MICHIGAN ,a11111

August, 1952 71

www.americanradiohistory.com Model SG-6 Shipping Wt. 7 lbs.

The new Heathkit Signal Generator Kit has dozens of improvements. Covers the extended range of 160 Kc to 50 megacycles on fundamentals and up to 150 megacycles on useful calibrated harmonics; makes this Heathkit ideal as a marker oscillator for TV. Output level can be conveniently set by means of both step attenuator and continuously variable output controls. Instrument has new miniature 1-IF tubes to easily handle the high frequencies covered. Uses 6C4 master oscillator and 6C4 sine wave audio oscillator. The kit is transformer operated and a husky selenium rectifier is used in the power supply. All coils are precision wound and checked for calibration making only one adjustment necessary for all bands. New sine wave audio oscillator provides internal modulation and is also available for external audio testing. Switch provided allows the oscillator to be modulated by an external audio oscillator for fidelity testing of receivers. Comes complete, all tubes, cabinet, test leads, every part. The instruction manual has step -by -step instructions and pictorials. Its easy and fun to build a Heathkit Model SG -6 Signal Generator.

NEW S GN t.¢t ANO UNIVERSA R q C E KIT TEST A / CHECKER SPEAKER K17 CONDENSER ., ó0.4 $1950 -:.,,

Model T s1950 shlpp,ng -2 Wt . 7 lbs. popular Tracer Model C -2 r Heathkit Signal lbs. bined now been Shipping Wt. 6 with universal com- at no increase test types of condensers The same i Checks all ceramic high quality patte' mica follows Y tenter - paper - - signal from All co to speaker m antenna - electrolytic. and ser -saves - intermittents are direct reading valuable tes scales multipliers. service - finds defective quire no charts leakage s Works time _ multi MFD can read. The- test equally well on gives greater income Covers range that read. Measures speaker per service Molar Condenser Vspan either push-pull an assortment or to ltage for 20 50% ed. Measarees phones,st orssingle fcswitching TV and porto 0% and indicator pickupsuscku output cm test electrols magic eye ph and PA systems. impedances. tch factor of 5 megohms. The nest Comes Also tests é00 ohms to 5 60 detailed complete:mplete: micro- listante from and comes corn- instructions tubes, test cabinet, IlOV testingkiti operatedope rn- ttions for assembly probe, all necessar makes cyclecY transformer panel Y and Y kit is 110V be tube, cabinet, calibrated and use. Parts, The tube, is eye for assembly allot herharts. clear detailed instructions other parts. lias

e u TUBE CHECKERt KIT The Tube Checker is a MUST for radio repair men. Often customers want to SEE tubes checked, and a checker like this builds customer confidence. In your repairing, you will have a multitude of tubes to check - quickly. The Heathkit tube checker will serve all these functions - it's good looking (with a polished birch cabinet and an attractive two color panel) - checks 4, 5, 6, 7 prong Octals, Loctals, 7 prong miniatures, 9 prong miniatures, pilot lights, and the Hytron 5 prong types. AND ITS FAST TO OPERATE - the gear driven, free - running roll chart lists hundreds of tubes, and the smooth. acting, simplified switching arrangement gives really rapid set -ups. The testing arrangement is designed so that you will be able to test new tubes of the future - without even waiting for factory data - protection against obsolescence. You can give tubes a thorough testing - checks for opens, shorts, each element individually, emission, and for filament continuity. A large BAD -? -GOOD meter scale is in three colors for easy reading and also has a "line -set" mark. Model -1 TC You'll find this tube checker kit a good investment and it's only $29.50. Shipping Wt. 12 lbs. $2959 -

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a10ff .GENf ROCKE INTERNATIONAL CORI. 13 E. 4011, ST. NEW YORK CITY 1161 °?tie HEATH C COIN PAIVY CE11 E1.E -N r ... BENTON HARBOR 15, MICHIGAN 72 RADIO R TELEVISION NEWS

www.americanradiohistory.com NEW 195 2 Vteeaeltkir

Can be used as battery charger. Continuously variable output 0 - 8 Volts - not switch type. Heavy duty Mallory 17 disk type magnesium copper sulfide rectifier. Automatic overload relay for maximum protection. Self- rnsett ng type. Ideal for battery, aircraft and marine radios. Dual Volt and Ammeters read both voltage and amperage continually - no switching.

The new Heathkit Model BE 1 incorpDrates the best. Continuously variable output control is of the variable transformer type with smooth wiper type ccntacts. There are no switches or steps and voltage between 0 and 8 Volts is available at 10 Amperes continuous and 15 Amperes intermittent. Maximum safety from overloads and shorts provided by automatic overload relay which resets itself when overload is removed. The new rectifier is a 17 plate Mallory magnesium copper sulfide type. This is the roost rugged type available for long trouble -free use. Output is continuously metered by both a 0 - 10 Volt Voltmeter and a 0 - 15 Amp Ammeter. Shorted vibrators indicated instantly by ammeter. Equip now for all types of service - aircraf: - marine - auto and battery radios - this inexpensive instrument vastly increases service possibilities - better be ready when Model BE -3 the customer walks in. Shipping Wt. 17 lbs. THE NEW Ceitade NEW SQUARE WAVE HANDITESTER SINE AND K I T $TER A precision portable KIT GENERATOR ohm milliam AUDIO high quali meter. Uses only usefulness. L..n. /r IrtYparts- with versatility. the AG -7 vision Allpre- Designed . resistors, in mind, wave deck three and deldependability two most needed switch for Fives you the the mounting trouble-free shapes square wave: designed of parts,ris, specially' avegand the cali- battery switch and bracket, range give l rapid smooth frequency cting bratedeayed selection, and adjust ohm easy frequency toutputpto control, permits setting molded beautiful control bakelite case, any desired level; switch sets micro -amp 400 -low impe.dance meter A high for either high etc. movement, the instrument h igh or cow output and on DC and impedance impedancedance load, AC voltage ' nett high a impedance Model AG -7 8e ranges to work into DC re- lbs. Ohms 1300 - 5000V. low with negligible Shipping Wt. 15 range00 0- ! I 300,000. - 3000 and sistance. 20 to 20,000 $e 0 is from Peres 0 - Milliam- Coverage x345 lÓ Ma,an$e cycles, and distortionruststhe output wave Easil 0 _ You can really Y assembled $ SO con- plete instructions from tom shape. 4 gang tuning circuit, and all Six tubes, qquality metal surd - determining tre- torial diaerame and pic_ power transformer, plus,nat frequency manualma t, A denser, ; precisionkite- construction condenser,, l' complete hirer eland low. .Mer Parcs the price is true' mendousmcndous ket. N E W Tea afar T.V. ALIGNMENT GENERATOR KIT Here is an excellent TV Alignment Cae:._:.etur designcdro do TV service work quickie easily, and properly. The Model TS -2 when used in conjunction with an oscilloscope provides a means of correctly aligning television receivers. The instrument provides a frequency modulated signal covering, in two bands, the range of 10 to 90 Mc. and 150 to 230 Mc.- ALL ALLOCATED TV CHANNELS AS WELL AS IF FREQUENCIES ARE COVERED. An absorption type frequency marker covers from 20 to 75 Mc. in two ranges- there- fore, you have a simple, convenient means of frequency checking of IF's, independent of oscillator calibration. Sweep width is controlled from the front panel and covers a sweep deviation of 0-12 Mc. sweep you could possibly need want. -all the or Model TS -2 And still other excellent feature. are: Horizontal sweep voltage available at the front panel (and controlled with a phasing control -both step and continuously variable attenu- Shipping Wt. 20 lbs. orlon for setting the output signal to the desired level -a convenient Instrument stand -by position- vernier drive of both oscillator and marker tuning condensers -and blanking tor establishing a single trace with base reference revel. Make your murk easier. save rime. and repair with confidence -order your Heathkit TV Alignment Generator now!

YOU SAVE BY ORDERING DIRECT FROM MANUFACTURER -USE ORDER BLANK ON LAST PAGE

ROM INIINNAIIONAl (Ort Ir F. 40,5 SI NAW YORK CITY . . BENTON HARBOR 15, MICHIGAN Vintia.1. 1452 73

www.americanradiohistory.com This Impedance Bridge Kit is really a favorite with schools, industrial laboratories, and serious experimenters. An invaluable instrument for those doing electrical measurements work. Reads resistance from .01 Ohms to 10 meg., capacitance from .00001 to 100 MFD, inductance from 10 microhenries to 100 henries, dis- sipation factor from .002 to 1, and storage factor from 1 to 1000. And you don't have to worry about selecting the proper bridge circuit for the various measurements - the instrument automatically makes the correct circuit when you set up for taking the measurement you want. Bridge utilizes Wheatstone, Hay, Maxwell. and capacitance comparison circuits for the wide range and types of measurements possible. And it's self powered - has internal battery and 1000 cycle hummer. No external generator required - has provisions for external generator if measurements at other than 1000 cycles are desired. Kit utilizes only highest quality parts, General Radio main calibrated control. Mallory ceramic switches. excellent 200 microamp zero center gal- vanometer, laboratory type binding posts with standard 3/ inch centers, 1% precision ceramic-body type multiplier resistors, beautiful birch cabinet and ready calibrated panel. (Headphones not Model 1 B -1 B $695° Shipping Wt. 15 lbs. included.) Take the guesswork out of electrical measurements - order your Heathkit Impedance Bridge kit today - you'll like it.

feea t LABORATORY featlZ` LABORATORY KIT RESISTANCE DECADE POWER SUPPLY KIT S piece 4 ee4. An indispensable No load..... - Variable laboratory equipment 25 150 -400V of MA Variable DC Resis- 50 30 -310V - the Heathkit MA . DC Decade Kit gives Higher loads: 25-250 tance Voltage drops off proportionally resistance settings Every you experimenter needs ohms ply for electronic a good power sup- from 1 to 99,999 unit setups of all STEPS. has been expressly kinds. This ONE OHM HV supply designed to, act IN and a 6.3 V as a accurac. . source. Voltage filament voltage For greatest HV output control allows selection ceramic - desired (continuously of Isle precision within limits outlined), variable resistors and switch provides and a Volts -Ma body type A large choice of output ceramic plainnly marked metering. highest quality meter scale indicates and directct reeadding are used. put in Volts either DC voltage $Z95O Wt 4 lbs. wafer switches or DC current out- Shi ing Range of meter output in Ma. Bridge above, D.C.), 0 -500V D.C 0 -200 Model the Impedance Instrument has convenient Ma. PS -1 Ship. Wt. to match cabi- Comes stand-by 20 lbs. Designed a beautiful with Y Dosition and pilot Decade Kit has two power transformer, filament light the Resistance uild, and comes tubes, completely transformer, panel. It's constructionnt punched and o rectifier, net and attractive manual. lf formed chassis, s ande construction Parts to make the bines. complete with all p kit complete.p lTexQGC ECONOMY . . . 6 WATT HIGH FIDELITY 20 WATT AMPLIFIER KIT AMPLIFIER Choice of 4 -8 -15 ohm output impedances. KIT Response flat ± 11/2 db from 20- 20,000 cycles. 6 watts output. The A8 (or A -8A) is a high quality Good fidelity at low cost. amplifier for those who want high Output tubes working in push pull. fidelity output at moderate cost. Fre- Volume, bass, and treble controls. quency response within ± 1db from Two separate inputs. 20- 20,000 cycles. Distortion at 3db below maximum power output (at The purpose of this kit is to provide 1,000 cycles) is only .8%. Kit has a to the kit builder a low cost ampli - Chicago power transformer in drawn MODEL A -8 MODEL A -7 fier with excellent fidelity. The steel case and a Peerless output trans- Shipping Wt. 18 lbs. Shipping Wt. 8 lbs. circuit consists of four tubes with former with output impedances of following functions: a 12SL7, one 4 -8 -16 ohms. Bass and treble con- section working as an amplifier and trols permit listener to select outpu t $145ó one as a phase splitter, two 12A6 with tonal qualities of his own liking. output tubes working in push pull, The tube lineup is composed of a $3350 and a 5Y3 rectifier in a full wave rectifier circuit. 6SJ7 voltage amplifier, a 6SN7 ampli- The unit operates from a husky power transformer, and has good fier and phase splitter, two 6L6's in output transformer with a choice of 4 -8 -15 ohm output impedances. push -pull output and a 5U4G rectifier. All parts furnished (speaker not in- (Speaker not included). cluded) and the construction manual makes assembly easy. The kit provides excellent listening pleasure and the price is really MODEL A -8: For tuner and crystal phono inputs. Has two position selector low. Compare it with all others. You won't find a Netter buy. swit It for convenient switching to type of input desired. MODEL A -7: For tuner and crystal phono inputs. Has two position MODEL A -8A: Features an added 68.17 stage (preamplifier) for operating from selector switch for convenient switching to type of input desired. variable reluctance cartridge phono pickup, mike input, and either tuner or Model A -7 -A: Has a 12SH7 preamplifier stage with special compensa- standard crystal phono pickup. A three position selector switch tion network for operation with reluctance phono input. provides flexible switching. Shipping Wt. 18 lbs. Shipping WI. 8lbs $16.50 $35.50 YOU SAVE BY ORDERING DIRECT FROM MANUFACTURER -USE ORDER BLANK ON LAST PAGE

AGO, ROCKE INTERNATIONAL CORP. I, E. 450, sr. E NEW YORK CITY 116)

711 RADIO & TELEVISION NEWS

www.americanradiohistory.com Model BR -1 Broadcast Model Kit covers 550 Model AR -1 3 Band Receiver Kit covers to 1600 Kc. Shipping 550 Kc. to over 20 Mc. con- Wt. 10 lbs. tinuous. Extremely high sensitivity. Shipping Wt. 10 lbs.

TWO HIGH QUALITY r=eatit.-4Cr

S U P E R H E T E R O D Y N E R E C E I V E R K I T S Two excellent Heathkits. Ideal for schools, replacement of worn out receivers, amateur and custom installations. Both are transformer operated quality units. The best of materials used throughout - six inch calibrated slide rule dial - quality power output transformers - dual iron core shielded. I.F. coils - metal cased filter condenser. The chassis has phono input jacks, 110 Volt output for phono motor and there is a phono -radio switch on panel. A large metal panel simplifying installation in used console cabinets is included. Comes complete with tubes and instruction manual incorporating pictorials and step -by -step instructions (less speaker and cabinet). The three band model has simple coil turret which is assembled separately for ease of construction.

T R U E F M FROM eeat,4C.Cg FM TUNER KIT The Heathkit FM Tuner Model FM -2 was designed for best tonal reproduction. The circuit incorporates the most desirable FM features -true FM. Utilizes 8 tubes: 7E5 Oscillator, 6SH7 mixer, two 6SH7 IF amplifiers, 6SH7 limiter, two 7C4 diodes as discriminator, and 6X5 rectifier. The instrument is transformer operated making it safe for connection to any type Model FM -2 receiver or amplifier. Has ready wound and adjusted RF coils, and 2 stages of 10.7 Mc IF (including limiter). A calibrated six inch slide rule dial has vernier drive for easy tun- Ship. Wt. 9 lbs. $225° ing. All parts and complete construction manual furnished.

THE I O R D E R B L A N K M A I L TO SHIP VIA COMPANY topft HEATH Parcel Post 15 r BENTON HARBOR Express MICHIGAN Freight Best Way

Ouantity Item Price Quantity Item Price Heathkit Oscilloscope Kit - Model O -7 Heathkit H.V. Probe Kit - No. 336 Heathkit VTVM Kit - Model V -5 -A Heathkit R.F. Signal Gen. Kit - Model SG -6 Heathkit FM Tuner Kit - FM -2 Heathkit Condenser Checker Kit - Model C -2 Heathkit Broadcast Receiver Kit - Model BR -1 Heathkit Handitester Kit - Model M -1 Heathkit Three Band Receiver Kit -Model AR -1 Heathkit Power Supply Kit - Model PS -1 Heathkit Amplifier Kit - Model A -7 (or A -7 -A) Heathkit Resistance Decade Kit - Model RD -1 Heathkit Amplifier Kit - Model A -8 (or A -8A) Heathkit Impedance Bridge Kit - Model IB -1 B Heathkit Tube Checker Kit - Model TC -1 Heathkit A.C. VTVM -KIT - Model AV-1 Heathkit Audio Generator Kit - Model AG -7 Heathkit intermodul. Analyzer Kit -Model IM -1 Heathkit Battery Eliminator Kit - Model BE 3 Heathkit Audio Freq. Meter Kit - Model AF -1 Heathkit Electronic Switch Kit - Model S -2 Heathkit Square Wove Gen. Kit - Model SQ -1 Heathkit T.V. Alignment Gen. Kit - TS -2 Heathkit Signal Tracer Kit - Model T -2 Heathkit R.F. Probe Kit - No. 309 On Parcel Post Orders, include postage for weight shown and insurance. (We insure all shipments.) Enclosed find Check Money Order for_ On Express Orders, do not include transportation charges they - lbs will be collected by the Express Agency at time of delivery. Please ship C.O.D. Postage enclosed for ALL PRICES SUBJECT TO CHANGE WITHOUT NOTICE

INTPERNATIONAL CORP. I] E. 400, ST. YORK CITY (16) ... BENTON HARBOR 15, MICHIGAN August, 1052 75

www.americanradiohistory.com For additional information on any of the items described herein, readers are asked to write direct to the manufacturer. By mentioning RADIO & TELEVISION NEWS, the page. and the issue number, delay will be avoided.

CRAFTSMEN AMPLIFIER All of the units have dual speed 3.75 The Radio Craftsmen, Inc., 4401 N. or 7.5 inches per second, with auto- Ravenswood Avenue, Chicago 40, Illi- matic amplifier equalization for each nois has introduced a new high -fidelity speed. The dual -track feature permits audio amplifier which has been de- up to 2 hours of recording on a seven - signed for custom installations. inch reel. In conjunction with the duo - The Craftsmen 400 circuit features motor drive there is a separate idler a direct -coupled, split -load triode take -up mechanism for lowest wow and flutter. FOR ELECTRONIC COMPONENTS Complete specifications on this new We offer immediate delivery from our vast series are available from the company stock of more than 25,000 items -all on request. standard make, carefully inspected and fully guaranteed. Our prices are below market. FOLDED -HORN ENCLOSURE Electro- Voice, Inc., Buchanan, Mich- Always Check Wells' Stock First! igan is now marketing a moderately - Quotations and quantities available will priced folded-horn corner enclosure be given immediately upon request. which has been designed for use with the E -V SP8 -B or SP8 -BT 8" speaker ADEL CLAMPS ANTENNAS or any other 8" loudspeaker. Insulators, Most Sections phase inverter driving push -pull 6V6 Utilizing the Klipsch principle of BINDING POSTS power output tubes. Use of 131/2 db folded corner horn loading, the "Baro- 419 BLOWERS inverse feedback around the entire am- net" conceals in approximately 11/z Nov/ CABLE ASSEMBLIES cubic feet of furniture housing the CHOKES plifier results in a 4 :1 output damping COILS factor or an output internal impedance CONDENSERS of 2 ohms at the 8 ohm tap. Oil Filled, Bathtub, Hearing Aid, Transmitting Specifications on the 400 include a Micas, Ceramic, Variable, Trimmer Micas, Silver ± 1 db from 15 to 20,000 CRYSTALS response of DYNAMOTORS & BRUSHES cps at 10 watts output; total harmonic FILTERS distortion of less than 1% at 10 watts FUSES & MOUNTINGS output; intermodulation distortion of GENERATORS less than 5% at 10 watts (60 and 7000 GROUND RODS ; of ± 1 db HEADSETS cps, 4 :1) frequency response IF COILS from 10 to 30,000 cps at % watt; and JACKS a hum and noise level 70 db below the JACK BOXES rated output. 4, 8, and 16 ohm speaker KEYS, Telegraph are provided. The entire unit KNOBS outputs LAMPS measures 14" x 41/2" x 51/4 ". LORD MOUNTS LUGS MOTORS & BRUSHES TAPE RECORDERS PLUGS Masco Electronic Sales Corporation RECTIFIERS of 32 -28 49th Street, Long Island City Selenium, Copper Oxide, Meter, Diode 3, New York has announced six new a horn formed by the walls RESISTORS -All Types throat of tape recorders which feature fast for- of the room itself. SELSYNS new duo -motor drives. SOCKETS ward speeds and The new unit measures 231/2" high, SWITCHES 141/2" wide, and 101/2" deep at the top Aircraft, Micro, Switchettes, Toggle 141/2" deep at the bottom. The en- TIMERS and TUBING-Flexible closure is available in mahogany and TUNING SHAFTS blonde finishes. For complete details TRANSFORMERS -All Types on the "Baronet" write direct to the VIBRATORS company. WALKIE TALKIES Available Now! TEST INSTRUMENT Corp., Ocean- A complete signal corps stock number Precise Development listing of items in our stock. Write for list- side, New York has released a new test ing No. SG -200. (For government agencies instrument in its line, the Model 635 and contractors only.) universal a.f. sine, square, and pulse Manufacturers and distributors -write for generator. Radio -Electronics Catalog No. H 501. Designed to facilitate audio and the néw unit Write, Wire, Phone Your Requirements video troubleshooting, features a Wien bridge oscillator; pro- all phones: SEeley 8 -4143 vides sine waves, square waves, and Of the six models the 52R, 52LR, and pulses; has a variable impedance, 52CR have a built -in AM tuner; the 52 cathode -follower output; voltage regu- and 52R have a carrying case; the 52C lation to insure a constant output; and 52CR have a self- contained metal minimum overshoot and round -off cover; and the 52L and 52LR have no through 30,000 cycles on square waves sine waves through 200,000 833 W. CHICAGO AVE., DEPT. R, CHICAGO 22, ILL. covers. and pulses; 76 RADIO & TELEVISION NEWS

www.americanradiohistory.com co,,, 07 R (IN TELLS HOW- lope,, WE GUARANTEE TO TRAIN AND COACH YOU AT HOME 1411.0 44 IN SPARE TIME UNTIL YOU GET

Ours is the only home A rp study course which °N YOUR FCC LICENSE supplies FCC -type ex- If you have had any practical experience aminations with all TELEVISION includedij -Amateur, in Army, Navy, radio repair, or experimenting. lessons and final tests. ENGINEERING our Training and Coaching !TELLS HOW- TELLS HOW - OUR AMAZINGLY EFFECTIVE JOB- FINDING EMPLOYERS MAKE JOB OFFERS SERVICE HELPS CIRE STUDENTS GET BET- LIKE THESE TO OUR GRADUATES TER JOBS. HERE ARE JUST A FEW RECENT EVERY MONTH! EXAMPLES OF JOB -FINDING RESULTS: Leiter from Chief Engineer, Broadcast Station, North Caro- lina. "Need men with radiotelephone 1st class licenses, no GETS CIVIL SERVICE JOB experience necessary. Will learn more than at average station for we "Thanks to I are equipped with Diesel Electric power, your course obiaMed my 2nd phone license, transmitting and am now employed by Civil Service at Great Lakes and studio equipment." Naval Training Station as an Equipment Specialist." Telegram from Chief Engineer, Broadcast Station, Wyo- Kenneth R. Leiser, Fair ming, 'Please send latest list available first class oper- Oaks, Mtd. Del., McHenry, III. ators. Have November 10th opening for two combo GETS STATE POLICE JOB men." Letter from Chief Engineer, Broadcast Station, Texas. "I have obtained my Ist class ticket (thanks to your school) "Please, send list of latest licensed graduates." and since receiving same I have held good jobs at all These are just a few of the examples of the job offers times. I am now Chief Radio Operator with the Kentucky that come to our office periodically. Some licensed State Police." Edwin Healy, 264 E. 3rd St., London, Ky. radioman filled each of these jobs: it might have been yoa: GETS BROADCAST JOB "I wish to thank your Job-Finding Service for the help in securing for me the position of transmitter operator here HERE IS YOUR GUARANTEE at WCAE, in Pittsburgh." If you fail to pass your Commercial Walter Koschik, 1442 Ridge Ave., N. Braddock, Pa. License exam after completing our course, we guarantee to continue your GETS AIRLINES JOB training without additional cost of any

' kind, -Due to your Job -Finding Service, I have been getting until you successfully obtain your many offers from all over the country, and I have taken Commercial license, provided you first a lob with Capital Airlines in Chicago, as a Radio sit for this examination within 90 days Mechanic." after completing your course. Harry Clare, 4537 S. Drexel Blvd., Chicago, Ill.

HERE'S PROOF FCC LICENSES ARE OFTEN SECURED Your FCC ticket is Reces. IN A FEW HOURS OF STUDY WITH OUR nixed in All Radio Fields COACHING as Proof of Your Technical AT HOME IN SPARE TIME: Ability. Nome and Address License Lessons Lee Worthy, 22101;2 Wilshire St., Bakersfield, Cal 2nd Phone 16 Clifford E. Vogt, Cleveland Institute of Radio Electronics Box 1016, Dania, Fla. 1st Desk RN -44 -4900 Euclid Bldg., Cleveland 3, Ohio Phone 20 (Address to Desk Ku. to avoid delay.) Francis X. Foerch, I want to know how I can get my FCC Ticket in a minimum 3f Beucler Pl., Bergenfield, N. J. 1st Phone 38 of time. Send me your FREE booklet, "How to Pass FCC S /Sgt. Ben H. Davis, License Examinations" (does not cover exams for Amateur 317 North Roosevelt, Lebanon, III. 1st Phone 28 License), as well as a sample FCC -type exam and the Albert Schoell, amazing new booklet, "Money -Making FCC License information." 110 West Ilth St., Escondido, Cal 2nd Phone 23 Tell me about your Television Engineering Course. Name CLEVELAND INSTITUTE OF RADIO ELECTRONICS Address Carl E. Smith, E.E., Consulting Engineer, President City Zone.... State Desk RN -44, 4900 Euclid Bldg., Cleveland 3, Ohio Paste on 2 cent postcard or send air mail.

.%ugust, 19Lí2 77

www.americanradiohistory.com 4,************************** cycles; coaxial type fittings; 1% ce- testing and alignment of AM -FM and ramic resistors; an illuminated drum TV receivers when used with a fre- * dial; and a completely shielded, wrin- quency- modulated r.f. oscillator or TV RECEPTION * kle steel cabinet. sweep generator. * * The Model 635 has five ranges cov- This model has a sensitivity of 10 UP TO * mv. r.m.s. per inch to permit the prop- 200 MILES * er viewing of TV response curves. The * ON ACTUAL FIELD TESTS WITH instrument covers from d.c. to 500 kc. and is usable to beyond 2 mc. * NEW DX630 CHASSIS * * * Provision is made for the direct con- * USING THE CASCODE TUNER nection to both horizontal and vertical * will operate in fringe areas or in localities * plates of the cathode -ray tube. In ad- * remote from TV broadcast stations up to 200 * miles. * dition, line phasing control, negative * and positive synchronizing, reversing * HAS 4 MICROVOLT SENSITIVITY -10 times any * for both horizontal and ver- other TV receiver. Will pick up distant stations * switches without use of booster or special antenna arrays * tical deflection, and provision for "Z" -and with less noise. Will operate any tube * axis modulation, are included. including 24 ", greater brilliance, improved JP' 4( keyed AGC circuit (eliminating flickering and * Complete information on the Model . fading). Uses the best materials with a high * 670 is available on request. * factor of safety to insure trouble -free op- * * eration. STD. RTMA GUARANTEE free re- * ering 20 -40 cycles; 40 -200 cycles; 200- * placement of defective parts or tubes for 90 * GAUGE * days. Completely factory -wired chassis ready * 2000 cycles; 2000- 20,000 cycles; and PRESSURE * to operate with 12" P.M. Speaker. 20,000-200,000 cycles. Garrard Sales Corp., 164 Duane Price Including Excise tax w$144.50 * * Street, New York, N. Y. has introduced * RECORD -REPRODUCE HEAD a new accessory unit which is designed TELEVISION PICTURE TUBES * to measure the stylus pressure of pho- Standard Brands The Brush Development Company, * 3405 Perkins Avenue, Cleveland 14, nograph pickups. * ONE -YEAR GUARANTEE * Ohio has expanded production on the The new stylus pressure gauge * 121/z" (Black Glass 16" * BK -1500 series multi -channel magnetic or $22.50 4( White) Round (Black).$24.50 record -reproduce heads to include two * Glass 14" Rec- Glass 16" Rec- 24.50 * tangular (BIk.)$23.50tangular (Blk.)$ * additional variations which are avail- * 17" Rectangular (Blk.) $24.50 '1,, able at standard prices. 4( 19" Round (81k.) $34.50 * The BK -1500A series are supplied in 4( 20" Rectangular (BIk.) $34.50 * cartridge form less housing. These 1; 21" Rectangular (BIk.) $36.50 * units are wrapped in Mumetal foil and - 24" Metal $67.25 * are available with from 1 to 14 chan- * Consolette cabinet of beautiful design made * nels. These heads have a channel width * of the finest veneers and good finish. Size 39" * * high z 24" wide x 223/4" deep. Finished in ma- * of .050" with center -to- center channel * hogany or walnut. Cut for 630 chassis with 12" * spacing of .125 ". Gap width is .0005 ". * speaker; will take either 16, 17, or 20" tube. * * (Please Specify Size.) * Four free lead wires per channel are it Price including mask and excise tax $43.95 * provided. checks the weight exerted by any tone * Extra for glass $2.75 * The BK -1500N series may be sup- arm or pickup on the record grooves. * For the various other cabinets in our large se- * plied in cartridge form or in housing. The unit is scientifically calibrated * lection we will furnish photos and other NECES- * The channel width has been reduced with large, easy -to -read markings at SARY INFORMATION, ON REQUEST. * * * to .044" to provide a wider land be- one gram intervals. All moving parts TELEVISION COMPONENT SPECIALS* are of lightweight alloy and completely * sealed so that no damage can be done * "Faster Than Hotcakesl" * to the delicate spring mechanism. Per- * That's how these original 13- channel RCA Tuners * formance characteristics will not alter * are selling. Uses 3 -6J6 tubes. Sold as is, less * * tubes, only $3.95 * due to weather conditions or continued use. The gauge is housed in a red and * NEW STANDARD COIL * ivory plastic case. * CASCODE TUNER * * The tuner that will give you stronger, better and * POWER UNITS * clearer reception. Uses I -6J6 and $ 19,95 í-68K7 Intercarrier 'V is * Opad -Green Company, 71 -3 Warren * New-DuMont Tru Focus Conversion Kit St., New York 7, N. Y., has announced * Convert your old set for even focus over entire * a new series of industrial power units * screen. * that supply 115 or 230 volts d.c. from i( DuMont 70° Yoke, Model Y2A1- * * distributed winding $6.57 * existing a.c. power lines. * DuMont 70° Flyback Transformer * Starting at 125 w. capacity, the series * Model HIAI $6.57 includes 42 standard models. Units * DuMont Linearity Control- * so two multi -channel are available for use with 115, 230, or * for above units $0.75 * tween tracks that DuMont Width Coil -for above units $0.75 * units may be mounted in staggered 440 volts, 60 cycle a.c. All of the units * fashion with interlacing channels. are housed in ventilated cabinets. * AUTOMOBILE RADIOS * Design features include precise gap * Custom -Built for any of the following 1949- * alignment, balanced magnetic con- NEW INSULATION i( 1950 -1951 -1952 automobiles- Dodge, Plymouth, s. struction, and Mumetal shields be- Gustin -Bacon Manufacturing Co., . Chevrolet, Hudson, Studebaker, Henry J. and * assembly i( Ford. Every Radio is a powerfully built, 6 tube * tween channels. The entire 1412 W. 12th Street, Kansas City, i( superhet with R.F. Stage and 3 gang conden- * is cast into one integral block of spe- Missouri, has recently introduced an i( ser. Each radio is Custom Built and can be * resin which * mounted in the dashboard within 4 minutes. * cially selected synthetic improved double -duty glass fiber in- * Your price including aerial $38.47 ea. * makes the units moistureproof and sulation which has been tradenamed * * non -microphonic. "Ultralite." * All Merchandise Subject to Prior Sale. All The new insulating product is made * Prices Subject to change without Notice. * 5 -INCH SCOPE of long, fine textile -type glass fibers, * -set- WRITE FOR COMPLETE CATALOG N -5 * Hickok Electrical Instrument Com- bonded together with a thermal pany, 10677 Dupont Avenue, Cleveland ting plastic resin to form a resilient, EDLIE ELECTRONICS INC.:*- 8, Ohio has recently released data on semi -rigid insulation material. It is 4, is ex- 154 Greenwich St. New York 6, New York * its new Model 670 5 -inch scope which available in varying densities. It * (Continued on page 101) ix * * * * * * * * * * * * * * * * * * * * * * * * ** has been designed to permit the visual 78 IL1DI11 .1i TELEVISION NEWS

www.americanradiohistory.com Rauland Tubw give you a prettier profit pieture

Rauland picture tubes are first the war than any other company. what any .other line can give you. choice of an ever growing number Installation and adjustment of You get quality you can count on, of service dealers and men. First, Rauland tubes is faster and bet- because of the completeness of too. Rauland production employs ter. The Indicator Ion Trap gives the Rauland replacement line. machines unique in the industry you the surest known protection -many of them designed by against ion burn and shortened Second, because you get the ben- Rauland engineers and built in tube life. efit of acknowledged leadership Rauland's own plant. in picture tube engineering. Rau - Specify Rauland- deliver Rau - land research has developed more And finally, you get assurance of land -and assure yourself of picturé tube improvements since customer satisfaction beyond pleased picture tube customers.

THE RAULAND CORPORATION PEA/ e, may/ 4245 N. KNOX AVENUE CHICAGOR 41, ILLINOIS August, 1952 79

www.americanradiohistory.com WCEMA-IRE WEST COAST MEET By RALPH L. POWER, Ph.D.

Western Electronic Show to be held August 27, 28, and 29 in Long Beach.

ONE of the highlights of the year, as far as the West Coast electronics industry is concerned, will be the Western Electronic Show and Convention held this year at Long Beach, California, August 27, 28, and 29. Co- sponsored by the West Coast Electronic Manufactur- ers' Association and the Seventh Region of the Institute of Radio Engineers, this year's event will include a comprehensive display of electronic equipment which will be on view in the more than 200 booths that will occupy two floors of the Long Beach Municipal Auditorium. The Show Committee, which is made up of representatives from both the IRE and WCEMA, is headed by R. G. Leitner with Hecker Parker serving as business manager. Howard Grove is vice -chairman for the IRE on the committee while Leon B. Ungar, president of WCEMA, is vice - chairman representing that group. The technical papers committee, headed by Frederick Suffield, has planned a well- rounded program which will feature well -known speakers discussing topics of interest to IRE members and other technically-minded conven- close tioneers. The committee has planned several papers and sessions under each of twelve professional sections : airborne elec- Much like the umpire-4f tronics; antennas and propagation; audio; broadcast trans- call them, if you can se& 'fhéinp= mission systems; circuit theory; electron devices; electronic computers; information theory; instrumentation; so in television it's the "picture data handling; radio telemetry; and remote control. In quality" that determines whether addition they have planned some evening sessions on engineering management and engineering patents for those in- or not you can see them. terested in these specialized topics. The lecture hours Be sure the TV set is have been staggered to permit those attending the conven- "picture tion to cover as many of the meetings as possible. powered" with an Amphenol In- The annual IRE luncheon will be one of the highlights of the action -packed three-day schedule. The Seventh Re- line Antenna -one of the first TV gion's annual achievement award winners will be an- antennas created and still the nounced at the luncheon. A prominent speaker will address the gathering. best broadbanded type providing The all- industry cocktail party, which is open to all seg- uniform gain and signal strength ments, is expected to be a sell -out. The Log Angeles and San Francisco chapters of "The across the entire range of VHF Representatives" which have always assisted with the channels. liaison work, manning the information booths, etc., will again help smooth the way for convention delegates. Call the with close ones WCEMA'S BACKGROUND Amphenol. The West Coast Electronic Manufacturers' Association was organized in 1943 to assist West Coast factories in obtaining government contracts for electronic equipment. While individual manufacturers tried the direct approach AMERICAN PHENOLIC CORPORATION to obtain such contracts, it was not until WCEMA spokes- 1830 50. 54TH AVE. CHICAGO 50, ILLINOIS men went after the orders did the West Coast receive its fair share of the electronics business. By pooling industry resources, government officials could get an over -all picture of existing facilities in the west, the potentiality of the field, the availability of skilled craftsmen, designing and engineering facilities, and the, type of AM "know -how" which could be utilized. PHf Noi Once a year WCEMA publishes a directory in which are listed information about the member -companies, an index of products manufactured, and a compilation of the Asso- ciation officers, and other pertinent data. Publication office for the Directory is at 767 Castelar Street in Los Angeles. ' The secretary of the San Francisco Dealen, Installers, and Own. Council (J. J. Halloran) can be reached at 6021 College -INLINE- ers of TV sets will all be Avenue, Oakland 18, California. George B. Clark, the Los interested in this free book. Angeles Council secretary, is located at 4054 Ocean Park Write Department 13A. Avenue, Venice, California. -- 80 RADIO & TELEVISION NEWS

www.americanradiohistory.com 611Y TEST EQUIPMENT ON THIS RADICALLY NEW TIME PAYMENT PLAN NO INTEREST!! - NO CARRYING CHARGES!!]

USE CONVENIENT TIME PAYMENT ORDER BLANK BELOW

Superior's New Superior's 1 Model TV -1-11 TUBE TESTER JUNIOR SUPERMETER Uses the new self- cleaning Lever Action Switches for individual ele- MOST COMPLETE AND COMPACT MULTI- ment testing. Because all element, SERVICE INSTRUMENT EVER DESIGNED e are numbered according to pin number in the RMA base numbering sys- Measures : * Voltage * Decibels *Capacity cResistance tem, the user can instantly identity *Current *Inductance which element is under test. Tubes *Reactance having tapped filaments and tubes with filaments terminating in more Specifications : U.C. Volts: 0- 7.5/75/150/ than one pin are truly tested with -,e I. -,n0 Volts. A.C. Volts: 0.15 /150/ the Model TV -11 as any of the pins :too I-.00130(10 Volts. Resistance : 0 -10.- may he placed in the neutral posi- 000 /100,000 ohms. 0 -10 Megohms. D.C. tion when necessary. .Uses nn Current : 0- 7.5/75 Ma. 0 -7.5 amps. Ca- combination type sockets. Instead pacity :.001 Mid. -,2 Mfd. .1 Mfd. - individual sockets are used for each 20 MM. Electrolytic Leakage : Reads type of tube. Thus it is impossible quality of electrolytics at 150 Volt to damage a tube by inserting it in test potential. Decibels: -10 Db to the wrong socket. Free -moving +18 Db. + 10 Db. to + 38 Db. + built -in roll chart provides complete 38 Db. to + 58 Db. Reactance: 15 data for all tubes. Phono jack ohms-25 K ohms 15 K ohms -2.5 on front panel for plugging in either Megohms. Inductance :.5 Henry -50 phones or external amplifier detects Handsome round cornered Henries 30 Henries-10 K Henries. Operates on 105-130 Volt 50 micropllonic tubes or noise due to molded Bakelite case 3'iä° 17 Plus Good -Bad scale for checking I.0 Cycles A.. C. Han bbed x 5r/e" x 2';s" complete with oak cabinet complete with NET faulty elements and loose external all test leads and instruct NET the quality of electrolytic condens- portable cover connections. fions ers. Superior's N-Aew M SUPER.- METE R A COMBINATION VOLT -OHM MIL - 'her BAR GENERATOR LIAMMETER PLUS CAPACITY RE- Throws an Actual Bar Pattern ACTANCE INDUCTANCE AND DEC- on Any TV Receiver Screen!! IBEL MEASUREMENTS SPECIFICATIONS: Two Simple Steps: D.C. VOLTS: 0 to 7.5/15/75/150/750 /1,500/ I. Connect Bar Generator to 7,500 Volts. Antenna Post of any TV A.C. VOLTS: 0 to 15/30/150/300/1,500 / 3,000 Volta Receiver. OUTPUT VOLTS: 0 to 15/30/150/300/1,500 / 2. Plug Line Cord into A.C. 3,000 Volts. D.C. CURRENT: 0 to 1.5/15 /150 Ma. 0 to Outlet and Throw Switch. 1.5/1:, Amperes. RESULT: A stable never -shifting RESISTANCE: 0 to 1,000 /100,000 Ohms 0 to 10 Megohms vertical or horizontal pattern pro- CAPACITY: .001 to 1 Mfd. 1 to 50 Mfd. tected on the screen of the TV lQuality test for electrolytics) ',elver under test. REACTANCE: 50 to 2,500 Ohms, 2,500 Ohms TV Bar Generator comes com- to 2.5 Megohms plete INDUCTANCE: .15 to 7 Henries 7 to 7,000 with shielded leads and Item ies Power supply: 105 -125 Volt 60 Cycles. Power detailed operating DECIBELS: -6 to +18 +14 +38 +34 to +58 Consumption: 20 Watts. Channels: 2 -5 on panel, instructions. Only 7-13 by harmonies. Horizontal lines: 4 to 12 The Model 670 -A comes ADDED FEATURE: tVarisble). Vertical lines: 12 Wised). Vertical NET housed in a rugged. The Model 670 -A includes a sweep output: 60 cycles. Horizontal sweep crackle -finished steel cab- special GOOD -BAD scale for output: 15,750 Cycles. inet complete with test leads and operating in- checking the quality of elec- structions. Size 6l4"x9yz" trolytic condensers at a test x4'/0 ". s2840 potential of 150 Volts. NEW TIME PAYMENT PLAN ORDER BLANK New Model 200 AM and FM MOSS ELECTRONIC DISTRIBUTING CO., INC. Dept. B -29, 38 Murray Street, New York 7, N. Y. Please send me the units checked bellow. 1 am enclosing the down payment with SIGNAL GENERATOR order and agree to pay the monthly balance as. shown. It is understood there will be no carrying, interest or any other charges. provided I send my monthly pay- Provides complete coverage for A.M, -F.M. and TV alignment ments when due. It is further understood that should I fail to make payment when Ilse balance IL P. l'requeucy Itau;'cs: Illii due, full unpaid shall become immediately due and payable. hiloeycie, to 150 Megacycles. JUNIOR SUPER METER Total Price $21.40 Modulating Frequency: 400 ('tel. »-. $5.40 down payment. Balance $4.00 monthly for 4 months. May be used for modulating the MODEL TV -1I Total Price $47.50 1{.F. signal. Also available 'ep- $11.50 down payment. Balance $6.00 monthly for 0 months. arately. Attenuation: The con - stant impedance attenuator is iso- MODEL 670 -A Total Price $28.40 lated from the oscillating circuit $7.40 down payment. Balance $3.50 monthly for 6 months. by the buffer tube. Output im- TELEVISION BAR GENERATOR Total Price $39.95 pedance of this model is only 100 $9.95 clown payment. Balance $5.00 monthly for 6 months. ohms. This low impedance re- MODEL 200 Total Price $21.85 duces losses in the output cable. $5.85 Oscillatory circuit: Hartley os- down payment. Balance $4.00 monthly for 4, months. cillator with cathode follower buf- I enclose $ as down payment. fer tube. Frequency stability Is as- Ship C.O.D. for the down sured by modulating the buffer payment. tube. Accuracy: Use of high -Q permeability tuned coils adjusted against 1 /10th of 1% standards Signature assures an accuracy of 1% on all ranges from 100 Kilocycles to to Megacycles and an accuracy of Name 2 on the higher frerplencics. * Tubes used: One 954 as oscil- The Model 200 comes Address lator; one 954 as modulated complete with output $ 85 buffer amplifier; T -2 as modula- 21 cable and operating in- N ET tor; 7193 as rectifier. street io ns City Zone State

August, 1952 81

www.americanradiohistory.com IT'S A BIG PUBLIC ADDRESS SYSTEM YEAR -LOOK AT McGEE'S VALUES ESPEY 12 -TUBE FM -AM CHASSIS, $64.50 50 -WATT BOOSTER AMPLIFIER -$39.95 * BUILT -IN PRE -AMP FOR G.E. VARIABLE RELUCTANCE PICK-UP * WIDE RANGE AUDIO * WHY NOT ORDER WITH A COAX- IAL SPEAKER AND A RECORD CHANGER? SEE OUR SPECIAL OF- FERING McGee'., 1952 model 12 -tube FM -AM chassis. Latest design with phono inputs for 2 -Mike Pre -Amp. all types of recinvl players, crystal or G.E. $12.95 Extra. variable reluctance. Receives standard broad- Booster $39.95 cast 55(1 to 1700 kc and FM 88 to 105 ''+e.. 50 -Watt Wide range audio response (push -pull 6V6 c.output) and bass boost 25 -Watt Horn $28.95 tone control. Loop antenna for broadcast and 300 ohm line type A sensational slue, 50 watt booster amplifier with push -pull FM antenna may be stapled in cabinet. Attractive lighted slide rule dial. Chassis size. 50 -WATT BOOSTER p output Lobes. Connect to your present amplifier as 1311 x 9" high and 9' deep. Complete with tubes: allel 61.6 6BE6. 6BA6, 6A6,Bled 12AT7, 6SH7, a booster or s with the PR-2X Pre -amp to add the use of 2 mikes and one low level 6ALo. 6SQ7 12AT7,6SQ7, 2- 6V(IGT and 5Y3GT rectifier. Shipping weight 20 lbs. lb. one a watts Stock No, 7Ct -X Espey 12-tube FM -AM chassis. input. The has amplifier input Sale price, $64,50, less speaker. Output audio. Booster haé G6 fidelity output transformer, matches aker matches voice coil of our 12" or 15" coaxial speakers. with 4.8.16 ohm voice coil also 60 and 250 ohm line. Booster has a 225 mill power supply with 5U4 rectifier. Price secludes tubed: 4 81bo t and SUI. The ESPEY DEAL (1), 0104.95 ESPEY DEAL (2), $118.95 ESPEY DEAL (3) $131.95 two fable controls for master aping control and base boost tone ea. Size Espey 7 -C chassis complete Espey 7 -C chassis com- Espey 7 -C chassis com- 8 61/a x 14t/z. Stork No. PA-55N. Shipping weight 26 lbs. Sale price $39.85 ea. with 12' coaxial PM speaker plete with 12" coaxial l'll plete with THREE 12" co- CU -14V and VM -950 G.E. 3- speaker Pre -amplifier pings in directly to the PA -55N Booster amplifier. CU -14Y and the axial PM speakers CU-14Y 2 -MIKE PREAMP, It enables use of 2. CrYStol o Dynamic Mikes plus one !OW level speed hanger equipped with English Garrard 3 -speed these three 12" coaxial a G.E. c turnabout input. Furnished oily 4 fout cables and plugs for remote control of the 55 watt Booster variable re- hanger equipped with a speakers give a cone area luctance cartridge. A better G.E. variable reluctance Amplifier. Small eras,. size 5 x 31/4 x 4 ". Stock No. PR -2X, with tubes 7F7 and 7N7. home nusic ystem than or- turnabout cartridge. Our equal to an 18" speaker) Net price $12.95 c dinarily available. Espey best home music system. and a Garrard 3 -s peed 5 -watt Driver and 31/2 -toot air comme re- entrant Trumpet. The Deal 51. Sale price $104.95. Espey Deal 53. Sale price changer with G.E. varia- 25 -WATT HORN Stan uype trime antl driver yóu s e the most. Drivers are With 15" coaxial PM speak- 5118.95. With l5 "coaxial ble reluctance turnabout 100% weatherproof, horn is spun aluminum.t. offered tu ( at a considerable soot .,s. er P15 -CR Instead of CU. I'M speaker Pl S -CR instead cartridge, Espey Deal 53. Stock NoNo. MA-33. Shipping weight 20 Pis. Net prive $28.95. 14Y. $10.00 extra. of CU. 1 4 V. 510.00 extra. Sale price $138.95. CAPEHART CABINET, $79.95 25 -WATT 6 -110 VOLT MOBILE AMPLIFIER, $115.95 REGULAR $190.00 LIST -1952 MODEL BLANK OR CUT TO FIT ESPEY CHASSIS Buy this cabinet with Espey chess s and the VM changer listed 25 -WATT TRUMPETS AND DRIVER above and have a fine radio -phono combination for less than the value of the cabinet alone. TI is beautiful cabinet was in- $28.95 EACH EXTRA tended for a Capehart $800.00 combination. It is the finest 25 watt Mobile Amplifier has built-in phono unit, illuminated possible furniture quality cabinet workmanship. 37" high. 40" control panel, separate volume controls for microphone, and wide and 21" front to back, Hin E.ed top lifts in two sectionv. 251/2" lid covers the changer compartment and 141/2" is the phono and tone control. Power output 25 watts at less than width of the radio compartment. panel 5% distortion. Peak power 38 watts. Frequency response: Changer mounting is Plus or minus 2 db. 30 to 15.000 cps. Overall gain: Mi- furnished blank. Radio panel Is sh pped ready cut to fit the 7 -C 82 db. Espey chassis. Baffle is out to ho d 2 -12" speakers. Made f crophone channel 115 db.; phono channel Hum sop Duality walnut veneer. 7/g" material used throughout. level: 60 db. below rated output. One microphone and one Shipped via truck, rail d phono input. Input impedance: 10 meg. microphone chan- or express only. Shipping wt.. 160 lbs. nel, 1/2 meg. phono channel. Controls: Microphone volume. ,. D< t'- 1 ; -'... e ith 'tanel cut to Espey 7 tor No. lit -C. $79.95. Stock No. B- 17.,8. with blank phono volume, tone with AC switch, standby switch and change, mid I:,,li . p:uml. $79.99. Buy 2 -12" 32 oz. Alnico I'M speakers for use in this motor off t I.', ..nil (57.50 11hono on -witch. Output Impedance: 2.5, 4, 8 16, 250. 5 00 ohms and 70 volt 515.00 each). constant voltage tap. Operates on 117 volts 60 cycles AC r 6 voltsDC. Draws 24 amps on DC operation. Tubes: 784, 6C5. 8SN7GT, 2- 61.6G, 2- 6X5GT. Overall 'z 111/2" deep, 10" high and 161/2" wide. Shipping weight, 40 lbs. Stock No. 2370.25¢ watt MCGEE'S $62.50 LIST 15" COAXIAL SPEAKER, $24.95 6.110 volt amplifier. Net price. $115.95. 21 OZ. ALNICO V MAGNET -5" TWEETER Use either 2, 3, or 4 of our MA -33, 25 watt trumpet d driver combinations, pictured at top this ppage. Net price, $28.95 each: or any combinationm f PM speakers and baffles This 11e nt I.;' coaxial l'itI -p,al.er value lliat cue have ever shown below. Astatie JT -30 and offered. New 11152 production. of a famous manufacturer of fine crystal mike desk stand. $9.95 extra. speakers. The 15" speaker has a 21422 ' . Alnico V magnet: equal W 68 oz, of the Alnico 3 type magnet- The cone is free floating, of e piece construction. Will reproduce low frequencies down to 20 TERRIFIC VALUES IN SPEAKERS AND BAFFLES cps. The 5" tweeter is .tally suspended and has a ridged cone to reproduce only the high frequencies. It will respond up to 17.- 12" PM AND WALNUT 500 P The hih- 8" PM AND LEATHER- pass filter is concealed BAFFLE, $9.95 under the pot cover. 12" COAXIAL SPEAKER, $12.95 ETTE BAFFLE, $4.95 LOTS OF 3. $8.95 leaving only two wires McGee offers the new 1952 to connect both t h e model 12" coaxial PM speak- The finest built 12" Wal- tweeter and woofer to er. Quality you would put in LOTS OF 10, $4.15 nut plywood wall baffle outputut áyour finest sets if you were of. Factory cost transformern sformer8 of manufacturer. 12' woofer ofknowthe famous juke box dio, or high fidelity The finest Leatherette Baffle we slave ever manufacturer s has 6.8 o.. Alnico V mag- offered. New self -supporting exceed ra Ir Insets amplifier. Stock No. PlS -CR, net. Tweeter is coaxially sus astic grill $7.00, e offer with a hipping weight 13 lbs. Net price $24.95; material. baffle is covered tan with match- 12" PM for little more. You paw only $9.95 Fended and has a metal dif ing; grill. Offered a 2 for $47.95. fuser. High ss filter is um with good heavy duty in ingle lots. or $8.95 in 3 lots for both two 8' Alnico V PM speaker with 3.2 ohm a 12"s Quam Alnico V PM with 3.2 ohm der the pot cover. Only voice l. Stock No. 818. Speaker and Baf- voice coil and the beautiful wall baffle, 12" JENSEN PM, $15.95 wires to connect to your ra- fle, $4.95 ea.: lots 12" 12 dio or audio amplifier. 8 ohm of 10. $4.75. Speaker Baffle combination, Stock No, BS- Another McGee Scoop! Jensen Concert ", 8 ". Baffle only. Stock No. NV -8, $2.29 i SQ. $9.95 co.: 141/1 oz. Alnico V magnet PM speaker. 8 with 18 watt peak and 10 lots 3. $8.95 en. 12" ea.: 10 for $19.95. Iktd e only'. ±SEC US hm voice coil. Will take 25 watt audio. w' a t t average. Shipping -12, 4.95 each. you save dollars on this speaker. Just 100 weight 8 lbs. Response from to sell. Shipping weight 8 lbs. Stock No. 30 to 17,500 cps. Stock No- CU -14Y, Sale P -12P, Sale price $15.95; 2 for $30.00. price $12.95 each: 2 for $25.00. MIKES AND STANDS 3- STATION INTERCOM MASTER, 9D -T, high impedance dynamic $14.95 mike with 12 feet of cable. USE 3 -SPEED CHANGERS ON SALE AT McGEE sale price. $10.95. 35" to UP TO 3 -SUB 64" chrome floor stand f o r STATIONS, (tike, $5.88. $4.49 EACH WEBSTER CHICAGO MODEL 100-2 ONLY $2695 A red -hot intercom For the first time we offer the world famous Webster -Chicago, McGee's Super High master value. A full model 100 -2. Features a ewty designed spindle. that drops the :i tube. 110 volt AC- records flat: air- cushioned n to the turntable. Pickup arm sets Fidelity DC master, with (3 down automatically after the last record plays- Plays all rec- Best Value station selector switch and easy mile ords automatically. 331. 78 and 45 rpm. New balanced tone volume control. Small compact size. - m with Electro -Voice Tilt- A -Metic cartaidge with dual needles. in U. S. A. 6 "x6 ;" high. Makes an attractive inter- Ordinarily cost over $37.00- McGee offers them for only $26.95 com installation. May be used with from each. Base size 12 "x123 /4 ". Shipping weight 14 lbs. OUTPUT one to three of our G -4T substations de TRANS. scribed below- Intercom master is quiet at 20- 20.000 95 all times, except when press -to -talk switch V.M. 3 -SPEED MODEL 406 $22.95 is pressed at either the master, or one of CPS. the subs. Shipping wt. 5 lbs. Stock No. VM model 406. deluxe 3 ed automatic record changer. Plays them all. Intermixes 0p3aHl$2lfldelity300utpr transform. KA -3, master less subs. of with twin needles. Model station, Net $14.95. records the same speed. Equipped with a flip over crystal pickup hy for Stock No. G -4T, brown plastic substation. Base size, 121/.0)13 ". Shipping weight 12 lbs. VM -406. Net price $22.95. our A -4033 is available $7,957 Im- with Alnico V PM speaker and press -to -talk pedance, 6600 shins plate to plate for PP witch. May be purchased with or without 3 G.E. 6L6 or 6V61. 10G',, winding.inding. 4.8- master station, Shipping weight 2 lbs. Net. G.I. -SPEED CHANGER WITH 15 -250 and 500 ohm secondary. Housed in $4.49 ea. VARIABLE RELUCTANCE TURN -ABOUT CARTRIDGE $2295 a potted case. Net weht 6 lbs. Recom- 3 wire plastic intercom cable, 100 ft. for all ampli Dicrs up to :34 netts. $1.95: ,t 1, P. 58.95. Another tremendous McGee Scoop! Brand new General Instrument mended 3 -speed automatic record changers. Complete with RPX -050 G.E. svariable reluctance cartridge with turn -about stylus. Plays all 3 peeds automatically: 7 ". 10" or 12" records. Has reject button. TERRIFIC FLUORESCENT FIXTURE SALE Repeats last record. Base size. 12 "x127/3 ". Shipping weight 14 Ihs. Stock No. 700 -GE. Scoop price. $22,951 A IS YOUR SERVICE DEPT. PROPERLY LIGHTED? ELECTRONIC RADIO and TV TUBES SAVE 50% ON THIS 4 -LIGHT 6 MONTHS' GUARANTEE INDIVIDUALLY CARTONED IN RED AND BLUE DE LUXE VARNISHED CARTONS FIXTURE EVERY TUBE SET TESTED FOR YOUR PROTECTION $12.95, TWO FOR $25.00 ORDER 50 ASSORTED -TAKE 0% OFF. Prices as Low as 36c OZ4 ..5 .59 6AL5 ... .49 658GT .. .89 7Z4 .69 WITH LAMPS 6AC15 .49 657GT., .59 12AT6 .. .49 183 .. .79 ... ILLUS ' l'IRA'l'ION io ATU6 657GT., .59 12AT7 .. .69 TOP -')'his the finest GAT6 .. .59 value in a tl mlreseent pis tore that we have .59 6AÚ6 ... .49 65E07GT .69 12AÚ7 .. .89 25L6GT. .59 ever offered. Constructed of heavy gauge 12AV7 .69 . .79 .59 6ÁV6 ... .69 6567 ... .69 25Z6GT metal with white enamel finish. .59 6BAO . .59 6597 . .69 12AX7 .. .69 35C5 .59 lustre .79 6BA6. .69 6SK7GT. .69 12606 .. .59 35L6GT. ,59 All General Electric high power factor ballasts. Furnished with General Electric 36". 30 .59 12606 .59 -49 be mounted next to the ceiling or suspended ILA4 .79 6BA7 ... .59 6SK7GT, .. 35W4 watt white fluorescent lamps. Fixture may bench. 11.83 .79 6BE6 ... .59 65N7GT .69 128E6 .. .69 35Z5GT. -49 on beautifully service ILG5 .79 6BE6. .29 65N7GT. .69 128E6 .. .59 35!51 .. .69 in your display roomuorsinryorrrfcoffice. randconstructed.in factory ecartons packed for 1.29 .69 12866. .79 -59 to We bought 6 truck loads and are passing I LN5 .79 63969.. 6577.7. shipment. These fixtures sold for $30.00. shop. Shipping ILN5 .59 66.16 .. .59 6U 7G .79 12J5GT.. .69 .49 our hs. a o tod. Why pay to fixturere 1R5 .59 66 .99 606 .59 12J7GT.. .69 .79 I each. 51Shipped esmore. all Freight or Trucknonly.zyour 155. .59 6 .99 6 GT .. .59 120701'. .69 .89 complete. Net $12.95: 2 for $25.00. 174 .59 6646BQ6 97, .99 6X4W 497 . .49 120701'. .69 SOBS ... .59 .59 6C6 .... .59 6X4 .49 12SF5GT .69 5005 .59 lÚ5 .... .89 6C6 .... .59 6X79... .49 125FSGT .69 gOL6GT. .59 DELUXE MODEL WITH GLASS, $14.95; CEILING CANOPY, $1.95 2X2 .... .69 6C66 ... .49 6Y75 ... .59 125/]77 .59 .49 Canopy for stispendine either of the above .69 6CD6G ,. 1.49 7136SG .59 12507 .59 .49 Bottom Illustration 30 " from the ceiling. 7E5 1250797 .59 .49 fluorescent fixtures .69 6JSGT .. .59 .... .69 430X. some as No. For use where it isn't advisable to mount .49 6JSGT ., .49 7E6 .... .89 14547 .. .69 76 .49 Deluxe Model No, MK- fixture flush or suspend it on chains. Canopy 1.49 6KGT .. ,59 7E6 .89 14A4 ... .89 77 .69 MK -930 described above ith the excep- box 574 ...... r glasslass over the kit is complete with stamped metal SU4. .69 6K7GT .. .59 7E7 .... .79 1405 ... .99 78 .., .69 tion that it has translucent hardware for mounting to any .09 7H7 .59 14C5 ... 1.79 85 .79 lamps to diffuse the light. CAN- cover with 3/3" 5X4. .40 6G ...... is shown. $1.95 extra. Shipping, outlet box and 2-30" lengths of white .69 6L6G 1.09 7N7 .99 14H7 ... .99 89 .79 OPY that O lbs. Fixture 605 .... :;:5 Net price $14.95; 2 for enameled Pitting. Ship. wit. 054 .69 6L7G 1.09 7V7 .... .99 1908 ... .99 117L7GT 1.49 weieht Ils. canopy kit. Na. 1-30. $1.95. AJ5 .99 65497 .59 7X7 .... .99 1978 .89 11723 . .49 528.00. 6AK5 ... .99 654 .... .59 ]Y4 .... .]9 2560697 .99 955 .79 vine. P.o.B, K.C. Send 25% Deposit with TELEPHONE VICTOR 9045. WRITE FOR FLYER or4.r, Bolan,:. s.ne c.o.o. with rar..) 1422 KANSAS CITY. MISSOURI McGEE RADIO COMPANY e.t (rear., Inom Pwtae GRAND AVE.. 82 RADIO Si TELEVISION NEWS

www.americanradiohistory.com TELEVISION FRONT ENDS on SALE at McGEE- STANDARD COIL, RCA, SARKES -TARZIAN STANDARD COIL CASCODE TUNER $19.95 GENUINE STANDARD COIL T.V. BOOSTER $11.95 The Cascode Circuit of the Standard Tuner offers a new development Not Surplus, But Right From the Factory of this famous TV front end assembly which affords a 2 -to -1 improvement in gain and a 35% to 0% reduction of noise over the Latest Model B -51 Standard Coil Television Booster, McGee pentode tuner. Other advances include: easy conversion to UHF re- makes another lucky purchase and as usual, passes the saving ception by terchange of channel inductors: increased on to you. The famous Model B -31, 12 Channel Standard TV sensitivity for TV which Coil sets In fringe areas: elimination of booster use: and a high profit booster, lists for $35,00. is offered to you for only item for the serviceman as a replacement unit sale. Brand $11.95 each. Brand new, factory cartoned and fully guaranteed TV -2000 new factory eartoned. Series by McGee. This TV tuner. compi. with tubes 6IlK7 or 01107 and a 6.16. Sco,ilr price. $19.95 top quality single stage booster utilizes ea. printed high frequency circuits. for improved performance on all channels. Uses OAKS tube. Average gain. 6 to 7 volts on low THE ORIGINAL STANDARD COIL TV TUNER and 5 distorting switch $1295 low nolise factor. BContContinuous one -knob tuning channel selector control for ANOTHER McGEE SCOOP off -on and by- passing 300 ohm lead -in to et. Modern design, dark brown plastic cabinet, 8 "x4[/4 "x41;2. Made for Olt. Five millions of 12- 110 60 cycle AC operation. Shipping a t ght -,. lbs. this channel Standard Coil tuner now in Ifs I i. Model B -51, Sale price, $11.95 popular model with clip -in channel inductors and each, or buy 2 for only $22.00. shaft. You concentric fine t.j: :, ::: save over h n0. Price includes tubes. Stock No. 1,1-947, $12.95 each; 2 for $25.00. Choice of 234" or 31/ee length insulated McMURDO SILVER BOOSTER shaft. . Used on Emerson Model $10.95 650D. Gao, etc. Filaments connected Sensational value. Continuously variable inductance type tuner, ies 112 volts) and shunted .6 amp drain for AC -DC TV sets. from channel 2. P riced with tubes BAGS ttr 6BC5 and 6.18. inrluding the FM band. through channel 13. Stock No, SC This booster is self powered for 110 volts AC operation. In- -948, $13,95 each; 2 for $27.00. Available with either corporates a 6J6 tube. 1 ". 31/2 ", or O Input for 300 ohm TV line d 300 shaft length. Filaments re in parallel for 6.3 volts ohm output to the TV set. knob AC operation. Price includes tubes 6AG5 a or Single toning Attractive Both BBC5 and 636. Note: plastic case. McMurdo- Silver Super Sonic TV-FM booster. tuners have IF coil attached for intercarrier sets. For sets with Stock No, GB -OB. Shipping separate sound we suggest using the convertor coil on the following weight 5 lbs. McGee's terrific bstage. (Diagram furnished with each tuner.) Bakelite channel sale price, $10.95 each, two for $20.00, ossed channel markings, 59c extra. selector knob with em- 1952 MODEL ASTATIC $19.10 1952 MODEL REGENCY $19.10 New Astatic "Stanafar" TV booster with New Regency GENERAL INST. T.V. TUNER $7.95 improvements to match DB -520 TV booster with ex- then c model TV clusive circuit stabilizer and newly Ie.signed This popular General instrument TV tuner has been used on thou - receivers. Minimum noise .eitih maximum sands of late model TV sets. has cabinet only 4I/2x6x41/2 ". Improved c rcuit It built -in fine tuning and 12 gain. Balanced cascaded circuit with 6JO with push -pull ß,J6 is eutial to the best cas- channel selector control. This tuner differs from other tuners In and OBQ7. Input and output for both 72 that it is around a tle circuits and has higher gain. Matches built tuning condenser instead of a coil switch- and :100 ohm. Mahogany finished metal 72 or 300 ohm. Net price 519,10. ing arrangement. A convertor coil is not mounted on this tuner. high. Model CT -7. Priced complete with 3 -6.16 tubes. Shipping wt., 3 lbs. Stock Net i price $1 No. GI -WT3, with tubes, Net price, $7,95, Specify 9.0A414 a/ " shaft length desired, either 1 or 7 ". ALLIANCE TENNA ROTORS CUSTOM BUILT TO FIT $2.95 SPECIAL. 61 -312, same as above GI Tuner only less tubes $26.43 and in repairable condition. 13/4" and 7" shafts available. Two free to AUTO RADIOS ModeltrHfl1 ea tmatically at 6 tube superheterodyne 3 gang tuning. the station you select. Just pointerinter to Custom the position desired. Model e DIR starts, Built to fit individual makes of cars. 3 -TUBE SARKES -TARZIAN T.V. TUNER stops and reverses instantly. Meter shows Simple to Install. no cables or drilling nec- This popular antenna position at all times. Both essary. Packed in original factory cartons. Sarkes -Tarzian Type 3 tuner i s'i iciY fully encased have used. 13 channel rocrotary ttype e switch - motors. Operates on 110 t individu- volts. price tcab either. $26.43. Made for Price Puce ally tuned coils. Price is complete with diagram and $995 we connecti '49 and .50 Ford..$511,95 539.97 three tubes: 6C4 one.. 66H B R.F. and 6AG.n mixer extra, '49. '50 Dodge. RegularB factory cost Is twice our price. Each tuner is wired ready Plymouth .... 59.95 39.97 to hook up to a video and sound IF strip. May be used with 300 OHM T.V. LEAD IN $12.95 '49 & '50 Chevrolet 59.95 41.97 Inter- carrier separate sound IF circuis. as built -on convertor Best quality 300 ohm TV lead in wire. 55 1951 Ford 59.95 39.97 coil, built In fine frequency control, mil polyethlene with 22 gauge tranded 1952 Ford 3 tubes. Net price, herkes-Tarzian TV tuner, with copper 59.95 39.97 $9.95 each- Specify shaft length, either 21y " or 41/4 ", conductors. Will not crack ands break '51 and- , Dodge 59.95 39.97 extreme 'fi & '52 Chevrolet 59.95 39.97 tord branded. t st plus. Stock No. P -3120. '48 thru '52 Hudson 59.95 39.97 $12.95 per 1000 ft. metal spool. '50 thru '52 Stude- RCA 201E1 T.V. Open line TV lead in. Copperweld 1/6 licher 39.97 TUNER $7.95 the loss of regular 300 ohm. For fringe '51 area ption. & '52 Plymouth 59.05 41.97 Terrific buy on this RCA tuner. We $4.95 per 100 ft. 250 ft. 1951 Henry J.... 59.95 39.97 have a limited quantity of the Sir $12.00. 500 ft.. $22.95. Universal tfnderdash 49,95 32.97 famous original 201E1, 13 channel completely wired and tested TV front end tuners. Ready to connect to your TV video I.F. strip. Of- fered at a sacrifice. Price was $44.00- Now only $7.95 each, with NOW YOU CAN CONVERT TO A 17" OR 20" tubes. Each toner in good condition hut has been repaired. Stock No. RCA -13P, TV front end tuner. Convertor roil type for separate sound PICTURE TUBE WITH ELECTRO STATIC FOCUS as used in the famous 630 chassis, Complete with 3 -636 tubes, The I7HP4 $7.95. Specify shaft and 20HP4 are 17" and 20" black face picture length desired, either 2" or 4 ". tubes of the electromagnetic deflection electrostatic type of Ionising. Focusing Is accomplished by a 5 meg, pot con- WIRED VIDEO I.F. STRIP $3.95 SARKES- TARZIAN -SPEC. $2.95 nected as a bleeder between ground and the cathode of the damper tube. The arm of the focus pot connects 6 of This wired video I.F. a Type 4, Sarkes- Tarzian 12 channel TV tun - to pin the strip is perfect re- CR tube. to apply a focus for several model Crosley TV Requires 2 BAG5 or 2 OOC.5 and a voltage of from O to 300 volts. placementsets, such as Model No. 11.442MU, 11- 12AT7. Has 1/e" diameter shaft, 23/4" This new type tube is called low voltage electrostatic focus. 446MU and many others. Offered at less long. Screwdriver slot fine tuning adjust- Very simple to use and operates from 8.5 KV to 14 KV. Most than the factory production cost. it tubes r ent. It differs front other tuners in that set makers are using this new tube In several models. The are required. 2 6AU6, lst and 2nd video, it has no concentric fine tuning shaft over trend is almost completely to this type gun. 6A1.5 video detector and either 2 6A05 or the channel selector shaft. Very One for llECS 3rd and 411i video. 1st I.F. mc, experimental use building field strength 20" CONVERSION 22.9 meters. etc. Sarkes -Tarzian KIT $32.95 11" CONVERSION KIT $24.95 2nd 26.55 ow. 3rd, 22.2 mc. 4th 24 m Type 4, TV The new 20HP4 blackface picture tube op- The This strip has dozens of resistors, ceramic tuner less tubes. $2.95. Set of 3 tubes new I7HP4 blackface picture tube op- for this timer. 51.630 erates from 10 to 14KV, high voltage. it erates from 8 to 1411', high voltage. is capacitors and slug tuned I F c it Id al extra. is the conventional 20" rectangular It for net builders, or perfect to rob parts from a Shape the conventional 17" rectangular shape. A A standard 70° yoke and single ion trap are standard 70° yoke and single ion for TV servicing. Stock No, CR -51F, $3.95 SNOW FILTER FOR FRINGE AREA required- Focusing Is accomplished trap are each. Kit of 5 tubes for by elec. required. Focusing is accomplished by elec. this I.F. strip, Reduces glare, increases contrast. Easily 11u-static means, applying from 0 -300 volts fro- static $3.50 extra. installed with double faced adhesive on the focus means, applying from 0.3011 volts with sup- anode. pin No. 6, All other on the focus anode. pin No. 6. All other plied filter. Available in Blue or connections and characteristics are similar lnecttons and characteristics are Smoke color, in sizes for 16" to 20" to a 20í-P4. (No focus similar screen. roil or focus magnet Cora I7BP4, No focus coil or focus magnet is needed,I You get the 20HP4 tube. a 20" is needed.: You get the 17HP4 tube. 17" MEISSNER TV TUNER No. 126. 12" x 16" for 16 and 17" tubes, rectangular plastic safety mask with gold Blue or Smoke, $1.95 ea. plus rectangular plastic safety mask, nith gold trim. tube characteristics, all for trim. plus t u b e characteristics.. all for No. 152. 1:5" x 20" for 20" TV screen, $32.95. Stork No. WITH 3-6J6 Blue Sr Smoke. HPM -20, shipping weight $24.95. Stock No. HPM -17. Shipping weight $2.85 ea. 40 lbs. 30 lbs. 7711 -X. Universal flyback with connecting 77 .11 -X. Universal Flyhack with connecting .. 14 instructions. ^ KV FLYBACK ONLY $2.95 $3.95. 70° Deflection Yoke, instructions. $3.95. 70° Deflection .. $2.95- Width ('oil. 69c- Yoke, Genuine General Electric flyback made for 5 meg. focus con - $2,95. Width Cnil. 69c. 5 meg. focus con- Tc. $5955.95 Arvin. Conventional type for 70° deflec- I trill. 59c. trol. 59c. tion yokes and all 14 ", 16' . 17 ", 20" Meissner 12- channel television tuner- and 21" rect. tubes. wired Ready Delivers up to 14.000 and with 3-636 tubes. A 12-chan- volts. Has fiber punched for 1x2 rectifier . 14" CONVERSION KIT $19.95 IO" nel rotary hsocket. Used with (ìßQ6. 613011 PICTURE TUBE $14.95 ied sw itch type with separate coils orizonal or 6CD6 You get an RCA 14" rectangular blackface for each channel. Built -in fine frequency output and 1B3 or 1x2 rectifier. safety 1OMP4, 10" picture tube made by Sylvania. control- Ideal for Schematic with each terminal identified is escutcheon, plus builders, experimenters. furnished. No. T-77J3, $2.95 each. la 70a° dfectionsyo Perfect replacement for 10ßP4, no circuit Stock No. 13 -7624, Sale price, $5.95 each. each lots $2.50 a 14.000 volt flyback transformer, all for with in of 5 or more. 70° Deflection $19.95. Stock No. RC -14X Conversion ehanges required. Brand new factory car- tubes. Yoke $2.95 extra. diagram furnished. toned, Net price 1 IMi'4. $14.95 each. COMPLETE RADIO, TELEVISION AND AMPLIFIER KITS AT McGEE 3 -WAY PORTABLE KIT 8 -Tube Hi -Fi Amplifier Kit $29.95 10 -TUBE RADIO KIT $29.95 6 -TUBE 2 -BAND KIT A complete $14.95 kit, including 10 tube Popular with $1595 tubes: 3 -7E,,, broadcast schools a n d col- 2-7F7. radio chas- leges for A NEW '52 MODEL 2 -0A3, plus sis kit, rectifier dia- complete hantubeadio klit with New 1952 Model 3 -way gram and with tubes; Plastic cabinet. Re- personal portable radio photos. In- 2 -6SE7, ceives broadcast k i t. Operates on 110 puts ra- 6SA7. n 6 to 18 m Volts AC -DC or 67 Va B dio tunerr r OHO, shortwave. Full 2 Plus 11/ volt self-contained batteries.rie and any kind 6SQ7. gang superhet with leatherette covered case size, 5/z of p h o n o 2-12AX7. 5" speaker a n d Receives broadcast 550 to 1650x KC. A pickup Icrys- 2 -6V6 slide rule dia. A conventional 2 -gang superhet Circuit with plus chal 0 r G.E. ¡ . complete kit with tubes: 12517, 456 KC iron core IF's. Incorporates the variable eer, d 12SK8, new re- ia- 12SK7, 12SQ7, 351.6 and 3525. diagram super gain stick loop antenna. All í105e. ei and either crystalohl or dynamic gram a n d and instructions, Factory quality. Cabinet plated chassis. l.ab, approved c i s u mike. instructions. 3 gang superhet with 8" size "x431 matched parts. Price includes all parts.it- Output matches 8 ohm voice coil slide 13 "xOul4 /4 ". Shipping weight 12 Twin sill, bass and treble tone n rule dial. Chassis size. "x fdeliyx61/, lbs. Model ME6 -2. Net $14.95. t tubes, diagram, Alnico V PM speaker- A trots with rangera gy selector switch for either audio Fe atures push-pull high factory quality kit. Stock No. PN -4T, ship - brillantUsymphonic audio. Output matches 3 to 8 ohm voice ping weight 7 Ids. The complete Less jr with heavy bass responseR coil peakers- kit. range. Response 18 Inputs for G.E. variable 5 -TUBE AC -DC KIT $12.95 batteries, $15.95. 671/2V. B, $1.59; 11/5V. to 20,000 tube ta or crystal phono up and crys- A. 39c extra, kit. completely iitthtltulles11 Shippingmweight tal e. Heavy d le5 power transformer. Model RS -5. A 5 tube AC -DC straight broad- 25 lbs. Model 7X5. Net $29.95. BK -RIO .pecker. cast kit. housed in the same cabinet as weight I8 lbs. Net 829.95. MEO.2 above. Complete with tubes. Ship- Build Your Own ping tvelght I0 Jr,. Net $12.95. Phono -Mike 10 -Watt HI -FI Amplifier Kit $14.95 A complete kit IT, 20" Broadcaster of parts includ- ---- T.V. Kit $59.95 Less Tubes Kit Model DE -GR. With ing tubes AC POWERED BROADCAST this mple kit, you can A complete kit of 12AX7. 12AU7, parts to build an build n a 9 -tube TUNER KIT $12.95 phono plus AC transformer op- oscillator that also has rectifier,tifier,n din - a mike erated television A self -powered, 3- input- Will chassis for use with broadcast over any ra- s tionsd t o gang superhet tuner vitnn your none, (about 75 feet) from build a h i g h rectangular kit with R.F. stage. 1000 to 1500 kc. Inputs for crystal mike or fidelity w n pictre crystal t i tube. The 12 Chan- This complete kit is into pickup. Fader control fades tone control au- el Sarkes -Tarzian furnished with a from mike to record, d i O mplifier Ideal for a home P.A. t u n e r I s ready diagram, photos and system, baby listener and home entertain- with bass and wired, ment, A complete kit of parts including treble boost. Inputs for as is the 4 tubes, 6AU6 R.F.. tubes. radio tuner. en's - tube video IF strip. 8BE8 Klt Model DE -6R, Net price, S7.95. mike and crystal phono pickup. Output Circuit is of the oscillator T, wired and tested, Net price, matches 8 ohms. Response from 50 to conventional design. Do not buy R.F., 6AU6 I.F. de- 59.95, Crystal mike and desk stand, 54,95 15,000 cps. Chassis ready punched. this unless tector, 6A1,5 diode. AVC. plus rectifier. lated cover, Venti- you understand Television. It is difficult to extra, Concealed microphone unit, only 1" Straight forward circuit with wire. We furnish schematic. Kit model Connect to any audio amplifier. Ideal for in diameter and 14" thick- twin triode gain stages and 2 -50LO tubes in use with S Specify hidden push- 14 WH -20. Ship, wt. 40 lbs, less all tubes, our -2020 TM -16 or 7x5 ampli- mike when ordering. Stock No. T -001. Net. lIlI. Size, 10" x 5.5/s" high. Net $59.95, fier kits. Chassis -Rios. Model AP-10R. ship. wt, 8 lbs. Sale 914x4x41/._" hi_h. $3.95 extra. $14.95. price Kit of 22 tubes. less picture Why $16.95. vh ipping weight. 7 Ib=. lirvadcns:. 0in,,r 17" 17BP4A, $19.95. !0ííl' -l. 525.00. I.ì( ,,Iiul 1;7' -, 4. \. Net price. 512.95. Pate, F.O.B. k c Send 250b Deposit with TELEPHONE VICTOR 9045. WRITE FOR FLYER McGEE RADIO Order, Balance sent C.O.D. With Parcel COMPANY Post order., Include Postage 1422 GRAND AVE., KANSAS CITY, MISSOURI August, 1952 8:1

www.americanradiohistory.com Signal Tracing Probe ME RI T (Continued from page 59) from poor sync stability to "over -contrasty" pictures lacking in definition. In most cases, the exact cause of the complaint is difficult to find, especially tv full -line* when using conventional servicing techniques. Where a signal tracing technique is components give used, on the other hand, distortion is readily apparent as a change in the detected video signal. universal coverage Either the top or bottom (or both) of the video signal may be flattened or clipped. See Fig. 5C. Where the top of the video signal is flattened, as at 1 in Fig. 5C, the complaint will be either loss of sync or sync instability. Sync instability usually shows up first in the horizontal sweep circuits. Where the picture portion of the VA composite video signal is flattened or tops again! clipped, as at 2 in Fig. 5C, the uneven and jagged video signal is replaced by NEW IMPROVED HVO-7 FOR GREATER COVERAGE a bright and straight line. The "body" Tapped AFC Winding. Covers Admiral Chassis 21.24 Series. of the signal will still be shaded, how- MWC -1 UNIVERSAL WIDTH COIL ever. With this type of distortion, the (3 -27 MH) A Tapped Secondary For AGC or AFC. picture will lack definition and may be over -contrasty. Under some circumstances, both ((( t ,.(((((Da types of distortion may occur at the it 0 IF -RF COILS Only complete line of TV replacements. same time -compare the distorted video signal in Fig. 5C with the appearance of the "normal" video signal of Fig. 5A, noting particularly the - "COSINE" YOKES in top and bottom por- Complete with leads A network. differences the tions of the signal. Distortion may be caused by incor- with our latest MATCHED FOR DIRECT DRIVE rect operating voltages, a defective MDF -30 HVO.8 tube, too strong an input signal, im- A -3080 Vert. Mtg. product - the new A -3081 Horiz. Mtg.;`"`'f proper operation of the a.g.c. circuit Autoformer w and similar defects. Once the distortion is isolated to a specific stage, using R E the probe, it is a simple matter to A R identify the exact cause of the trouble by making voltage checks and trying a substitute tube. S E A T He Under some circumstances, distor- "(V KIT NO. 1000 MATCHED SET FOR SPEEDY tion may cause the output signal am- - g.. PROFITABLE SERVICE! plitude to be less than the input -a SPEAKER symptom similar to that obtained with a "weak" stage. Extreme overload may cause a reversal in signal phase due to detector action in the i.f. stage GRILLE itself. EASY TO FORM MERIT . HQ for PRACTICAL TV Since the detection of the i.f. nor- Service Aids mally takes place in the probe, the ALUMINUM MERIT'S 1952 Catalog No. 5211 with new video signal seen on the screen of the FITS ANY CAR MERIT IF -RF Coils. CRO will maintain the same phase re- Other MERIT service aids: lationship regardless of which i.f. BEAUTIFULLY FINISHED TV Repl Guide No. 404, 3500 models & stage is being checked. If the pulses chassis. of the video signal (on No. RSG 60K Cross Ref Data, IF -RF Coils, Form No. 14. are at the top they should remain with mounting screws, switch, See your Jobber or write: Merit Coil and the scope screen), Transformer Corp., 4425 Clark Street, there regardless of the point at which bracket and wire. Chicago 40. the probe is touched in the i.f. strip. If detection occurs in one of the i.f. No. RSG 60 stages, on the other hand, the video with mounting screws only. These three MERIT extras help be seen to reverse phase SEE YOUR LOCAL DISTRIBUTOR you: signal may Exclusive: Tapemarked with on the screen of the CRO when that specs and hook -up data. Full technical data packed with stage is checked. every item. Listed in Howard Sams Photo- As experience is gained in using the facts. probe, the technician will soon be able to tell the most probable cause of the ELECTRONICS MFG. CO. im. distortion from the appearance of the 'Merit Is meeting the TV 9820 IRWIN AVENUE provement, replacement and con - distorted video signal. version demand with a line as INGLEWOOD, CALIFORNIA complete as our advance in. formation warrants! 41- s%: TELEVISION NEWS 84 RADIO

www.americanradiohistory.com Within the Industry (Continued from page 26)

The move provides additional facilities for the manufacture of the company's outsells all others combined line of relays, thermostats, etc. . . . AJAX CONDENSER CO., INC. of Chicago MODEL 260 VO H M-M has opened a West Coast factory at LT-O ILLIAMMETER 10905 Chandler Boulevard in North Hollywood, California. The' new firm will be known as AJAX CONDENSER CORP. and will supply condensers for the electronic and electrical industries on the West Coast ... ALPHA METALS, INC. has a new address. The firm is nOw located at 56 Water Street in Jer- sey City, New Jersey. The mail address is P.O. Box 34. Bergen Station . . GENERAL ELECTRIC COMPANY is building a multimillion dollar transformer manufacturing plant in Rome, Georgia. Completion is scheduled for mid -1953. The plant will provide employment for about 1700 persons ... JERSEY SPE- CIALTY COMPANY, manufacturers of TV lead -in wire, etc., is scheduled to move into its new and modern plant on Route 23 in Mountainview, New Jersey by mid -September. The new factory will provide 1250 square feet of manufacturing space ... COLUMBIA BROAD- CASTING SYSTEM has purchased a de- pot and office building at West 56th Street in New York which will be converted into the largest TV programming plant on the Atlantic seaboard. The present building contains over 1385E D= ALER'S NET 405.000 square feet of floor space. SIMPSON ELECTR C COMPANY 5206 K. KINZIE H. EVERETT SMITH has been named ST. CHICAGO 44 president of The Wilcox-Gay Corpora - tion and Garod Ra- ,COLL.MBUS 1.1221 dio Corporation of Charlotte, Michigan, and Brooklyn, New York. . Mr. Smith recently resigned his position as senior vice - president of the Marine Midland Trust Company of New York to accept this new post. He will occupy the position formerly held by Leonard Ash - bach, who continues as chairman of the board of directors of the two companies and chief executive officer. Mr. Smith had been associated with the Marine Midland Trust Company for a period of 11 years and prior to that served 14 years with the Manu- facturers Trust Company. He will maintain offices at the company's TOOLS AGE A MU. EASY TO LEARN CODE Brooklyn plant at 70 Washington IN RADIO, T.V. AND ELECTRONICS It Is east to learn or tncrease upset Street. with an Instruetngraph Code Tcarher. t Ycur tool Affords tie quickest and most prat box is 1 Tina! method yet developed. For be- JOHN Q. in:omplete f it ginners a- advanced students. Avails. CANNON, assistant secretary Me tapes from beginner's alphabet of Radio Corporation of America, has lacks Moody Kit gigs - to typical messages on all subjects. pr?cision Speed raree 5 to 0 WPM. Always been named secretary of the company small aglir 1....,1% 011M. tool sets. The by the board of directors. ENDORSED BY THOUSANDS! He has been PA -5 Kit shown The with the company since 1945. . The Instrtctoraph t,.lc Teach, lit - cortains five in rally tat..is the place ul an op .ator French Government has conferred the Instructor and enables anyone cc ter:hangeable Allen type and PI-illiFs head learn and muter code without fur. rank of Chevalier in the National Or- screw drivers. Ask to see the Cher assistance. Thousands of sueressful ocerato-s hays comp ete Moody 'acquired the code" with ire Instructorrm-1h system. der of the Legion of Honor on DR. line at your ccal sores. Write cocan for convenient rental and pur ans. ALLEN B. DU MONT. The honor was !END FOR : REE DESCRIPr1VE BOO;LET bestowed in recognition of his services `IIte-Gd' MACHINE PRCDUCT' CO. INC. INSTRUCTOCRAPN COMPANY on behalf of the Allied cause during 4 =ulver Street, Providence 5, Rhcde stand 4711 SHERIDAN ROAD. CHICANO 40. ILLINOIS August, 1932 85

www.americanradiohistory.com World War II, through his scientific work, and for his contributions to commercial relations between the U. S. and AMAZING NEW France . HENRY MARKS has been named assistant general manager of Jerrold Electronic Corporation of Phil TRANSMITTING -RECEIVING adelphia. He has been with the firm since 1948 . . . AL FRIEDMAN is the new national field sales engineer for Ram Electronics Sales Co. He has been associated with several well - STATION known electronics firms and is familiar with all Phases of the radio and electronic industry . . . DONALD C. CAR- TER has joined The Magnavox Company as assistant to the president. He joins weighs 7 lbs... the Fort Wayne firm after three years as a plant manager for Ford Motor sends 40 miles Company . . . THOMAS F. JOYCE has been elected president of Raymond Rosen & Company, Inc. and the Phila- delphia Appliance Service Corporation. Prior to joining the distributing firm in 1945, he served in various executive plugs into ordinary 110V capacities with Radio Corporation of America.. . . DARRELL KNIGHT has AC receptacle...6V battery been named manager of trade press relations for Motorola Inc. He succeeds or auto cigar lighter DALE SAMUELSON who has left the company to accept a position as national sales promotion manager for a well -known electronics manufacturer Now, you can have a completely port- in the East . . . The board of directors able, transmitting and receiving station of P. R. Mallory & Co., Inc. has elected that operates from either a fixed or mo- FRANK B. POWERS to the post of vice - MODEL CD 144 bile location, for only a fraction of the president in charge of manufacturing. He was formerly associated with Fed- cost you ever thought possible. Today, Also ONLY eral Telephone and Radio where he the new Deltronic simple, low -cost unit available was vice -president in charge of opera- all other complicated systems of the board of di- makes for 6 and 10 $1695° tions and a member . . . SAMUEL B. WILLIAMS has obsolete. meters and rectors Includes Federal Excise been named assistan.t to PRESIDENT Tax. Microphone and SIMPLE! FOOLPROOF! commercial DON G. MITCHELL of Sylvania Electric frequencies crystal not supplied. been of approximately 7 pounds, the Products Inc. He has director Weighing public relations for the firm since 1949 CD 144, measures only 63%" wide, 6" . . . ED FALLS is the new regional man- deep and 93'z" high. Equipped with 19" ager for Motorola's southwest sales whip antenna and jack suitable for cou- area. He will cover the states of Texas, Louisiana, and pling to other antennas. It plugs into an Oklahoma, Arkansas, two -way communication. The unit con- New Mexico . . . VIRGIL B. DAY has ordinary 110 volt AC receptacle...plugs tains complete line isolated power sup- been named manager of employee and into the cigar lighter of your car...or plant community relations for General ply and vibrator, a built -in noise limiter runs on an ordinary 6 volt battery. The Electric Company's receiver depart- and crystal controlled transmitter using range ...UP to 40 miles! ment . . . JACK ABEL has joined the the newest miniature tubes. Its two Insuline Corporation of America where ENJOY THESE FEATURES meter band is calibrated for 143.8 to he will take charge of the company's mechanical engineering department Company, with its vast re- 148.1 Mc. Deltronic . . . CBS -Columbia, Inc. has appointed sources and electronic "know -how" has See your distributor or write direct BERNARD M. DOVER to the post of proj- built the new CD 144 Transmitter -Re- for complete information about the new ect engineer. He was formerly asso- Radio and Pho- ceiver to assure you of reliable foolproof Deltronic CD 144 Transmitter- Receiver. ciated with Emerson nograph Corporation in charge of its tuner department . . . IRVING HER - MAIL COUPON TODAY RIOTT, JR., district sales manager for Zenith Radio Corporation, passed away recently while in Washington, D. C. on DELTRONIC COMPANY a business trip. He had been associated 9010 Bellanca Ave., Los Angeles 45, Calif. with the firm since 1937 . . . GEORGE information about the new Rush to me AT ONCE complete W. HENYAN has resigned as chief of the CD 144 Transmitting-Receiving Station. components branch of the National Radio Operator 1 Am A Jobber Dealer Production Authority's Electronics Di- Electric Com- Name_ vision to rejoin General pany as assistant to the general man- AVE. 9010 BELLANCA Firm Name ager of the Tube Department . . . LOS ANGELES 45, CALIF. JAMES M. SKINNER, JR. has been named Street Address Manufacturers of Electronic Equipment vice -president- distribution for all do- for the Armed Forces City _ State mestic divisions of Philco Corporation of Philadelphia. 30 TELEVISION NEWS 86 1t.nl/1 .0

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If you do . . . you want Delco Radio service parts from the world's largest manufacturer of automobile radios. You can depend on the high, uniform quality of Delco Radio service parts. These replacement parts are identical in quality with the original equipment parts that make Delco the big name in car radios. Both Delco Radio original equipment and universal serv' ice parts are available promptly through United Motors THINGS TO REMEMBER ABOUT wholesalers. DELCO RADIO SERVICE PARTS

DELCO RADIO PARTS Offer largest market for original - equipment replacement parts. A GENERAL MOTORS PRODUCT A UNITED MOTORS LINE 2 Backed by world's largest factory de- DISTRIBUTED BY WNOL ESAL FRS EPERYWNERE voted exclusively to automobile radios.

DELCO RADIO Designed by one of the largest and most groups DIVISION OF GENERAL MOTORS CORPORATION 3 forward -looking engineering de- radio. KOKOMO. INDIANA voted exclusively to automotive August, 1952 87

www.americanradiohistory.com THE 3Bo ... BEETHOVEN, BRAHMS AND BACH

they're different they're improved

Readers are asked to write directly to the manufacturer for they re better than ever! the literature. By mentioning RADIO & TELEVISION NEWS, the issue and page, and enclosing Yes, Bach, Beethoven and Brahms are now the proper amount, when indicated, delay will be prevented. better thon ever -we don't mean we've improved their music, but we do mean we've improved the reproduction of their recorded music. NEW MACHINE BROCHURE Chicago Rivet & 111w-hille Co., 9600 It's the new, improved Pickering Cartridges that give credence to W. Jackson Blvd., Bellwood, Illinois, are different. They're im- this claim. Yes, Pickering Cartridges is offering copies of its two - proved. They're better than ever. Pickering patented Cartridges currently with Dynamic Coupling' are superior in every way, by providing: color broadside which describes in de- HIGHER FREQUENCY RESPONSE NEGLIGIBLE INTERMODU- tail the company's new No. 214 double LATION DISTORTION BETTER TRACKING CHARACTERISTICS riveter. DYNAMIC COUPLING ASSURES This unit, which is suitable for var- constant stylus contact with the record grooves over the entire ious types of assembly work, can set audio spectrum (20. 20,000 cps) full frequency response full two rivets at a time on either one of transient response no resonances no mistracking no grinding two selected fixed centers. The foot - of groove walls operated pneumatic control instantly shifts one riveting head from one selected riveting position to the other at PICKERING and company, incorporated the will of the operator. Adjustable stops permit a wide selection of any Pickering High Fidelity Components are desired riveting centers ranging from available through leading Radio Parts dis- , , to 21/2" with a maximum of 6 ". tributors everywhere; detailed literature The new bulletin describes in de- sent upon request. Address Department C tail the operation and setting up of Oceanside, L. I., New York IIIILILILILILI the unit and lists complete specifications. A copy of the broadside is available without charge from the company SUMMER SALE BUILD UR OWN direct. PRICES SLASHED 10 W. XMITTER! STEEL FASTENINGS NOVICE A new 20 -page catalogue which pro- T.V. TUBES-ROCK BOTTOM PRICES In lots of 6 each No. only vides detailed product specifications to 6nG6 99c OBQO 74c IUBG6 99e 6AQ 490 Based on article aid in selecting and ordering stainless 12AX7 59e BCDO $1.29 t:CB6 59e 6S4 49c in the 1952 RADIO steel fastenings has just been issued by tiAK5 79e AMATEUR'S HANDBOOK Wrst:nghouee Kuy oe Iteetiner 0.64 Amp. 28 Star Stainless Screw Company, 195 Snits. 110g $11.00 ea. Speelal $1.95 INEXPENSIVE 2, New 12 BRAND NEW 1O' PHONO RECORDS-Asst. Union Avenue, Paterson Jersey. Jais- Popular. Rhythm -Blues. Please specify.$1.79 XTAL -CONTROLLED Illustrations of the products in each Slope Pole-10 Pos. 2 Gang Switch 29e 2-TUBE KIT for the BEGINNER! 2 piece. 5 pole Male and Female separable Amphenol classification quickly identify the var- plugs. Both with Flex shielded cables. Approx. Complete with Power Supply! 5 ft. long. 350 pair 3 pr. for $1.00 ious items. Specifications such as Grind your own Crystals. Pure Brasilian Quarte. Vari- Arrow Electronics has brought out in kit form all and materials are ous sises and thicknesses. 1/4 Ib. pkg. $1.00 needed to build the novice or beginner's measurements 29c each the parts 4 Tube Drilled Chassis, 41/2'I161/3"x11/2". crystal -controlled 80 meter transmitter described on clearly listed in easily -read chart form. 4 inch P.M. SPEAKER $1.50 in the 1952 Radio Amateur's Hand- $1.35 pages 154.158 The product categories include all M. 450 ohm Dynamic Speaker book. Arrow has modernized it so that the entire signal Corps Phones -2 M. Ohms 18 M. Ohms on one screws, nuts, bolts, washers, S51.25 1xt. unit, including power supply, will mount types of 2 Ft. E Cord und Plugl 40c metal chassis. Simple to wire, almost anyone can pins, studs, rivets, nails, etc. TOBE TUBULAR ELECTROLTTICS assemble it in a few hours. Operates with almost 2020 MFD. 150 V...49e 30 -30 MFO. 150 V...57* any random length of wire as antenna. On the four pages devoted to stain- 40.40 MFD. 150 V...59c diagrammatic Low-Less Short i GANG T Look At These Many Features! less steel specialties, Leek Type er (VVARIABLE Vuia le CeAA drawings are provided to fully describe Con. 65c 10 Watts Input Builtin E 4 5 PI.- 2OMmfd. 140 .000365 sev- V. Power Antenna the various fittings. In addition, ¢ 1- 7 PI. -25.30 Mmfd 15e 350 Tuner to decimal 8 PI-30.33 114mfd 19e ail 61il" Supply eral pages are devoted 24e SWITCH 15c Built -in 14 PI: 58 Mmrd 0.100 Ma DC equivalents of pertinent fractions and 1,000 OHM WIRE WOUND POTENT WASTER. ..150 Keying Jock 30 NY- FILTER CHOKE $HI ..... 3 for. $1.25 Meter and so Meter the structural quality suitability IE20 CRYSTAL NOLDER$..12 for $1.00 -19.00 per C Xtol- Controlled, 3700 -3750 Kr Operation of the standard stainless steels. RCA Sand Swttenes- Y. 3 gang. 3 pos. 3 band.30e 6 gang. pos. 4.5 band.40c Uses 6AG7 1 Prices f.o.b. N. 11S V. AC with Trimmer. Awl. -all ,se,antite- s,ngIes. .oial: Line 6X5 Tubes 2S% deposit triples -100 asst. 52.25 C.O.D. orders HAM BOOKLET Double Pots ....350 Ph1100 push button Rotary Switch Complete kit of ports, including 2 A little booklet, designed to stimu- ATTENTION:PreensTTort.Eepl HiddenTreasurest tem- Construct U.S. Army TY0* of Metallic Mine Detector tubes, blank aluminum chassis, has AmpliA.r. Amplifier unit only ,less tubes and hat.. plate, 80 M. coil, condensers, resis- late interest in becoming a ham, terres) cables. headphone and Jack. Army cord. 5 tors, meter, power supply components, chokes, lugs, been issued by the American Radio with Ad less wire, Cond. .001. 100 í0r...950 wiring diagram and instructions, etc., RCA Asa't Mies Pau 490 Relay League, West Hartford 7, Conn. 8 or 9 Gang Push utton Switch solder and crystal ...... 519.95 250 111111.I.ED CHASSIS FOR 5 -6 tubes 5"10 "811/2" 80 meter crystal ...... additional $2.70 Entitled "You Can Be There," the PHONE TACKS -OPEN 9 CLOSED AUTO.... 18c 156 -1 RATIO VERNIER DIALS -4 In. SA In. Ilub 35e booklet describes many international SALE -PHONO 11F:CORD ALBUMS- 12 --:1 comp. 150: W2JRF W2UG2 in attendance will comp. 20e: 12 comp. $9e W2PGP 10-3 comp. -150í help you with any of your "hand' pfeblems. adventures awaiting amateur oper- VULCAN HEAVY DUTY 100 WATT ING IRON. Milli for U.S.N. -Brand New-Emily. sells for ators .and points up one highlight of $8.50 OUR PRICE $2.99 radio contact with MINIMUM ORDER $3.00 -NO C.O.D. recent years -direct SHIPMENTS -PLEASE INCLUDE POSTAGE "Kon- Tiki." ARROWI/ELECTRONICSINC. NEWARK SURPLUS MATERIALS CO. Distribution of the first 100,000 copies a] COr1lNDT St., D.p, C. N r 7. N r Cobte cO,ECicO-N Y- 324 Plane Street Dept. AU NEWARK 1. N. J. of the pamphlet will be through youth NEWS 88 RADIO & TELEVISION

www.americanradiohistory.com organizations, educational and civic groups, and electronics manufacturers and distributors.

SNAP -ACTING THERMOSTATS LAST WFEK.WNEN THE TVS ON NE SEE. SINCE THE DAN WAS Stevens Manufacturing Company, LONG TIME,NO THE InYA GEORGE! FRITZ,I SUPPOSE NE AK, FE HAD THE Mb. FOR' Inc., 69 S. Walnut Street, Mansfield, ABOUT BRINMNG OOGTO2 HOW'S PLAY BRIDGE! TOMORROW CAN DINNER! Ohio, is currently offering copies of a ('VE TO DINNER new illustrated bulletin on the com- EVEN ING pany's line of snap- acting thermostats for operation on wide or narrow dif- ferentials. 7.1-171-1` / In addition to suggested applications, the bulletin describes the operating principle and illustrates it with ( nllll schematic diagrams. Ratings, typical DIOSy'f . R ,,c ENSE , . NONE M performance curves, dimensions, and GET JAKE M°SUCH GEORGE -IERE, CAN construction data are included. NILE INVITATION FROM A nit WORKING- Copies of Bulletin L -4144 will be for- 5E-7 warded without charge to those making their requests direct to the company.

TEST LAMP DATA Details on the company's "Bull's - Eye" lamp are included in the new bulletin just released by Lindly & Co., 248 Herricks Road, Mineola, N. Y. The lamp, which has been especially designed for close work and assembly operations, is illustrated and its advantages and construction features described. Copies of the bulletin are available without charge.

FLASH HANDBOOK A new 16 -page handbook on home RSA construction of electronic flash equipment for amateur photographers has been published by Sprague Products REPLACEMENT Co. The new publication gives complete H I- VOLTAGE circuit details on four different photoflash units using the company's new Type FF-1 low- leakage condensers, "DOORKNOB" rated at 525 µfd., 450 volts in a can 2" in diameter by 41/2" long. Copies of the "Electronic Flash CERAMIC... Handbook," Form C -703, are available from all Sprague distributors for 35 FURNISHED WITH cents or may be obtained by sending 35 cents in coins or stamps directly to the company at 51 Marshall Street, SCREW-IN TERMINALS North Adams, Massachusetts. PYRAMID CATALOGUES TO Pyramid Electric Company, 1445 MEET EVERY NEED! Hudson Boulevard, North Bergen, New An ingen ous screw -in terminal system makes Sprague's Jersey, has announced publication of new type 2)DK -T5, 500 mmf, 20,000 vol: molded case four new catalogues which provide ceramic caprcitor fit most every TV set. All you have to do specifications, construction and engi- is select the proper set of terminals, two twists of the writ, neering data, sizes, and prices on the company's line of condensers. and there you are! Catalogue PG-1 lists miniature With this new Sprague development, you need only one "Glasseal" condenser types PGH, PGM, capacitor in your kit to service sets up to 21" tubes. and PGX. These units operate at tem- Sprague's 20DK -T5 "Doorknob" ceramic is molded in peratures ranging from -55 degrees genuine thermosetting plastic, non -flammable and moisture - to +125 degrees. resistant. Guard rings are molded in bot.1 faces to lengthen tl-e Catalogue IMP-1 describes the com- surface leakage path. Write for complete catalog C -608 to pany's newest line of molded plastic Sprague Produc :s Co., 51 Marshall St., North Adams, Mass. tubular units. The "IMPS" are impervious to moisture and will withstand a temperature of 100 degrees C. Don't Be Vague! Catalogue MP -2 gives detailed information on the company's ultra -com- Insist, On Sprague pact metallized paper types while Cat- alogue J -7 is a 32 -page compilation of WORLD' 'AR p a p e r, electrolytic, oil- paper, and CAPACITOR MANUFACTURER metallized paper condensers. August, 1952 89

www.americanradiohistory.com Free copies of any or all of these The new bulletin provides complete This detailed and illustrated two - catalogues are available on letterhead descriptive data and specifications on color, 12 -page brochure includes com- request to the company. the seven different sizes of clips now plete drawings and electrical and me- currently available. chanical specifications covering a ELECTRONIC WATTMETER Copies of the bulletin, along with a broad selection of standard variable Keithley Instruments, 3868 Carnegie price list, will be mailed to executives, air condensers. The items described Avenue, Cleveland 15, Ohio, has re- engineers, and purchasing agents who are stock items which are available leased a two -page bulletin which de- make their requests on their company from jobbers and dealers throughout scribes its Model 109 electronic watt- letterheads. the country. meter in some detail. Requests for copies of this catalogue The new unit, which is especially CONVERTER CATALOGUE should be addressed direct to the com- useful where a high input impedance Carter Motor Co., 2644 N. Maple- pany. or sensitivity to low- voltage and low - wood Avenue, Chicago, Illinois, has re- power circuits are required, is de- leased a new catalogue which lists its TV CATALOGUE scribed fully. Specifications and sug- entire line of d.c.- to -a.c. converters. The LaPointe Plascomold Corpora- gested uses are also outlined. This 16 -page catalogue provides tion, Windsor Locks, Connecticut, now Copies of the bulletin will be sup- complete electrical and mechanical has available copies of its 1952 "Vee- plied without charge on request. specifications, the company's selector D-X" TV catalogue which are being chart which has been revised to con- offered to service technicians and RIDER CATALOGUE tain the latest in television and record- others concerned with television instal- John F. Rider Publisher, Inc., 480 ing equipment, and a complete di- lations. Canal Street, New York, New York, rectory of the company's sales repre- The new catalogue contains a com- now has copies of its revised catalogue sentatives. plete listing of the company's antennas available for distribution. The new publication is punched to fit and accessories. Containing 24 pages The 8-page, 81/2" x 11" catalogue all standard loose -leaf binders. Copies and printed in two colors, the cata- contains a complete up -to -date listing are now obtainable from the manu- logue features not only the company's of the company's Manuals, "Tek- File ", facturer. Ask for Catalogue No. 452. standard products but its special de- and books. Information on the com- velopments in the television field. pany's books to be published soon is HAMMARLUND CATALOGUE First released at the Radio Parts also included. T h e Hammarlund Manufacturing Show in Chicago, the new catalogue is Copies of the catalogue are available Company, 460 West 34th Street, New being distributed by "Vee -D -X" repre- from the organization's distributors York 1, New York, has announced pub- sentatives and jobbers. Copies may or directly from the publisher. lication of a new 1952 condenser cata- also be obtained from the company logue which is being offered to elec- direct. CLIP BULLETIN tronic manufacturers, the military Prestole Corporation of Toledo, Ohio, services, research and design engi- VIBRATOR REPLACEMENT has just issued a data sheet covering neers, and other interested individuals A complete and concise replacement its new and improved condenser clip. and groups. vibrator guide has just been issued by

OLSON'S PENNY PROFIT POLICY MEANS GREATER BARGAINS DON'T MISS THIS AMAZING VALUE 10 WATT HI -FI PUSH -PULL AMPLIFIER .Bass & Treble Boost. Inputs for crystal and MAJESTIC magnetic pickups, ra- DIV. OF WILCOX-GAY dio tuner and crystal 8-TUBE AM-FM 6 Tubes mike. RADIO ' Elk Stock No, RA -102A Aluminum Chassis. Bombshell Value! It's unbelievable. A full 10 watt Hi -Fi Amplifier, completely assembled and ready to play. Has built -in PRE -AMP for G.E. and similar types of magnetic 1 phono. 1 magnetic 1 radio. 1 mike. 4 Controls: CHASSIS pickups. 4 Inputs: crystal phono. 4, ohms. I Bass, 1 Treble, 1 Volume, 1 Phono -radia Switch. Output Impedances: 8, 16 Peak power output 17 watts. Order this amplifier today and see what brilliant, realistic tone it will deliver. Supply is limited. Everyone in factory sealed carton. You couldn't buy the parts alone for this 5 price. Remember this is a full size amplifier. transformer operated, not an AC -DC job. Frequency response 20 t o 20,000 cps ut le-. than 1 of I , , distortion. 5 Tubes: 1- 6S1.7, I -6SC7, 2 -6V6, t -5Y3. Complete n ith tubes. Size 12 "x61/2 "x51/2 ", Shpg. wt. 44!A 15 Il.. Can he used with any pl.nn...... :.her. Stock No. RA -52A TRANSPARENT BOXES 1c LATEST Stock No. AS -65A With every MODEL $195 Kit of Trans- Complete net of 10 sixes parent Boxes Complete: Tubes, Loop Antenna, assorted .... you order you Made can get an Ak- Escutcheon, Knobs, etc. Clear asglasthsie. but rad .1 mfd 600 won't break with ordinary use. volt Condenser You gel 10 different, all poPU- This is not a kit or a tuner. It's a real high -powered AM -FM Radio Chassis that will hinged retail value pull in distant stations with amazing volume and brilliance of tone. Makes a perfect lar size boxes. All with custom installation In existing cabinets, book -cases walls, etc. Servicemen and Ex- covers. Boxes re from 8` 45e -your Cost v i Handy for nuts, lugs, only 1 sent. perimenters: Make money installing these for friends and customers. :i:.... s I I tO 1" x 1" ". The circuit is modern and employs 8 tubes (12AT7, 613E6, 2 -6BA6, 6A1.5, 6AV6, cis, etc. Get several hits today. Shpg. wt. 2 lbs. eve and 5Y3). The entire R. F. assembly and the 4- section tuning condenser is rubber mounted. Tuned R. F. tage lus two I. F. stages give this set terrific FM sensitivity. Separate FM oscillator tube for extreme stability, and triode R. F. and mixer circuits plus radio detector assure noise free, high fidelity FM reception. PLASTIC RECORDING TAPE Two modern dual knobs control on-off, volume and tone plus AM -FM, phone switch. le the buy of your life. Save up to 64,e Equipped with two panel lamps and edge lit dial. Phono input socket and AC recep- Get A large With everY On high quality RECORDING TAPE. 10 rolls of tacle at rear of chassis. Chassis size 1:3" wide, 71/2" deep, 71/4" high. Cut out 111 had to sell his inventory and - cabinet requires Output impedance S on manufacturer Plastic Record 8x31,. chols operates 110.125v AC. 60 cycles. he unloaded the whole deal. Olson now of- Shpg. wt. 20 Il.. In factory sealed carton.. fers you this high grade recording tape at which defy competition. Standard order, you can prices get a 50 ft. 14" wide.i Frequency response 50 to 8.000 with each. roll of hook-up COMBINATION DEAL Plastic Reel included val- 600 Ft. Reel Stock No. 1200 Ft. Reel Stock No. wi re- retail RADIO AND 12" CO -AXIAL SPEAKER $4995 X -275A. Single. each X i248Á, Single, ear. ue 51.00 -Your LOTS OF 10, É2Á.18, LOTS OF 10. cost only 1 cent. You the above Majestic AM $1.49, 199 get -FM Radio chassis exactly NO. F-A. 129 as described above PLUS a model S-168A 12" Co -axial speaker, 1952 model, as described on opposite page. RA5268A Both packed in factory sealed cartons. Don't Throw Away Old Picture Tubes You can get excellent pictures on old dim kinescopes 1e for an additional 900 to 3200 hours by simply at- PHONO PRE -AMPLIFIER taching the slew l'ernia -prover TV Tube "Britener." TV t Tube Brit Fully automatic. Just plugs onto back of old TV e you o9grder.ver $895 For use with G.E. and other low level magnetic Tube. Not a gadget. Laboratory tested and approved. pickups. Can be attached to any radio or amplifier. Regular retail price $9.75. Order yours now. Make 10, OOOnvolt TV N- Built on aluminum chassis, finest workmanship big money selling TV "Briteners' to your friends Condenser -re- RA-loOlA throughout. Ample bass boost provided. Operates and customers. Shpg. wt. 3 lbs. Stock tail value On 115 volt AC. Sizes 4l/4"x21/8"x31/2 ". Complete No. T-USE á5.7JJ $1.25 - your with 12AX7 tube. Shpg. wt. 2 tbs. ORDER BLANK ON NEXT PAGE cost only Cent.

477 OLSON RADIO WAREHOUSE 275 E. Market St., Akron 8, Ohio 90 RADIO .c TELEVISION NEWS

www.americanradiohistory.com 5" ALNICO 5 PM SPEAKERS KINESCOPE TESTER lc SPEAKER Tests all picture tubes $2995 Model 106A 1` SALE At last you can test picture tubes quickly, easily Thousands have been sold and positively WITHOUT removing them from the With every chassis or cabinet. Tests magnetically and elec- Kinescope by Olson for $1.79 trostatically focused picture tube and shows exact Tester you or- We must make room in our condition on a 31/2 meter. Checks for: high der, you can warehouse volage breakdown, leakage, gas between elements, kit of 24 conductance. high lta "e anode, screen or aetassorted C -D Buy 3 and get cathode to control grid voltage from set and bright - and Solar By- C ae s control voltage. Also has built -in hm -meter ret nd e ÿae ra the 4th for only nd volt-meter with scales 0 -500 and 15 KV. tail lue Order Stock Complete with plugs, sockets and instructions. $ 6.00 your Shpg. 7 lbs. - No. S-169A At lc Olson will sell plenty of 5" PM Speakers. No wt. cost only 1 cent. one else would dare make this offer. But our new Fall 1st Speaker.$1.79 merchandise is coming in any day now and we need ROOM. Buy 3 speakers at our bargain price of $1.79 2nd Speaker. 1.79 each and get the fourth speaker for only lc. Order 6 STANDARD COIL TV BOOSTER speakers at $ 1.70 each and gget 2 speakersP for onlyY 2e 3 rd Speaker. 1.79 additional. Remember, for every 3 speakers you buoy, This is the latest model mid niu- Olson is making speaker is only Don't miss this this exclusive offer f 100 ft. of .100 ohm Poly- 4th Speaker. .01 It bAnCANNOT repeated whenhtn sold out. Every speaker ethylene Twin Line for I cent with each Booster is brand new inIn original factory cartons. FuH 5" diam- you order. The standard Coil TV Booster is the eter. Duetp.2 oh inside and out. akercf 5 magnet. latest Model 11-31 which regularly sells for $35.00. 1` Four $538 coil 3.2 s The radios speaker for extension This offer ill not be repeated when supply is speakers. sets. AC -DC radios and intercoms. Shpg. gone. Brand w, factory- sealed cartons nd fully For wt. peaker guaranteed. This Booster has printed high fre- With every quencyuency circuits and gives superior reception on standard coi I all channels. Does nut distort sound or picture TV Booster you but dues give them tremendous boost. Perfect for order, you can 12" CO -AXIAL SPEAKER fringe areas. Continuous one -knob tuning and channel selecting. If you have trouble with snow" ft.tcessi of 300 Our new 1952 Model. Guaranteed to ic Model $.51A or if any channels re weak in your area -this ohm poly twin- outperform any speaker in its price booster will do wonders in overcoming these. Get lead-retail Gl- class. Equipped with two "high con- brilliant, clear, now- free" pictures with this ue $5.00 -your centration' Alnico 5 magnets and a With every $1 095 booster and get the 100 ft, spool of 300 ohm cost only 1 cent. high frequency diffusor. The 12" sec- 5.168A Coaxial twin -lead for just 1 cent, Cabinet size A" x 41/4" tion delivers the bass while the inner Speaker you or- x 41/2". For 115 volt AC operation. Shpg. wt. o lbs. tweeter speaker section delivers the der. y o u can treble tones. Together they give you ine Yivinf, tone." This speaker is uncon- matching (trans- ditionally guaranteed to satisfy even the f or m e to 12" Magnavox Speaker and Baffle Close -Out most critical user or Olson promises to a t e h a 5000 refund your money. Only two wires to line t d You get Magnavox' 12° PM speaker connect to any radio or amplifier. Voice speaker etaiil Stock No. with magnet.fine as you'll $1295 coil impedance A ohms. Frequency re value $3.00 - AS-66A find In those eexpensive Magnavox Super - sponse 30 to 17,500 cps. Shpg. wt. your cost only Radio Phono Combinations., Power ut- With every Stock No. S -I68A 10 lbs. 1 cent. Get both put 8 watts. Voice coil fully dust- proofed. M a g n a v o x for only ... Impedance 6.8 ohms. In ddition you Speaker a n d alnut Baffle you order PRESTO -Call Intercom the full row ded tones of the Mag- you can get a navox 2- STATION Communi- $795 Speaker. Baffle may be mounted on 50' roll of 2 The Modern Electronic wall r It will stand on a table. Here's conductor INTERCOM SYSTEM cation System the ideal combination for extension speak- speaker exten- Now talk with anyone, any - In lots Of 4 ers for porches or other rooms. Can be sion wire where at the mere flick of a but- connected to any radio or amplifier. Or- I value ton! All electric master station One set for der 3 or more sets and install them in $3.00 -your and sub -station ive clear, pow- $8.95. restaurants, auditoriums, halls, etc. cost only, eau t. erful voice reproduction to rooms or other buildings up to 1000 ft. away. Thousands have been sold 1` for use in restaurants. on farms. offices, stockrooms, factories and With every $250 Phono Amplifier in homes. Just plug master sta- 2- Station Inter- tion Into any 115 V AC electri com you order, Stock No. RA -98A Stock No. RA -96A cal outlet -connect 3 wires and 2óu can get you're operating. Modern design. Kit of 20 popu- Only 1000 amplifiers to he sold by Olson during Olson Special Price for Each unit measures 41/2x41/ax 1` with lar 10 a t t this sale at this remarkable low price. Efficient Master Station Substation 51/2. Equipped rubber feet Wire wound 2-tube amplifier. Input for crystal mike. Can and easy slide switches. Hand Resistors re- With every and 50 only some appearance -gray crackle - be used with any PM speaker from 4" to 12 ". Amplifier you ft. of cable tail value Delivers 3 watts of audio finish. High amplification -use 3 your with excellent fidelity. order you can $10.00 - Equipped with both volume control and tone con- get an output cost only 14. trol. Less gular list pricesiaR $37.50. u Shpg. wt. 3 lbs. tubes. transformer- get the master station, substation retail $1983 and 50 ft. of 3 conductor cable. Kit of 2 tubes (35W4 and 5085) for above amplifier. -y o úpß Complete with tubes. Shpg. wt. ' 2 costonly1cent. 8 lbs. Both for 28 VM 2 SPEED AUTOMATIC RECORD CHANGER IT'S EASY TO ORDER FROM OLSON'S Now you can take advantage of How to order Order directly from this ad, For con- this deal that Olson ran across. venience use this order blank. Fill in columns below Incorporates the latest design with quantity desired, stock .number. description and to play the records In most de- erice. You ay send remittance with order [include MONEY BACK GUARANTEE: mand. 78. Records Hough for postage or parcel post 331,3 and 1` shipment,, or if you Everything you from may even be intermixed on the prefer SEND NO MONEY. Olson will ship C.O.D. and order spindle. Will you may pay mail or expressman for merchandise and Olson is guaranteed as ad- 12" din onee load- With every postage. vertised. If you are not ing. Records slide down the VM more than satisfied, you may center shaft with utmost you order, you return merchandise for cash precision. Low pressure tone an tean WE SHIP SAME DAY refund. arm is quipped with an RCA trn -over cartridge and two AC Cord h needles. SV WE GET YOUR ORDER Please Minimum Order 53.00 Stock No. afteralast record. Has ejereject ae 754 - coulr RA -99A button also. Sise 12" x 13 ".t cost only 1 cent. e Operates on 115 volts AC. Each 60 QUANTITY TOTAL cycles. Shpg. wt. 15 lbs. NUMBER DESCRIPTION EACH 5 TO 50 WATT WIREWOUND KIT +Contains 50 Resistors Think of it. You get 50 brand new Wireoundw' Re- ic i No. sistors in a wide range of Stock ohmages from 5 watts to 50 With every AS -63A .watts. That's less than 7e Wirewoond Kit each. These resistors would that you order, cost you at least $20.00 if you can get an bought separately. But Ol- 8 ofd 450 volt I son bought the the stock condenser -re- $349 of a tremendous manufactur- tail alue er and you can cash in dur- $1.25 - your ing this big summer sale. cost only 1 sent. I NOTICE -RADIO MANUFACTURERS Olson Radio has established a tremendous market g radio servicemen, amateurs, universities and industrials all over America as well as countries. Our famous rapid mailing service is the talk pritci tl foreign I If you have any good, clean surplus radio material which you wish to dispose of. contact Olson at once. We can use: Radios, amplifiers, condensers, chassis, phono motors, pickup arms, volume controls, test equipment, speakers, in fact any radio or electronic part or piece of equipment. Here is your opportunity to torn idle inventory into cash.h. Write, wire or I call Olson, the popular name in radio. TOTAL INAME SEND FOR OLSON'S BRAND NEW BARGAIN CATALOG. GET NATION- ALLY FAMOUS RADIO PARTS AND SUPPLIES AT BIG DISCOUNTS ADD CLEVELAND, OHIO CHICAGO, ILLINOIS IADDRESS POSTAGE 2020 Euclid Ave, 623 W. Randolph Street If you live in or near Cleveland If you live in or near Chicago visit our store, get these and many visit our store, get these and many TOTAL more bargains. more bargains. CITY I ZONE -STATE AMOUNT MAIL ORDERS SHOULD BE SENT TO AKRON, OHIO - ° OLSON RADIO WAREHO August, 1332 91

www.americanradiohistory.com P. R. Mallory & Qo., Inc. of Indian- apolis 6, Ind. 630 STANDARD INDISPENSABLE! The new publication contains com- TV KIT plete cross -reference charts, specifica- installation For 121/2" Tube tions, and illustrated With the new Cascode Tuner. Com- PH0T0FACT BOOKS instructions for replacing car radio plete set of finest selected parts for of mobile communica- the well known and original RCA 630. and other types Comes complete with all tubes, hardware and step by tion equipment vibrators and their ac- step instruction manual. Less CRT $99.99 cessory buffer condensers, along with a & wire. list of the company's recommended 630 SUPER DELUXE 31 -TUBE TV KIT replacements. Some as above, including voltage doubler & AGC. $ Listed are the original equipment re- For all tubes 16' to 24' 119.44 ceiver manufacturer and his model the numbers of the cor- SIGNAL TRACER KIT numbers with Complete with probe, tubes, 4" responding Mallory replacement vibra- speaker. Battery operated. capacity values of secondary Make servicing a pleasure with tors. The a signal tracer. Can trace a Photofact Television Course. Covers TV principles, oper- buffers and the correct replacement signal from antenna to voice ation and practice. 216 pages; profusely illustrated; 81/2 coil. Locate those devilish inter - x 11". Order TV -1 Only $3.00 units are also given. mittents with ease. Will pay for cross -reference charts include itself the first week. Comes in 2nd edition Describes all Other Television Antennas. New applications, beautiful gray metal cabinet. Less TV antenna types; tells how to select, install, solve troubles. vibrator types with their batteries. $10.95 Saves time; helps you earn more. 200 pages; illustrated. vibrator numbers Only $2.00 original equipment Order TAG -1 with correct replacements, and re- THE FAMOUS WILLIAMSON Television Tube Location Guide. Volume 2. Accurate AMPLIFIER FOUNDATION KIT vibrator numbers with cor- CT mils. diagrams show position and function of all tubes in hundreds placement 1 Power trans. 810 volts I' 225 of TV sets; helps you diagnose trouble without removing rect replacements. 6.3V 8 amps. $6.95 chassis. 224 pages; pocket -size. Order TGL- 2. Only $2.00 5.0V l' 3 amps. 2 10 Mfd 600 volt oil cond. with brackets. Television Tube Location Guide. Vol. 1. Over 200 PICTURE TUBE DATA $1.14 ea. 2.28 on hundreds pages of TV receiver tube position diagrams The Cathode -Ray Tube Division of 1 12 -Hy 250 mil choke 70 ohms. 2.95 of models. Order TGL -1 Only $1.30 1 Hi fidelity Chicago output trans. (See below) 4.89 Allen B. Du Mont Laboratories, Inc. 17.07 Making Money in TV Servicing. Tested proved methods of a of operating a profitable TV service business. Covers all has announced the availability If purchased as unit $15.99 important phases. Authoritative, valuable guide to success. of its Tube Data MM -1 Only $1.25 new edition "Picture Over 130 pages. Order Chart." WILLIAMSON TYPE HIGH FIDELITY Servicing TV in the Customer's Home. Shows how to The chart, printed on heavy stock OUTPUT TRANSFORMER diagnose trouble using capacitor probe and VTVM. Short- Pri -9000 ohms. Sec -8 ohms. Freq. cut methods help save time, earn more on outside service and suitable for wall mounting, lists range 30 cy. to 20 KC ± Yzdb. Used TC -1 Only $1.50 calls. Order the electrical and physical character- for PP 807S- KT66S. Made by Chica- go Transformer Co. Selling at a frac- Manual. Vol. 3. Covers 1949 -1950 Record Changer istics of any modern RTMA- registered tion of its original made in 1949, including multi -speed changers 44 models cost. and wire and tape recorders. Original data based on actual TV picture tube. $4.89 analysis of equipment. 286 pages; 81/2 x 11 "; paper- Now in its fifth printing, the new THE NEW CASCODE TUNER bound. Order CM -3 Only $3.00 chart has been especially designed for For all sets: 630, etc. Complete 1948 -1949 Changer Manual. Vol 2. Covers 45 models with television re- with schematic. Our new low $19.95 made in 1948.49. Paper bound. Order CM-2. Only $4.95 those concerned price ceiver design, research, and servicing. 1947 -1948 Changer Manual. Vol. 1. Covers 40 post- are obtain- RAM TV CONVERSION KIT war models up to 1948. Order CM -1 Only $3.93 Copies of the new chart For all sets. Convert your 10' or 12' set to any size Consists of 16KV High Voltage Flyback Sound. Edition. able from the company's tube distrib- up to 24'. Recording & Reproduction of 2nd Trans. 70 °. Full focus cosine yoke, linearity coil, widtt New, completely revised and vastly enlarged edition of the utors. 30 treat- coil and 500 Mmfd 20KV mica $ outstanding original volume. The most authoritative cond. List $25.00. 1 1.95 ment of all phases of recording and amplification ever A multi -purpose test lamp finds many uses written. Over 800 pages. 6 x 9'. Order RR- 2 .Only $7.95 OIL FILLED CONDENSER A three - on Fred J. Lingel's test bench. 10 Mfd. 600V. Rated at 220 v.a.c 10 for way bulb is mounted to the bench with a Standard brands 99E ea $9.2 5 short piece of metal strap of the type used Brackets. 150 ea. to hold packing crates together. The CARTER DYNAMOTOR lamp may be used as an eye -level source Stock No. 4037 AS input-6 of light for small work or for servicing in VDC Output-400 V (a) 375 $26.95 List $71.50 Brand new dark corners of the chassis. By connect- mils. ing the lamp in series with the set or ap- Complete catalogue of fest equipment. in upon request. pliance to be repaired, the lamp can be cluding kits, available used as a load check thus speeding the lo- When you deal with Acorn you save Write for Quantity Prices cation of a fault. It can also be used as a un- data on TERMS: 30% cash with order, balance Ç.O.D. Audio Amplifiers. Vol. 3. Clear, uniform, accurate continuity tester for transformer, motor, or rated. Prices F.O.B. our areheuse N. Y. C. 50 important audio amplifiers, plus full coverage of 22 FM 5 ,, ,vom order $3. NOTE: Due to conditions be- are subject to Change. and AM tuners, produced during 1950. 362 pages, 81/2 heater windings. Mr. Lingel also uses the yond our control. prices WOrth 4 -3270 x 11". Order AA -3 Only $3.95 lamp with its twisted cord as a dummy an- Phone Vol. 2. A complete analysis of 104 tenna load when he operates as W2ZGY. ACORN ELECTRONICS CORP. Audio Amplifiers. Y. well -known audio amplifiers and 12 tuners made 1949 -50. 76 Vesey St., Dept. N -8, New York 7, N. 368 pages, 81/2 x 11 ". Order AA -2 Only $3.93 Audio Amplifiers. Vol. 1. 102 amplifiers and FM tuners made through 1948. 352 p. Order AA- 1 Only $3.98 Auto Radio Manual. Complete service data on more than 100 post -war auto radio models. Covers over 24 mfrs. 350 pages, 81/2 x 11 ". Order AR -1 Only $4.93 COURSE Communications Receiver Manual. Complete analysis AUDIO (SOUND) ENGINEERING of 50 popular communications models. 246 pages, 81/2 x HOME STUDY TRAINING CR -1 Only $3.00 11 ".Order Prepare yourself, in your spare time for a B.G Radio Receiver Tube Placement Guide. Accurate dia- PAY JOB as on AUDIO ENGINEER. Practical, written by nationally grams show where to replace each tube in 5500 radio easy -to- understand lessons, and models, covering 1938 -1947 receivers. 192 pages, pocket - recognized Audio Engineers Educators. size. Order TP -1 Only $1.23 Prepare for a SUCCESSFUL CAREER in the TEL RADIO, DISC AND TAPE RECORD- made EVISION, Dial Cord Stringing Guide. Vol. 2. Covers receivers ING, ELECTRONICS AND MOTION PICTUIRE you the one right way to from 1947 through 1949. Shows INDUSTRIES. thousands of models. Pocket-size. Order string a dial cord in with present employ- DC -2 Only $1.00 Training will not interfere ment. Dial Cord Guide. Vol. 1. Covers sets produced 1938 EARN WHILE YOU LEARN through 1946. Order DC -1 Only $1.00 WRITE FOR COMPLETE DETAILS -TODAY B. M. Klekner, D.Sc..Ph.D. Yresidcnt Order from your Parts Jobber or write direct to 1HOWARD W. SAMS & CO., INC., 2201 E. 46th St., Indianapolis 5, Indiana HOLLWOOD TECHNICAL INSTITUTE 3359 Cahuenga Boulevard HOWARD We SAMS & CO., INC. Hollywood 28, Cdlifornia A: TELEVISION NEWS 92 IL.\11/

www.americanradiohistory.com Design Curves (Continued from page 43)

formulas. The nearest available value of 68,000 ohms is suitable for The only other value to be determined is that of condenser C. Reference to Fig. 6 shows that 3 db of boost is obtained at an abscissa value of approximately 1.0. We may now solve for C.

224 CR2 = 1.0

1 1 C 22rf R2 - 22, (500) (20,000)

C = 1.59x10-e = 0.0159 mirrofarad

A suitable value is 0.015 microfarads. We note from the curves that for this example the boost at 50 cycles can be about 14 db. Fig 4 shows these values placed in the circuit. It may be of interest to determine the gain of the circuit including the tone control. The "Resistance- Coupled Amplifier Chart" shows a gain of 45 to the plate of the 12AX7. Subsequent to the tube gain of 45 our circuit has a voltage divider formed by R. and R_ which attenuates the voltage by a factor (R.+R.) /R2, or 4.4. The over -all voltage gain, therefore, is about 10. This value of gain corresponds to the zero db reference level used in the curves. ILas- _%Itenualing fireuit A circuit designed to accomplish variable bass attenuation is shown in Fig. 7. This design requires that the equivalent source impedance of the tube V. be small compared to R.. In order to be practical we have assumed some source impedance in the equivalent circuit of Fig. 8 which was used for analysis. Because the use of this circuit does not cause any loss of gain, only one PERMA -TUBE sheet of design curves was considered necessary; there is no harm in designing for more attenuation than may be ... the Steel Television Mast that's UP to STAY! required. The curves of Fig. 10 were computed with the ratio R, /R2 equal to it was a big blow -the hurricane of vision grade 0.1 and R /R2 equal 10. PERMA -TUBE Steel to The curves November 1950 that hit the New a product that is pre -treated with are also substantially accurate if the York area with devastating force. Vinsynite and coated with a metal- ratio of R, /R2 is less than 0.1. It may Television masts were crumpled and lic- pigmented vinyl resin base inside be noted that this circuit gives a small flattened like straws in the path of and outside. amount of bass boost, the specific the wind ... all but those made of what's more, they're easily, amount depending upon the value of PERMA -TUBE. PERMA -TUBE quickly and economically installed. R,. This circuit is actually a special Masts Stayed Up! ... and why did Their new Fitted Joints can be PERMA -TUBE Masts stay up? For slipped together in a matter of sec- case of a circuit to be described in the the next very good reason that they're onds. And you can obtain PERMA - article which will give either bass made of sturdy, corrosion- resistant TUBE in standard lengths, diam- boost or bass attenuation with a single steel . . . Jones & Laughlin Tele- eters and wall -thicknesses. control. The method of applying the curves FOR COMPLETE INFORMATION -MAIL THIS COUPON TODAY! to a design problem should be apparent from a review of previous examples. We can think of no particu- Jones 8i Laughlin Steel Corporation 495 Jones 8. Laughlin Building lar pitfalls which might be encoun- Pittsburgh 30, Pennsylvania tered in the use of this circuit. The Without charge please send me:- only advice which seems appropriate J8L Name of nearest distributor is that a medium -mu triode is usually Complete information on Permo -Tube the best choice for V, in order to satisfy NAME the requirement for a small source im- STEEL pedance (R,) to the tone control. COMPANY (To be continued) ADDRESS August, 1952 93

www.americanradiohistory.com No Gall hacks\ WHAT IS [IIIOPIIOII? for me, pal Details on CBS's color system for theater TV lieewing, as recently unveiled in New York City.

THE EIDOPHOR projector, a devel- electron beam strikes the end of the opment of a group of Swiss scien- tube and causes the phosphor material tists at the Federal Institute of Tech- to glow point -by -point and line -by -line, nology and Dr. Edgar Gretener A.G. of with a brightness which is proportional Zurich, is similar to a motion picture to the point -to -point brightness of the projector. The arc lamps are practi- original scene. cally identical and projection lenses In the Eidophor projector, however, are used to magnify the desired images the electron gun causes the liquid to on the theater screen. take on tiny surface irregularities and Through the joint efforts of this thus to change its optical properties. Swiss group, CBS, and the technical The picture thus produced appears W. recommend staff of Twentieth Century -Fox Film very much like the relief image in TUNG -SOL Corporation, the original black -and- hardened gelatin used in some photo- ELECTRON TUBES tor Radio nd Tiri610n white equipment has been converted in graphic processes, after the silver im- order to provide color transmissions age has been bleached away. By means for theater projection. of auxiliary lenses and properly ar- In the case of the motion picture ranged mirrors the instantaneous pic- projector, a band of film carrying a se- ture on this "image bearing" layer of liquid is projected to the screen. Tung -Sol "Quality Control" recog- ries of images is passed intermittently through the light beam, a shutter be- The Eidophor image is in a position nizes but one standard. All Tung -Sol "optically equivalent" to the position Tubes meet the highest original ing provided to cut off the light while the film is traveling. In the Eidophor of the film in a standard projector. equipment requirements of leading im- This point should be explained further. radio and set manufacturers! Use projector, instead of photographic tv film, a of In the motion picture projector the Reliable Tung -Sol Tubes. ages on a strip of sequence images is created on a thin layer of a center line or the light beam passes TUNG -SOL ELECTRIC INC. special liquid (about the consistency through the center of the picture be- Newark 4, N.J. of honey) which is placed on a slowly ing projected and along the same line Sales Offices: Atlanta Chicago Culver City Dallas Denver Detroit Newark rotating mirror surface in a position through the center of the lens to the of center of the screen. In the Eidophor TUNG -SOL MAKES; optically equivalent to the position the film in an ordinary projector. The system, however, the light from the All -Glass Sealed Beam Lamps, Minia- auxiliary lenses to ture Lamps, Signal Flashers, Picture succession of images on the thin liquid arc passes through Tubes, Radio, TV and Special Purpose layer is produced by means of elec- a plane mirror arxanged in parallel Electron Tubes. trons deposited on the surface of the bars -and set at about 45 degrees to liquid. These electrical charges are the light beam direction -which re- proportional to, and controlled by, the flect half the light downward. (Half television signal, in much the same of the light because the width of the manner that a television signal is used mirror bars and the spaces between to produce an image on a regular TV them are substantially equal). Thus picture tube. half the light is lost, just as it is lost The essential difference is, of course, by the shutter blades in the standard that in the home receiver tube the motion picture projector. The light

Mechanical layout of the Swiss- inspired "Eidophor" theater projection system.

I. ARC LIGHT SOURCE. TUNG -SOL R. APERTURE PLATE. RADIO, TV TUBES, DIAL LAMPS 3. COLOR WHEEL. 4. CONDENSER LENS.

5. MIRROR BAR SYSTEM. 6. ELECTRON GUN AND DEFLECTION SYSTEM.

7. SPHERICAL MIRROR WITH THIN LAYER OF EIDOPHOR LIQUID.

8. ELECTRON BOMBARDED LIQUID AREA THAT MODULATES LIGHT BEAM. at- Here's a real lively "stopper" to 9. KNIFE EDGE DETERMINING tract attention to your place of busi- THICKNESS OF LIQUID LAYER. ness and emphasize the quality of 10. PROJECTION LENS. your service. Colorful-bright red and II. DIRECTING MIRROR. two shades of blue. 15 inches high. Your jobber salesman will tell you la. THEATRE SCREEN. how to get one.

II.\1 /10 Si TELEVISIONISION NEWS !1 1

www.americanradiohistory.com ARDIOz AUGUST, TELEVISION never 1931 NEWS static:

RADIO & SEPTEMBER TELEVISION 1952 NEWS

N 1NIS ISSUI

& Look - RADIOADIO just part of the September issue TELEVISION A converter which receives both phone and C.W.1 This unit transforms any a.c. -d.c. N EWS midget receiver into o full- fledged "communications" receiver! Ideal for the novice -o godsend for the seasoned amateur!

A Remotely Controlled AM Tuner! Five re- you can't afford lays - five different stations! Expand this miss great idea for operation of other type units! to a single vital "Data Print" No. 5! Pertinent details for conversion of small screen Television receiv- issue! ers to large screen operation!

A Two-Station Intercom! Build it for two- way conversational system in your home! Each month RADIO & TELEVISION NEWS is No "push -to- talk" switch needed! charged with new ideas, new cone -:pts, new profit methods in all phases of electronics. other top-flight articles regular features qsubscrlbo today! (lower per -copy soot saves you money)

Publishers also of RADIO- ELECTRONIC ENGINEERING edition of RADIC & TELEVISION NEWS PHOTOGRAPHY PHOTOGRAPHY ANNUAL, 1933 Editior MODERN BRIDE FLYING FICTION GROUP ZIFF- DA-VIS CDMICS tiugus1. 1952 95

www.americanradiohistory.com A catalogue covering the new "Sta- belex D" units is now available from MALE HELP WANTED USE PHOTOFACT the company on request. ENGINEERS - SCIENTISTS CAPACITY BRIDGE the world's best Radio and Simpson Electric Co., 5200 W. Kinzie, MATHEMATICIANS -STATISTICIANS Chicago, Ill., has developed an im- TECHNICIANS - DESIGNERS TV Service Data proved version of its Model 381 capac- ... ity bridge which makes it more com- COMPUTERS pact and easier to use. MACHINISTS, Precision A button is pressed for the desired range, the bridge arm is adjusted for Specialties: electronic, optical, mechani- maximum meter deflection, and the ca- cal, servo- mechanisms, etc. Fields: measurement. recording, transcrip- pacity is read on the scale. tion. computation and analysis of guided Ideally suited for radio and TV serv- missile and guidance systems performance. ice work, the new Model 381 is housed Work Types: operation, maintenance, de- in a bakelite case with etched alumi- sign, development, construction, research, num panel. study. Further information on this bridge Work at: lab, shop and /or outdoors. will be supplied by the company. INSTRUMENTATION

NEW CRYSTAL MIKE of guided missiles and aircraft blind WE'LL PROVE YOU'LL SAVE TIME The Turner Company, Cedar Rapids, navigation systems. Equipment worked with: cinetheodolites, PHOTOFACT Iowa, is now in production on a new and EARN MORE WITH ex- special optical instruments, recorders, crystal microphone which features radars, telemeters, data transcription de- tremely compact construction. vices, digital computers. many types of Service Technicians: Although not much larger than a IBM equipment. We'll send you any cigarette. the frequency response is 80 Locations: Air Force bases near Alamo - Photofact Folder listed in rnrdo. New Mexico and Dayton, Ohio. FREE the "PF INDEX and Tech- Other openings: throughout U. S. A. and nical Digest." If you ( world. haven't an Index, get a free copy from Advantages: excellent opportunity for advancement, rapidly expanding organiza- your local Photofact distributor or write tion. Personnel and family transportation for it today. To obtain Free Folder, be sure reimbursed, company -paid insurance, and to state Photofact Set and Folder Number other benefits. as shown in the Index. Salary: you'll be interested! Write for application form to: NOW -learn for yourself how PHOTO- FACT makes your Radio and TV work LAND -AIR. INC. quicker, easier, more profitable! get to 7000 cps with a sensitivity of ap- Just Hollomon Air Force Base New Mexico and use an actual PHOTOFACT Folder. proximately 58 db below 1 volt /dyne/ Discover why over 35,000 successful sq. cm. service technicians count on this invalu- Additional details on the Model 80 able data daily. No other service gives microphone are available from the you PHOTOFACT'S completeness, accuracy, company on request. uniformity and lowest cost. PHOTOFACT is NEW ELECTRONICS the only Radio -TV service data prepared SINGLE -PHONE HEADSET from laboratory analysis on the actual Airphone Co., Suite 309, Calument equipment. Get your FREE Folder now. TRACERS Examine, use, compare. See why you Building, Miami, Florida, is now offer- SIGNAL can't afford to be without PHOTOFACT! ing a new CAA -approved single -phone type headset to the trade. NOTE: Our FREE Folder offer is limited to The new "Airphone" consists of a Service Technicians only. Attach coupon be- specially designed miniature earphone low to your letterhead and mention your in jobber's name. Experimenters and others similar to those used hearing aids, may obtain the Photofact Folder by remitting hut more rugged in design. The ear- amount shown below.

HOWARD W. SAMS & CO., INC.

HOWARD W. SAMS & CO., INC. 2201 E. 46th St., Indianapolis 5, Ind.

I am a Service Technician. Send me Free Folder No ... which appears in Photofact Set No. (as listed in the PF Index).

I am an Experimenter. Enclosed $ Send me Folder No which appears in Photofact Set No. ITV- $1.00. AM /FM -50c. Record Changer. or Communication Receiver -75c) phone is attached to a supporting, in- Name dividually -fitted earpiece by means of in- Address a snap fastener. Component parts Write for literature and clude a personal volume control with name of your nearest Jobber City Zone State lapel clip, two double- twisted vinyl covered cords, and a PL -55 plug. PAY AS YOU EARN! Ask your FG\S\ON X.VE«QONVa,V. The complete assembly weighs only 111, AVE EASY distributor about this amazing 6 4\-64 M \ VMP1L`F-`NO,S 12 22, l\`1 plan. Only $18.39 puts the en- 21/2 ounces but is said to be times CN\ cPGO PAY 411. tire profit- boosting Photofact more sensitive than conventional head- PLAN! library in your shop now! phones.

102 WWII/ TELEVISION NEWS

www.americanradiohistory.com Spot, Radio News (Continued from page 18) /1 that the ... "welfare of the people and not the happiness of the FCC is at stake in this situation. . . . Every applicant is entitled to his day in court without years of delay and it cannot SALES INC. be given to him unless we provide the money to hire the minimum of exam- SCR 62S Famous Mine Detector MN26C B E N D I X RADIO For Prospectors, Miners, Oil Companies, iner teams." According to the Sen- Plumbers, etc. ators, the appropriation of $800,000 COMPASS 'Phis unit is being offered now at a consider- can "set in motion a chain reaction able reduction in price. Recently advertised at ...... complete with tubes, MN28C con- 579.50 it is now available in the same brand which in two years' time will create trot box, loop transmission cable. new wrappings in ,uitcase style carrying case $3- billion in business ... figures which UN20E loop, flexible ca- tress batteries) at WHILE are ultra- conservative." Lilt's, plugs, etc $67.50 $59 LASTHEY "We ought not to shirk our duty," 50 members of the committee declared. Tee0g4 1f;' cte Pzceea "We ought to appropriate the money eelcea Cede - pm to authorize the recruiting of the 20 BC-733-0 LOC .ILI'LED IRECI:IVI ;IR. Complete with SCR -522 1 III, TRANSMITTER & RECEIVER. Avail - tuhe.. and er u lal,. able a. cnmpa re rie.tallation or just transceiver. examiner teams or frankly tell the DM53-A DYNAMOTOR for above. R89 /ARN -5 ej,IDI? l'ATII RECEIVER. FT -293 MOUNT for 733 R57 GLIDE PATH RECEIVER. people that because money is not avail- BC -732 CONTROL BOX for 733. BC -638 -A FItEYlttt:N(Y METER. l'LUOS for 733. BC -376H TEST OSCILLATOR. able for processing their television ARN -7 AI-TO\IATIC DIRECTION FINDER. Complete IDS /APN -4 LORAN INDICATOR. applications, they must wait 6 to 10 installation. R9 /APN -4 LORAN 1:1;c1:1,1.11 POWER r--4ITP1.Y: SCR -269 -G .\ t' TOM A TIC DIRECTION FINDER. RT34 /APS -13 TRAIT.- WAR-XIN(7 TR.ANsl' h:IVE11. 420 years for TV in many areas of the complete in-tallat ion. \IC, States." United COMMAND EQUIPMENT (SCR -274N) Used New Used New DOLLARS REQUIRED for the ex- BC -442 ANTENNA RELAY. Less eolid.S 1.95 BC -453 With tubes $19.95 n ith road. . . . $ 3.95 Less tubes . 14.95 aminers and other members of the BC -451 TRANSMITTER CONTROLT BOX 1.50 MC -211 90° ANGLE COUPLING UNIT. $0.95 BC -450 3- RECEIVER REMOTE FT -234 MOUNTING RACK for single Commission was also the subject of a CONTROL BOX 2.95 transmitter 2.95 3.50 MC -215 MECHANICAL DRIVE SHAFT. FT -226 SIOUNTrNG RACK for 2 Corn- Per length ...... - . 2.95 Mond Xmtrs. . . . . 3.95 fighting talk by Commissioner Ed Web- BC -496 2-POSITION RECEIVER FT -221 MOUNTING PLATE for FT -220 1.50 CONTROL BOX 2.95 FT -220 MOUNTING RACK for 3 re- ster, before the Indiana Broadcasters BC -459 Less tubes ...... 12.95 ceivers ...... 2.25 BC -455 6 -9 MC RECEIVER. With tubes 9.95 14.95 FT -225 MOUNTI \G PLATE for 8C -456 2.25 Association. Leas tubes 7.95 BC -456 MODULATOR. For SCR -274.. 4.50 Noting that often many have asked why the Commission with over a thou- NON,ttey S&iced! sand employees should have any diffi- Gí REVERSIBLE MOTOR culty disposing of the matters that 2 TRANSMITTERS RL -42 24 VDC. With antenna reel and clutch. BC -457 (4 -5.3 MC, and BC -458 (5 -3.7 MC). USED $4.50 come before it, Webster declared that ('onmlanrl tranoni tt crs. Shipment just in. Lim- ited (Quantity. L,..+ tubes and xtals. Good cond. N K\V 6.75 the average person has no conception I:. )CI I $4.55 l'EIt SET. 9.50 of the innumerable duties and respon- sibilities of the Commission and its MOTOR ARC -4 TRANSCEIVER staff. Explaining the structure of the 24 VDC. Series wound, reversible, riitIi clutch. 140 -144 VIC. Complete with control box, tube,, Turns 11,000 RPM, geared to 1,100 Itl'\I. Corr- 12/24, VDC dynatnotor. This is a special rednc- Commission's staff, the Commissioner plete with junction box, 2 ad.iu.tahl $9 rim, tr i thi. month only. @qe1 said that of the 1115 persons employed, limit switches. Good rou,titoar IDD 95 Lila n, 7 JJ LL. 50 393 are located in field offices throughout the country. There are 722 em- G7 N dceileuteoad Sfiecíaed ployees sparsely scattered throughout T -32 -DESK STAND MICROPHONE. Good used condition $ 2.75 35 HS -18- HEADSET, 8,000 ohms. New 2.45 Washington, with assigned to the HS -30- HEADSET, Featherweight type, low impedance. New, $2.49, Used 1.49 Commissioner's offices, 16 to the gen- HS -38- HEADSET. Used, excel. condition, $1.49. New 3.50 HS-23-HEADSET. High imp. New, $4.95, HS -33- HEADSET. Low imp. New 6.95 eral counsel's office, 22 to the chief CD-307-EXT. CORD for HS- 23 -33. New, 95e. LIP MIKE. Navy Type, new .98 EXTENSION CORD and SWITCH ASSEMBLY for lip and throat mikes. New .98 accountant's office, 77 to the chief engi- RS -38 -MIKE- New, $4.95. RS -38 -MIKE. Used 1.75 neer, 59 to the field engineering and 1 -97 -BIAS METER. New, $3.95; Used 2.95 TU -6- TUNING UNIT. (3 -4.5 MC) for BC -375 and BC -191. Used 2.95 monitoring bureau, 127 to administra- PE- 125 -AX POWER SUPPLY for BC -223 Xmtr, 12/24 VDC input. New 14.95 tion, 7 to the opinion and review CATHODE RAY TUBES 3FP7 $ 1.95 5FP7 $1.95 4AP10 95e section, 32 to the 5C P1 4.50 5BP1 secretary's office, 20 16DP4 4.95 16JP4 $19.95 to interdepartmental activities, 110 to 19.95 5BP4 3.95 All these carry a 90-day guarantee! 7U-17-TUNING UNIT ( 2 -3 MC. r for BC -223 Transmitter. Used 2.95 the safety and special radio services 7U-25-TUNING UNIT (3.5 -5.2 MC) for BC -223 Xmtr. Used 2.95 bureau, 84 to I- 70- "S" TUNING METER. New, $2.50. IN- 4A -L /R TUNING METER. Used 3.95 the common carrier FL -8 -RANGE FILTER $1.95 FL -5 -RANGE FILTER. '1.25 bureau and 121 to the broadcast bu- WOBULATOR: See Page 43, Dec., '61 RADIO NEWS 5.95 BC -709- INTERPHONE AMPLIFIER. Battery operated, light wt. Complete with tubes, shock mount reau. In addition, there are a dozen and Instruction Manual. New 3.95 clerical assistants in various offices. RC- 43- MARKER BEACON ANTENNA INSTALLATION KIT. Complete with plugs and insulators. Less wire. New.. 1.95 Of the 121 in the broadcast bureau, BC1023 -75 MC. MARKER BEACON RECEIVER. Complete with tubes, mtg. rack. New 10.95 only 61 are professionals: 27 engineers, 22 lawyers, and 12 accountants. It is MC -217 COMBO LOOP MOTOR to this group that the problems of AND AUTOSYN TRANSMITTER BC -624 VHF RECEIVER. Freq. rarae torl.t SR \1C. ASSEMBLY. Complete with instructions for Less tubes & crystals. with enmersiso modifications, license renewals, assign- matching to I -82 Indicator. Used, excellent dope. Used, good rnnd. $19.95 BC -625 VHF TRANSMITTER. Fr ranee 11111-1 ;r, ments, and transfers are relayed. And, condition. MC. Less tubes & crystals, wi th c,n version dope. Used. good Condition- $12,95 declared Webster, only thirteen mem- Only BOTH & RECEIVER. $12.50 eTRANSMITTER $29.95 bers of this staff, or 6 engineers, 2 lawyers, 2 accountants and 3 secretaries, ` INDUSTRIAL CORPORATIONS $5.00 MINIMUM ORDER ACCEPTED. All shpts. F.O.B. RVrite or wire for our new Catalogue listing whse. Cal. re >idents add sales tar. with remittance. 20 ;'i are in the television division, which is complete line of Military Electronics Equipment. dep. Specify slips. instructions. expected to handle the forthcoming avalanche of applications for new sta- 7460 N. Varna tions. Describing North Hollywood, California the processing problems ARROW SALES INC. SUnset 3 -7319 that are expected, on the basis of prior experience, the Commissioner said that Cable Address: ARROWSALES August. 1952 103

www.americanradiohistory.com undoubtedly, hearings on at least 500 pounced by several operators. No defi- OIL FILLED CONDENSERS applications will be obtained soon after nite programs can be set up until the ALL NEW! ALL GUARANTEED! ALL BARGAINS! summer has set in. With the present FCC decides whether the present rules I mfd 600 vde C.D 76010 $ 0.79 2 mfd 600 vde C -D TJL -6020 .89 staff of seven examiners, it might be permit the use of a beep signal for 2 mfd 600 vdc Aerovox 605 .89 8 x 8 mfd 600 vde Tobe plug in 1.59 possible to take care of 84 cases a year, switching talk programming. It is ex- 12.75 mfd 600 vde)C -D XX3127A 2.95 it was noted. But, he said, there's more 10 mfd 500 vdc CD TJU -15100 4.75 pected that a general rule- making 15 mfd 2000 van C -D TJH -15150 6.95 to it than this, for 5 mfd 2000 vdc C -D TJU -20050 4.95 hearings must be hearing on the subject will be held soon 6 mfd 2000 vdc C -D TJU -20060 4.95 10 fd 2000 vin C -D TJU -20100 6.95 held on matters involving services other so that industry will be able to plan 2 mfd 2500 vdc Industrial 25SAU2C0 3.39 4 mfd 2500 van Aerovox 2509 5.95 than broadcast. As a matter of fact, accordingly. 10 mfd 2500 vde C -D TJU- 25100A 7.95 I mfd 3000 vde C -D TJU -30010 3.50 he noted, there are now two common Before the courts called 0.1 mfd 4000 vde C -D TJU -40001 2.50 transit -radio 0.5 mfd 4000 vac C -D TJU -40005 3.45 carrier 2 mfd 4000 vdc Aerovox 4009 5.69 matters designated for hearings illegal last year, about a dozen cities 4 mfd 4000 vde C -D TJ- 40040G6 11.95 0.02 mfd 5000 vdc CD MV -843 1.98 which may take six months from the featured a transit -radio service : St. 0.1 mfd 6000 vdc Aerovox 6012 2.75 1 mfd 6000 vdc C -D TJ- 600010A 6.95 beginning to the issuance of initial Louis, Cincinnati, Houston, Washing- 0.01 mfd 7500 vdc Aerovox 7512 1.65 0.03 mfd 7500 vde Aerovox 7512 1.85 decisions by each of the two examiners ton, Worcester, Tacoma 0.1 mfd 7500 vde Aerovox 7512 2.95 (Wash.), Ev- 1 x 1 mfd 7500 vac Aerovox 7520 27.50 designated to 0.02 mfd 8000 vdc Aerovox 10233 1.95 hear the cases, leaving ansville (Ind.), Wilkes -Barre (Penna.), 0.65 mfd 12500 vde C -D 18120065 -1 19.50 3 mfd 12500 vdc West Inerteen 258043 49.50 five examiners for TV and all other suburban Pittsburgh, Allentown (Pen - 0.25 mfd 15000 vdc Aerovox 15020 17.50 0.03 mfd 16000 vdc GE 26F380 4.95 hearings. In view of this, Webster felt na.), Huntington (W.Va.), Des Moines 0.25 mfd 20000 vdc GE 14F64 27.50 1 mfd 25000 vdc West Inerteen 1166899 49.50 that it would not surprise him if no (Ia.), Topeka (Kan.), and suburban G -E PYRANOL SUPER SPECIALS more than 60 to 70 TV application Washington. 0.5 mfd 5000 vdc. GE 26F405, with mounting brackets, 33/4" x 41/2" x 21/4" S 3.95 hearings would be conducted within Before transit -radio was introduced 1 mfd 5000 vdc, GE 23F49, 33/4" x 41/4" x 41/a" 4.95 the next year. in many communities, 1 msfd 10000 vde, GE 14F104. 71/2" x 91/4" x assorted surveys 27.50 It is sincerely hoped that everyone were made to determine its virtues. In 12 mfd 1500 vde 0.5 mfd 2000 vde will realize the seriousness of the Com- St. Louis, a study made by a newspaper Industrial 15SAU1200 C -D Dykanol TJU -200501" 4,. 4X/8 17/e'. x 2%a,. 33 /a (with bracket) mission's plight and funds will become and a university indicated that nearly $4.95 51.45 available immediately to hire the ur- 75% favored radio in buses and trolley RELAY BARGAINS Save up fo 75 %p1) gently needed legal staff. cars. Commenting on 6 VDC or 24 l' 60 cy AC. Large Contact, the survey in an 8P-ST $1.89 4P -ST $1.69 editorial, the Post -Dispatch said that KLIXON circuit breaker. 5 A. bakelite handle, two TRANSIT RADIO, providing for the poll hole mount with ON -OFF plate. 2" x 4s" x 1" the revealed some interesting re- Only 69e, 10 for $5.955 pickup of programs in buses or street- sults: "Young people are overwhelm- NOVICE 80 METER CW XMTR cars, which has been subjected to some ingly for music on the streetcars. Here's a neat and compact surplus item which con - arts very simply to 3700 -3750 KC crystal controlled. rough treatment in the courts, finally Nearly 93% of them favor it. Older Condition? Guaranteed suitable. Instructions? Yes. we furnish them! Complete. comprehensive. step-by- won its freedom, and from the highest people, those 50 years of age and more, step; nothing left to guesswork. This is 5.3 -7. the command transmitter which has been such a favorite bench in the land. In a 7-to -1 vote, are less with Id- timers. By the time this ad appears. the the enthusiastic. That the objec- BC -4.57. described in November QST. will be all gone. so we worked out the conversion on 5.3 -7. It had to Supreme Court declared that it is per- tors object, there can be no doubt... . be converted anyway. so why not convert the lower priced and available unit? Just as easy. Now don't fectly legal to broadcast news, music, At this point, the 'ayes' seem to have wait until these are all gone! ONLY 57.95 and commercials to vehicles, and it is it." COMMAND EQUIPMENT not an invasion of privacy as cited by With free dope sheets and schematics RECEIVERS the Circuit Court of Appeals a year THEATER TV, whose future has been BC -455. 6 -9 mc. NEW 512.95. GOOD USED $7.95 TRANSMITTERS ago. questioned by many because of the T -19 /ARC-5, 3 -4 Excellent...... $17.95 BC -457 r T-20 /ARC -5, 4 -5.3 - Like new. 12.95 According to Associate Justice Har- repeated hearing delays, will MOD BC -456. Brand new 55.95. eExcellent used 2.49 now have As. is. for parts...... : .. 1.29 H. 274N PLUG. 7 -prong t ale plug to lit back of command old Burton, this form of broadcast- to wait until next year, or specifically v s. and trs. This is the same plug as used In the racks.r NEW each 21e; five for.. 51.00 ing does not violate the First and Fifth January 12. 1953 before its place in the L ucal Control Adapter Parts for 2 74N or ARC -5 rev, Exact pot, switch. knobs, etched plate, and instruc- Amendments to the Constitution, which sun can be determined. Originally de- tion data. Ready tomount $1.29 SPLINE TUNING KNOB 79c guarantee freedom of speech and pro- layed by the pressure of allocation BUILD TV -FM -AM SWEEP GENERATOR tection against taking away liberty or business and other acute communica- (See Dec. Radio 6 TV News) Now you can build that VERSATILE SWEEP FRE- property without due process of law. tion problems, a shortage of manpower QUENCY GENERATOR "I We've got a few more of those vital APN -1 magnetic units. With reprint of the arti- In his decision, Justice Burton wrote has now been cited as the reason for cle 56.95 that however complete the passenger's postponement. SUPER HI -FI HEADSET BUY! privacy ... "may be at home, it is sub- Uses annular -grooved plastic fibre cones with voice ocoils as in speakers, and padded chamois ear muffs U) stantially limited by the rights of A btain spacing for correct acoustical load. Gives finest DESPITE CONSIDERABLE tend- music reproduction, fiat far beyond upper and lower limits of auditory perceon. Pair in series has meas- others when its possessor travels on a ency toward more extensive use of ured impedance off 600 ohms at 1000 cycles. obtained with built -in high quality transformers. However, se- public thoroughfare or rides in a pub- very -high frequencies for voice com- vere makes no apparent difference. For rior to crystal phones. Manufacturer's net price is lic conveyance." munications between aircraft and 545.00 per pair! tEach unit can also be used as high quality dynamic mike with 300 ohm output impedance.) Associate Justice William O. Doug- ground, high- frequencies will con- They come to you checked out with freshly laundered chamois pads In cellophane bag. Our iginal Navy lot las, lone be in sold out immediately. but we managed to locate more writing the dissent, declared tinue to used many parts of the in Hawaii. Seems that's all that's left, so better not wait! Get yours now $7.95/ 7 that outside the house, one . . . "has world for the forseeable future. Thus immunities on Edgar A. Post, superintend- CHAMOIS HEADSET PADS. Clean. In glassine bag. from controls bearing reported wear Pr. They're a real pleasure to $1.50 his privacy." In his opinion . . . "if ent of navigational aids for the United BROADCAST BAND & AERO liberty is to flourish, government should Air Lines, in an interview on a sympo- MN -26 -C Remote Controlled navigational di- never be force people to sium on internationl air transportation rection finder and communications receiver. allowed to Manual DF In any one of three freq. bands, listen to any radio program." He felt conducted in Copenhagen recently, dur- 150 to 1500 KC. 24 V. Self contained dynamotor supply. Complete installation, includ- that forcing people to listen to the ing which communications and elec- ing receiver, control box, loop, azimuth con- of 20 airlines, 30 manu- trol, Left -Right Indicator, plugs, l@oocpQetrans- ideas of others created a powerful tronics experts mission propaganda weapon. "Today it is a facturers, and 6 other international BRAND NEW, ORIG. PACKfts. tvs7 uJ MN -26 -C alone, New $39.50 business enterprise working out a radio organizations and agencies, plus the MN -20 -E Loop, Brand new 6.95 7 MN -52 Crank drive, New 2.50 program under the auspices of govern- civil aviation departments of states ment," the Justice continued, "and to- and the military air forces of 3, parti- PORTABLE POWER KITS morrow, it may be a dominant political cipated. 1. Includes 2 volt, 20 AH wet cell lightweight transparent plastic, fibrite separators. 3 ball hydrometer. religious Once is 4" x 3" x 51/2" high, shipped dry: also 2 volt syn- or group. ... privacy One of the interesting technical sub- chronous vibrator, no tube needed: also 2 volt charger, is a 113 v 50/60 ry in. This high quality unit uses step - invaded, privacy gone.... Once jects discussed at the meeting was the down. transformer and dry disc rectifier. with pilot lamp in output to indicate and regulate charging rate. man is forced to submit to one type of possible operational advantage of sin- With eyedropper type battery filler and instructions. ALL 4 ITEMS, BRAND NEW $4.93 radio program, he can be forced to sub- g l e- s i d e b a n d over double -sideband 2. Six volt Vibrapack kit. Vibrator plus non -sync transformer with two outputs: 345 v 145 ma for mit to another. ... It may be but a transmission on the high frequencies. plates. 15 v for bias. With schematic. GAseG BRAND NEW .717 short step from a cultural program to It was pointed out that the ssb system ANTENNA MAST SECTIONS. MS -49. 50, 51, 2, a political program." consists basically of transmission of 55. New, original packing Eaeh39C The decision, won by WWDC -FM in messages on a carrier tone and one side - G.L. ELECTRONICS Washington, created quite a flurry of band, rather than with the two side - 905 S. Vermont Ave., Los Angeles 6, Calif. along -radio row, with bands which is customary. A form of All Prices F.O.B. Los Angeles Cal if. Buyers Add Sales Tax activity transit SEND FOR OUR CATALOGUE. temporary plans for expansion an- ssb using a voice -suppressed carrier 104 RADIO 8- TELEVISION NEWS

www.americanradiohistory.com THE NEW IMPROVED AIREX "630 FA"* TV CHASSIS ... DESIGNED SPECIALLY FROM RECOMMENDATIONS OF TV SERVICEMEN AND ENGINEERS ALL OVER THE COUNTRY Tube Mtg. Brackets $6.50 - This amazingly advanced 30 tube TV chassis is years ahead in Specify Tuse Size sue engineering and gives you the ultimate in TV viewing and listen - ing pleasure. To assure you trouble free TV our engineering staff has incorporated into the "630 FA" design the experiences I! of hundreds of TV servicemen and engineers. Receiving range includes stations up to 200 miles away. Nothing has been spared to bring you this finest of TV chassis. Only the best and most Mfr. expensive parts are used. There is no other chassis that com- RMA Lic. pares with the "630 FA" *For fringe area. GUAR. by RCA \ CHECK THESE EXCLUSIVE FEATURES V 10 WATT push -pull audio output. Frequency range from 60 to 12,000 cycles Link coupled Standard Coil Cascode Tuner prevents radiation Retrace Blanking Circuit allows you to raise the brightness without the annoying vertical retrace lines Heavy duty front focus control Automatic gain control potentiometer allows you to adjust the threshhold sensitivity as low as 4 microvolts & still keep the full 4MC band width Separate high & low frequency sync amplifiers Set aligned for 21.75 MC. New Ham band will not interfere Im- proved fused high voltage power supply gives full 14.5 KV under load Will handle all picture tubes up to 24 inch with full sweep Improved video amplifier has a gain of 32 All moulded plastic condensers give long life & trouble - free operation New TIOGA tube. Thermal delay allows filaments & parts to warm up before B+ is applied -preventing parts & small tubes from breaking down because of surge voltage. Protects cathode emission of picture tubes & gives longer tube life Easily adapted fo new UHF stations in 2 minutes by iust changing a strip in the tuner Extra heavy duty power transformer with large safety factor 6CB6 tubes in Video IF to give full gain Extra filtering in power supply for hum & ripple free operation Color connection on with chassis which is adaptable to the cathode followero er circuit of color converter '. Ph ono Connectionf switch'tl h on chassish allows youy to play your phonograph or 12'' RCA tuner through the built -in 10 watt hifidelity amplifier Extra heavy duty focus coil, whichi runs cool.I Hi -Fi Speaker wy7 Complete Service Manual á Lets CR FED. TAX INCL. SEND FOR FREE NEW TV PARTS & Tube For "630FA" or Super 630DX -S1 I HIFIDELITY EQUIPT. CATALOG

SUPER 630 DX 30 TUBE TV CHASSIS 38 BARGAIN -PRICED CABI. NETS FOR THE 630 AND TV TUBE EXTRA WITH STANDARD OTHER TV CHASSIS . . . Standard Brands -Black Glareless COIL Send for FREE folder and price Factory list. Full line table models. New -1st Qual. -Guar. 1 Year 7J1'4 ...$14.95 1 7 GASCODE TUNER. 94095 consoles, consolettes and Radio - ' BP4 $27.95 ax TV Phono combinations. Many 1OBP4 ... 17.95 20" TV Tube 34.95 INCLUDES 12" RCA HI-7-1 SPEAKER Incl. styles. Mahon.. Blond etc. 16GP4° .. 24.95 21" TV Tube 39.95 16JP4* . . 24.95 24" TV Tube 69.95 All n rch.ntdise Is brand new. factory fresh @ fulls guaranteed. Mail & phone oilers filled upon receipt of certified check tt or money order for $25 as deposit on TV chassis. tort On other items. Balance C.O.D.. F.O.B N. Y. Prices Ring and Sleeve for 24" Tube.. $7.50 subject to change without notice. No Fed. lanes to pay. Prices lower Cryan OPS Regs. Guaranteed for 6 months only C2.97, N . Y . TV GOLD PLASTIC MASKS 16" & 17 ", $4.95; 20" & 21 ", $7.95; AIREX RADIO CORP. "' Phó tr2 á0. 24 ", $14.95

IO BUILD 15 RADIOS FREE SOLDERING IRON ABSOLUTELY NO PREVIOUS TRAINING NEEDED EXCELLENT BACKGROUND FOR TELEVISION GET A WELL- PAYING JOB 10 -DAY MONEY-BACK GUARANTEE > WHAT THE 1952 PROGRESSIVE RADIO iiEDU -KIT" OFFERS YOU: This is a practical house radio course. You learn theory, construction, operation, trouble shooting, code. You build RECEIVERS, TRANSMITTERS. AMPLIFIERS. I v ill. OSCILLATOR, SIGNAL TRACER. You start with a simple radio circuit. and gradually advance to more complex circuits. No previous background is required. No instructor is needed. All parts and instructions are included and every single step is clearly explained. All parts are guaranteed, individually packaged, identified. and explained. There is nothing extra to buy. You receive all parts, tools and instructions at once. You keep everything; there is absolutely nothing you return to us. You can easily pay for the kit in a short time by repairing radios. Use the tester and signal tracer for servicing. The signal tracer alone is worth more than the price of the entire kit. GO INTO A PROFITABLE BUSINESS AND PLAN FOR A FUTURE USED BY RADIO SCHOOLS AND GOVERNMENT AGENCIES! The Progressive 1 idin 'Edo -ICìt" includes tunes, paper Mottienser:. MIMI condensers, electrolytic condensers. variable condensers. selenium rectifiers. chassis, hardware, tie strips, tube sockets. solder, wire, soldering iron, tubing, coils. instruction book, radio tester, etc.; in brief, everything you need in a practical radio course. Send for further information and receive FREE Radio & TV Trouble -Shooting Guide. Or order direct from this ad and receive FREE Code Oscillator Key (Value $2.95) in addition to Radio and TV Trouble Shooting Guido. l'u.vin,n prriniid *ni l'rlsh 0/4,'r8-C.O.D. pith r.c nrrr?)frd in i7.S.A. PROGRESSIVE ELECTRONICS CO. 497 UNION AVE. DEPT. ( BROOKLYN;] NEW YORK August, 1952 105

www.americanradiohistory.com system is now under experimental test in Britain and has been reported to Standard Brands S have exhibited five advantages : A large 1I_T improvement of 9 db in signal strength; 'IF better intelligibility in the face of in- Individually terference; almost complete absence of distortion due to selective fading; a halving of the probability of jamming by a single strong interference signal within the broadcast band; and the OZ4 5 _45 613126 $ .45 126A6 S .43 50L6GT $ .50 6AX5GT 5 .40 6S117 5 .59 1T4 .55 613E6 46 125E6 .48 1B3GT 63 6840 ... '95 6517 .47 ability to pack more channels into a ITS 64 6BG6G 1 49 12BH7 .63 INSGT 55 6BA7 ... .65

6SVGT . .65 1X2A 63 68Q6GT .90 12SA7CT .50 185 54 6BF5 . ....,.. .55 given frequency space. The disadvan- 3Q5GT 63 6C86 53 12517GT .47 1S4 .63 60116 60 6SR7 .. .38 tages of ssb, revealed thus far, lie in 504G .40 615GT 40 12SK7GT 50 IS5...... 45 6816 .50 6SS7 .. .48 5Y3G .28 616 63 I2SN7GT 55 IU4 55 fiBN6 ... .81 " ' ...,.. 678 .75 the necessity for accurate crystal con- 6AG5 .53 6K6GT 39 12SQ7GT 45 1U5 45 6C4 39 6AK5 95 6SA7 45 19B06G 139 3A5 1.06 6C5 51 12AU7 52 trol, using a close synchronizing toler- 6AL5 40 6SN7GT 52 25AV5GT .83 3Q4... 60 6CD6G 155 I25G7... .52 ± 6AQ5 46 6SQ7GT 45 25BQ6GT .90 3S4 57 6D6 .65 19T8 .75 ance of 300 cycles, as a matter of 6AR5 35 6V6GT .51 25L6GT .47 3V4 .58 6E5 66 25Z6GT . .41 6AS5 .48 6W4GT 49 35B5 .47 574 108 6F5 46 course, and the increasing complexity 6AT6 36 6W6GT.... .50 35C5 47 5V4G .73 6F6GT 48 1175701 1.09 of receiver 6AU6 41 6X4 .35 35L6GT .47 6A84 46 636 49 11787X7 1.09 the due to the need for 6AV5GT .87 6X5GT 35 35W4 .31 6AC7 80 6L6G .81 117Z3 .42 automatic -frequency control. 6AV6 .36 12AL5 48 35ZSGT .30 6AG7 84 6S4 ..... _.. .42 17BP4.. I9.50 6BA6 .43 12AT6.... .40 5085 .47 6AH6...... 75 6$C7 .68 Airborne equipment using ssb, it was 6BC5 53 12AU6.... .46 SOCS .48 6AS7G . .. 2.88 6SF5 . .51 20CP4...... 24.50 Many other types equally low priced -include all your tube needs with your order. said, would be generally equal in weight One of the largest stocks in the country. and bulk to the dsb type, and create a Terms: DEDUCT 2% when enclosing full payment with order; C.O.D.'s, 25% with order: Min. Order: 525.00; lighter drain on the F.O.B. New York City power supply, but All merchandise subject to prior sole would require a more complicated transmitter and receiver circuit. It was also disclosed that the ssb receiver used on the ground will accommodate dsb reception as well, without any altera- 125 Cedar St., New York 6, N. Y. COrtlandt 7 -4307 tion, but with some loss. French technicians at the meeting suggested that a slight variation of the basic ssb, using an unsuppressed carrier, would eliminate some of the troubles stemming from the need for STAN-BURN very stable crystal -controlled radio EASY MONEY!! carriers. While this would If you don't get our postcards sacrifice a telling substantial amount of the theoretical the cash we'll p&y advantage of ssb, it was said to be * ANTENNAE SPECIALS -K for that surplus gear you *CIRCLE X Limited quantities more adaptable to airline use. 1.11 $ 12 Or Mo e* bought when the buying *DOUBLE V 313" 52.98 $2.20 * *DOUBLE V fie" Doi, el 3.45 2.45 was good, then YOU ARE INDUSTRY'S striking contribution to * DOUBLE V {/a" Dnnel 3.95 2.95 *r- * 10 Element Conical % 3.55 2.55 LOSING MONEY! 5o send us the critical material stockpile received *Folded Hi Straight Low quick REg * and address IyOW tfi" elements 425. 3.25 your ndme a stirring tribute from Donald S. Par- *WINDOW CONICAL MASTS 4.95 3.75 and GET ON OUR MAILING LIST/ ris, deputy director of the electronics *5 FOOT SWEDGED .79 .69 division NPA, *10 FOOT PLAIN 1.39 1.29 * G. L. ELECTRON ICS of during a meeting of TV WIRE * management personnel * 55 M.I. 300 OHM 514.95 M Ft, 905 S. VERMONT AVE.,LOSAN(OELES 6 at the recent 1'72 OHM COAXIAL Parts Show in Chicago. Compliment- CATHODE RAY TUBE SPECIALS * ing industry on their *10BP4 ZETKA $14.95 16TP4A DUMONT $26.00* conservation *10884 N. U. 19.95 17BP4A FEDERAL 23.00* plans, voluntarily put into effect to *10BP4A N. U. 19.95 17BP4A DUMONT 28.00 *12LP4 ZETKA 18.95 19AP4 SHELDON 29.95* save critical metals, Parris said that *12184A THOMAS 19.95 I9AP4A G.E. 39.95* *16884 ZETKA 26.00 198848 THOMAS 39.95* ON -THE BATTERY substantial quantities of copper and I6AP4A G.E. 38.00 20CP4A DUMONT 41.00* SPOT RECORDER *16DPIA THOMAS 28.80 20CP4A SHELDON 37.00* nickel were saved through ingenious *16GP4A RAULAND 33.00 2IEP4A DUMONT 42.95* a lb. miniature BATTERY WALKIERECORDALL RECORDER-PLAYBACK production and design techniques. 16GP4 ZETKA 26.00 24AP4A SHELDON 63.00 * G.E Continuous. permanent, accurate, indexed recording at P4A THOMAS 24AP4A * Without *161 28.80 Single len T. raps ...76.0039c* only Sc per hr. Instantaneous. permanent playback. such self- imposed programs, *16RP4A GE & NU 26.00 Double Ion Traps . ...590* Picks up sound up to BO ft. Records conferences. lec- tures. dictation. 2 -way phone AL sales talks: while both the civilian and military fronts *CHASSIS 630 REGAL. a Ith l'n.ccode T uner..$139.5011 walking. riding or flying. Records in closed briefcase *211 T3 FLY BACK tSimiln. I.. RCAI 2.98 withhidden mike "! Write for Detailed Literature. would have been seriously affected, *OPEN FACE CABINET ... 39.00* Parris declared. The component and * TRANSFORMERS * MILES REPRODUCER CO., INC. *RCA type for 16" to 24" X032 $3.55 812 BROADWAY Depi NEW YORK 3 N Y accessory makers deserve a round of type for 16" to 24" X045. .. 3.85 * RN -9 * These a very special prices while they last! * applause for their enviable efforts, he DEFLECTION YOKES *COSINE FERRITE TODD YOKE TO $4.20* added. L W. * SPECIALS it *4 Prong Vibrators, each. 1.29* BUILD TOUR OWN Lots of 12 or more S 1.19 * TV Tuners. 18.95 *Standard12" Heavy Slug Speaker Special 4.98 * GEIGER COUNTER! *AUDIO DEVICES. DISCS d SCOTCH TAPE IN STOCK* Its to your own Sea«hmas- *Audio Plastic Red Oxide Plastic tape- EASY build * Half hour spool $2.30* ter Geiger Counter with this COMPLETE One hour spool. 3.30* kit. Contains everything you needl WIRE RECORDERS IN STOCK * Headset, tubes, batteries, metal case. *WILCOX GAY -Model 2810 § 89.97* Fully guaranteed! Sensitive to both beta * PENTRON - Model 9T3C - 2 -speed Tape Re- radiation! Illus. instructions. corder Net 134.50* and gamma Write for FREE Catalog * RADIO CRAFTSMAN FREE radioactive specimen. Model RC2 -IIIFi Amplifier Net 42.89* '299: "Creative Tools for the Model RC10 -AM -FM Tuner Net 130.84* * Model CS- Williamson Amplifier Net 99.45* MODERN SCIENCE LABS Scientist of Tomorrow" *tasende Guaranteed Tuners ,with tul>ea) tee, St. Clair With Nolltwaod, cela. *SPECIAL,! While they last ...... 521.95* * AUTHORIZED DISTRIBUTORS for: General Eler. * tic, Kenrad. Tung -Sol, National Union, Jewel. * * De Wald. Regal. Automatic and Setehel Carlson. * *We carry a Complete line of popular rn akes of Radio* **and TV tubes. at SOO/p tlisoou nt. Also many other RADIO and TELEVISION ELECTRONICS speeial purpose and transmitting types, and II lee -* T ironic parts and equipment at lowest prices. Send us* in all Technical Phases *a list of your requirements for prompt quotations. *Terms: 200/ with order. Balanni COD. All priors* New Classes (Day and FOB. NEW YORK Warehouse. Minimum order 55.00.* Evening) Start 1st of Write for our latest price list to Dept. RN -8 . ) Dec., Mar., June, Sept. RADIO and Free Placement Service for Graduates For Free Catalog write Dept. RN -52 STAN -BURN ELECTRONICS CO. RCA INSTITUTES. INC. (C.B.S. THEATRE SLOG.J A Service of Radio Corporation of America FAIRHURST 1697 BROADWAY NEW YORK 19, N.Y. 350 WEST 4th ST. NEW YORK 14. N. Y. 106 RADIO A: TELEVISION NEWS1

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THE RCA Tube Department trouble-shooting techniques applicable proudly announces the publication of to all TV sets. It's information you can't pe vs THIS BONUS Volume IIII of the famous RCA TELE- afford to be without. "TV Servicing Supplement " - Trouble VISION PICT -O -GUIDE ... another sig- For a limited time only, Shooting "Tough" Sets or "Dogs." This in- nificant you can have addition to the PICT -O -GUIDE your choice of PICT -O -GUIDE dispensable book by John Meagher tells series, Vole you how to handle recognized as the most useful, I, I1, or III with each order for RCA the really tough TV sets practical servicing information 75 ... the ones that take the in the receiving tubes or 3 RCA kinescopes. industry for helping you most time to analyze and locate and solve It's as simple as that. repair. TV troubles by picture analysis. It's a "Post -grad- This is your chance to get the complete uate course" in TV trou- Authored by John R. Meagher, RCA's set of three matched volumes ble- shooting. You get noted to bring TV Service Authority, Volume III your library up -to -date. But don't miss a bonus copy with each contains completely new data on tele- out on this limited offer! Place your Pict-O -Guide volume vision interference, you earn. This is a built -in and external qualifying tube order with your RCA ghosts, hum troubles, and a host bonus offer you of Tube Distributor at once. won't want to miss! RADIO CORPORATION of AMERICA ELECTRON TUBES HARRISON., N.J. August, 1952 107

www.americanradiohistory.com lish talk 2100 -2110. (Kary, Pa.) Is par- International Short -Wave allel on HI4T, 5.970. WE GREW UP (Continued from page 65) Dutch New Guinea-A station heard on 7.126 signing off around 0700 is be- THEM lieved to be Radio Hollandia. (Stark, WITH Colombia-HJCX, 6.018, noted Sun- Texas) days to after 0200 at excellent level. Egypt -The Chief Engineer of Radio ver since radio was in "knee (N. Z. DX Times) Cairo, 9.715, states that schedule re- Curacao- Willemstad, 5.014A, noted mains 1345 -1700. (Bellington, N. Y.) pants," Supreme has been with English program on Wednesdays Noted with news in French after 1345 providing aids to help elec- 2000 -2030. (Kolberson, N. J.) sign -on. (Pearce, England) Has news tronic technicians use their training Czechoslovakia-Prague, 9.55, noted in English 1400. with English for North America 1930- Et h i o p i a-Radio Addis Ababa, and experience more efficiently and 2000; fair. (Boggs, Mo., others) 15.047A, noted 1230 -1245 with native profitably. We know that in tele- Denmark -By this time, Copenhagen music and singing; faded severely vision today, as it was with the TRF's should have a new program on the air around 1250. (Cox, Dela.) Reported to for Greenland daily 1900 -2000 on OZF, sign off now around 1306. (Pearce, and neutrodynes of yester -year, they 9.520, with the program for South England, others) must have high quality, dependable America changed to 1730 -1830 on Mon., France -Current schedule for the test equipment to save time and keep Wed., Fri., on same channel: (WRH) Overseas Service in French from Paris Is now scheduled to Australia, New includes 1830 -2000, 9.685, 11.700 to An- up with this progressive electronic Zealand over 15.180 on Tue., Thur., Sat. tilles, Guiana; 2230 -2245, 7.105 to Mad- industry. We also know that service 0400 -0500; to India, Burma, Malaya, agascar, Reunion, Fr. Somaliland; technicians do not want Supreme to Indonesia on Tue., Thur., Sat. at 0900- 0030 -0130, 9.550, 17.850, to Tahiti, Pa- 1000; broadcasts are followed by a 20- cific; 0145 -0230 to Fr. East and Fr. sacrifice quality by substituting un- minute program for Danish seamen in West Africa and 0230 -0300 to New Cal- proven materials in place of those areas to which the transmissions are edonia, New Hebrides, 15.240, 17.850; temporarily under control due to our directed. (Radio Australia) 0530 -0600, 17.850, to Antilles, Guiana; Dominican Republic -HI2A, 9.680, 0800 -1000, 15.400, 15.350, 17.850, to In- nation's mobilization program. They Ciudad Trujillo, is noted in Sweden at do- China; 1500 -1600, 9.540, 11.700, will, as they have in other emer- fine level from around 1855. (Engberg) 15.240, to Fr. East and Fr. West Af- 1730 -1800, 9.675, 11.920, to Indo- gencies, give us extra time, if needed, HI2T, 9.735, noted recently with Eng- rica; to deliver a product that is "Supreme By Comparison" in every respect. USE YOUR 4.1141 FOR _ALIGNMENT Supreme's mission in our defense ly LEWIS S. HUGHES program, just as it was during World War II, is to help the technicians in THE grid dip oscillator is well -known a dip near the frequency given in the our armed forces locate that faults to most hams but very few service chart, the condenser is bad. (The fre- technicians are aware of its usefulness quencies given on the chart may vary part or maladjustment quickly by ar d the shop. It can be used as a slightly from the frequencies at which supplying them with well designed marker generator for TV and FM align- the dip occurs because of differences in ment, for setting traps in television lead length and distance between the and reliable testing equipment. For a sets, and, believe it or not, for checking two sides of the loop. If the frequency quarter century Supreme has been a condensers in a set while the set is varies too much, it would be well to turned on -witl t unsoldering one compile your own chart.) major contributor to the efficiency of side of the condenser: It's wonderful For that condenser you suspect of grew for catching that intermittent con- being intermittent, you can clip your the electronic technician -we denser that heals itself the minute you loop across it, couple the grid dipper to up with them. By continuous re- touch a test prod to it. the loop, and wait for the set to fail. To use the GDO as a marker gener- When it goes out, a quick glance at the search, development, improvement, ator, set the grid dipper near the re- meter will show whether it is the sus- and production of equipment for ceiver being aligned and tune it to the pected condenser or not. The added desired marker frequency. You may capacity across the condenser in the maintenance of electronic devices - have to move it around a bit to get just set will not throw the circuit off enough plus our close contact with the elec- the right amount of coupling you need to bother the picture or sound to any to keep the pip as small as possible. If appreciable extent. If the condenser in tronic technician -knowing the job the pip is too large, it will change the the set opens up, it is very possible the he has to do-what it could mean if shape of the curve. Use the grid dipper condenser in your loop will take over and marker generator to get two pips and do the job, so the set will not fail he fails -leads us to accept new chal- on the curve. In this way you will not as long as the loop is clipped into the lenges with confidence and pride. have to keep running the marker gen- circuit. However, the meter will still erator back and forth to check the show the condition of the condenser Supreme's "know- how," gained both other side of the curve. in the set. in peace and war, is one of this na- For setting traps, the GDO is not as accurate as the sweep generator and Frequency settings on the GDO when unit tion's assets in times like these. scope, but it serves the purpose by per- is used to check the condition of con- mitting the touching up of the traps densers. No dip on the meter shows that in the field. Set the grid dipper at the the condenser being tested is no good. Our 25th Year trap frequency and tune the trap for (lip on the meter. It has been the ex- SERIES perience of the writer that complete CONDENSER CONDENSER TUNE GDO TO alignment on stagger -tuned sets with 2.5 µµfd. 220 µµid. 225 mc. method is not accurate enough for 10 µµfd. 220 µµfd. 100 mc. SUP this 51 mc. EME 50 220 µµfd. µµfd. service work. 100 µµfd. 220 µµfd. 42 mc. Testing Instruments Where the GDO shines is in checking 220 µµfd. 220 54d. 31 mc. condensers while the set is in operation. 390 µµfd. .001 Aid. 22.5 mc. "SUPREME BY COMPARISON' 470 µµfd. .001 pfd. 19 mc. An eight inch loop of wire in series 680 µµfd. .001 pfd. 17.5 me. TUBE TESTERS SIGNAL GENERATORS with a condenser of the proper capacity 1000 pµ id. .001 pfd. 16 mc. is hooked across the suspected conden- .002 Aid. .005 pfd. 9 mc. PANEL METERS MULTI- METERS .005 µfd. .005 µfd. 7 mc. ser. See chart. Couple the grid dipper 6.2 mc. OSCILLOSCOPES .01 µfd. .005 pfd. to the loop and tune to the frequency .02 pfd. .005 Aid. 5.5 mc. Supreme, Inc., Greenwood 1, Mississippi specified on the chart. If you can't get 108 RADIO .Y TELEVISION NEWS

www.americanradiohistory.com China; these periods are over 100 kw. transmitters. (WRH) French Equatorial Af rica-Brazza- ville, 11.970, noted with news 0015. has the (Hoffman, N. Y.) "specials" French West Africa -WRH says Ra- dio Dakar has been logged on 7.198 with news in French 1515; verified this channel with new QSL card. Noted on 11.896A with French news STOCK now at 1800 and signing off around FOR 1813. (This is an additional news pe- "SPECIAL" riod.) (Bellington, N. Y.) Noted at AIRCRAFT good level from 0130 with all- French session, mostly music. (Saylor, Va.) - Germany- Hamburg, 6.270, is heard Three - in Sweden around 0400. (Engberg) Ra- NO. HP3 -140. CAT. cycle step-down dio Free Europe now operates on ap- phase 400 Pri: Y -Y connected. proximately 9.080 at 1500 and on 5.960 transformer 3 phase, per phase, around 1000. (Engberg, Sweden) Leip- 115 volts volts per Sec: 28.5 zig, 9.728A, noted from around 2300 400 cycle. "H" type va capacity. with fair signal. (Cox, Dela.) phase, 140 MIL -T -27 Greece -The North American mounting; meets trans- Class 1 specifications. mission from Grade A, /a isft.high. Radio Athens, 9.607, at 27/8x2t;16x3 2000 -2100, is only poor to fair; news in Dimensions: Greek 2002 and 2055; news in English 2043 -2055; fills in with music; has severe QRM. (Kart', Pa.) Heard on this channel with English 1430, French 1445. (Pearce, England) Guatemala -TGNA uses 9.668 and 11.850 for English daily 2200 -2230; Wednesday's Mailbag feature ( "Script by You ") runs around 2230 -2300; still The HP3 -140 unit is just one of many asks for reports. (United 49'ers Radio "specials" regularly stocked in the CHICAGO New Equipment Line. Society) TGWA, 9.760A, noted recently CHICAGO makes a practice of stocking "specials" that are ending English session at 2259 (may be hard -to -get elsewhere. You'll find the answers to your transformer only Mon., Wed., Fri.) (Bellington, needs for practically any of today's circuit requirements in N. Y.) TGWB, 6.180A, is heard at fair CHICAGO'S exclusive "Sealed -in- Steel" New level to 2300 when Equipment Line - has interference in stock at leading electronic parts distributors. Whether your from Munich, 6.185. (N. Z. DX Times) transformers must pass Hawaii -WWVH, 10.000, Maui, noted the most rigid MIL -T -27 specifications or recently through WWV's modulation are intended for average applications, it's wise to choose CHICAGO at 2230. (Peddle. Newfoundland) "Sealed -in-Steel" units (the world's toughest) for that extra Holland -Radio Nederland, 9.59, margin of dependability under all operating conditions. noted with news 2130. (Hord, Ind.) Heard on 15.220 at 1050 with program in Dutch; weak to fair. (Cox, Dela.) "Special" or "Standard: the world's toughest transformers Heard on 11.730 at 1630 with English, good level. (Baetz, Ill.) are in CHICAGO'S "Sealed -in- Steel" NEW EQUIPMENT LINE! Honduras -HRP1, 6.354, San Pedro All CHICAGO "New Equipment" transformers Sula, noted lately with improved sig- H -TYPE nal; news in Spanish 2230. (Ferguson, feature one -piece drawn -steel cas' -the N. C.) Hermetic sealing meets strongest, toughest, best- looking units you all MIL -T -27 specs. can buy. The Hong Kong -ZBW3, 9.525, heard best Steel base cover is one -piece seamless design, deep -seal soldered into enclosing an electronically perfect around 0530 -0630. (Sanderson, Austra- case. Ceramic bushings. lia) Stud- mounted unit. construction, provides the best possible India -Engberg, Sweden, notes electrostatic and magnetic shielding, affording Delhi complete with news 0300 on 17.760 parallel with 5 -TYPE protection against adverse 17.740. atmospheric conditions. For every application: Steel base cover Fitted AIR, 11.850, noted with news 1930. with phenolic terminal Power, Bias, Filament, Filter Reactor, board. Convenient Audio (in 3 ranges), MIL -T -27, (West, Virginia) Parallels 15.290. numbered solder Step -down- lug there's a CHICAGO "Sealed -in- Delhi, 15.160, noted in External Serv- terminals. Flange - Steel" transformer, mounted unit. available in ice to East Asia, Southeast Asia, Aus- a choice of 3 mountings. tralia, New Zealand opening 2030. Free "New Equipment "Catalog Indo- China -"Voice of Vietnam," C -TYPE Saigon, is noted on 9.62 With 10" color -coded Get the full details on CHICAGO'S and 7.09A with leads brought out New Equipment Line -covering news daily 0845 -0900 sign -off; at pres- through fibre board "Sealed -in- Steel" transformers ent, 9.62 is best signal. (Balbi, Calif.) base cover. Lead ends designed for every modern circuit are stripped and tinned application. Write for your Free Radio France -Asie noted on 11.924 for easy soldering. copy of this important catalog to- with French news 1745; on 15.420 at Flange- mounted unit. day, or get it from your electronic 0500 with (English) news, music. (San- parts distributor. derson, Australia) Iran -Radio Teheran is now broadcasting its Overseas Service over EQA, 896 kc., EQB, 6.155, and EPB, 15.100- CHICAGO TRANSFORMER 1345 English, 1400 Persian, 1430 Ger- DIVISION OF ESSEX WIRE CORPORATION man, 1445 French, 1500 English, 1515 Russian; EQB is "announced" as 6.16. 3501 ADDISON STREET CHICAGO 18, ILLINOIS rKAUr MARK RCS. August, 1952 109

www.americanradiohistory.com (WRH) EPP, 3.835, Teheran, noted Become an through ham QRM at 2130 -2200; frequency varies a great deal. (Peddle, Newfoundland) Electrical Ellioeer Iraq-In verifying, Radio Baghdad stated that the English session ( "Date With Baghdad ") opens 1413 with the song of the Bulbul (the nightingale of Iraq). Station operates on 11.724 and closes 1500. (Pearce, England) Israel -Tel Aviv, 9.O10A, still noted with English 1515 -1600 sign -off. (Say- lor, Va.) Italy -New schedule for Radio Ital- iana's European Service is 0615 -0715, 6.010, 9.570; 0810 -0910, 6.010, 7.110, 9.570, 9.630, 11.900; 1220 -1710, 6.010, 9.570, 11.900. (with French 1340 -1420, German 1420 -1500, 1620-1640) ; 1245- MAJOR IN ELECTRONICS 1340 on 11.810, 15.400 (English 1245- 1320), 1415 -1615 on 9.630, 11.810; 1620- An active DX -er -Lee Neeley of California. B. S. Degree in 36 Months 1710 on 11.810, 15.400 (Portuguese Radio -Television Technician 1620, Spanish 1645); 2215 -2245 Russian with BBC news relay 1300; closes down on 6.010, 7.110, 9.710, 11.900, 15.400. 1500 with "God Save the Queen." Certificate in 18 Months (WRH) (Pearce, England) By 1954 there will be at least two positions for Rome, measured 17.802, noted with Lebanon-Beirut, 8.036A, noted with every engineering and technician graduate. news when tuned 1510; news ended news in French 1400; news in Arabic This College offers a tested plan that permits 1520, then had continued with 1300. England) you to enter these vast employment oppor- talk; (Pearce, tunities at an early date. First - you save music 1525; good signal in N. C. Heard Luxembourg-Radio Luxembourg, a valuable year through optional year -round on 15.400 at 1244 with interval signal 6.090, noted with sponsored programs study. Second you can receive advanced followed by news to 1300 after which in English 1600. (Pearce, England) credit for prior- training gained in the armed forces, other schools or field experience. had a talk. (Ferguson) Heard at nice Malaya -BFEBS, Singapore, noted level closing down 2200 on 11.81. (Lund, at fine level on 15.435 at 0845, good on Enter Both Radio and Television Iowa) Noted with news to Britain, Ire- 11.955. (Balbi, Calif.) Heard on 9.690 Through This Plan land 1245 -1300 on 15.400. (Cox, Dela.) to 0615 sign -off when announced was 12 months or one -third of the B. S. degree Heard at excellent level 1930 on parallel 6.175; good level. (Ferguson, course (Electronics major) - also brings 11.905A. (Golden, Mass.) N. C.) Lists current schedules as daily you the Radio Technician's certificate. An Somaliland 0800 -0900 on 17.755; added 6 -month course qualifies you for the Italian -Mogadishu, to India, Pakistan Radio-TV Technician's Certificate. Recent 7.385A, noted around 1220 tune -in to 0915 -1030, 15.435; 1030 -1145, 17.755, developments open unlimited opportunities 1300A closedown; news in Italian 1225. 15.435; to Burma and Thailand daily for TV technicians and engineers. (Pearce, England) 0800 -0815 on 11.955, 7.120; 0815 -0900, The Proven "UNIT CHASSIS SYSTEM" Japan -The Japanese Standard Fre- 7.120; 0900 -1030, 11.955; 1030 -1145, of teaching was quency Station JJY, Tokyo, broadcasts 11.955, 7.120. To offset poor reception developed here. It 1600 -0600 on 4.000 and 8.000; every ten conditions from London, BFEBS has "breaks down" the warning BBC news 0800 -0815 on TV set by stages. minutes has radio propagation been relaying You learn every in Morse code; has been testing at 1900 11.820 to listeners in Australia and the component of all on Mondays on 2.500, Wednesdays Islands. (United 49'ers Radio Society) types and makes 5.000, 10.000; power of each Monaco Monte Carlo is now and are prepared- Fridays -Radio for future design outlet is 1 kw. (Wada, Japan, via on the air Sundays 0100 -1730; week- changes, including WRH) days 0100 -0310, 0600 -1730; on Fridays, the advent of color. According to verification, the Far Saturdays remains on air to 1800. General Preparatory Course East Network, AFRS, Tokyo, is now (Engberg, Sweden) Exclusive 3 -month course is tailor -made to on the air 1600 -1800,6.080, 4.860; 0815- Mozambique-Lourenco Marques help young men fulfill academic deficiencies 0330, 11.825, 9.605; 0345 -1000, 4.860. still noted on 9.795A with Portuguese and meet engineering admission requirements. (WRH) Radio Japan, 15.235, has strong session around 0030. (Bellington, N. Y.) Terms open October, January, April, July signal on West Coast in the North English session noted on 11.760 around Over 48,000 former students from all states 11.705 is 2345. Opens weekdays and 23 overseas countries. Faculty of trained American period 0000 -0100; (Kary, Pa.) specialists. Modern laboratories and equip- parallel. JBD3, 15.225, has fair level 2300, Sundays 0000 and parallels 4.913A ment. Nonprofit technical institute and in Home Service from 2200 onwards. which is also audible in Eastern USA. college in its 49th year. (Balbi, Calif.) Radio Japan is noted Pakistan -Radio Pakistan noted on daily 1030 -1130 using announced JOB2, announced 9.484 at 1500 -1600 sign -off MILWAUKEE 11.705, and JOA2, 9.675; news is 1030- with program of Western symphonic SCHOOL OF ENGINEERING 1045, then 5 minutes of commentary, music; is interspersed with Arabic re- FREE - Write for "Occupational followed by 15 minutes of Japanese cordings; weak to fair with severe Guidance Bulletin," "Your Career" music; at 1105 uses Japanese until 1130 QRM. (Kary, Pa., Ferguson, N. C., booklet, and catalog. sign-off. (Graybill, Wash. State) Heard others) Still tests to Turkey and on 7.180 in English 0700, fair level in United Kingdom 1430 -1600 on 7.010, Milwaukee School of Engineering JKI, 4.910, Nazaki, 9.484. Is heard on these channels also Dept. RN -862, 1025 N. Milwaukee Missouri. (Boggs) Milwaukee, Wisconsin has been coming in at fair level lately 1210 -1230 with news at slow speed, and Without obligation send Catalog for from 0300 with programs in Japanese. in Arabic to 1400 or later. (Pearce, Electrical Engineering, B. S. Degree, has recently major la Electronics; Power : "Your (Saylor, Va.) England) Radio Pakistan Career": Occupational Guidance Bulletin Kashmir -Radio Kashmir, Srinagar, been heard on a new channel of 6.195 on: Radio -TV; Electrical Power; Welding; Heating. Refrigeration Air Conditioning is now scheduled 2130 -2330 (Sun. to until 1030. (Engberg, Sweden) Kara- ['Mechanical Engineering, B.S. Degree ; Ireparatory. 2345) on 4.860; 0100 -0230, 6.110; 0630- chi, 7.0115A, noted 2130 -2200. (Peddle, Name a.. Age 1200, 3.335. (WRH) Newfoundland) And on 11.845 to 0915 Broadcasting or later. (Stark, Texas) Noted by San- Address Kenya Colony- Forces Service, East Africa Command, 7.265, derson, Australia, on 15.325 at 2130 City zone State Nairobi, noted 2302 with BBC news re- with news, music; this one is believed If veteran, indicate date of discharge lay. "Nairobi Calling," 4.855, heard to be Dacca. L RADIO di TELEVISION NEWS I Ill

www.americanradiohistory.com Pakistan heard testing around 2015 -2100 or later on 11.885 (squeezed) and 15.335; has news 2130. (Kary, Pa., others) Panama -HOLA, 9.505. Colon, noted opening 0645 in Spanish. (Ferguson, N. C.) And ending English 2203 and then going into Spanish. (Cox, Dela.) Peru- OAX4T, 9.562, noted 1900 at strong level in Mo. (Boggs) OAX4Z, 6.082, heard to 2355 and at times to 0055 at good strength. (N. Z. DX Times) OAX4J, Radio Colonial, 9.330, noted fair recently 2100 -0200 fade -out; all-Spanish. (Saylor, Va.) Philippines -QRA for Radio Free Asia in Manila is P.O. Box 3161. This one is noted by Balbi, Calif., irregularly on 11.940A and daily on 6.11 with English 0845 -0900. The Guam outlet, 9.490, has been heard by Dilg, Calif., and at 0920 sign -off announces a call that seems to be KUJZ; CWQRM is severe. Current schedule of RFA is 0700 -0920. Far East Broadcasting Co., Manila, lists schedule of 1600- 0100, 0300 -1200 over DZB2, 3.32; DZH6, 6.03; DZH7, 9.73; DZH8, 15.300; DZH9, 11.855. (Boggs, Mo.) Since BFEBS, Singapore, Malaya, has vacated 15.300, DZH8 is sometimes audible to readable here in West Virginia around 0700. DYH2, 6.140, Cebu, noted with weather report, news - 0500. (Sanderson, Australia) Poland-Radio Warsaw, 11.915, noted with English to North America 1700; however; announces "11.8." (Hord, Ind.,, others) A "revised" summer schedule from Radio Polskie lists English for North America as 0715 -0800, 15.120; 1700, 1730, 1930, 2315, 0030 all on 11.815. (Golden, Mass.) Portuguese India -The Commercial Service of Radio Goa *Ungar's little Angels, of course is heard at good strength in Sweden 0030 -0400 with request program in English for listeners in India on the new channel of 17.890. (Engberg) Portuguese Guinea -CQM, Bissau, is now listed on both 5.838, 6.160, according to verification received recently. (Radio Sweden) New Caledonia- Sanderson, Australia, reports Radio Noumea on 6.000 with French session 0400. Ungar ELECTRIC TOOLS, INC., Los Angeles 54, Calif. (Continued on page 112) O M M Y N I C T I O N S E OUIPME NT CO. ELECTROLYTICS STEP -DOWN XFMRS SCOPE TRANSFORMER 210 -250V PRI- 110.220V SEC SPECIALS PRI: 115V, 60 Cy.. Sec WATTS PRICE Gibson Girl Emery. Xmtr $12.95 3000V5 MA, 6.4V 8 7A, 6.4V Screen .6A. 5V /3A, 360 -0- 3601/.200 Mod. Trans. for 51, -'.... . I.19 Watts Price 3 -4 MC MA, Twist Coils for ARC -.-i -6029, 1.25V /,3A -Prong MTG. 250 $5.95 Sel: 2.75 $3.95 Cap. Mfd WVCD Price 300 7.49 400 Cy Volt Reg. RH Transtat. In: 115V. 400 Cy. Out. 75-120V, FILTER CHOKES RU /GF COIL SETS 8 450 $0.16 500 10.95 6A SINGLE 30 300 .18 17.75 Stock Descripticn Price BAND RCVR UNITS 1000 19.95 Klixon Breaker: Thermal. 35A.... .69 BAND FREQUENCY 40 450 .38 CH -917 10H/450 MA -10KV $12.95 L 4011- KC 1500 24.95 T -30 Carbon Mikes. New ,89 600 50 400 .38 Supersonic CH-366 2011/.3A 6.95 C 45 850 KI' 60 300 .21 Rochelle XTL .50 CH -8 -19 SWING, .006H /5A, .035H/.5A .032 1330 Kr. T.V. Lead -in, 300 ohms, Hi-Q. 1.0- E I85Ó- 2040 KC 80 150 .29 Loss 1000 -Ft. Roll 17.50 ohs DCR,1KV TEST... . 3.95 F 2040- 3000 KC 8-8 450 .24 POWER TRANSFORMERS BC386 Interphone Jack Box .79 CH-776 1.288/130 MA /75 ohms ... 2.25 G 3000- 4525 KC 30 -20 25 .16 CH -344 - - H 4000- AN /109 -A Antenna 1.98 1.5H/145 MA /1200V Test 2.35 6000 KC 20 -10 150 .23 Comb. Transformers-115V 50-60 cps input CH -43A 10 HY /15 MA -850 ohms DCR M 200- 7700 KC C- 30-ARC -5 Control Box 1.75 N 80 -80 300 .21 C7J5-2-600VCT/.2A, 50/6A. 1 5.95 2.35 CH -999 15 HY /15 MA-400 ohms DCR 6000- 9050 KC EE -89A Telephone Repeater 1.95 K 9050. 13.375 KC 90 -10 350 .21 12.50 CH -511 6 H /80 MA ohms DCR CT-15A 550VCT .085A 6.3V -.6A, EE-65A Telephone -310 2.45 PRICE: $1.50 EACH 80 -10 450 .49 Test set 50.00 CH3 -501 20.58 /400 MA RCVR. DUAL BAND COILS 6.3V 1.8A 2.35 11124 /ARN -9 Cross 2.79 150-50 -25 150 .49 Point Indicator 6.95 CH -188M 5 HY 200 MA. LOW BAND HIGH BAND CT-164 4200V.002A/I2KV Test. 5VCT/ TU -8 Tuning Unit 1.79 400 -600 KC KC 80- 10 -10 -10 350 .21 6.2 -7.7 me 4.95 CH -303 300H/.02A, 2500V Test 1.69 6000.9050 3A/12KV Test, 6 3V 0 6A/ BC496 -A Dual Revs. box, 3 -6 540 -830 KC 521)0 -7700 KC 40- 40 -20 -2 150 .28 Coll CH-408 .02H/8A 4.49 195.290 KC 290- 435 KC . & 6 30.15 -15 5400V Test. 12.95 -9,1mc 1.75 -15 300 .28 AN /104 -A Antenna, 150mc 1.49 CH -932 SWING 9- 6011/.4-.05A, 10KV 7 95 540 -R30 KC 40- R30 KC 80- 10 -10 -10 350 .32 CT-341 1050 10 MA, 6250 C 5 MA, 26V p1 PRICE: $2.25 EACH BC704 Indicator. 5" CR Tube. New 22.50 4 10 450/350 .55 4.5A, 2x2 5V -30, 6 3V (n 3A 22.50 UNIVERSAL 40/20 BC929 Indicator. 313P I , all tubes. 150/25 .21 CR-825 360VCT .340A 6.3VCT/3.6, New 29.50 POWER TRANS. 40/50 400/300 .28 6.3VCT/3A. 3.95 NOISE Filters, 100 AMP. G.E 1.39 80/50 450/50 .65 Pri: Vibrator Input e4 CT-071 110V .200A 33/.200, 5V/ MC211 Right Angle Drives. .19 6/12/24/110 VDC, AC 250/1000 10 /6 .30 IFTTRANS., 112 KC 10, 2.5 /10 . 4.95 Double Slug ëput: 110/220 -V 49 60 8 -8-10 450/25 .26 .69 10-10/10 150/25 .23 CT-367 580VCT .050A 5VCT '3A 2.25 IF TRANS., 1600 KC Double Slug. .79 Sec: 230 -0 -230 V-40 MA RU. GF XMTR COIL SETS 10 -10/20 450/25 .26 CT-99A 2z110VCT.010A 6.3/lA, MD /7 MOD. for AflC /5. All tubes. 7.95 6.3V-1.8A. As $1.49 20011 -2200 KC 10 -15/20 350/25 shown 3000-:1675 KC PRICE: .18 2.5VCT/7A. 3.25 ARC -5 XMTTR. TuningCond. x5032 1.49 31'75.4'25 15 -15/10 450/350 .23 MOD. XFMR ARC -5 x9466, KC $1.79 -16/25 CT-931 585VCT .086A 5V/3A, 6.3V/ FF807 3:190-735() KC each 16 450/50 .23 to PAR 8117 3.25 SELENIUM RECTIFIERS 7 ...-,11- 1050 KC 80- 40/150 400/50 .45 6A 4.25 MOD XFMR ARC -3. T 104, PP 61.6 UP TO 18 VAC 120 -60/20 150/25 .45 CT-610 1250 .002A 2.5V;'2. TO 832 1.75 IN- (F. W. BRIDGE) ACCESSORIES UP TO 14 VDC OUT REMOTE TUNING BOX 30 -30 -15/30 300/50 .39 2.5V/1.7IA, 5A. 4.95 MOD XFMR BC 375, PP UP TO 54 VAC IN- 211 to TYPE. I W-23012 51.75 40 -40 -20/20 350/15 .28 SING, 211 1.95 2A $ 2.50 UP TO 42 VDC OUT XMTR. CONTROL CT-866 330V .065A 6.3V/1.2, 6.3V 4A 2A 60 -40 -20/50 300/25 DRIV. XFMR ART -13, PP 6V6 to 4.00 $6.50 BOX. 1 W.23097 1.69 .28 /600 MA 1.75 PP 60- 40- 20/200 150/10 .39 811 1.29 6A 6.00 4A 8.50 RCVR. SWITCH CT-456 390VCT 30MA 6.3V/1.3A, í0A 7.50 UP TO 120 VAC IN- BOX, CW- 23006A 1.75 80 -40 -30/20 150/25 .36 28V DYNAMOTOR L 80 -40- 30/100 150/25 .36 5V/3A 3.45 DYNAMOTORS 12A 9.00 UP TO 100 VDC OUT FILTER BOX FOR 8/8/8 475/100/100 CT-160 800VCT 100MA 24A.... 18.00 2A $11.00 RU , .23 6.3V/1.2A, Input 10/50/100 350/100/50 .23 5V/3A. 4.95 Output Radio UP TO 36 VAC IN- 48.00 COMPLTE RU /GF S E T, Type Volts Amps Volts Amps Set INI2A 60.00 WITH ALI. PLUGS. MOUNT- CT -931 PE86 28 1.25 250 RC36 UP TO 28 VDC OUT 585VCT 86MA 5V/3A,6.3V/ .060 Special Rectifiers INGS. XMTR., R C V R.. °M416 14 6.2 330 .170 RU 19 IA s 3.00 TUNING UNITS. DYNAMO - 6A...... 4.95 DM33A 7 On Request 28 540 .250 BC 456 2A 4.00 TOR, INSTRUCTION POCK - CT-442 525VCT 75MA 5V/2A, IOVCT PEIOIC 13,26 12.6 400 .135 SCR515 Hi- Current Chokes READY TO GO-ALL BRAND, /2A,50V/ 6.3 800 .020 5A 10.00 .01 HY -12 Amp -0.46 SPANKING NEW....$97.50 DB AR 93 28 3.25 375 .150 í0A .14.50 200MA. . 3.85 23350 27 1.75 285 .075 APN -1 Ohms- .. $14.95 12A 18.00 ROLL YOUR CT-720 550-0-550V/250 MA, 6.3V/1.8A. 8.95 ZA0515 12,24 4/2 500 .050 .01 HY -2.5 Amp- OWN 13-19 pack 12 9.4 275 .110 MARK11 24A 36.00 Cased.. $2.25 Headset. 300 CT-43A 600-0-600V/.08A, 2.5VCT/6A, Soo .050 ohms imn.. 6.3VCT/lA...... D -104 12 225 .100 using R -30 6.49 440 .200 elements. CT-444 230-0-230V/.085A, 5V/3A, 6.3V/ DA -3A 28 10 INVERTERS Same INTERPHONE AMPLIFIER 300 .060 SCR522 as HO- 2.5A . 2.79 150 .010 115 VDC -116 VAC 30 but plush Easily converted to an ideal CT7-501 325-0-325V/200 MA, 63V, 7.5A, 14.5 .5 APN-1 Rated 500W int. and velvet ear inter-Communications t for 5053 28 1.4 250 .060 BC -375 ushions are office, 6.3V/8A, 5V/3A 5.67 PE73CM 28 19 1000 .350 350W Contin. All Brand c comfy. home, or factory. CW2IAAX 18 12.6 Original. N e w w /conver- CT-75B 600-0-600V/.6A, 2XSVCT, 6.2A, 400 .135 New, Famous Mfr. Kill all background noise. sion. Diagram 26 6.3 800 .020 With 6 in, cordd n 1 Pí:54 $4.75 6.3VCT/3A, 6.3V/.3A . 12.95 DM -34 14 220 .080 SCR528 $75.00 each plug. kit MAIL ORDERS PROMPTLY FILLED. ALL PRICES FOB N.Y.C. SEND M O OR CHECK OBLY SHIPPING SENT heo,tl,und, 2-lí -3Úf ele- CONCERNS SEND P.O. ALL MDSE. SUBJECT TO PRIOR SALE, AND PRICES TED ments. 1íh1,, -r inserts. As- SUBJECT TO CHANGE WITHOUT C NOTICE. ....e:::l,led in 131 Liberty St., New York 7, N. Y. Dept N-8 Chas. Rosen Phone: Dlgby 9 -4124 August, 1952 111

www.americanradiohistory.com New Zealand -When this was corn - DOW SURPLUS piled, ZIA, 15.280 (to Pacific), and GOING OVER BIG -NEW ZL10, 15.220 (to Australia) were corn- TELECHRON SYNCHRONOUS MOTOR 2005 Type C2M 115V -60 cycle Model 822 M. -6- ing through fairly well around DAVIS SUPER-VISION RPM- Removed from new Surplus $3.95 and later. (Kary, Pa., others) MISCELLANEOUS ITEMS -ALL NEW ALL- CHANNEL ANTENNA Rubber Grommets -100 asst. $0.89 Nicaragua -YNVP, 6.758, noted at BC 461 control box with counter 1.49 ea. FOR AREA or DX T44C mike and plug...... 95 ea. fair level 2340 in Spanish. (Hoffman, FRINGE Leeds & Northroup Graph Paper, Type 578, O to Infinity. Boxed per Roll .98 N. Y.) with ELECTRONIC DIPOLE SEPARATORS APC condensers. all sizes .49 ea. 1000 +ft. ItWL130 twisted Telephone wire .95 Nigeria -Lagos is testing on 6.100 at 'THE ONLY TV ANTENNA SOLD WITH A Antenna Insulators-I0 for .60 0000 -1115 and on 4.990 at 1145 -1700; 8 V VIBRAPACK KIT: Vibrator plus on- MONEY -SACK GUARANTEE" sync transformer with two outputs: 345 v, 145 rna for plates, and 15 v for bias. the 7.255 outlet is audible in Britain BOTH FOR .. 2.9S FILAMENT TRANSFORMERS-1109 -80 cycle from around 1430 to closedown 1715; input, Output 9V to 13V in 1V steps-output, rated 3 amps 1.89 has BBC news relay 1500. (Radio Am- G.E. Solenoids -14V DC -25 ohms- Myealex arm, many applications -new .49 ateur, London) GP7 TUNING UNITS, A TO F, for ECO, $2.95 ea. North Korea -The Pyongyang Cen- PANEL METERS. NEW RHEOSTATS tral Broadcasting Station now uses STANDARD BRANDS }SPECIAL SCALE Wants Ohm 4.400 and 6.250; programs are mostly 50.9$ SQ-SQUARE CASE 25 8 .98 in Korean but Japanese is heard 0830- 3" METERS 25 15 .98 0 -150 V AC S 5.95 25 25 .98 0900. (Wada, Japan, via Radio Aus- 0.130 V AC 5.95 25 75 .98 O to 120 V AC 5.95 25 100 .98 0.15 V AC 3.95 25 145 .98 tralia) 0-8 V AC WES 2.95 25 150 .98 0.2 V DC 3.95 23 Norway -Radio Norway, 15.175, Os- 0 -1.5 V DC 3.95 S 500 1.49 0-1 Mill DC SQ 6.95 25 1000 1.49 lo, noted opening 2000 with program 100.0.100 DC Mill 3.95 25 1000 1.95 Freq. 350 to 430 320 5 3.95 in 100 for Norwegians abroad, specifically cycles, 115 V 17.94 150 100 3.95 2" METERS 150 5000 4.95 North America and North Atlantic 0 -150 Micro AmP.S 8.25 0 -8 RF Amp 3.95 XMIT RF CHOKES waters. (Kary, Pa.) LLK, 11.850, is 0.3 DC Mill. 3.95 21/2 M- 100 mill..29e 0.1 RF Amp 5.95 21/2 MU- 500 mill ..59e fair level around 2100. (England, New S Tuning D.C. 1.95 21/2 MN -1000 mill..59e Hampshire) 10 OUTSTANDING FEATURES: TUBES HERE OIL CONDENSERS BUY Roumania -Radio Bucharest is noted 1. EXCELLENT FOR FRINGE AREA and DX SURPLUS SPRAGUE #k4884 ILDS $ .59 4/52.00 32 mfds. Four 8 mfd. see - on 6.208 (listed 6.210) at fair strength RECEIVING -and broad band receiving with 3HP7 1.95 4/ 6.00 tiens in one can 600V SFP7 1.95 4/ 6.00 -oil- perfect for ampli - to closing 0700. (Engberg, Sweden) high gain on all channels -2 through 13. OAKS 1.19 4/ 4.00 fiers $4.95 GALS .79 4/ 3.00 Heard with English 1400 on new chan- 2. CLEARER PICTURES UP TO 125 MILES OR 6SN7GT .79 4/ 3.00 2 fd 600V Round .79 65.17 59 4/ 2.00 2X1 mfd 6009 Round .89 in with 9.252, MORE -from the station. 13.4 Ballast .19 10 mfd 800V $3.95 nel of 12.032A parallel 15E 1.49 4/ 5.00 .5 mfd 5000V-oil 5.95 3. GHOST PROBLEMS REDUCED or eliminated 41 .59 4/ 2.00 1 mfd 6000V 6.95 6.210A. (Pearce, England) RK73 .59 4/ 2.00 2 mfd 4000V - oil due to excellent pattern. RK873 .79 4/ 3.00 GE23F47 Pryn Sao Tome- CR5SB, 17.677, still HY615 .39 4/ 1.35 oil 6.95 4. PROVIDES 10 DB OR MORE GAIN ON HIGH 801A .39 4/ 1.35 90 mfd 1209 AC noted Sundays in Portuguese 0700- 837 1.49 4/ 5.00 - needed most. 843 .39 4/ 1.35 GE28F68s Pryn CHANNELS where gain is 958A .59 4/ 2.00 oil 695 0800. (Pearce, England) 1816 1.95 4/ 8.00 5. EXCELLENT FRONT TO BACK RATIO on all 1825 .59 4/ 1.8o NEON INDICATORS Saudi- Arabia -Djeddah is noted in 1626 .49 4/ 1.60 NE 2 10c ea. channels. Eliminates co- channel interfer- 1629 .39 4/ 1.35 NE 48 29e ea. Sweden at good strength around 1115 2051 1.19 4/ 4.00 NE 30 37e ea. ence. 2J21A 8.95 11.850. (Engberg) Also heard 3BP1 3.95 on 11.950, 6. MINIMIZES INTERFERENCE: Airplane Flutter 5BPS 3.95 FUSES SBP4 3.95 Amp. Type Each 10 for 100 for by Pearce, England. -Diathermy and Ignition- F.M. -Neon 6C4 .69 1/ 8AG $0.03 $0.25 $1.95 2508 8.95 1 8AG .03 .23 1.95 South Africa- Johannesburg, 4.895, Signs -X -Ray - Industrial - Etc. RK39 2.75 We 3AG .03 .25 1.95 304TL 9.95 3 16 3AG .03 .25 1.95 is noted from 2345 -0045 in Afrikaans. 7. ELIMINATES DOUBLE STACKED ARRAYS, and 531 3.95 t/ 3AG .03 .25 1.95 803 3.95 1 3AG .03 .23 1.93 Radio," 4.945, out -performs 2 bay yagis on low band and 804 6.95 2 3AG .03 .25 1.95 (Saylor, Va.) "Springbok 807 1.50 4 3AG .03 .25 1.95 4 bay yagis on high channels. 849 19.95 10 3AG .03 .23 1.95 is at fair level some days around 2345 860 3.95 15 3AG .03 .25 1.95 B. ONLY ONE TRANSMISSION LINE NECESSARY. 1361 19.95 20 30G .03 .25 1.95 in English; uses commercials, has fre- 8012 1.49 1 4AG .05 .40 2.95 4 4AG .05 .40 2.95 quent time checks. 9. NO WORRY OVER POSSIBLE CHANNEL 10 4AG .05 .40 2.95 KEYS 15 4AG .05 .40 2.95 Spain S.E.U., 7.140, Madrid, CHANGES on either high or low channels. J -50 ...50.95 20 4AG .05 .40 2.95 -Radio 1.25 35 4AG .05 .40 2.95 10. CAN BE TIPPED WITHOUT TILTING MAST 1-30 ... 40 4AG .05 .40 2.95 0.8 kw., has Ukrainian session on Tue. J -32 ... 1.25 70 ACL .05 .40 2.95 to take advantage of horizontal wave J-38 ... 1.25 20 SAG .05 .40 2.95 1430 -1500, has Esperanto on Wed. 1430- .1-41A .. .89 40 SAG .05 .40 2.95 lengths. J-47 ... 1.25 50 500 .05 .40 2.95 1500, is in French on Thur. 1430 -1500, J -48 ... 1.25 70 SAG .05 .40 2.95 AT YOUR JOBBERS, OR WRITE TO: and in Portuguese on Sun. 0800 -0830; VARIABLE CONDENSERS-ALL NEW Dual 35 mmfd per Section. Miniature $1.49 news in Spanish is daily 1635 -1645. DAVIS ELECTRONICS 1 -13 Dual -100 mmfd 49 4313 West Magnolia Blvd., Burbank, California 3 Gang 385 Per Section .98 Radio Nacional de Espana, nonfd Section (WRH) SIRS: RUSH INFORMATION TO ME AS CHECKED 5 Gang385 2.95 9.363, Madrid, noted signing off second BELOW: JK26 -PL54 Set $0.49 Technical Data on new SUPER -VISION SK ohm 20W..50.15 3 AG fuse post .25 English period for North America at o SK ohm SOW.. .69 4 AG fuse post .2S SendFre 8 AG type HJM .20 2245; fair strength in Oregon. (Gard- NEAREST JOBBER. 6K ohm 29W.. .35 807 Tube Sockets .29 Send Name and Address of 10K ohm LOW.. .15 Acorn Sockets .21 well in the 10K ohm I50W.. 1.25 MG149F.. ::49.50 ner) Cadiz, 7.200, is heard Name 250K ohm 2W., 3 for .10 MG153F 3 Phase Kingdom until 1800 closedown. 65K ohm 2W., 3 for .10 1put V400 Cycle Ou5149.50 United Street (ISWC, London) City State SHOCK MOUNTS EDWARDS BUZZERS Sweden,11.705, noted /111,94-115 V-60 Sweden -Radio Most Types. Send an your $0.98 coming on air 2300 to Australia; opens requirements for price. :t 15 -siee 0-12V DC works on GV less cover. Ore.) Noted with Code Prac69c in English. (Gardner, 12V and 24V Soldering Sets Eq. Iron $2.95 ea. 10 English on 11.88 at 1900; fair level but for $4.95 Iowa) Heard on 4 Speed Hobby Motors $12.95 bad QRM. (Lund, Or Air Pumps for CO-Ax Lines .95 Voltage Regulators. Made by Leland 2.49 15.155 with English 1600 -1630; some Mike Cable. Per Foot .04 HRH 28- Put -Put 1500W 28 Volts DC 59.50 QRM. (Graybill, Wash. State) Heard 30 ft. hook-Op wire Plastic Cover.. .. .10 Luminous Pant Kit. For Dusting. Painting or with English on 15.155 at 0700 and Mixing. Glows w the Dark. Complete .79 RADIO ENGINEERING 6 ft. AC line cords ea. .15 0900. N. C.) Single Hole mtg. Push Button Switch .19 again (Ferguson, Flux Gate Amp. Less Tubes 1.65 Toggle 89A Sw-SPOT- center off 3/ 1.00 Switzerland-SBC is again using DEGREE IN 27 MONTHS Toggle BIB SPDT 3 fer 1.00 good Complete Radio Engineering course, including Telev., Toggle 811 SPOT Momentary 3 for 1.00 HED7, 15.12, at 1145 -1330; rather Science also In Micro Switch B2-11041 SPDT Bachelor Bus. Resistor Kit Good Sizes...... 100/ 2.89 strength in Sweden. (Engberg) Noted Mech.,, Civil, Elect., e and É g.; A62 Phantom Antenna for 10 Meters- new...... 75 Acct. Extensive campus, modern buildings, well 35 FOOT STEEL ANTENNA MAST KIT. 7 -Five at good level here in West Virginia; equipped labs. Low cost. Prep courses. Personalized, foot sections-new 12.95 1884. Placement serv- Soldering Paste 1/2 lb. can. Big Bargain .10 1220. practical instruction. Founded ends English session around o, ice. Growing shortage of engineers. Prepare 3 In unlimited opportunities ahead. Enter Write us for your meter wants. Over 000 HEI3, 7.210, heard 2210 at good level IIILd now for for stock. Write for Our 16 -Page Bulletin. e®® September, J , March. June. Write in North American beam. (Hoffman, catalog. DOW RADIO, N. Y.) 1759 E. Colorado St. Pasadena 4, Calif. Syria- Boggs, Mo., reports Damas- PHONE: Sycamore 3.1196 51.50 min. order 25% deposit with cus on 7.145 at fair level at 0735; on Send full remittance to save C.O.D. charges Ave. ANGOLA, INDIANA All merchandise fully guaranteed. Subject to prior sale. 11.913 at 1630 (beginning English pe- 1682 College NEWS 112 11.%111/1 R TELEVISION

www.americanradiohistory.com riod) with strong signal; signs off 1730. Engberg, Sweden, says Radio Da- mascus is noted irregularly around 1200 on 9.525. Tahiti -Radio Tahiti, 6.980A, Pa- peete, is again audible around 0000- 0100 in parallel with 6.135. (McPhad- den, Calif.) Noted on 6.980A around 0050 -0130 sign-off ; mostly in French; closes with "La Marseillaise." (Kary, Pa.) Taiwan -BED3, 15.235, fair 2300- 2400 in English; from 2400 has QRM by Radio Japan. (Balbi, Calif.) BED26, 10.080, noted 1700 with American marches, then news in Chinese, music. (Sanderson, Australia) Taipeh, 11.735, noted 0800 at fair level. (Boggs, Mo., others) Engberg, Sweden, says Taipeh is operating now on 11.915A in Chinese NEW GOODLINE AIRLEAD has everything you want! to 1115; has QRM from Rome on 11.905. Tangier-Pan - American Radio is Sharp, clean, "snow- free" pictures. now on 7.290, 2 kw., daily 0700 -1000, 1500 -1900 in Spanish, French, English. Correct impedence for "ghost-free" reception. Nominal 300 (WRH) Radio Africa, 7.126, noted 1638 ohms. in Swedish; at 1705 goes into Spanish Lower in cost than other leadlines purported to accomplish and French. (Pearce, England) same results. Thailand -Bangkok, 6.240, noted Correct spacing 0615 with news; parallel on 11.960. for minimum radiation loss -Less than 1% (Sanderson, Australia) of operating wave length. Trinidad -Radio Trinidad is install- Fully insulated- approved by safety experts. ing new equipment and during the next Pure, unadulterated polyethylene insulation - specially few months will be making changes in treated by both power and frequencies. (Radio our chemists for extreme weather. Amateur, London) High-efficiency conductors : Flexible, stranded - to insure Turkey-Radio Ankara's English long life. program for Western Europe is noted Easily installed -with standard insulators. now around 1600 -1645 on TAU, 15.160A, excellent level; in Turkish 1645 -1700 Packaged in convenient lengths: 100', 250', 500', 1,000', sign -off. (Kary, Pa.) TAP, 9.465, par- 2,500'. allels but has poor level and much AT YOUR DEALERS, or Write For Free Samples and CWQRM here in West Virginia. Ac- Literature. cording to WRH, has German 1445- *Patent Pending 1515; French 1515 -1545; Turkish 1545- *Trade Mark U.S.and Foreign Patents Pending EXCLUSIVE LICENSEE AND SOLE MANUFACTURER 1600; English 1600 -1645; Turkish 1645- 1700 over TAU, 15.160, and TAP, 9.465; 1014 FAIR OAKS AVENUE English for USA- Canada is still on SOUTH PASADENA, CALIFORNIA TAT, 9.515, 1815 -1900. USI- Ambon, 11.097A, is still noted around 0645 to 0800 or later; some days fades in before 0500. (Stark, Texas) OTHER OUTSTANDING GOODLINE PRODUCTS: Programs in English are radiated daily VARIABLE TELETRAPS -2: Highly effective for eliminating interfer- by Radio Republik Indonesia, Djakar- ence from FM STATIONS, and DIATHERMY and AMATEUR SIGNALS within ta, on 4.910 and 15.150 at 0600 -0700; its tuning range. on 4.910, 11.770, 15.150 at 0930 -1030; HI -PASS FILTER: Eliminates or greatly reduces interference picked up for Europe and New Zealand on 11.770 by I. F. AMPLIFIER or TV RECEIVER interference arising from strong, and 15.150 at 1400 -1500. (Radio Swe- local low- frequency fields: X -Ray, Diathermy Equipment, Neon Lights, den, others) Etc., Etc. USSR -Moscow, 11.920, noted in Tur- kish session 1250 and heard to 1300, then in German. Noted on 11.950 with news in Spanish at dictation speed to 2130 sign -off; a channel of 11.980 is A Word to the WISE! noted beginning relay of the "main" Home Service with news in Russian STOCK UP NOW 2205. (Kary, Pa.) Yakutsk, 5.980, noted 2350 with program in Russian; weak at Low Summer Prices level, slight heterodyne. (Cox, Dela.) With credit controls lifted and TV sets avail- Moscow announces these outlets for its able with no down payment at many dealers, "evening" beam to North America in it is natural to expect greatly increased sales. English 1820-0100--15.33, 15.25, 15.23, Lifting of the freeze on TV stations in many 15.11, 11.91, 11.83, 11.81, 11.71, 9.67, 9.65, parts of the nation also means more sets sold at dealer 9.55, 7.24; news is listed for 1830, 2000, level. 300 OHM TELEVISION 2100, 2200, 0000, 0030. (England, 300 -Ohm TV Lead -In Wire -finest quality TRANSMISSION New CAMES Hampshire) (Some of these outlets are J.S.C. Wire -is now at low Summer prices. With prices certain to rise in the Fall, it's satellite countries relaying Moscow. WISE TO KRB) - STOCK UP NOW.... Be Pro- tected . . . Stock Up! You Get Highest Quality and Top Efficiency Vatican-HVJ has English daily When You SEE YOUR NEAREST Buy Wire Products from the Dealer 1000 on 9.646, 11.740, 15.120; at 1315 J.S.C. DISTRIBUTOR Displaying the Orange and Blue J.S.C. Disc!! August, 1952 1 I:

www.americanradiohistory.com on 5.968, 9.646, 11.740; also Tuesdays cards which show the Coast Guard in- NOW! TWO GREAT PLATT 1030 on 1L740, 17.840. (Engberg, Swe- signia and a sketch of the "Courier." den) Noted on 9.646 with German 1445. (Bellington, N. Y.) BARGAIN STORES IN Na Y. C. (Ferguson, N. C.) Radio Indonesia, Djakarta, USI, Yea, for the convenience of his many customers WhO r n shop in person, PLATT has opened another BIG Venezuela -YVNB, 4.820, Coro, noted states it will put a new 50 kw. trans- BARGAIN STORE at 159 GREENWICH ST., N.Y.C. It is centrally located for easy access by BMT. IRT, Hud- announcing at 0615; YVMM, 4.910, Ra- mitter into service in October; the new son Tubes & Independent Lines. In addition to the TERRIFIC VALUES in Surplus Eqquipment, you will 2030. 100 kw. transmitter will be located at find the top standard lines stocked -such as Ohmite. dio Coro, is heard to after (Stark, Cornell- Oubilier. Bud Products. RCA Tubes and many Z. other nationally advertised lines. Who not make it a Texas) Kelejoran, near Djakarta. (N. DX point right now to stop in at either of PLATT'S BAR- GAIN (Mail to continue going to Yugoslavia-Radio Yugoslavia, Bel- Times) main store and arehuseort a489BROOMEST. N.Y. 13. N.Y.) grade, recently sent QSL by registered Radio Sweden says the Home Service RAND NEW! mail. (Harris, Mich.) Noted on 9.505 of Radio Eireann, Ireland (Eire), is TUBES JAN! BOX DI TUBES with bad QRM, with news 1645. (Bel - now heard in Europe on 3.400, 5.110 826 39e 1629 22e 2C26A ... 9e 1625 29c 7193 19e 306 390 0800 -1700; may be harmonics. VT -127 ..150 BolA 15R 39e lington, N. Y., others) Summer sched- around i90 39/44 ...290 3C24 984 841 290 is noted on RK34 99e 215A .. . 9e ule is 6.100,0830 -1030, 1630 -1845; 6.150, HJEF, Cali, Colombia, 304TH ...$5.95 864 19C 722A ....99e 1616 490 954 130 316A ....295 2300 -0015, 1700 -1800; 7.240, 0130 -0230; 4.765 to 2300 sign -off weekdays, to 0100 1619 19e E1148 49c 9006 ....190 1626 19e 2C26 9e 9002 ....690 9.505, 1030 -1300, 1600 -1800; 11.735, Sundays. (Cushen, N. Z.) 1315 -1545; is 0215 -0230 on HCJB, Quito, Ecuador, is now oper- SCR -274N English at COMMAND 7.240; 1100 -1115 on 9.505; 1315-1330 on ating in the 31 -m. band on 9.745A and 11.735, and 1645-1700 on 6.100, 9.505. (moved from 9.970A) ; now is on the ARC -5 EQUIPMENT (WRH) air most days to 0300 (last hour and a EXCELLENT s s s half in English) ; by this time should RECEIVERS USED USED NEW have ceased use of 12.455 (10 kw.) and BC-453 -190 to 550 KC 529.95 Press Time Flashes BC -454-3 to 6 MC S8.95 9.95 516.95 Predicted Zurich Sunspot Number should be using a new frequency of BC-455--6 to 9 MC. 9.95 11.95 16.95 TRANSMITTERS for August is 49, down 2 from July. 11.915. (Boice, Conn.) A- 958 -2.1 to 3 MC 29.95 Texas) Radio Pakistan still noted testing to BC- 458 -5.3 to 7 MC. 7.95 9.95 17.95 (Stark, ARCS -T -19-3 to 4 MC...... 24.95 34.95 The first transmission of "Sweden Indonesia 0630 -0715 on 17.835, 15.270; BC-459 -7 to 9.1 MC 13.95 15.95 24.95 ADDITIONAL EQUIPMENT Calling DX -ers" is now aired Fridays with news 1015 -1030 on 11.845 (prob- BC -456 Modulator 2.95 5.95 2.49 ably moved from 11.675) ; with news BC -450 Control Bol (3 Receiver) 1.49 1.95 2.75 1045 over 6.065. (Radio Sweden) BC -451 Control Bor (Transmitter) . L29 1.79 2.39 A powerful "clandestine" outlet is 0200 on 17.710A. More recently was BC -442 Relay Unit (ANT) 2.39 2.89 3.69 Plugs: PL -147, 148, Ill, 152, 153, noted in Sweden on 6.680 opening 1100; noted using 11.914 (instead of 7.010) in 154, I56 -EACH 1.25 Flexible Shafting with gear to fit probably is located in Yugoslavia. parallel with 9.484 with the test period receivers... 2.69 Espana Indepen. for Turkey and Britain at 1430 -1600. 3 Receiver Rack . 2.29 2.98 (Engberg) Radio 2 Transmitter Rac, 1.69 2.39 3.97 Single Transmitter Rack 3.97 diente is currently noted on approxi- (Pearce, England) DM -32 Dynamotor for Command Set. 3.95 5.95 mately 14.880 with news in Spanish "Voice of Free China," 11.920, now DM -33 Dynamotor for Command Set. 2.95 3.95 Shock Mounts for 3 Receiver Rack, 1730; unusually strong level in Pa. has English 1320 -1345 (schedule is one 2 Trans. Rack, Modulator or Antenna Relay Unit 1.95 2.45 (Kary) hour earlier than formerly) ; Chinese SWL's who sent reports to the "Cou- music 1400; news in Arabic 1420; Rus- TURBO AMPLIFIER FIRE EXTINGUISHER TIRE INFLATOR rier," VOA's "Floating Truthship," on sian (jammed) at 1350. (Pearce, Eng- Made lw leading Detroit reception of test transmissions some land) Auto Mfr. Es- pecially ec- weeks ago when the ship was in Pan- BFEBS, Singapore, 11.955, Malaya, ommended for oil. gas Zone waters, are receiving noted signing on 0700 at weak level. and electrical fires. ama Canal Guaranteed by mfr. against defects. 4 tube Amplifier used by Order two-one for U. S. Air Force. 115 V. Your home; one for input at 400 cycles. Your car in case of Without tubes fiats or fires. BRAND NEW - CIRCUIT IMPROVEMENT SPECIAL $1 ONLY $2.29 each By GEORGE A. OSMUNDSEN HEADSETS IHAVE built one of the amplifiers position shorting type. Either the Cen- HS -33 low impedance with cord suggested by Mr. Boegli into a con- tralab Type 1414 or Mallory Type 1225L and plug. used. fine condition $2.79 trol unit and am very pleased with the would work nicely. -107 HS -23 high impedance. BRAND NEW with ear pads 4.95 result. Being cramped for space, it oc- HS -33 low impedance. BRAND NEW with ear pads, cord curred to me that with so many ele- Proposed simplification of an equalizer cir- and P1.54 plug $4.95 a considerable re- CD -307A Cords. 6 ft. NEW .89 ments in common, cuit based on "Phono- Equalizer Chart" by HIB /U high impedance. Includes two re- in size could be effected if a ceiving units 3.95 duction Charles Boegli in the April 1952 issue. HS -16 high impedance -used 2.49 suitable switching arrangement could Two versions are shown; one in solid lines be developed. and an improved one in dotted lines. ARC- 5/R -28 The circuit diagram, as shown in the 2 RCVR solid lines, is based on Mr. Boegli's new MTR chart and is the one I used in building $29.95 up my present unit. The new data sim- 0i Here is the 2 -meter superhet you have been looking for! Absolutely plifies the problem somewhat and, ex- one of the BEST available today! Tunes from 100 to 158 Mee. in four crystal channels. cept for the Columbia LP characteris- (Easily converted to continuous tuning., Tube lineup 3 is fn tic, could be made up on a -gang 717A -R.F.. 717A-Mixer. 2 -120H7 -1st and 2nd K.F. 18.9 Mc. switch. I2SL7 -Det. AVC Spueleh. 1251.7 -1at audio- epelch amplifier. Since Mr. Boegli's latest article men- 12A6-2nd audio. 12SH7-R.F. Osc. -4th Harmonic a 3 a FLAT Gen. tioned the use of -gang switch as 717A -Trip. 12th Harmonic Gen.. 717A -Dblr. -12th 500 O Harmonic. means of making the unit more com- P2 Excellent, used 529.95 pact, I thought I would pass along a M I few additional changes made (shown NAB O BC -221 Frequency Meter dotted in the diagram). 3 3 3 Real Value! QUANTITY IS LIMITED .0 .3 -so first come. first served. They Lug "D" can be used as a tie-point are Just like a with original cali- 150K bration charts. w, Range 125- 20,000 for junction of the two .01 µfd. con- KC with crystal check points In all the LP ranges. Complete with densers and the 33,000 ohm resistor. crystal and toles. $129.50V1L,7 N 56 OR 6.6K MODULATED TIFF $159.50 Any of the spare contacts (C2, Dl, D2. MODULATED TYPE WITH IMEG. AC POWER SUPPLY..... 179.50 D3, or D5) may be bent down, broken AES O These Frequency Meters are factory tested, checked for frequency alignment and GUARANTEED. off, or otherwise altered so as not to be see make contact. These contacts can a Pi MINIMUM ORDER $2.00 used as a ground terminal for connec- 7B O Immediate Delivery -Send 25% deposit on C.O.D. or- s é ¡i00025 ders. All shipments F.O.B.. N.Y.C. (N.Y.C. residents tion to a common ground bus. A .003 VALUE WHICH WHEN ADDED add sales tax to your remittance.) Add. condenser, connected between TO 33,000 GIVES CLOSEST switch points C4 and C5, may be used APPROACH TO ORIGINAL PLATT ELECTRONICS CORP. CALCULATED VALUE OF R6 in place of the .0015 )sfd. condenser 550K) 39K Dept. A, 489 Broome St.. N. Y. 13, N. Y. shown connected between C5 and sim- PHONES: 4.0821 and WO 4-0828 ground. The switch used in this WO plified version is a two -deck, 4 -pole, 5- 114 It.1IDIO & TELEVISION NEWS

www.americanradiohistory.com OTM2, 9.380A, Radio Congo Belge, Leo- poldville, Belgian Congo, heard 1440 to after 1500 with uninterrupted recorded music. (Kary, Pa.) ORDER BY MAIL FROM Radio Nederland, 9.59, noted on Sat- urdays at 2230 with Mail Bag program; good level; also heard on 15.220 WHOLESALE at 1100 -1140 with English to Africa, RADIO Asia, much fade but readable. Radio Low Prices Complete Stocks . Fast Shipments Sofia, 15.33, Bulgaria, noted signing off in English 2315, good level. (Alcock, Ky.) Cet Snyder's Amazing New Stop Monkeying Around with "Rabbit Ears" Radio Peking, 15.06A, noted with INDOOR ALL DIRECTIONAL English by woman at 1745, weak sig- SNYDER TV ANTENNA nal; not audible at that time on 11.69A, ALL DIRECTIONAL Adheres to any sur- 10.260. ZL8, 9.62, face. Ceiling, atti,. Wellington, New closet, etc. Elec- Zealand, 95 tronically switch- is now used instead of ZL3, beamed to cover 11.78, from 0200 onwards in parallel TV 360. area. Flick l AERIAL COMPLETE Nothing else on any chan- with ZL10, 15.22; Radio Sofia, 15.33, Flick of switch t. buy tore Same Clear Pix clears picture nel. Model ID -307. Bulgaria, heard with news 0100; signal You get an- You g e t antenna. As Motor Rotating instantly 25 ft. selector switch, 2.. Stick in closet lead -in, - ft. lead fair; signs off 0115. (Balbi, Calif.) Stick in attic lector -in. CONT. Aerial Systems any- switch FLETE - NOTHING Radio whereat hardware. ELSE TO BUY. Nacional de Espana, 15.620, Costing 1045 Triple noted in Spanish with. S -6 signal; This Price is Madrid. Montevideo, 11.835, Uru- Price Slashing C/oseout guay, noted in Spanish signing off FOR FRINGE AREA Famous Make TV BOOSTER 2200; 4VRW, 9.988A, Port -au- Prince, only $1695 Slade by one of Àmeriea'e most famous electronic Rep- $:0 List Haiti, heard 1100, and found there also houses. Takes 300 oco, Complete with beam se- twinleadtwin or75 ohm co- when rechecked 1400 and 2145. (Cleve- lector switch and 75 ft. Model axial. Two 6dt's and sel. $ land, 3 conductor cable. AX -599 rect. One tuning contrct. Md.) Electronically beams in L1I, app. * complete 380° rotation to give clear picture on all channels. You choose direction with Directronic selector switch mounted Acknowledgement on or near TV set. Complete double- stacked ar- YAGI rays with 18 hi- tensil double -alloy TV ARRAYS Thanks for the fine reports. ISW ments. aluminum ele- DEPARTMENT monitor cards for Model TX -599 same as above plus three 31% ft. For Fringe & mast sections, guy ring and 1952 -53 are now being sent out to mounting base. . $18.95 Ultra Fringe active reporters; they are gratis Highly directional and -and SAVE closely to each with "AUTOMATIC" Low ' High tuned newcomers are welcomed! Send re- Channels c,hann..is channel. Cuts interference a n d noise to a ports to Kenneth R. Boord, - Custom Built Auto Radios 2 7--RY5Y7 948 Stew Hor 3- r 9 9 minimum. Five ele- /14-HY4 0 ments; one folded di- artstown Road, Morgantown, West a -HY5 p e, three directors All with 6 _H -Hla 2 -á i á andn0d1 one reflector. In- Virginia, USA K R B tubes t (l.3,f-R,{Ycl3 array for each $7.95 J $4.e5channelchannel desired. 3 Gang TI15 RODS Condensers for stacking 2 Yagf Arrays Specigpali or Lo band pair 85c HAM EST5 SCHEDULED Easily THE Federation of Long Island Radio Installed "PRECISIE" RF -AF -TV Clubs, Inc., representing nine radio MARKER GENERATOR KIT clubs on Long Island and FOR ALL Dealer Net in Brooklyn, F -100 '49,'50 Ford $39.97 Fundamental thru 110 nlc. has scheduled its 16th annual hamfest D -200 '49, '50 Dodge - 330 me on Harmonics PASSENGER Plymouth 39.97 and dance for Friday evening, Audio: 211 -20,000 cycles. Septem- C -300 '49, '50 Chevrolet 41.97 Cathode follower output: ber 12th, at Lost Battalion Hall,- Elm- Cars& Trucks F -151 '51 Ford 39.97 variable per cent modula- F -152 '52 Ford . 39.97 tion. Stepping attenuator. hurst, Queens. D M1,ndr -251 '52.'51 Dodge . 39.97 External modulation. C -351 Hams from the metropolitan New A -I$ '52. '51 Chevrolet 39.97 Speech amplifier, crystal H -451 '52, '51. '50, '49. York area as well as Five '48 Hudson 39.97 those from other 630` K °Kit...$33.95 sections are invited to A tubes 5 -551 '52, '51. '50 attend. prize Studebaker 39.97 With pre - assembled 11F Completely factory will be awarded to the amateur coming Universal Mtg. P -651 '52. '51 Plymouth 41.97 wired. K-751 . the greatest distance to attend this '51 Henry .1. 39.97 6h3e0a dl.( $38a95 630 W $53.95 affair. Tickets are $2.00 for hams, and Address Orders fo Dept. RN -8 Write for Free FYI $1.25 for XYL's when ordered in ad- Bulletin vance. An additional 50 cents will be collected on each ticket sold at the door. Tickets may be obtained from WHOLESALE RADIO PARTS CO., Inc: Julian N. Jablin, W2QPQ, FLIRC Sec- retary, at 147 -14 Charter Road, Jamai- 311 W. BALTIMORE ST., BALTIMORE 1, MD. ca 35. New York. * rilHE Baltimore Amateur Radio Club TRAIN AT HOME FOR 11HF -TV AND is holding its fifth annual hamfest- picnic at Triton Beach, Mayo, Mary- land on Sunday, August 10th. Tickets are $1.00 with 50 cents payable at the entrance to the beach and the balance payable at the pavilion. This fee includes bathing, bath house, and locker facilities, and the use of the picnic tables and pavilion. Learn practical, professional type TV Servicing without lean- Prizes will be awarded for the best ing sour present job. Included are money- making extras such as net conversion, master antenna installation. UHF -TV, field home -made mobile installation and servicing short cuts. You can start earning Television money the best commercially -built installa- after first few lessons. You learn to test, trouble shoot and re- tion. There will be an interesting vari- pair all types of TV sets. ety of contests for all. The HERE'S HOW YOU GET EXPERIENCE! affair will You train on a large screen. MILTON S. I(IVES, President modern TV receiver, furnished TELEVISION COMMUNICATIONS INST. start at 10:00 a.m. and all hams are in- with the course and yours to keep! As an optional feature you can 205 W. Wacker Cr., Dept. I -Z. Chicago 6. III. vited to pack a picnic get two weeks actual experience with Chicago's largest in- Rush basket and join dependent servicing organization. FREE Catalog and Sample Lesson. 1 ant You learn by doing! Age is not obligated. Salesman will not call. the fun. no barrier. Many students are over 401 ACT NOW! Send for For full details write Chairman Ernie FREE Catalog and SAMPLE LESSON today! Name Age Dobos, W3JCL, 2208 N. Fulton Avenue, TELEVISION COMMUNICATIONS INSTITUTE I Address City Baltimore 17, Md. 205 W. Wacker Dr., Dept. 1 -Z, Chicago 6, III. Zone.... State HH BEGINNERS check for l're -TV Radio Course. August, 1952 115

www.americanradiohistory.com Cinemagnetie Recording (Continued from page 47) tat,

SPINTIT operated from 117 volts a.c. but other 6EMOFTNEfumes - REG. U. S. PAT. OFFICE models available which can be op- are 62 SENSATIONAL BUYS I erated from 220 volts a.c., 50 or 60 BC -222 PORTABLE 10 -METER TRANSCEIVER: Freq. range: 28 -32 MC. Y.F.O. Battery operated, with tubes, from d.c. for location telephone -type handset and antenna- Less batteries. cycles, and also Like New $32.50 16, COLUMBIA MARINER: 100 W. 4- channel, x -tel con- work. It can be adjusted to handle trolled. FCC approved. 12 or 24 V. input. COM- PLETE. READY TO GO ...... $349.50 171, or 35 mm. film at the normal Unconditional 50 -day guarantee. JOHNSON MARINE TRANSMITTER: 90 W. VERY speeds for these film widths. A special EASY TO OPERATE. 12. 24. 32. 115 V.D.C. input. COMPLETE. ONLY...... $299.95 feature of the recorder is that the Unconditional 90 -day guarantee. BC -223 TRANSMITTER: 25 W. 4- channel, x -tai con- feed spindles can be trolled. 12 or 24 V. input. Less Crystals. A SUPER takeup and BUY. With 12 or 24 V. power supply, all tubes A factory-made cable with plugs. Brand new $85.00 quickly set in another location so they ARS RADIO COMPASS RECEIVER: 195 -9005 kc. MOST COMPLETE MARINE RECEIVER MADE! will handle 1500 feet of film. At 45 Checked out with ALL accessories 585.00 DU.1 1,00P for above item. ONLY $27.50 feet -per- minute or at the normal 16 JEFFERSON- TRAVIS 5 W. MARINE RADIO TELE- PHONE: f V. input. COMPLETE. less crystals. mm. speed of 36 feet -per- minute, a SPECIAL 589.95 continuous half -hour program can be THUMBNAIL INFO ON NEW REDUCTIONS! TRANSMITTER: BC -375. 100 W. Phone or recorded. This is quite important to CW. Complete with 24 V. dynamotor, tuning unit, all tubes Si cables. Excel. cond..$47.50 DYNAMOTOR: PE -103. 6 or 12 V. input. the growing television film industry. 500 V., 160 ma. With filter base mid cords. Excel. cond...... 24.95 Figs. 3 and 4 show detail construction T -23 VHF ARC -5 TRANSMITTER: 2 meters, novice, CAP. Excel. cioci. With ALL tubes. 37.50 of the recorder. CAREER BEACON RECEIVER: BC -357. used 5.00 ARC -4 VHF TRANSCEIVER: For novice. The mixer amplifier (Fig. 1) pro- CD or 2- meter. With tubes 32.50 BC -659 10 METER FM MOBILE TRANS- high CEIVER. Power supply. hand set and an- vides two microphone inputs; tenna. Complete ..- 55.00 SCR -625 MINE DETECTOR: Now $59.50 level mixing; dialogue equalization; .. 39.50 Like New high and low -pass filters; oscillator for SURPRISE PACKAGE! 15 lbs. of radio oil,. -tali( -.. coml.. chokes,t re i stors. channel line -up; audio slater and talk - x- formerspots, coils. tol,. etc,. etc.: PER PACK S $1.50 between mixer BEAT COMMAND EQUIPMENT: Limited quantity! back system; intercom Sold as is, less tubes. Rebuild 'em or use for ts. operator, recordist and microphone 3 -4 MC $7.95 5.3.7 MC $2.95 4.5.3 MC...... 2.95 7.9.1 MC 5.50 boom man; and monitoring from either -MD -7 PLATE MODULATOR 6.50 the direct signal or from the recorded TUBE KIT FOR COMMAND XMTR 1.25 TV TEST EQUIPMENT at the press of a button. The DUMONT OSCILLOSCOPE: \I rdel 208 -B. signal Excel. cond...... $175.00 HICKOK OSCILLOSCOPE: Model 195 -B. recordist monitors from the recorded Excel, ond, 115.95 JACKSON OSCILLOSCOPE: Model CRO -2 track during a take and his head- Like new 149.95 RCA TV CALIBRATOR:...... Model WR -39A phones are automatically switched Like new .. 169.50 RCA TV SWEEP GENERATOR: Model WR- back across the line when the recorder 59A. Like t 179.50 H ICKOK TV DC KILO VOLTMETER: Model 120 is stopped so that he can be aware of 41i.-,. With pro he. Co nr. ci orli tiro 39.95 STYLES what is taking place on the stage. In ARC -5 OR 274 -N TRANSMITTERS 2.1.3 mcs. $19.95 short, all of the convenient features 4 -5.3 mcs. Used, good cond. 6.95 and 5.3.7 mcs. 5.50 for doing production recording are pro- 7.9.1 12.50 ARC.5 OR 274 -N RECEIVERS SIZES vided in this channel of equipment. .19 -.55 kc. Excel. cond. $14.95 -1.5 mcs. Used. Excel. cond 27.50 As pointed out previously, all the 1.5.3 mcs. Brand ew 24.50 3 -6 mcs. Less tubes 6.95 "OK" takes on the magnetic film are 3 -6 mcs. With tubes 9.95 6 -0.1 mcs. Brand new 11.95 transferred to photographic tracks. :1 -9.1 mes. Used 7.95 RACK FOR DUAL TRANSMITTER (274 -N) 2.95 and made ready RACK FOR DUAL TRANSMITTER ARC -5. 3.95 These are then edited TRIPLE RECEIVER RACK 5.00 BC -442 -A ANTENNA RELAY with 50 for re- recording. At this stage of the mmfd. crnden.cr. Excel. con 3.95 film has again been process, magnetic AIRCRAFT EQUIPMENT found very helpful in saving time and ARN7 MN -20 -C SCR-269 ARR -5 THE ARR -7 HS -33 Headset VHF ARC -S MN24C Dubbing or re -re- FL -8 Filter -New and used. Loop (CAA, doing a better job. APN -O ARC -1 ARC -3 APR -4 APR -5 ART -13 RTA -IB SCR -522 cording a picture for release involves NOTE: We tock most complete line of TS gear in West Coast. sWrite us for prices and types available. ORIGINAL mixing together at least three and per- MONEY TALKS! Especial) hen y u re planning va cation! If YOU need DOUGH sell YOUR new or used WRENCH haps as many as twenty or more dif- radio gear to us! We pay top buckl All orders F.O.B. Los Angeles. 25 % deposit required. ferent soundtracks. Controlling the All items sublect to prior sale. WITH THE and possibly COLUMBIA ELECTRONIC SALES level, frequency response, 522 South San Pedro St., Los Angeles 13, Calif. SCREWDRIVER the amount of compression of all of ACTION these tracks places a severe burden on the mixer operators. The use of magnetic film makes it possible for these SOUND POWERED mixer operators to play back im- PHONES RCA -MI -2454 Complete with 24' of Or mediately the results of their efforts Rubber Covered Wire. rather than wait until the next day NEW EXPORT PACKED as is necessary when using the photo- Shipping weight 6 lbs. ASSEMBLY WORK graphic process. Dubbing mixer opera- $9.95 per set REPAIR WORK tors are enthusiastic about the use of 2 for $19.50 magnetic film for this purpose since it EACH SET GUARANTEED RADIO Brand N ew- Gov'tE. Cost. $42.00 represents an improvement in quality INCLUDE POSTAG WITH ORDER TELEVISION as well as a significant saving in time. McCONNELL'S 3834 German tow n Ace. reel satis- Phila.. Pa. RA 5.6033 INDUSTRIAL When they have dubbed a factorily on the magnetic film, it is AIRCRAFT then transferred to the photographic release negative. GET OUR PRICE FOR YOUR Still another extensive use of mag- RADIO & AIRCRAFT EQUIPMENT! netic film is for the storage of sound- We'll go the limit to buy your parts or equip- tracks. It is becoming common practice ment. Send us a description of the type and con. dition of equipment you have -tell us your top to record the three separate sound- dollar asking price-and be pleasantly surprised at tracks of a picture on one piece of 35 the fast action you'll get! STEVENS WALDEN, Inc. R -1 mm. film. RCA was the first to supply ALVARADIO SUPPLY CO.-Division WORCESTER 4, MASS. 4665 Melrose Avenue Los Angeles 29, California equipment for this purpose. All of the 116 RADIO .Ik TELEVISION NEWS

www.americanradiohistory.com dialogue is recorded on one track, the music on another, and the sound effects on the third. Such a film is quite use- SEE LEO FIRST FOR .... ful in making foreign versions where the dialogue can be omitted but all of the other sounds are mixed together at the proper level. Engineering knowledge is available hallicrafters to introduce magnetic soundtracks into the theaters on the release prints. It I can SAVE you money... Liberal Trade -ins would of course be necessary to modify theater equipment to reproduce mag- SPECIAL NOTICE -NEW SX -73 NOW AVAILABLE AND IN STOCK- $975.00 netic soundtrack and in many theaters the sound systems should be improved to benefit from the extended volume and frequency range of such magnetic soundtracks. It would cost more to re- record the magnetic soundtrack on each release print than it now does for the photographic track because the photographic soundtrack is printed simultaneously with the picture in the same machine on the same film stock, $169.50 $199.50 whereas a magnetic strip would have S -76 RECEIVER to be applied to the film and the mag- SX -71 RECEIVER netic soundtrack re- recorded thereon. Extra selectivity with double superhetro- dyne circuit. One RF, two conversion and Double Conversion sharp selectivity, However, magnetic sound recording 3 IF stages. Range 550.1550 Kc, 1.7.34 plus built -in NBFM at moderate cost. is developing rapidly, and many new Mc in four bonds. 8 tubes voltage plus 11 tubes plus voltage regulator devices are now being designed to regulator and rectifier. Complete with and make better use of magnetic film. This tubes, less speaker. rectifier. Low down payment. will undoubtedly continue because this NAME YOUR TERMS LOW DOWN new medium of sound recording offers PAYMENTS PERSONALIZED SERVICE so many possibilities not readily at- HALLICRAFTERS RECEIVERS AVAILABLE tainable with the photographic process. FOR IMMEDIATE SHIPMENT S -38B $49.50 S -72 Portable $109.95 S -40B $99.95 SX -62 $289.50 A SUGGESTION S -81 $49.50 S -78A $89.50 S -82 $49.50 R -46 Speaker $19.95 By RAYMOND D. BRYANT AVING noticed an item on page 173 Famous WRL RADIO of your May 1952 issue (TV Trouble- REFERENCE MAP 25c JUST OFF THE PRESS! shooter), I wish to offer my comments. The idea of the so- called trick is good, WRL 1952 CATALOG so good that I've been using it for a year Send for your copy today. Con- and a half. However, I am convinced tains everything new in radio and that I obtain better results. Plastic television. Jam -packed with bar- alignment tools, being somewhat soft, gains. Leo I. Meyerson, WfóGFO do not give the best results. I find that with a a -inch diameter fiber align- CU on 10 -20 & 75 Meters ment tool with a plastic handle, I can locate internal arcing in the windings NEW LOG BOOK 25c For mobile or fixed station. Spiral bind. of a high voltage transformer, arcing Ing. Full column log listing all FCC re quired info. Will accommodate 1.525 sta- or leakage in a high voltage filter con- tions. "0" rlggnnals, phonetic alphabet. amateur international prefixes. I WORLD RADIO LABORATORIES denser, arcing in "open" high value 744 West Broadway IF Council Bluffs. Iowa resistors, etc. PHONE 7795 WRITE -WIRE It seems the fiber will reproduce and t Please send me: / Rodio Map s -76 Info conduct the vibration better than will New Catalog SX -7t the softer plastic materials. I Info hope used Equipment List New Log Book other readers will benefit from my experience in this matter. Iv. Q Name - LABOaATOsits\ Address COUNC L BLUFFS.\ City State A simple method for keeping tester leads from draping over the meter scale, as suggested by Fred J. Lingel, W2ZGY. As the picture shows, this is done by running the tMAKE THIS YOUR HOME FOR IMPORTANT leads through the slot in the end of the WORK UNDER IDEAL CONDITIONS . leather carrying strap. It also prevents the TEST E. INSPECTION ENGINEERS FIELD ENGINEERS accidental disconnection of the when plugs ELECTRONIC ENGINEERS LAB. TECHNICIANS there is too much tension on the lead wires. TV RECEIVER DESIGN ENGINEERS NEEDED TO WORK ON. YOU BENEFIT FROM high wages, a Radar, G. C. A., Mobile modern, air- conditioned plant, paid Radio, Auto Radio, Airborne vacations and holidays, group insurance Communication & Naviga- and a good chance for advancement. tion Equipment, Television, Antennas, Microwave Housing immediately available in the Equipment, Servo Mechan- beautiful suburban and country areas isms and Guided Missiles. that surround the Bendix Radio plant. Write, Phone or Wire Mr. E. O. COLE, Dept. O ßendixl Radio DIVISION OF BENDIX AVIATION CORPORATION BALTIMORE 4. MARYLAND .ftuuvt. 1952 117

www.americanradiohistory.com The very popular Elmac Transmitter for portable or fixed PRODUCTS station service NEW TV .. r.... An outstanding little transmitter designed primarily for under -dash mounting yet with features that make it well suited for fixed station service. Pi- network output permits operation into lines or antennas from approx. 30 to 600 ohms. Crystal control provisions for noon the Market. vice use. Also has excellent, built -in calibrated VFO. Coverage: Four bands. 3.5 -4, 14 -14.4, 26.96- REPLACEMENT PARTS Ring convolutions are molded into the 27.23 and 28 -29.7 mcs. Power: 50 watts input max. Requires 6V @ Standard Transformer Corporation, surface of the 20 kv. condenser to pre- 4.5A and 300 -500V (a 250 ma. max. Microphone: Any standard carbon type. Special 3580 Elston Avenue, Chicago, Illinois vent surface leakages that are caused hi- impedance mike models also available at has the availability of four- by ordinary handling and a consequent slightly higher price. announced Metering: Uses dual scale meter with switching teen new television replacement corn- deposit of conductive materials. for final grid or plate current. VFO or Xtl: Built -in VFO with excellent stability. ponents. A catalogue covering these bypass Calibrated dial scale for each band. Size: 71/z" x 75/2" x 12 °. The new additions to the line in- condensers is available on request. Tubes: RF, 807PA, GARS, 3- 6AG5's, AF, 6C4, six power transformers, two fila- 12AÚ7, 2 -6L6GA mods. Also 0A2, VR. clude Complete with tubes, (less carbon mike) $139.00 ment transformers, two. horizontal de- MARKER GENERATOR Ocean- TRANSFORMERS -CHOKES: flection and high voltage transformers, Precise Development Corp., 325 -0 -325 @ 225 ma. 6.3 8' 5A. 5V @ 3A. two filter chokes, a vertical deflection side, New York is now in production Pri. 110V, 60 cy AC. Size, 41/s" x 41/s" x Witt". Only $6.95 ea. output transformer, and a width con- winding. 920 -0 -920 or 740 -0 -740 AC @ 200 ma. Pri. trol with a.g.c. 115V, 60 cycle, AC. Upright shielded case. Ex- Replacement recommendations for cellent for 807'a Only $10.80 ea. these new units are listed in the new 5V. 25A. Pri. 115V, 60 cy. AC. A real rugged job RAM meso 0041 as excellent for 304TL- 4 -250A etc. Limited quan- "Stancor TV Replacement Guide and tity. Only $4.50 ea. Catalogue" which lists 2416 TV models 1011, 200 ma choke. Hermetically -sealed steel case. Also has hum-bucking tap. A beautiful item and chassis. only $1.98. Power tranef. Pri. 115V, AC, 60 cy. Sec. 520 -0- NEW REGENCY BOOSTER 520 @ 200 ma. $5.25 ea. A new and exclusive circuit stab- 350-0-350 @ 300 ma. 6.3 @ 4A. 6.3 @ 8A. features 5V @ 3A. Pri. 115V, 60 cy. AC.. . only $7.95 ea. ilizer is the principal of ten

450 -0 -450 @ 200 ma. Pri. 115V, 60 cy. AC. of the new television signal booster 5V @ 3A, 6.3 @ 5 amp. In shielded case. Regency Division of Only $8.90 ea. made by the I.D.E.A., Inc., 7900 Pendleton Pike, In- 350-0-350 @ 350 ma. 6.3 C' 10A. 5V @ 6A. Pri. 115V, 60 cycle. Only $8.95 ea. dianapolis 26, Indiana. on an r.f.- a.f. -TV marker generator, NEW! PORTABLE The stabilizer provides both induc- GEIGER COUNTER tive and capacitive neutralization to the Model 630. A small light -weight unit 12 Available in kit form, the Model 630 (2 pounds: , with a sensi- assure maximum stability on all tivity that compares fa- v.h.f. channels. Other features of the will reach 110 mc. on fundamentals and vorably with instruments is many times its purchase new Model DB -520 include ease of in- 330 mc. on harmonics. The unit price. Rugged and de- with the r.f. head preas- pendable and intended for stallation with the TV set plugging furnished professional use. Batteries used provide long life sembled and calibrated. and low replacement cost. Each Geiger counter into the booster and the booster into comes complete ready for use with instructions the wall outlet; an "on -off" switch of Audio frequencies from 20 to 20,000 and radio -active ore sample for comparison tests. mod- $35.00 3 amp. capacity; a single tuning knob; cycles can be measured with the variable in both per -cent and 110V, AC POWER SUPPLY FOR a push -pull triode in a balanced cir- ulation 20 20,000 cps. The ANY 274 -N RECEIVER cuit; link coupling for optimum im- frequency from to Just plug it into the rear of your 274 -N RE- unit has a cathode -follower output, CEIVER . any model. Complete kit and black metal case, with ALL parts and diagrams. Simple stepping attenuator, external modula- and easy to build in a jiffy. Delivers 24 volts speech amplifier, crystal marker, plus B voltage. No wiring changes to be made. tion, Designed especially for the 274 -N receiver. and crystal amplitude control. The Only $8.95. Filament trans.. for 274N receivers. Pri. 110V, circuit also incorporates r.f. and a.f. 60 cy. AC. Sec. 24V @ .6A. An excellent buy at $1.95 ea. standby, a Wien bridge a.c. oscillator, a Colpitts r.f. oscillator, individually O -R exclusive . tuning knobs for 274N Re- ceivers, a hard -to- obtain item Only 89e ea. tuned coils, constant output impedance, vernier tuning on a.f. and r.f., a LOOK! NO HANDS! separate r.f. section, and complete This mike leaves both hands is separately free for mobile QSO's. Fas- shielding. Each band tens to operator by simple loaded for constant output from range snap strap. Adjustable. Double action sw. operates to range. push -to -talk or holds on. Only $2.00 ea. NEW TRIO PRODUCTS LIGHT SOURCE pedance match; improved circuit con- Trio Manufacturing Company of ULTRA -VIOLET has introduced Again available . . . 8 watt ultra -violet light trol for greater tracking accuracy; a Griggsville, Illinois just source that has found wide usage for experi- its line of TV menters, schools, labs and fluorescent lighting of compact cabinet; and a broadband re- three new products in rock specimens. A thousand uses in medical, equipment. chemical, art, stamps. etc. sponse. This model carries UL ap- In kit form including Sylvania 8 watt black light The new units include a television tube, ballast, starter. tube clips. mounting panel, proval. reflector. line cord /plug, hardware, instructions. rotator and direction indicator, a new Simple to make shadow box for outer housing. tower, and an accessory Sure -fire, easy to assemble. TV BYPASSES all- aluminum Complete kit, (less outer housing) ..only $4.95 Erie Resistor Corporation of Erie, control unit. which utilizes two NOVICE POWER SUPPLY PARTS Pa. is offering two new high voltage The rotator 24 volt motors, will sup- Filter condensers. 4 mfd, 600V oil... $1.25 ea. "Ceramicon" TV bypass condensers heavy -duty Filter choke. 10H @ 200 ma 1.98 ea. to port the heaviest arrays even in 80 Bleeder resistors. 20,000 ohms, 100 which have been designed especially watt. A regular $1.50 ea. net value .only .75 ea. supply high voltage power supply fil- m.p.h. winds. A positive- acting elec- 360 de- Minimum order $2.00. All items subject to prior sale. tering for television receivers. trical stop at both ends of the All prices subject to change without notice. 20 a de- lead damage. The posit must accompany all orders, balance C.O.D. The Style 412 is rated at 20 kv. and gree turn eliminates the Style 414 at 10 kv. The case in- rotator may also be used for the 10, 6, OFFENBACH -REIMUS sulation is of low-loss, molded ther- and 2 meter ham bands. It turns at 1 1564 MARKET STREET mosetting plastic, which provides ex- rpm and can be fastened to any pipe SAN FRANCISCO, CALIF. cellent moisture sealing properties. up to 2" o.d. 118 RADIO & TELEVISION NEWS

www.americanradiohistory.com The all- aluminum tower weighs less !¡+ áis¡iiñüii7á¡r sO/ than one pound per foot. The tower \ may be raised from a horizontal posi- 11-\_{ -K tion in heights up to 40 feet. For additional height, sections can be added from the bottom. The tower comes in 5 -foot sections : a bottom section, a top section, and as many center sections "CONIC REGISTEFED as desired. TRADE MARK The accessory control unit provides an automatic line switch for booster, rotator, TV lamp, or other accessories. By plugging the line cords from these "BAT WING" accessories into the control relay unit, all such accessories can be turned on with the one switch controlling the TV set. TV "SERVISET" Lee Electronic Labs. Inc., 233 Dud- ley Street, Roxbury 19, Massachusetts the finest has developed a handy, compact cir- - cuit analyzer whi,ch has been trade - named the "Serviset." TOP -OF -SET The unit, which is self- contained, SUPER -PERFORMANCE! antenna ever can be used as an r.f. and a.f. signal Beyond a doubt, the finest top - tracer, as an r.f. and a.f. signal in- of -set TV antenna ever offered produced! jector, can measure a.c. and d.c. volt- the trade. Outperforms any other ages from 0 to 20,000 volts in four indoor type and requires no tuning or pruning. No fuss, ranges, indicate d.c. polarity, act as a bother or time consuming adjustments. SUPERIOR low ohms continuity and short indi- STYLING! Featuring modern design that enhances any living room. Rich aluminum elements are mounted on a cator, serve as a high ohms continuity finely finished, tip -proof base. WRITE FOR NEW LIT- and leakage checker, function as a sub- ERATURE with complete information on the whole stitute condenser or resistor, and check Teirex line for TV, UHF and FM. speakers or phones for acoustical coupling as well as continuity. CLOVER -V -BEAM E -Z RIG design. A The Model EC is compact, light, and high gain, compact array for attic or portable. It is simple to operate and outdoor installation. has no controls to adjust. Its use will i not load or detune the circuit under NEW! Teirex "FISHBONE". Ten WORK- test. ING elements. Guaranteed to outper- The unit comes complete with an in- form any yogi on the market. struction manual; a high- impedance, high- sensitivity Alnico phone; special phone extension cord; an insulated a "Klipzon" type extension tip; a high .- voltage adapter; a kinkless test lead F NEW! "CONICAL -V- BEAMS" WITH HI- with built -in lamp remover; and a fab- V- REFLECTOR - UNIVERSAL SERIES - ric pouch which houses all of the ac- customized for your locality. cessories and the manual. "CONICAL -V- BEAMS" are covered by Patent No. 23,346 CANADIAN and FOREIGN PATENTS PENDING ASTATIC BOOSTER The development of a new and improved television booster has been announced by the Astatic Corporation of AMERICA'S Conneaut, Ohio. OUTSTANDING Tradenamed the "Scanafar," the TELEVISION new booster is claimed to provide a BEAM

NEW! MOSLEY WALLTHRU For TV, FM and Amateur Transmission Line Fits Any Wall Up to 13" Thick!

Completely Weather - Proof! For Standard Flat 300 Ohm Line or RG -59/U Co -ax Cable! MOSLEY Lead -"n Socket Can Be Mounted Di- 625 Cat. No. rect to Inside List Price $1.95 Plate! Cat. No. 625 -PK Wall Precision Molded Polystyrene End Plates! lower noise figure 'Ihru, complete and higher gain with Easily, Quickly Installed! whether used with new or old style MOSLEY Universal receivers. The circuit is a balanced, 'TV Lead -In Socket cascaded type with a neutralized 6J6 and Plug. MOSLEY ELECTRONICS tube driving a 6BQ7. Both tubes are List Price $3.00 2125 Lackland Rood Overland, Missouri August, 1952 1 14

www.americanradiohistory.com used over the entire TV frequency of which is marked with the manufac- range. turer's part number as well as with Bandwidth is over 7 mc. on all chan- the IRC stock numbers. HARVEY nels. Two control knobs operate the The new line also includes the com- booster, one an "on -off" switch and low pany's "Concentripaks" with a special For the FINEST in AUDIO or high band selector and the other a selection of universal parts for specific fine -tuning control. The metal cabinet makes of TV concentric dual controls, WILLIAMSON HR-15 AMPLIFIER is finished in simulated mahogany all housed in a sturdy plastic box; a new dealer "Concentrikit" assortment KIT woodgrain and gold. Additional information on the Model in a standard IRC all- metal, four - CT -1 is available from the company drawer cabinet; and the Form S012 on request. which lists replacements by tradename and part number along with the IRC TV CABINETS equivalent. Standard Wood Products Corp., 43- For complete information on the new 02 38th Street, Long Island City 4, control line, write for a copy of Cata- New York has added seven new period- logue DCIC. 503 TV cabi- The famous, original Williamson HR -15 ... still style models to its Series acclaimed the leader ... In kit form, with the net line. ANTI -STATIC AGENT original Partridge output Transformer. Assemble is Series this kit, and in 3 hours or less, enjoy the finest One of the new cabinets the A new anti -static agent developed by sound you ever heard. Operates from a tuner, 503 French Provincial. This unit will Chemical Development Corporation of phono- preamp, crystal pick -up, or other signal source. Absolute gain is 70.8 db with 20 db of Danvers, Massachusetts is now avail- feedback. Frequency response: 7.1- .5 db, from 10 able for a wide variety of electrical to 100,000 cps. Output impedances to match all speakers from 1.7 to 109 ohms. Kit is complete equipment applications. with 5 tubes (1.5V4, 2.6SN7, and 2 -5881 (or 807 Although originally developed to if requested), 2- Punched Chassis, 2- Resistor on Mounting Strips, Sockets, Partridge WWFB Out- eliminate dirt and dust attraction put Transformer, Assembly Instructions, and All plastic surfaces, it has been found that Other Necessary Parts for Amplifier and Power Supply. $76.50 it can be used on glass, painted sur- HR -15, as above, but with Partridge CFB Output faces, and on other areas where Transformer (Hermetically Sealed) $90.00 charges accumulate. PARTRIDGE OUTPUT TRANSFORMERS - Available The product can be applied by spray- Separately. WWFB $26.00 CFB $40.00 ing, dipping, or other con- HR -15T WILLIAMSON Kit -Furnished as above, brushing, with TRIAD Transformers and Chokes $69.50 ventional methods; polishing is not NOTE: HR -15 and HR -15T Kits may be had with necessary. British KT -66 Output tubes for $3.00 additional. Tube and electrical instrument companies are invited to secure complete FIRST AT HARVEY! details on this new product by writing The Sensational 'Hit' of the the company. New York and Chicago Audio Fairs The New R -J house all 630 -type chassis and other TV TRANSMITTER SPEAKER models of similar dimensions and all The General Electric Company has announced the availability of a line of ENCLOSURE sizes of round and rectangular tubes. Like the other models in the line, this u.h.f. television transmitters which Designed for use with ANY 12 or 15 inch speaker, to needs of dif- this new sensation in high- fidelity has no counter cabinet is supplied complete with all have been tailored the part in anything available today. The R -1 is a new necessary mountings for the picture ferent sized communities. concept. Large enough only to accommodate the A for small speaker, it reproduces tones to the lowest limits tube and yoke and can be furnished lower power transmitter of audibility, cleanly and without hangover. The with a record changer pull -out drawer towns is already in production at the R -1 is the amazing solution to the problem of Electronics Park plant at space versus quality. at the bottom at a slight additional company's Three models Now Available for Immediate Delivery. charge. Syracuse, New York. Specify for 12 or 15 inch speaker. The cabinets measure 40" high by will comprise the line for the present, Model FM (Mahogany) $49.95 a 100 watt, a 1000 watt, and a 12,000 Model FB (Blonde) 54.50 24" wide by 24" deep. The line is available in mahogany, walnut, ebony, watt unit. A specially- designed an- or blonde finishes. tenna gives the three transmitters ef- HI -FI PICKUP CARTRIDGES fective radiated powers of 1 kw., 100 AUDAX POLYPHASE COLINEAR ARRAY kw., and 200 kw. conditions, the low - DL -6 "Chromatic " -.001" Diamond and Fretco, Incorporated, 1041 Forbes Under average .003" Sapphire Styli $41.70 Street, Pittsburgh 19, Pa. is now in power u.h.f transmitter and the special L-6 Sapphires, 001" and .003" 20.70 G will provide satisfactory KL-4 Same as L-6, but higher output production on a new television antenna -E antenna (for record changers) 20.70 which has been tradenamed the "Fret - reception 8 to 10 miles away. G. E. VARIABLE RELUCTANCE aray." RPX -040 Sapphire .003" $5.97 This broadband colinear array re- TV MAST RPX-041 Sapphire .001" 5.97 Company RPX -050 "Triple Play " -.001" & tains high gain on all channels. It is The Baker Manufacturing 003" Sapphires 8.37 light in weight and of sturdy construc- of Evansville, Wisconsin has added a PICKERING tion. One antenna will receive all new unit to its television mast line. S -1405 Sapphire .001" $15.00 channels. Only one transmission line The 10 AM is a ten -foot mast with a D -140S Diamond .001" 36.00 special tapered joint for stacking ten - S -120M Sapphire .0027" 9.90 is required. Assembly consists of tight- D -120M Diamond .0025" 24.90 ening the unit and mounting it. foot sections together to provide a .001" for 331/3 & 45 rpm on this new fringe area mast of any desired height. This spe- .003" & .0025" for 78 rpm A data sheet antenna is available from the company cial joint insures tight and rigid con- NOTE: In view of the rapidly changing market Constructed of 1Y/4" o.d. conditions, all prices shown are subject to on request. nections. change without notice and are net, F.O.B., N.Y.C. "Perma- Tube" steel, this mast is elec- and long TV CONTROL LINE trically welded for strength International Resistance Company, life. Broad Street, Philadelphia Complete details on the mast line 401 North company. 8, Pa. has announced a completely new are available from the TV control line which includes 295 factory- assembled "Exact Duplicate Con- CHECKER- REACTIVATOR centric Dual Controls" individually Electronic Beam Corp., 923 Old Nep- packaged in uniform size cartons, each perhan Avenue, Yonkers 3, New York do TELEVISION NEWS 120 (RADIO

www.americanradiohistory.com has added a cathode -ray tube checker and reactivator to its line. According to the company, with this I SCR 625 Famous Army Mine -Detector For Prospectors, Miners, Oil Companies, portable unit the television technician Plumbers, etc. can check picture tubes without re- WANTED! This unit is being offered now at a considerable reduction TV All TS, APR, APS, ARC, ARN, ART, SCR, R89 in price. Recently advertised at $79.50 it moving them from the sets or their is now available in the same brand new wrappings and BC equipment ... write today! in suitcase style carrying case (less batteries) at Quote prices in your first letter. WHILE THEY Used, like $59.50 LAST! new, $39.50 Closing Out All TUBES 1611.4 $16.95 304TH $8.95 805 $2.69 9003 .... $1.29 4AP10 $1.95 16DP4 16.95 304TL . .. 8.95 9001 .99 6AJ5 2.29 5CP1 3.95 14CP4 16.95 830B 1.69 9002 .79 6ACT .79 5BP4 3.95

RT7 APN1 TRANSCEIVER UNIT -Used as an altimeter, it may be converted for signaling MIKES and HEADSETS HS -33 Low control circuits, etc. Complete with 14 tubes and Impedance Headset, dynamotor they are in good used condition at exc. $2.95 new $5.50 -307 Ext. the amazingly low price of $24.95 CD cord for HS 23 -33 like new 1.29 Used, less tubes, with wobulator 9.95 Throat Mike -T 30 New .98 Lip Mike -Navy Type New .98 Extension Cord and Switch Assembly for BC 604 FM Transmitter -20 -27 mc. 10 hp and throat Mikes New .98 Channel crystal controlled push- button, ex- 49505 cellent for conversion to 10 and 11 meters, CW High Impedance headset complete small quantity on hand, in good used condi- with leather headband and rubber 1 95 tion, less dynamotor, some missing side cushions. Used covers, etc. --- otherwise complete, RS-38, Microphone new $4.95 including tubes $7.95 TS 10 sound powered HAND SET.. used, ea. 5.95 Like new $12.95 HS-38 exc. $1.95 new 2.29 HS-30, miniature headset new 2.49 shipping cartons. He can also reac- used 1.49 the tube without removing Used New HB -7 Headband, used, exc .. 1.25 tivate it BC -453, less tubes $10.95 ..... from the set. BC -454, 3 -6 me receiver, less tubes 5.95 Complete MN26C The new Model 10 is housed in a BC-455, 6-9 mc receiver, with tubes 9.95 $14.95 200- 1750KC, manual directional finder, complete with all parts . cabinet measuring 9" x 6" x 5" and less tubes, as is 5.95 $79.50 BC- 457, 4 -513 mc transmitter, less weighs 21/2 pounds. It is self -powered tubes 4.95 DYNAMOTOR and operates from standard 117 volt BC -458, less tubes, as is 4.95 The best dynamotor for conversion to 6v. Multiple a.c. lines. As a tube checker the Model BC -459, less tubes, as is 10.95 windings! After conversion you get choice of 190 10 can for BC -496, 2 position Rec. Control Box 1.95 or 350 v at 50 MA or 250 v at 100 MA. No test shorts, cathode emis- MC -215 Mechanical Drive Shaft, brushes to shift around, no mechanical work, sion, leakage, etc. in cathode-ray tubes. per length 2.45 Or use it as a 2:1 or 1:2 step -up or step -down BC -450 3 Receiver Remote 1.29 2.95 transformer for DC voltage! Changes 6 to 12, or Control. 12 to 24, or vice versa, up to 3A. Or use it as a BC -451 Transmitter Control .69 1.50 MASTER TV SYSTEM Box... GENERATOR. Turn with motor, get 12 v DC at BC-442 Antenna Relay, less con- 12.6 A or 24 v DC at 6.3 A, plus high voltage. Technical Appliance Corporation of densers -used 1.29 Includes easily removable self -contained 800:1 sealed -in-oil gear reduction unit. Complete dope Sherburne, N. Y. has introduced a new sheet furnished. TV master antenna distribution sys- MONTHLY SPECIAL RT 34 APS 13 Transceiver used as a tail BRAND NEW $4.65 tem which has been designated as the warning radar on 415 MC. Containing a "Super Series 2500." 30MC IF Strip and various other parts, these BC 624 receiver (SCR 522), leas tubes, units have been stripped of RF sections and used $19.95 The new system features an output all tubes but are an excellent buy if only for BC 625 transmitter (SCR 522) less tubes, of 6 volts peak -to -peak and provides parts and IF Strip. Used $4.95 used 14.95 SCR 522 transceiver, complete in case with a voltage gain of more than 500. This top bracket, less tubes 29.95 gain results in better fringe -area per- WOBULATOR Transceiver - 100 -156 mc, 2 meter, used, excellent condition, less dynamotor, with formance. Proper stability is main- See page 43- December "Radio News" tubes tained in output stages so that no dis- $5.95 ea. $32.95 tortion is present in the 6 volt peak -to- SURPRISE PACKAGE WRITE FOR PRICES peak output. Amplifier strips employ 20 pounds of assorted radio parts. A real BC1033 BC376 SCR510 value at BC610 BC639 MP 10 6AK5 tubes with 6AN5 output tubes. ..$2.45 BC939 BC638 LP21LM The master chassis provides the pow- APS13 RA42 TS170 er for the amplifier strips. Shipments FOB warehouse. 20% Deposit ARN7 RA52 TS34 Rectifica- on orders. Minimum order $5.00. Illinois res- SCR269F&G RA62 TS61 tion of the line current is handled by idents, add regular sales tax to remittance. SCR6I9 RTA1B TS92 JB70 TAU B C 1277 the tube circuit, thus eliminating sele- Prices subject to change without notice. R70 APS15 CRT3 BC1287 nium rectifiers. The amplifier strips mount directly on the master chassis by means of Jones plugs. The mixer Dept. N, 1112 -P14 S. Miehigan Are., C7 hi9374cago 16, III. unit for the transmission of amplified R W ELECTRONICS HONE: HArrison - signals into a single transmission line is an integrated part of the master chassis. Two high- strength outputs are RADCOM pays highest prices for provided on the master chassis. WANTED.. surplus equipment, parts and tubes.

"KINE -LITE" TCS -7 and up SCR -508 . . . BC -604, BC -603, Vidaire Electronics Mfg. Co. FT -237, Crystal Sets. of Lyn- SCR 274N, BC 696 brook, New York is currently market- SCR -506 ... BC- 653 -A, BC- 652 -A, ing a picture tube brightener and re- SCR 399 Equipment JB 70, DM -40 -A, FT- 253 -A, BC- 658 -A. juvenator which has been tradenamed the "Kine -Lite." JB 60, BC -939A BC -610 -E RA- BC312, 342, 348 Receivers. The new unit is designed to add in- 63, EE8. BC- 614 -E, PE95, PE197, SCR522 Equipment, SCR -211 Freq. creased brightness to any TV picture Trailer K -52, Cords, LS -3 Meters. RA -34 Rectifiers. tube having low emission and may be Phone Bigelow 2 -6666 MANUALS TUBES TEST SETS used on all standard picture tubes having duo -decal bases. 41440 R'lglit ?Vitk Ea41 ?Wet No soldering or other circuit alterations are required to install this unit. Livit.ngs St A data sheet giving all pertinent data RADCOM EngineeringEli iineer inng Co. Newark N. J. is available. August, 1952 121

www.americanradiohistory.com Electronic Growth TOP QUALITY! LOW COST! I (Continued from page 39) casting stations and the motion picture studios in California. In keeping with its credo that a modern electronic parts distributor must be more than a passive vehicle for the supply of parts, the company has sponsored educational meetings for both its industrial and FISHER dealer customers. For example, the HIGH QUALITY company recently sponsored an "Image Orthicon Seminar" which was attended by virtually all key television camera technicians located in Southern Cali- Phonograph PreamplIfIer fornia. In addition, the company developed Here is the top quality, reasonably priced preamplifier you have early in 1949 a series of charts and always wanted. The FISHER provides exact equalization for low- paper invoice forms which dealers level magnetic pickups of any make, such as GE, Pickering, Audax, could use to break down their charges Clarkstan and others; also used as a microphone preamplifier. for the repair of television sets. These invoice forms, which the company List $29.95 printed and sold to its dealers without profit, allowed the dealer to estimate Outstanding Features: his charges intelligently and to explain Uniform response,30 to 20,000 cycles. to his customers the breakdown of his Self powered. Two stages of triode repair bill at the time when television amplification. Extremely low hum. repair was an uncharted field. These Full low- frequency equalization. High dealers report that these forms have gain. Completely enclosed chassis greatly helped them in customer rela- with bottom cover. Plugs supplied. tions and have been responsible for Output cable can be up to 50 feet in many repeat sales. length. size: 33/4 x 35/B x 35/B high. Today ten dealer -salesmen regularly WRITE FOR FULL DETAILS cover a territory extending from the Pacific Ocean into Arizona and from FISHER RADIO CORPORATION Fresno and Paso Robles far into Mex- 39 E. 47TH ST., NEW YORK ico. Resident salesmen are located in Bakersfield, Santa Barbara, Riverside, and San Diego. The company's export department has been in existence for fourteen years. Five industrial sales- NEWESTi ITEMS! LOWEST PRICES! men call regularly on every important

1 PERMOFLUX industrial account in Southern Cali- REAR DECK fornia and counter salesmen of long- standing amateur status take care of MAGNETIC TAPE SPEAKER KITS the ham customers. RECORDERS The design and construction of Ra- Easy to install; provides greater radio enjoyment In your car. Requires only connection to speaker dio Specialties Company's new home terminals in auto radio. 3 -way wired switch permits speakers to operate separately or together. was based on years of experience. Complete with metal grille and protective speaker instructions. etc. Where the average parts distributor screen, hardware; template, displays most of his stock, which con- RS46A 4" x 6" Speaker Kit $7.94 RS961 6" x 9" Speaker Kit S10.29 sumes from 60 to 100 per -cent of his NOVICE TRANSMITTER KIT total area, this firm's store takes up less than 10 per -cent of the total area 0 NETWORK with the other 90 per -cent being given RECORDER over to warehousing facilities. No NWR1 stock is located in the store itself. Only one sample of each basic part is dis- for beginning amateur or for use as a stand- on by rig. Operates on 80 and II meters. Big pictorial played, the small parts being shown and schematic diagrams for easy assembly by any- sample boards located along the walls one. Complete with two punched chassis, coil forms and wire. tuning indicator, and all other and in specially designed glass- covered assembly parts plus standard telegraph key and tubes (6V6. 6L6 and 5Y3GT). Less crystal and islands on the sales floor. Large items small amount of hookup wire and solder re- there' which need to be demonstrated, i.e., just like being quired. $32.58 Novice Transmitter Kit test and sound equipment, record play- THE ONLY low cost high BARGAIN LOW PRICE ers and changers, etc., have one sample fidelity tape recorders FLYBACK each located along the walls under the delivering professional TRANSFORMER sample boards and under a large mural performance. Professional showing RCA products and factory (Similar fo GE 77J 1) processes. These large units are the users' net prices begin at Regular $11.00 list price high voltage ranstormer similar to General Electric 7711. Used for general only items which can be touched by replacement in many sets up to I4KV and with up to 19" tubes. Not available elsewhere at our low the customers. $34500 price! A -1827 Flyback Transformer $2.49 There are no inefficient ladders to Write for Bulletin ;.,---102 COMPLETE STOCKS climb in either the warehouse or store, Just off the press . Manufactured 8y All Standard Brands at a height a BIG BARGAIN BULLETIN all shelves being designed Berlant Associates normal person can reach while standing on the floor. The warehouse has a 4917 W. Jefferson Boulevard \ ELECTRONIC los Angeles 16, California conveyor system which permits the DISTRIBUTORS, INC. rolled Dept. RN -8 -7736 S. Halsted, Chicago 20, III- merchandise to be unloaded and 122 RADIO & TELEVISION NEWS

www.americanradiohistory.com to the receiving room, checked, and then rolled on into the warehouse without lifting. The merchandise locations have been carefully studied with the result that heavy or bulky items are located either close to the receiving door or immediately adjacent to the Sensational conveyor system. Merchandise sold primarily over the counter is located as near the counter as possible while merchandise sold mostly through out- UBE SAUINGS side salesmen is located close to the order filling and shipping departments. UNBEATABLE! UNPRECEDENTED! The entire new layout and decorative Tried and true performance plus economical service scheme was an attempt to keep pace make these low, low priced, high quality, fully guaran- with the changing emphasis and rapid teed tubes the sensation of the nation. Every tube growth of electronics in a fast -growing rigidly tested, every tube a standout value. area. Radio Specialties believes that it has succeeded and that the gamble All Tubes Individually Boxed! Same Day Service! on the future of the Pacific Southwest's electronics industry was a shrewd one. /Check this list for Fully Guaranteed Tubes The industry is sound and the company Type Price Type Price Type Price Type Price Type Price has invested heavily to prove its point. OB3 VR9O .75 3Q5GT .49 6BC5 .44 6SQ7GT .37 125K7GT .48 1A5GT .46 3S4 .46 68C7 .70 6T8 .56 125L7GT .47 30- 1Á6G .59 3V4 .47 6BDSGT .59 6U5 .44 12SN7GT .52 1A7GT .47 5AX4 .37 6BD6 .45 6U8 .61 125127 .49 LABS .59 5AZ4 .39 6BE6 .39 6V3 1.10 1447 .44 MID-SOUTH Á14D10 SHOW 1115 .59 5Ú4G .40 6BF5 .41 6V6GT .39 14AF7 .55 1B7GT .59 5V4 .73 6106 .37 6W4GT .44 1486 .40 lovers and audio enthusiasts 1C5GT .43 5V4G .54 6BG6G .94 6W6GT .44 14J7 .60 itt:I(:in the area around Memphis, 1G6 .60 5X4 .40 6BH6 .46 6X4 .37 14W7 .60 1H5GT 40 SY3GT .32 6BJ6 .39 6X5GT .37 19BG6G .95 Tenn. are looking forward to the "Mid - 1L4 ..46 5Y3G .32 6BL7 .59 6Y6G .48 19C8 .80 South Audio Show" to be held at the 1L6 43 5Y4G .35 6BQ6GT .59 7A4 .47 19T8 .79 Peabody Hotel in Memphis August 4th 1LCS .51 5Z3 .39 6BQ7GT .72 7A7 .48 19V8 .97 1LC6 .48 6A3 .59 6C4 .37 7A8 .46 25BQ6GT .62 through 7th. 1LN5 .51 6A7 .59 6C5GT .39 7AF7 .53 25L6GT .39 Sponsored by the W & W Distributing 1N5 .46 6AB4 .44 6CB6 .44 7B4 .44 25W4 .56 (: pally of Memphis, the show will 1P5 .57 6AG5 .43 6CD6G 1.11 7C6 .40 25Z5 .40 105 .61 6AJ5 .90 6E5 .48 7E6 .49 25Z6GT .37 feature an extensive display of such 1RS .45 6AK5 .75 605GT .39 7F7 .59 32L7 .85 Hell -k n high fidelity equipment as 155 .39 6ALS .38 6F6 .37 7N7 .50 35115 .40 that made by Jensen, tit roniberg -Carl- 1T4 .45 6A05 .39 6G6G - .52 7X7 .69 35C5 .39 ITS .53 6AQ6 .37 6H6GT .41 12AL5 .37 35L6GT .41 son.. Elect ro -Voice. University, Steph- 1U4 .45 6AR5 .37 6J5GT .37 12AT6 .37 35W4 .37 ens. McIntosh. Newcomb. Bell, Radio 1U5 .39 61155 .50 6.16 .52 12AT7 .56 35Z4 .39 Craftsmen. Neissner, Browning, Am- 1X2 .63 6AT6 .37 6J7G .43 12AU6 .38 35Z5GT .37 2A3 .70 6AU6 .38 6K6GT .37 12AU7 .43 36 .60 pex. Concertone, Presto- Pen tron, Crest - 2A5 .47 6AV6 .37 6K7 .44 12AV6 .39 42 .42 wood. Rek -O -hut. Garrard. V -M, Web- 2X2 .59 6AX4 .53 61.6 .64 12ÁV7 .59 45 .55 ster. and others. 3A4 .45 6B4G .64 6L6G .64 12AX4 .48 5085 .39 \I ill 3E5 .46 6115 .64 607 .45 12AX7 .48 SOCS .39 Hotel reservations be made by 3Q4 .48 6BA6 .39 6S4 .38 12AZ7 .68 SOC6 .59 W W Distributing (' pally, P. O. 6BA7 .57 658 .53 12BA6 .38 5OL6GT .41 Box 436, for any out -of -town guests 65A7GT .43 12BA7 .46 5036 .46 65D7GT .41 128E6 .39 50Y7 .50 planning to attend this event. 6SG7GT .41 12BH7 .63 7OL7GT 1.09 65117 .73 12K7GT .46 75 .41 65J7GT .41 1207G .39 76 .44 65K7GT .41 1258 .70 78 .47 6SL7GT .48 1 25A7GT .44 117Z3 .37 í'111:1'H Tl 1t1: OPERATION 6SN7GT .52 125J7 .44 807 .99 By H. LEEPER receivers using a type 1113 rectifier TERMS T`' can he easily checked for operation A 25% deposit must accompany all orders - of this tube by bolding a neon bulb near balance C.O.D. All shipments FOB Irvington ware- the tube's top cap. If r.f. energy is being house. Orders under $10 -$1.00 Handling delivered to the rectifier tube. the r.f. Charge. Subject to prior sale. voltage nearby will cause the neon tube to glow. Now In New, Enlarged Quarters at While a two -watt neon lamp is shown "Integrity Is Our CO. in the photograph. a smaller (1/4 watt) Chief Asset" TUBE 115 COIT STREET bulb works even bet ter. Phone: Essex 5 -2947 IRVINGTON 11, N. J. Use only one harid when making this check. Keep the other hand away from the chassis and be sure not to contact . crown -rocs moues +woad nave +a'so the rectifier tube cap with the fingers. WE'LL PAY SWEET PRICES for Your °gC DUALITY SERVICE DEPENDABILITY RADIO & AIRCRAFT EQUIPMENT PERFECTLY We want to buy your parts or equipment -and r \+N DUMONT CENTERED get send us the we'll pay top dollar to it! Just b '-.' COMPLETELY Checking the 1B3 rectifier in a TV set. dope on your equipment, its type and condition- and your asking price. You'll get fast, profitable '' MOLDED `:>:. ',' CAPACITORS ction. It's just like taking "Candee" from a Sold and Preferred Everywhere baby! Write today. ;:;'Fa CANDEE- AIRCO, Dept. T -4 DUMONT Electric Corp. 3306 Burbank Blvd. Burbank. California 308 Dyckman Street, New York 34, N. Y.

ANNOUNCING THE VTDIDI * KIT At last every Engineer, Technician. Serviceman and Experimenter oho owns a siutpson 21ig, Triplett ono or similar multimeter can have a vacuum tube voltmeter at a very nominal. cost. The sensational VTJIM plugs directly into your multimeter to convert It into a Ile \'rs.\t with an 11 megohnt input resistance. 31easures Lt' volts to :tit volts. Ac:otin otiatcs a cryvtal diode type probe for AC and 11F voltage measurements. Self contained transformer type poser .supply for complete isolation. Highly degenerative circuit offers excellent stability. Very compact In size. 5'4" x 3" x 2ys" Complete kit including tubes. Model MM -1K $13.95. Crystal diode probe completely es assembled. Model CP -1 $5.95. Specify your meter make and model. 'Vacuum Sube Send check with order, we pay postage. modifier. meter AIR -O- TRONICS Box 31 LANCASTER, Calif. .August, 1952 123

www.americanradiohistory.com procedures, broadcasting, receiver circuit fundamentals, typical receiver circuits, picture tubes, projection receivers, TV test equipment, servicing, BOOKS troubleshooting, waveform analysis, PI color television, and color conversion E L E C T R O N I C S S U P P L Y "DESIGN AND CONSTRICTION methods. A separate chapter carries a MID -SUMMER CLEARANCE SALE! OF A WIIEATSTONE BRIDGE" television glossary. Try to Beat These Values! prepared and published by Technologi- The text material is lavishly illus- cal Developments, 475 Fifth Avenue, trated with line drawings, circuit dia- f,'ß - TV DEFLECTION New York, N. Y. 6 pages. Price $1.00. grams, and photographs which serve to YOKES Paper bound. amplify and supplement the author's 0 Major brand names. Most 6 contains com- explanation of the principles involved. popular types at LOW- This -page booklet EST PRICE! plete construction and design informa- The book is written clearly and with- Ea. ONLY 89cV77 tion on a Wheatstone Bridge. The out resorting to involved mathematics TV ANTENNA CONNECTOR CLIP: Clothes pin type... is in calculations. List price: 50c. YOUR COST ONLY Ea. 22c function of the bridge explained or complicated LOTS OF 25. VERY SPECIAL $4.75 book should meet the require- OPEN WIRE TV LINE: Copperweld 1x18. Ideal some detail including the necessary The for fringe areas! 100 ft. $ 5.20 250 0. SPECIAL! 12.50 mathematical computations. The au- ments of the budding television tech- INDOOR ANTENNA: thor has also outlined the various nician very handily. VIDEO BEAM T`" .oreEa s s * TUBES! NAME BRANDS! 100% GUARANTEED! points which must be considered when OZ4A $0.59 35L6 $0.59 1B3 .89 35W4 .49 such a unit is to be designed. QePRIMER OF ELECTRONICS AND 5U4 .59 3505 .72 6W4 .59 12AT6 .61 The balance of the text covers the RADIANT ENEIIt " by Don Cav- SOLE .69 129A6 .69 SOAS .83 12BE6 .69 actual construction of the instrument erly. Published by McGraw -Hill Book and explains how various measure- Company, Inc., New York. 334 pages. G.E. HIGH VOLTAGE FLYBACK ments can be made with the unit. The Price $5.50. Second Edition. TRANSFORMERS text is illustrated with large, clear This is a layman's book designed to diagrams which can be used in con- make the subject of electronics under- ./1 structing the bridge. standable to persons without technical 'I * s s training in that field. ó (I ee20 BASIC POINTS FOR TV- RE- The author has attained the often - N.; CEIVER SERVICE" by A. C. W. impossible goal of presenting a poten- Published by Paul H. Wen- tially- complex subject in a thoroughly Standard Replacement: Ea., $1.89 Saunders. del Publishing Co., Inc., Indianapolis. lucid style. Without condescension or purposely "talking down" to his audi- FUSE HOLDERS Fifth "Notebook" in the Television 3AG Extractor type. Mounts 2" behind panel. Eas, Technicians Lecture Bureau series. 44 ence, the writer has presented a quan- to mount THIS MONTH SPECIAL Ea. 15 Paper bound. tity of interesting data covering a wide PUSH -ON KNOB KIT pages. Price $1.00. De luxe assortment of 40 receiver type knobs in 1 This 11ew technician's notebook cov- range of topics. different styles! Match any cabinet styles. Serviee man or set builder -THIS ISFOR YOU! ers twenty of the basic parts of a tele- The book itself is divided into four Kit only 89 be parts dealing with electricity, magnet- J.F.D. 31/2^ SCREW-EYE INSULATORS: vision receiver which can used as 100 19 500 $10.00 and 1,ÓÓÖ FOR ONLY 517.50 the basis of a troubleshooting and ism, electromagnetic radiation, GUY WIRE: 4/20 Stranded. 1,000 ft. $5.25 tubes and sources of radiant 6/20 Stranded. 1,000 It. 6.95 servicing system. electron C.R. TUBES! NEW! NAME BRAND! 1 -YR. GUARANTEE! energy. Each of these main headings I6AP4A Ea. $24.95 The author's servicing technique, as PLASTIC RECORDING TAPE: Red oxide. 1,200 which cover ft. $2.29 developed in the text, involves the is subdivided into chapters FLYBACK TRANSFORMER: R.C.A. type. With prin- the major aspects of the primary topic. 6006 and 1B3 windings. SPECIAL ONLY 51.49 statement of twenty fundamental MALLORY TUBULAR CONDENSERS ciples and then the detailed explana- By using familiar analogies and a 40 MFD -150V .50.42 16 MFD -450 V 50.57 40/20 MFD -150V. .62 40 MFD -450 V .69 tion and amplification of the "theo- large number of diagrams and photo- 50/30 MFD -110 V. $0.69 WESTINGHOUSE DIAL LIGHTS: 100 to the box. rem." Using this method, the author graphs to amplify the text material, X44. #46, 7t47 $5.29 E51 4.29 deals with such subjects as the design the author has provided the reader SANGAMO MOLDED BY-PASS CONDENSERS video for broadband re- with at least an intelligent speaking .01 -600v $0.12 .001 -600V 50.10 of amplifiers .02 -600V .12 .002 -600V .10 with many of the man- .05 -600V .16 .005 -600V .10 sponse, control of stage gain, the func- acquaintance .1 -600V .19 .006 -600V .10 tion of a.g.c., tuned circuit response, made marvels of this century. gain and bandwidth comparison, stag- s * s SENSATIONAL ger tuning of i.f. stages, parallel effect "TEST INSTRUMENT APPLICA- =.; SPEAKERI VALUES of the grid circuit on the plate load, TIONS MANUAL" by Edward M. Most popular types for replace- design requirements of video detectors, Noll. Published by Paul H. Wendel ment and new construction! inversion properties of a Publishing Co., Inc., Indianapolis. Sixth 4 -inch PM $1.39 10 -inch PM $2.69 the phase 5- " PM 1.49 12- ' PM 3.49 conventional amplifier, etc. "Notebook" in the Television Techni- 6- " PM 1.69 8- " Electro- 4x6- " PM 1.49 dynamic 1.49 As with most of Mr. Saunders' lec- cians Lecture Bureau series. 48 pages. 6x9- " PM 2.49 10- " 500 ohm. 1.89 8- " I'M 2.29 12- " 1.000 ohm 2.29 tures, the text is written in a down -to- Price $1.00. Paper bound. omitting extraneous ma- The practical application of various PAPER CONDENSERS earth style Alidget, tubular types. 1110 V. or more. Many a:e terial. Technicians who have worked types of television test equipment is less than S4" diam. EACH ONLY 3e 10 for 25c with the "Notebooks" in the past will the subject of this information -packed (Specify value: .001, .002, .003..005. .01, .015, 02, prepared espe- .03, .04.1 find this newest release up to standard. booklet which has been PILOT LIGHT SOCKETS s * * cially for the service technician. Miniature, bayonet -base type. With spring type mounting clip. Load up at this low price. "AUDELS TELEVISION SERVICE The text material is divided into EACH ONLY 3c the fea- 10 for 27e MANUAL" by Edwin P. Anderson. three main sections covering OUTPUT TRANSFORMERS Published by Theo. Audel c& Co., Pub- tures and characteristics of various 251,6 Ea. 29c 6L6 Ea. 59c lishers, New York. 384 pages. Price types of TV test gear, how to know BVB Ea. 49c $2.00. your test equipment, and how to use it. MISCELLANEOUS SPECIALS! equipment is 6 -volt VI i!l!.\l It! Mat 1.29 This compact, pocket -size handbook The use of the test 2 -volt VI BItATOlt .49 explained by means of specific MIDGET I.F. 1'1!ANSI-l1I!MER, 456 KC .49 is a practical how- to -do -it presentation clearly VOLUME CONTROLS of television receiver installation and examples and service -tested procedures. With switches. 111,000, 250,000, 500,000 ohms. 1 meg.. The equipment covered includes such 2 meg. Each ONLY 49c servicing. In lots of 10. Each ONLY 44c The book contains eighteen chapters instruments as oscilloscopes, sweep os- All orders F.O.B., Los Angeles. and all goads sub- probes, ject to prior sale. 25% deposit required with all dealing with the placement of the TV cillators, v.t.v.m.'s, instrument orders. receiver, test patterns and adjust- and signal generators. Diode modula- Olympic Electronics Supply ments, TVI, interference traps, televi- tors, u.h.f. test equipment, and service DISTRIBUTORS are also consid- 1440 West Olympic Blvd., Dept. RN sion antennas and transmission lines, bench arrangements LOS ANGELES 15, CALIFORNIA master antenna systems, installation ered in some detail. -- 124 RADIO S TELEVISION NEWS

www.americanradiohistory.com Servicing Picture Tubes JUST WHAT YOU NEED ... CORDS -CABLES Standard 'l'c t Lead,. 4 "14 " l'im4...l'ao 39c -3 f/S I .00 (Continued from page 37) Phone Plug-Nickel Plated. Sere, CD -501 Cord f /GN -45 Generator 52.50 Terminals Ea. 39C -3 f/ 1.00 1'1)-318 Cord w /l'L-68 & SW -141 & Instrument Knobs- -Bar, Octagon. Round, Set Screw, JK-48F .89 Asst 10 1 skirts, f/ .00 CD -307 Cord -6.5 Ft. w /PL -55 & JK -26 .89 Line lord -Bro. Rubber 7 ft., Molded Rubber Note 2: Some customers have been Plug Ea.29c -4.f/ 1.00 CD -604 Cord w /C- 410Trans. & PL -54 Plug .89 CD-365 Cord for LP -21 Loop concerned over a luminous "flashing" line Cord -Black Rubber 6 ft.. Angle Molded I .50 Plug Ea. 39 c 3f/ I.00 siC -215 Tuning Shaft for 274N 2.00 which occurs for some time after the set is turned off. This trouble will not TRANSFORMERS AND CHOKES ANTENNA EQUIPMENT TRANSFORMERS -110 V. 60 CYCLE PRIMARIES: harm If is BASE the screen. it bothersome 600.0 -600 V. 200 MA-6.3 V. 3 A; 6.3 V. 4 A; MAST -INSULATED to the customer, try readjusting the 5 V. 3A -3% "x4 "x48'4" Stancor. No. l'- 6170.56.95 MP -132 BASE-as 325.0 -325 V. 50 MA-6.3 V. 2.5 A; 6.3 V..6 A illustrated at left. ion trap or the high -volt- (Rect. 6x51 Half 21/2"x3% "x3 " 1" heavy coil spring. 2" insulator. Over- slightly try Shell- -No. all length: 11W'. Weight: 2% lbs. age bleeder resistor just described. T -23 -28 2.75 Price 53.95 6.3 V. 1 Amp... 1.25. 24 V. 1 Amp I .95 1 3 t 5. DEFECT: Picture either washed - 24 V. Amp... I .50 24 V. 6.5 Amp 5.95 MAST SECTIONS FOR ABOVE 6 -24 -or 30 Volt 8 Amp 5.95 out or extremely "contrasty" (Fig. 3 Two 12 V. 4 A. windings. gives 12 V. 8 A. or BASE -Tubular steel, copper coated, or 4); brightness control will not af- 24 V. 4 A. 5.95 s uainted. in 3 foot sections, screw -in type. 6.3 Volt 6 Amp-6.3 Volt 4 Amp 2.25 SIS -53 can be used to make any length. fect brightness. 440 VCT /70 MA -5 V. 2 A.-6.3 V. 4 A 3.35 eith SIS- 52- 51 -50 -49 for taper. 700 VCT /200 MA -6.3 V. 4 A. -6.3 V. 4 A.- Price for any section 50c Ea. CAUSE: Grid -cathode or heater - 5 V.3A. 4.95 AIRCRAFT CONTROL CABLE 700 VCT /120 MA -5 V. 3 A.; 6.3 V. 4 A.; 32 cathode short in picture tube. (In cer- V. 2 A. 3/32" -7x14 sn:uul, Wea'hcrtroofed, Galvanized, 4.75 920 lb. Test. Ideal for Tele4ision Guying and many tain models, a shorted or leaky con- 490 VCT /60 MA -5 V. 2A.; 6.3 V. 4 A.; 6.3 V. 2 A. other uses. Prices: 31/í0 per Ft. -1000 Ft. or 3.25 nuore @ uer Ft. denser in the brightness control cir- 460 VCT /90 'MA -5 V. 3 A.; 6.3 V. 4 A. 3.75 3c cuit will cause the same trouble.) AERIAL WIRE- Phosphorus Bronze #16 Stranded. CHOKES: 200 lb. test. Weatherproof. 150 Ft. on Reel. RL -:t REMEDY 1: If the tube is within 5 Henries -150 SIA., 85 ohms DC -Res., Cased, w /Clips 5 I .50 2ß'a "x2% "x31/. " -No. 3769 S 1.95 Telephone Wire -3 Cond. copper & steel, 525 Ft 5.95 warranty, contact the dealer or dis- 8 henries -500 MA., 80 ohms. 5000 V. Ins 8.95 tributor for replacement. 7.5 Henries -400 MA., 60 ohms, 5000 V. Ins 6.95 85 KC IF COIL-7267-for BC-453 $3.50 6.2 Henries-300 MA.. 82 ohms, 5000 V. Ins 4.95 BFO-85 KC....75c 1415 KC-IF.... I.501?a. REMEDY 2: Try burning out the 1, Ilen vies -a00 MA.. 260 ohms 4,75 TU-7-8-9-10-26 for BC-1o1/BC-375 U,ed: 3.95 4.-12 Hero e. -^nn SIA.. 110 ohms, 1000 V. Ins 3.95 short by applying a.c., d.c., or r.f. DYNAMOTORS: across the shorted elements. The au- BC -223 TRANSMITTER -With Tubes & TU 17 Tuning Unit. Gov't Reconditioned DYNAMOTOR and BLOWER: 9 Volts DC input: out- 526.50 put 450 Volts 60 MA. 4500 RPM. At 6 Volts DC in- thor has found that r.f. voltage ob- CABLE -Transmitter to Power Supply 52.00 put; output 260 Volts 65 MA. 3000 RPM. TUNING UNITS- TU -17- 2000 -3000 KC.. TU -25- Price $4r95w tained from an amateur transmitter, 3500 -5250 KC. 53.80 EACH high voltage power supply of the TV OPERATING MANUAL for BC- 2239x 2.50 INPUT: OUTPUT: STOCK No. : PItIt'IS: SHOCK MOUNTING for PE-125 1.50 14 V. DC 600 V. 300 MA. BD-86 59.95 receiver, or a similar source of low - FT-173 MOUNTING for BC -223 2.50 12 V. DC 220 V. 70 MA. DM-24 6.95 12 V. DC 220 V. 100 MA. DM-18 4.95 current, high -potential is much more 14 V. DC 375 V. 150 MA. DM-375 8.95 effective in clearing shorted elements BLOWERS -115 VAC 60 CYCLE 14 V. DC 330 V. 135 MA. DM-330 7.95 COMPACT TlPE: 108 CFM, motor !milt inside squir- 14 V. DC 500 V. 500 MA. PE-59 14.95 (in any tube) than either 117 volts a.c. rel cage, 41/2" Intake; 3% "x3" Dis. Comp. size: 12 or 24 V. DC 275 V. 110 MA. USA/0516 3.95 414" W x 8%" H x 814 "D. 12 V. DC 250 V. 50 MA. DM-25 8.95 117 d.c. 28 V. DC 250 V. 60 S1A. DM-32 or volts The apparent reason Order No. RN -860 S 1 3.50 FLANGE TY1'E: 140 CFM. 31'1" Intake; 214" Dis. (Used) 2.95 is that most shorts of this type are not 12 or 24 V. DC. 500 V. 50 MA. USA/0515 3.95 Comp. size: 7W' W x 71/4' H x 6h" D. 14 V. DC 1000 V. 350 MA. BD-77 caused by direct contact between sag- Order No. RN -865 312.95 dl 8.95 SINGLE TYPE: 100 CFM. 2144" Intake; 2' outlet. 28 V. DC 1000 V. 350 MA. PE-U73 ging or displaced elements, but rather Complete size: 5 "x6 ". Order No. RN- 520....57.99 (Used) 6.95 from dislodged particles of the emit- DUAL TYPE: 100 CFM, 4" Intake; 2" Dis. Each Side. 28 V. DC 250 V. 60 MA. PE-86 5.95 Complete size: 8 "x6 ". Order No. RN-809 5 1 2.95 ting surface. The application of r.f. l'I.ANGE TWIN: 275 CFM, 4W' Intake; 31/4 "x3" Dis. Comp. size: 118'4" W x 8%' 11 x 81Áa" D. POWER SUPPLIES: tends to burn out or anneal these par- Order No. IIN -134 S20.95 VIBRATOR TYPE -6 Volt DC input; output 230 Volt DC 50 MA. -not filtered -w /tube. Ideal for Command ticles so that they cause no further AMPLIFIERS Receiver operation as receiver is filtered internally. trouble. (A number of such tests by Size: 41/4"x414 "x3%" 54.95 BC- 367 -Uses two 6V6GT Tubes. Carbon Mie. input, PE -157 POWER SUPPLY -2 Volt Vibrator Supply. the author have been entirely satisfac- Tapped output. Ideal for intercom. With Tubes & operates from BB -54 2 Volt Battery mounted in Case. Schematics, less Dyn. and Case-Used 54.95 Output voltage L4 V. % Amp 125 V. 50 MA. Less tory.) BC- 605 -With Tubes, Used 3.95 Battery. Speaker. & External Power Cord -with Vi- REMEDY 3: If the above method BC -703 -W /Tubes -New: 54.95 Used: 3.95 brator 54.95 BC- 317 -Less Tubes-Nee : 52.95 Used: I .95 BB -54 2 Volt Dry Battery 2.95 wjll not clear the short, isolate the Address Dept. RN Minimum Order $5.00 Prices F.O.B., Lima. 0. 25% Deposit on C.O.D. Orders shorted element by installing a separate filament transformer for the pic- 132 SOUTH MAIN ST. ture tube. (Any small, inexpensive FAIR RADIO SALES LIMA, OHIO transformer which will handle the i picture tube's heater voltage and current requirements will do.) Tie the cathode to one of the heater terminals but do not ground the transformer TAKES THE "PORTERING" secondary or center -tap. (Isolating the NEW GUARANTEED OUT TUBES OF PORTABLE RECORDING cathode circuit in this manner allows 082 $1.39 6AK6 ....$1.10 450TH .939.50 003 /VR90. 1.10 6AN5 .... 3.99 CK512AX.. 1,98 the brightness control to function nor- 0C3 VR1O5 1.10 GASS .... 3.30 702A 2.75 OD3 /VR150 .93 .... mally and in many cases will actually 1822 ... 2.25 705Á 1823 ... 7.95 YOUR 7O7Á 7.95 improve picture quality by reducing 1824 ... 8.50 SURPLUS 7078 ...14.95 1035 ...12.95 708A 3.95 transient and line noise effects.) 1N23 . 1.25 WANTED 7158 ... 8.95 1N23A . 2.25 We PaY ]228 ... 1.95 Battery-Operated Spring -Motor Note 1: The 2041 9.95 Highest 723p 6.95 above method obviously 2C40 ... 8.50 Paces! 727/1 /6 .5 2C43 ...24.50 7248 ... 2.775 PORTABLE TAPE RECORDER will not work in receivers which feed 2C44 .. 1.19 6Á57G ..$9.50 726A 6.95 2C52 . 6.95 603 3.75 Field recording can now be the video signal in through the cath- 2021 ... 1.49 ilif44 4.50 807 1.59 2E22 ... 1.95 6L6M . 1.85 810 . ..10.95 made with as little effort as 2E26 . ode instead of the grid, or in tubes 2.95 65N7WCT . 2.10 813 8.50 1.95 814 3.85 studio or home recording. which have a 2E" 1.59 VCE60 6.50 8298 ...11.95 cathode -grid short. 3A8GT . 1.39 75T1 832 7.95 Light and compact, the tiny 3AP1 ... 9.95 .. Burning out the short or replacing the 3824 495 830 1.10 832A Magnemite is the first completely 250TH . .21.50 833A ...34.95 3824 ... 490 304TH .. 8.95 884 1.75 tube are the only solutions here. 3B28 .. 3.50 304TL 8.95 955 .49 portable tape recorder ! Earphone mon- 321 .. 5.95 307A R1(75 4.25 958A .. .69 Note 2: The effect shown in Fig. 3 3021 3.95 959 1.50 itoring and playback facilities built in. 3024!240. 1.50 3500 .... 4.95 1631 can also be due to a weak -emis- 3033 .. 9.95 394A .... 4.50 Powered by self- contained dry cells or low 417A .... 8.50 2051 305GT 1.15 446A 1.19 8005 that last 100 operating hours. sion picture tube. In this case, how- 4C35 ...24.50 .... 8020 Choice of E27 ..14.50 8025 four models, including a unit designed ever, the brightness control will func- 4x150A ' ..35.00 Vacuum 9001 15 to NAB recording 5824 .... 4.50 9002 standards. tion normally. Substitution will prove 50 a. 5 t 5.95 9003 1.50 12 -20 6.50 Model 61 0-8: Compact (11 %x8 5GP1 ....14.50 50 -32 12.50 9004 ... .69 %x5% this condition. 5T4 1 98 9006 .49 in.) ! Light (IO lbs., including batter- 6. DEFECT: Magnetized Complete Line of Transmitting S, Receiving Tubes. picture Send Cash With Order and Save C.O.D. Charges! ! ies) Economical ($225, complete) ! tube (Fig. 5 or 6). CAUSE: Metal -cone picture tubes J. S. H. SALES CO. AMPLIFIER CORP. of AMERICA Dept. R -15. 7552 Angeles (16EP4, 19AP4, etc.) can become mag- Melrose Ave.. Los 46, Calif. 398 Broadway New York 13, N. Y. August, 1952 125

www.americanradiohistory.com netized if they are operated near a room to answer the phone, doorbell, PM speaker or other strongly -mag- etc., or if you listen to the sound only netized object. when preparing lunch or dinner, turn Sensational TV REMEDY: Remove the chassis and the brightness down. This will prevent move a small pocket compass over the damage to the screen if one of the metal cone. The affected area will sweep tubes should fail. If you are BARGAINS! usually be sufficiently magnetized to near the set, you will be able to turn give an indication on the compass. it off if this occurs. (Sweep failure Rocket Then de- magnetize the affected area will leave a bright, thin horizontal line YAGI by holding an a.c.- energized coil over if the trouble is in the vertical circuit; ANTENNA the picture -tube cone for a minute or some sets will have a bright vertical 5 ELEMENT TV fails, while Excellent Pictures in Fringe Areas so. (An old focus coil will serve if line if horizontal sweep HIGH GAIN. Clearer, sharper, steadier pictures. resistance is used to others will lose screen brilliance en- PERFECT PICTURES IN FRINGE AREAS. Minimum suitable series interference from ghosts and noise due to a directive on tirely if this occurs). pattern. Five elements include one folded dipole, prevent its overheating when used three directors, and one reflector. Supplied less mast. MATCHES 300 OHMS IMPEDANCE. Molded insulator 117 volts a.c. If you prefer, you can You can do your customers a favor provides additional Exclusive design amp prevents tenna tringor cantinguner ny make your own coil by winding 1300 and improve picture quality of their conditions. STURDY, TROUBLE -FREE CONSTRUC- TION. No return calls. No broken elements. Stands to 1400 turns of #24 cotton -covered older -model receivers by replacing the test of severest weather. Elements of extra heavy aluminum-clamped top and bottom. QUICK RIG into wire on a form 6" in diameter and 3" type 10BP4 and 12LP4 tubes with Completely preassembled. Just swing elements r, line and tighten wing nuts. Simple . . quick . 10FP4 and 12KP4's, respectively. easy. Available for any channel, high r low band. to 4 in length. A piece of linoleum Channels Channes C rug core, cardboard jelly, container, These aluminum- backed types will in- 2 or 3 $7.957..75 each 4, 5, or 8 $6.95 each Channels etc., will do.) Hold the coil endways crease both brilliance and contrast. 13 $3.95 each EACH CHANNEL requires a DIFFERENT Yogi. When over the magnetized area for a minute Since neither requires an ion trap Ordering specify exact channel number desired. or two. When you remove the coil, magnet, discard the old trap or, if coils Rocket DIRECTRONIC keep it energized until away from the are used, simply tape them out of the MOTORLESS tube; otherwise, magnetization may way on the chassis. TV ANTENNA again occur. The distorted raster 300° edges should straighten when the cone Electronically Switched Beam has been thoroughly demagnetized. No Motors Mac's Service Shop f 7. DEFECT: Hum in picture; curved Orientation or distorted raster edges similar to (Continued from page 60) F l i c k of s w i t c h Pic- Fig. 7 or 8. ture I n stantly CAUSE: In some cases due to in- No Electric obstetrician and the general prac- Power by dropping, No Ghosts ternal damage (caused titioner : one brings the babies into the The Directron- excessive vibration, etc.). 31 8 antenna world, and the other keeps them in it; is "finest REMEDY: Try substituting a new the more for theultrafringe and who dares say which has o r metropolt- before checking for trou- reNI picture tube important job? The PAC molded insu- bles in out -of- the -way places in the "You know it's a kinda funny thing, lator is a material of ex- high or low-voltage supply. (Experi- but almost every technician has a treme tensile whether a defective affectedstrength n o t ence will indicate- favorite story about a case in which a Bather or temperature, by filter, tube, etc., is most likely.) electrically. Included in the AX-599 Servicemen's design engineer tried his hand at serv- Array" are: goes 18 slue aluminum alloy elements. 8. DEFECT: Picture inverts or icing and was a miserable flop; yet Universal U Clamps for masts to 1 1/2.'. Directronic Beam Selector. negative when brightness control is nine out of ten of us secretly fancy 75 feet of Tri -X Cable. AX -59 Directronic. 9 element Single 10.35 advanced (Fig. 9). that we could give the engineering CAUSE: Defective picture tube; SENSATIONAL INDOOR ANTENNA boys some pretty sharp suggestions Indoor Directronic for use on ceilings, weak high -voltage rectifier tube; de- about their job if we were just a mind attics, closets. 380° coverage. Finest yr all channels. No ghosts. fective video i.f. or r.f. tube; weak or to." reception sharpern installation. teadipictures.focusing.id Strong- misadjusted ion trap magnet. to me," est signal. Minimum noise or interfer- "Well, you're not talking ence. Beam selector switch for best tubes listed above. picture on every channel. Kit contains I-ill 131.1 REMEDY: Check Barney said as he turned back to the three tape elements with insulator. mounting fasteners for use if needed. Directronic Beam Before trying picture tube, try adjust- little set on the bench. "I'm about Selector Switch, 25 feet Tri -X Cable, and Twin -X Cable Extension. ing ion trap or replace it with a new ready to admit that I'm a complete Only $5.95 complete. Model 10.303 one. idiot who knows nothing about either OTHER ANTENNA BARGAINS Correcting the foregoing troubles design or service. I've spent a half a ALL CHANNEL ALLCHANNEI.INLINE.$3.75 CONICALS ALL CHANNEL FOLDED will be left mainly in your hands. The day on this stinker and have not helped Single Bay .....$3.35 DIPOLE $3.95 Slacked Array with ATT. CHANNEL DOUBLE customer, however, can help extend it a bit." Tie Rods .... 7.40 VEE $3.75 the life of his picture tube by follow- "What's the beef ?" LOWEST PRICES ON TV ACCESSORIES ing these four basic suggestions : up ignition noise. Noise Mast Steel ,Dsaleoated 5' Crimped) I i/ " O.D.$ 1.05 "It picks Mast Steel (Dualcoated 10'1 11/4" 0.0..... 1.95 full Mast Steel (Zinc Plated 10') 11/4" 1.59 (1) Never turn the brightness from a car as much as a block away Mast Connectors for 114" O.D. Mast -1O'... .49 Chimney Mount Complete with Straps 1.19 on for any length of time. In large will ride right in over a broadcast sta- Peak Roof Saddle (will take up to 11/2" O.D ) 1.49 Lightning Arrestor -TV .69 tubes (i.e., 20 to 30- inch), only a few tion as though you were listening on Galvanized Guy Wire- 8 strand tt 20 2/4c ft. Galvanized Gov Wire -11 strand 220 11 /2e ft. at full brilliance can cause other way the Aluminum Guy Wire, 300 ft. Reel $4.95 seconds ten meters. In every Tri -X 3 Conductor Lead-In...... 4e ft. to the screen coat- selec- 300 ohm Twin Lead }t55 Mil Stranded (500' permanent damage set is normal. Sensitivity and Reel $8.501 2e ft. is not 300 ohm Open Line Twin Lead -500' Reel..$22.50 ing, especially if the ion trap tivity are good. All voltages check 300 ohm Low Loss Twin Lead, 100 mil Stranded e ft. Mast Stand-off Insulators -3" 8.50 C properly adjusted. right on the nose. I've put in a whole Stand-off Screw Insulators -3" 2.75 C Stand-off Screw Insulators-7' 5.50 C (2) Make sure the ion trap magnet new set of tubes." Rocket Products sold only by mail by National Electronics (if your set has one) is properly ad- "Did you use the signal tracer to see Prices Subject to Change Without Notice ALL PRICES F.O.B., CLEVELAND, OHIO justed. (Check with your technician where the noise seems to begin ?" Do not remit more than complete urchase price. Pay ship pping harges on eceipt f goads. 25 o deposit on or dealer if you are not sure about "Yes, I can first hear it on the grid C.O.D orders. please. Money -back guarantee. me PROBLEMS Write for FREE this). of the i.f. tube. That makes think it INSTALLATION No nmiga BOTHERING YOU tio,': (3) For daytime viewing, keep the starts in the 12SA7 mixer. Of course set away from direct sunlight. If it is the oscillator rush drowns out every- FREE CATALOG OF BARGAINS- near a window, draw the blinds on the plate of that tube." TV antennas, accessories t lowest prices. Tells about located thing else ourr fast service free installation help. Send name, -way. (The more now. or shades at least half "Got any theories ?" unnecessary light in the room, the "None that seem to lead anywhere. higher you will have to set the bright- I keep wondering how the set could be ness control to get a satisfactory pic- receiving a broadcast station on ture. Excessive brightness will reduce around a thousand kilocycles and at the life of your picture tube. the same time be sensitive to ignition (4) Don't leave the set on while you noise that likely peaks up around fifty 108 DELCO BUILDING, CLEVELAND 3, OHIO megacycles." ) visit with neighbors. If you leave the l2ß RADIO TELEVISION NEWS

www.americanradiohistory.com "Try putting a resistor of about 1000 ohms in the lead from the oscillator grid to the oscillator tank circuit," Mac suggested. Barney's diagonal cutters were at work almost as soon as Mac finished speaking, and the resistor was clipped r- in place. A pleased grin spread over Barney's freckled face as he tuned across the band without hearing any Well Not Damage Costly Parts! r) sound from the cars that were passing up and down in front of the shop. Vo rage Regula- Ign'liens One piece STOCK SAVING MONEY SAVING "Give!" he commanded his boss. ny- construction chors- ripelHangers ends -front, back, WASTE PREVENTION "Well I'll confess that I did not just thing with lately sale bottom, with whip keel comp Small What good are parts hat have been mangled? None! up the answer to that one right damage all- welded And they cost the repair man money. Too much accidental sides row," Mac said. "I sweated over just Transtermers all Mikes - money to overlook the fact that Equipto drawers and NO HOLES cabinets are Siîinfl Phono- designed to prevent waste and damage such a problem for a whole day before to valuable parts. amall brack:Bolts & Nuts Embossed Wten stopping to realize that every getting the answer. The trouble is a graph Needles Bridle Rings grooves along time you pull an ordinary drawer out, one with open Drive Rmgs the sides for slots along the sides, small parts can not help pro- parasitic oscillation in the oscillator cross dividers truding and very easily catch on the frame and either grid circuit that peaks up somewhere - NO HOLES break or damage beyond repair; and every time this around thirty megacycles. The igni- Instantly visible, happens it costs you from a few cents to many dol- extra large label lars. Multiply this by a very few times and you are tion noise mixes with this high fre- holders on all cross really losing money. After all, you are in business to wasting your and money! quency oscillation and goes right on dividers and on front of make money. Stop parts through the i.f. drawer--NO HOLES NO. 8 NO. 11 NO.22 system along with the 8 DRAWERS 18 DRAWERS 18 DRAWERS signal produced by the beat between 12" DEEP 12" DEEP 18" DEEP the regular oscillator and the broad- The handiest unit you ever had for cast station. That resistor simply taking care of your small parts. Stack, use individually or as insert in shelving serves as a parasitic suppressor." or under counters. A wonderful item "Well I'm certainly glad that is out for sales in stores or for keeping small parts handy in Electrical, Radio and TV of the way," Barney commented. "Now repair shops. Equipto's most popular I can get started on putting a new item power transformer in that console." Stack them high for the convenience "Are you sure it needs a new trans- of lots of drawer space. former ?" Write "Can't you tell by the smell ?" Division of Aurora Equipment Co. for "I can tell the transformer has been 800 Prairie Aurora, Illinois FREE overheated, but that does not always Phone: Aurora 9231 Catalog call for a new transformer. Those jobs will often take a lot of punishment. Pull the rectifier and check the voltages of the two filament windings. If &BARN both are normal, let the set run for a few minutes with the rectifier out of the socket. Listen carefully for any CHONIIME frying sounds coming out of the transformer and notice if it heats up. If either of these symptoms is present, you are safe in telling the customer CONVERSION he will have to have a new transformer; but if it runs cool and makes no Be Proud of Your noise, find out why it got hot before. Big Tube "Usually you will find a short in the "B- plus" circuit that is causing a heavy Conversion overload on the transformer when the or Custom rectifier is in its socket. Cathode type rectifiers often develop cathode -to- Installation plate shorts that cause transformers to TRAIN QUICKLY! OLDEST, BEST overheat quickly. Filament leads 3 EQUIPPED SCHOOL of ITS KIND in U.S. sometimes become shortei, especially $zGÿí /1ryed G /del around dial lamp sockets or where a professîopol Come to the Great Shops of Coyne in Chicago. Get practical training i1TELEV ISION- RADIOor ELEC- `hot' filament lead passes around a 4W TRICITY -vital in Defense Program. Prepare flow sharp -edged chassis projection or right ál¡ apis for a better job or better service rating. where these leads issue from Comm START NOW -PAY LATER the hole You can finance most of your tuition, pay for it later in the transformer shell. That is why in easy monthly payments. Special plan for men of 1. Metal Mask Tailored for Per'ect Fit. Draft Age. Part time employment service available. I wanted you to check for low filament Clip coupon for Big Free Illustrated voltages, indicating a possible 2. Heavy 1/4 Tempered Safety Glass. FREE BOOK Book. htdicate below, coerce that short, interests you. No salesman will call. Act NOW. before letting the set run. 3. Beautiful Gold Finished Metal B. W. Cooke, President A TECHNICAL TRADE "Once the cause of the overloading Escutcheon. INSTITUTE CHARTERED CIsc"°s7 NOT FOR PROFIT has been located and removed, put the Established 1899 rectifier back in All Popular Sizes: 14 ", 16 ", 17" and 20" 500 S. Paulin. Chicago the socket and let the ELECTRICITY * TELEVISION set run for at least a couple of hours, Easy 'oslallation Instructions included RADIO * REFRIGERATION * ELECTRONICS noting carefully if the transformer Order CRONAME TV CONVERSION KITS; I a. W. COOKE, Pres. overheats. Remember that most trans- CRONAME TUNING DIALS, KNOBS and COYNE School formers eventually reach a tempera- ACCESSORIES from Your Parts Jobher. l 500 S. Paulina St., Chicago 12, III. Dept. C2-85H Send FREE BOOK and full details on: ture where the hand can barely stand en d foror New CRONAME Catalog,ate og, I p TELEVISION -RADIO ELECTRICITY the heat. If everything seems normal, NAME do not replace the transformer. It may 4 It ELECTRONICS, iNC. I not hold up, but the odds are that it 911 N. Lorrabee St., Chicago ADDRESS will." 10, III. Mfrs. of Reptacement Speaker Cone Assemblies , CITY STATE _tagust, 1952 I27

www.americanradiohistory.com "How come so many transformers go bad in the summer time?" Special Purchase "The hot, humid weather is an important factor. When the surrounding NAVY SURPLUS air is around ninety degrees, the transformer has more difficulty in getting Transmitting Triode rid of the heat generated inside itself. here's Then, too, lightning often comes in VT 2 over the power line, even jumping an EQUIVALENT TO TYPES 931 AND open switch, and breaks down the in- 205B sulation between adjoining turns. WHILE THEY LAST transformer Once a transformer has shorted turns, it will heat up rapidly with or without external load and must be replaced. 99c news! "Whether you put in a new trans- i 6 FOR SC SHIPPED former or not, be sure and clean off PREPAID any of the sticky mess that runs out of a hot transformer onto the chassis CHARACTERISTICS AND APPLICATION DATA and cabinet. If you don't, a strong, SENT UPON REQUEST WITH ORDER pungent odor will be given off by the PARK ELECTRONICS set as soon as it gets warm, and this may last for weeks. 1447 Riverside Drive "If you do have to replace the trans- LOS ANGELES 31, CALIF. former, do your durndest to get one with the exact voltage windings as the original and also with the identical current ratings or just a little higher. Used Recording Tape (Plastic Base) Do not go all out on the 'safety factor' For 7" -1200 and try to use a transformer with foot Plastic reel. 199 Save 53.51 on much heavier current ratings than will every reel. Money cheerfully refunded If be needed, for this will mean that you do not find this tape cleanly erased and as good as new. voltages in the set and cost to the (If you are skeptical and from Missouri send us 10e and customer will both be higher than we'll roll you a sample on a 3" plastic reel). necessary. Always fuse We buy commercial and the primary government surplus plastic of tape. Tape must be Irish a new transformer. A two- ampere l4211 EWA). Scotch, or Audio tape, or any tape that will fuse is about right for consoles, and a meet government specifications MAabfAaqR1M6 COMPANY and must not have more than TRIAb TRAasfORMCR three -amp fuse will carry most TV one splice in any 1200 foot t§s Aa91lfS 4. Ea(saaaa,&> k CMS it5: spool. sets. Putting in this fuse is just good New Empty Plastie Reels in boxes for easy label- I on 5" and 7" reels, 24e each. insurance your service job. A new W'e'ng. also carry new, famous make tapes, recording transformer is blanks and tape recorders at large discounts. a pretty costly affair to COMMISSIONED ELECTRONICS CO. TRIAD the customer, and he is going to be 2405 15th St.. N.W. Washington 9, D. C. very unhappy if he has to repeat the CATALOG TR -52 operation as long as he has the set. I often drill a nest of half -inch holes in featuring: the cabinet shelf directly beneath the SCHEMATICS -CONVERSIONS transformer to give it added ventila- FOR SURPLUS GEAR "HS" (hermetically sealed) trans- tion-" NEW LISTI MANY ADDITIONS! Send stamped, self addressed envelope for formers to MIL -T -27 specifications "Can't we talk about a cooler sub- List B. Add 25c for chart ex pla,n, n9 AN ject," Barney broke in plaintively, as nomenclature. High quality Audio transformers R. E. BOX 1220 400 -cycle Power transformers he wiped the sweat from his forehead GOODHEART BEVERLY HILLS, CAL. with his handkerchief. "TRIJET" Miniature transformers 3U Toroids General Purpose transformers for CT CORD TIPS television and radio replacement I'Itl/'I AN /APR -4 COMPONENTS WANTED By ARTHUR TRAUFFER In any condition. Also top prices for: ARC -I. ARC -3. Geophysical transformers APR -I. APR -5A. etc.; TS -34 and other "TS." and stand- TO PROTECT my plume cords which ard Lab Test equipment, especially for the MICROWAVE Amplifier Kits REGION; ART -13. BC -348, BC -221, LAE. LAF, LAG. are continually bending at the tips, and other quality Surplus equipment: also quantity Spares, I slip 2" lengths of small diameter rub- tubes, plugs and cable. ber tubing over the tips and cords as ENGINEERING ASSOCIATES shown in the photo. 432 Patterson Road Dayton 9, Ohio Natural rubber tubing, about 1/4" o.d. Write for Catalog TR -52 today and 1/g" i.d., such as sold in hospital or pick up your copy at and medical supply stores or by chemi- BOOTH 1201 cal supply houses, is ideal for this WESTERN ELECTRONIC purpose. SHOW & CONVENTION The rubber covering for the tips reduces body capacity effects when using Long Beach, California the tips in experimental circuits. August 27 -28 -29 PHONO NEEDLES For Any Type Protect phone cord tips with rubber tubing. Record Player

Please send me FREE Jenselector. Picks the proper replacement. needle. Name TRANSFORMER MFG. CO. Address Plant, General Offices: 4055 Redwood Ave. City Venice Area, Los Angeles, Calif. Industries, Inc., woad Si., Chicago 12 Address correspondence to: Box 17813 3366. Los Angeles 34, Calif. - -to aaMM ti-fi RADIO TELEVISION NEWS 1 '28

www.americanradiohistory.com tube audio- frequency voltmeter to the Improved Speech Clipper reference signal jack, J2. Connect the (Continued from page 57) vertical input of an oscilloscope from J. to ground.* Increase the setting of Re until the scope pattern shows that the R Iprodco a suitable contrast between the pilot sine -wave peaks are just starting to lamp and the flashing neon lamps. be clipped. Note the value of signal TRIPLE PURPOSE The filter condenser cans containing voltage at J2. (It was 30 millivolts in C20 and C22 should be mounted on in- the unit described here.) Now increase EREC- sulating plates and all ground connec- the setting of R. until 1.3 times the tions for the power supply components previous voltage reading is obtained TOWER made with insulated wire and con- at J2. The waveform at J. will show nected at one point only to the chassis. that clipping is now taking place. Re- Shielded wire should be used between duce the setting of R24 to minimum, J,, J2, J3, J&, grid of V,, S, and their as- and increase R43 until the neon lamps MADE OF LIGHTWEIGHT sociated connections in the circuit. No are lighted. Slowly reduce the R,;, set- AIRCRAFT ALUMINUM trouble will be experienced if the nor- ting until all of the lamps are com- mal precautions for the construction of pletely extinguished. This procedure is QUICKLY PORTABLE a high -gain audio amplifier are taken. necessary because the gas -filled neon The component layout may be seen lamps, once lighted, will not be ex- SAVES TIME AND LABOR from the photographs and it is sug- tinguished until the bias voltage is gested that this layout be followed if reduced several volts below the igni- possible. In Fig. 3, V,, V2, and V. are tion voltage. Now increase R24 just TEST SIGNALS mounted in line along the front edge enough to cause the 2 db lamp to light, UP TO 80 FT. of the chassis with V. near the clipping and the calibration is complete. level control, and CH2 near the output Before the unit is calibrated it might With the Erec -Tower, you level control. V. and V. are located in be well to test the operation of the can line between CH2 and T2. The calibra- neon lamps to eliminate the possibility determine the height of the tion control, Rea, is mounted through of one or more being defective. This strongest signal ... as the top of the chassis between V. and may easily be accomplished by varying high as 80 feet. V,. J2 is mounted next to V, near the the bias control R43. The lamps should top edge of the chassis, and J., is all light within two volts of each other. mounted on the opposite chassis -end Any which do not operate within this ERECT PERMAN NT near CH2. The hum -balance and bias range should be replaced to avoid er- ALPRODCO TO ERS controls, R and R.3, are mounted on rors in calibration. the rear chassis drop, After along with J,, J6, connecting to the regular With the Erec- Tower, the fuse holder, and the a.c. receptacle. microphone and speech amplifier, two men can erect a 100 -foot Tube shields should be used on V,, V2, switch the clipper out of the circuit V3, and V4. and adjust the gain control on the reg- Alprodco tower faster, safer, The entire unit is constructed on an ular speech amplifier for 100 per -cent easier ... eliminating four aluminum chassis, 9 x 7 x 2 inches. modulation. Set the clipper output to ten men on every job ! The aluminum panel was cut to 103/4 level control to zero and increase the x 61/2 inches to fit a small cabinet that .clipping level control so that the de- was on hand. sired amount of clipping is obtained as DEMONSTRATE indicated by the flashing lamps. Switch Calibration anti Operation TV SETS

Connect a sine -wave signal source of If necessary test equipment is lacking, the unit about 30 millivolts to J. and a vacuum may be calibrated in a short time at nearly any Build Volume Sales. Show local radio service shop. your prospects in fringe areas close -to- perfect Fig. 5. Under chassis view. Ample room is available despite small over -all size of unit. TV reception right in their own homes. !l !L

WRITE TODAY for free literature and full information on the new, heavy duty, Alprodco Erec- Tower ... made by the makers of the famous Alprodco Aluminum 'ewers. Ad- dress Dept. 11.

Alprodcoelnc.

Kempton, Indiana j Mineral Wells, Texas Dublin, Georgia /

August, 1932 129

www.americanradiohistory.com the clipper back into the circuit and advance the output level until 100 per- cent modulation is obtained. The clip- CONDENSERS ANEW LOW per may now be switched in or out at 2. g, ' 5. will with no further adjustment of con- f4rp a level may 1. r 4. trols necessary. The clipping Figure 1 Mid. 2000 V. Each Mid. 5000 V. Each be varied at will from no clipping at .005 $0.85 .001 $1.95 ;PRICES .007 .8S .002 1.95 maximum available, with no 1.95 all to the .00003 . . . .85 .0025 2500 V. .0002 1.95 I BUY NOW and SAVE! adjustment of output level required, 1.95 1.95 D I .00025 .95 .00082 since the output voltage cannot exceed .0006 .95 . 000035 1.95 * * 3000 V. 4 * the value previously set. Mfd. Each Mfd. Each 4 WESTINGHOUSE OIL CAPACITOR * .003 51.65 .00062 51.65 The regular speech amplifier and .004 1.65 .00005 1.65 it IO MFD, 1000 VDC (Marked 440 VAC) * 1.65 .00009 1.65 modified to im- .005 1.65 if at $1.95 Each * modulator .should be .00015 1.65 .000091 4 A Terrific Bargain * as much as .0003 1.65 it 3 for $4.98 If prove the bass response Figure 2 Mfd. 1200 V. Each Mfd. 2500 V. Each * possible. The aim should be to improve .01 50.70 .01 50.90 G.E. RELAY CONTROL .02 .70 .015 .90 * * the over -all response of the system to .001 .70 .001 .90 *Contama a aigma midget 8,000 ohm. elay, (tripa at* .002 .70 .002 .90 * esa than 2 MA), high impedance choke, bi- metal* a square -wave signal and to eliminate .005 .70 .003 .90 -*strip, neon pilot and many useful parta. The atotal* .0062 .70 .004 .90 ive r atone worth much more than the total* as much phase shift as possible. The .0001 .70 .005 .90 price .00015 .90 * $1.25 eaeh. 10 for $9.90* .0005 .70 *,fw reader may refer to standard reference 600 V. POWER TRANSFORMER BARGAINS what of ac- Mid. Each Mid. Each (110 V. 60 cycle primaries) sources to ascertain course .01 50.60 .0001 50.60 @ 10 amps. .001 .60 .0002 .60 750 volts CT @ 200 MA, 6.3V cir- .60 5V p Fully cased. from TV equip- tion is indicated for his particular .0025 .60 .0005 me n GA. d riea oved .005 .60 each $2.95 cuit conditions. Figure 3 Mfd. 600 V. Each Mid. 1200 V. Each .01 50.35 .01 $0.60 .02 .35 .004 .60 FILTER CHOKE BARGAIN REFERENCES .03 .35 .008 .60 .015 .35 .0022 - .60 Fully cased 5 Henry 200 M.A., removedmoved .60 95.7 .001 .35 .00003 from T\' Equipment Guaranteed 1. Klippel, K. L. ; "Clipper and Filter Dis- .002 .35 .00008 .60 tortion Problems," CQ, October, 1948. .004 .3S Mfd. 2500 V. Each .009 .35 .01 50.90 2. Stuntz, S. E.; "Premodulation Clipping .0002 .35 .002 .90 FILTER CONDENSER BARGAIN and Filtering," QST, November, 1950. .00005 .35 .0015 .90 8x8 M.F.D. 000 vdc oll compound filled. (1 3. Neil, J. P.; "Cut -Off Frequencies and Figure 4 Only als 1950. Mfd. Terminal Loc. Each Audio Quality." QST, November, 4 SOV 15.25 $0.50 4. Technical Topics; "Some Facts of Mod - 30 150V 2s .50 1 200V 25,15 .50 POWER SUPPLY KIT ulation," QST, March, 1951. 5. W. B.; "High -Level Clipping Figure 5 Uses Power Transformer, choke, and 8x8 mfd Bruene, Mid. WV Terminal Lbe. Each Filter Condenser described above. $3 f18 and Filtering," QST, November, 1951. .5 200 2s $0.50 All for ADO a7 6. Topics; "Frequency Response 28.5 100 3t .50 Technical 28.1 400 3L.3s .60 and Intelligibility," QST, November, 1950. 38.1 400 3s.3t .60 .25 400 2s .60 .35 400 lb .60 SCOPE TRANSFORMER BARGAIN .5 400 Zb,2s.it .60 2500 V @ 3 ma, 2.5 V @ 2 A. 6.3 V @ .6 amp. .025 600 2t .70 Removed from TVu eqa ipment. Guaran- $1.49 .1 600 2s.2t .70 teed. Terrific value @ 2X.1 600 3b .70 3X.1 600 3t .70 1 600 3t .70 MORE TV LINKS 2 600 2s .70 Oil Filled Condensers RELAY MICROAMMETERS Mfd. Volts Price Mid, Volts Price SENSITIVE HE Long Lines Department of Amer- .2 600 50.99 12 2500 $9.95 ing il D'arsonval 4 600 1.89 1 3600 3.95 type, mounted meter 3" METERS * 2- Telephone and Telegraph Com- 10 600 3.29 3X.2 4000 7.95 ease. Adj. 700 m éroamps 1 4000 4.95 0 -200 UA 6.95* underway 1 1000 .90 1 ma. Made by Trip- pany has several projects 1 1200 .85 3 4000 8.95 to 0-500 UA lett. will eventually provide addition- 1 1500 1.79 2 7500 19.95 ea. $5.75 * which .5 2500 1.49 2X.15 8000 1.95 4" METERS * al television facilities for various sec- 2 2500 3.95 .09 15.000 8.95 0 -200 UA 8.95* *Oil impregnated paper 0 -50 UA 12.95* tions of the country. Micas Figure 6 started on laying Mid. Volts Mfd. Volts Price PANEL * Work has already .01 1000 .02 3000 Rock and .025 1004 .00015 5000 WRITE GE KV METER * coaxial table between Little .04 1000 .0002 5000 0 -15 KV DC, 31/2" SQ.* When completed, the cable .08 1500 .00009 6000 FOR * METERS Bakelite case, 500 UA* Memphis. .09 1500 .0002 10.000 *NEW GOV'T SURPLUS movement. Includes 30* will handle hundreds of telephone con- .03 2000 0.001 25.000 PRICES Meg. i% Ext. multi CD PL- 254 -46 * *Special Scale plier $12.75 ea.*-* versations simultaneously and provide Cash with order. California orders please include basic facilities required for TV 31/200 Sales Tax. Please include approximate post- if * the age. Excess will be refunded. METERS service when Little Rock is to be con- * 2" 2" GE Voltmeter ESEGE SALES COMPANY INC. *0.10 MA. AC. $2.95 1 nected into the nationwide television 40 -4 AMP OF 2.95 0 -30 Volts DC Aircraft* 1306 Bond St. type 8 -60 ....$1.95 ea.* network. * 3" METERS Los Angeles 15, California 40 -2 MA 4.50 * The company has also made applica- 40 -2.5 AMP OF . 5.95 to construct a micro- M A 4.95 OIL CONDENSERS tion for authority *0 4.50 y4'1.0.200.500 MA .. .. mfd 680 vac wave radio -relay system from Dallas to 0.100 VDC (1 MA) 5.95 3.75 52.45* MA) 5.95 50 mfd 600 ode 5.951 with the 40-200 VDC (1 mfd 1000 v4e 4.95 Austin where it will connect *0 -250 VDC (1 MA). 5.95 15 1 mfd 1500 vdc .891 existing Austin -San Antonio system. Read 1 mfd 2500 vdc 2.25* for com- * FILTER CHOKES 1 mfd 3800 vde 1.951 The new system, scheduled 6 Hy 90 MA 50.79 .1 mfd 7500 vdc 1.951 will make pos- &TELEVISION * 5 Hy 250 MA 1.95 .5 met) 7500 vdc 3.95 pletion late this year, RADIO 4 6 Hy 500 MA 4.95 .02 20,000 vdc 9.95W sible the addition of hundreds of tele- * * hill provide two TV NEWS f PIGTAIL MICAS * phone circuits and M M F: 5, 20, 50. 60. 100. Non -Inductive * channels between Dallas and San An- 4250.* 300. 400. 500, 750. * 800. 1000, 2000, 3000. Resistors tonio. Along the 192 mile route between Every Month *4000, 5000, 8000, Ohms: 500, 12.500 100* six ra- ea. watts 50.75* Dallas and Austin intermediate **10000 50.09 * dio -relay stations will be built to beam y. from one tower to the next. CASED MICAS BLEEDER signals 4 BAKELITE RESISTOR steel towers on which the A SMALL AD -BUT B -I -G MONETI «MFD VDC Pricel MFD VDC Price The tapered Pay for the Following: 50.65 100,000 ohm* be Here's What I'll 4.001 600 5.18'.024 150 watt vitre- Bell System antennas will mounted BC -348 or HC -312 up to $70.00 002 600 .24 24 1500 up to 250.00 02 2 KV .90 ous enamel re- * from 162 to 325 feet. ATC or T -47 Type ART -13 45.00 * 01 600 .26 2500 .55 will range in height BC -221 or R5 /AHN -7 up to 600 .26 005 .45 sister...... up to 175.00 * 02 .002 2500 radio -relay equipment, TS -251 filters. eachup to 6.00 *.01 1 KV .45 .004 2500 .50 Temporary FL -30 or F -21 /ARA -9 audio * .002 1200 .35 .0001 5 KV .70 559 each * which was installed between Dallas and Also want TS -147, TS -148, MG -149, RTA -1B or parts. I'll buy almost anythin not kidding. * * Austin for the national political con- Write -andie'mor wi BOB SANETT, 4668 Dockweller, Los Angeles, Calif. * WIRE WOUND RESISTORS ventions, will be removed upon com- 4637 * 50.09 ea, Telephone: YOrk 10 watt ohms: 25 40.18325.2K ?4K0 .15 ea.", pletion of the new system. * 150. 300- 750.1K -1.5K, * 20 watt ohms: .20 ea,* The third project is the addition of 30 wat! ohms:1 O00 2500. 5300 -18K .22 ea.* Phoenix. Arizona to the Bell System it* intercity television network. Television SLIDER RESISTORS * * ADJUSTABLE signals are to 1w routed from Los An- ELECTRONICS and RADIO 420 Watt: 1, 5, 300 ohms $0.25* --75 Watt: 100, 150, 200 ohms .391 geles over a coaxial cable, already in Engineering Laboratory and Classroom service for telephone use. The addition --Training. Day and Evening Classes. of Phoenix to the nationwide TV net- nut for illustrated Catalog PEAK ELECTRONICSICS CO. work makes live network programs New York I INSTITUTE, Inc. 1 318 Great Neck Rd., Great Neck, available to 107 stations in 65 cities. ELECTRONICS HENRY, DETROIT 1, MICH. I Phone Great Neck 2.0082 1 21 NEWS 130 RADIO & TELEVISION

www.americanradiohistory.com Microwaves for "Hangs- (Continued from page 34) a NEV11AfK Audio E4 u i P rn e nIt justment of the wave guide system. on Top Notch Propagating Characteristics s Save On Every Item The statement or belief that micro- Save More By Buying the Complete System waves can only be used within the un- PILOT HI -FI FM -AM TUNER. Save more than half on this obstructed horizon is completely er- deluxe tuner worth $89.95. Bandswitch has 4 positions: AM, FM, Phono and TV. Circuit includes I -stage audio amplifier roneous. Such ideas were also preva- with response, ± 2 db, 20 to 15,000 cps. Separate 3 -gang lent before the amateurs opened up tuning condensers and tuned RF stages on both FM and AM. FM section has temperature compensated oscillator for the short -wave band in 1922 and when minimum drift; AM section has IF wave trap for rejection "five- meter" radio opened up in 1932. of signals in the IF passband. Sensitivity: FM, 20 mv for .3 volt output with quieting; AM, 3 mv for .3 volt output. With: Skepticism was rampant when police 6-6BA6, 1 -6BE6, 1 -6AL5, 1 -6AT6, 1- 6X5GT. Self- contained two -way radio began expanding on power supply. Has built -in FM and AM antennas, plus provision for external ones. l It/2x6x9 ". Wt., 81/2 lbs. v.h.f. around 1935 and when radar on 81E003. Special Price 42.95 microwaves moved up into the 200 mc. NEWARK LOW -COST AMPLIFIER. Compact 8 -watt amplifier region and above in 1940-41. In every using 2 -6V6 or 6K6 push-pull output tubes. Employs 6SN7 as Audio Driver and Phase Inverter; 5Y3GT is rectifier. case, equipment has operated beyond Response, 50 to 12,000 cycles. Has continuously variable the horizon, with many instances hav- e Complete System tone and volume controls. Outlet for- AC phono motor plug on back. Output impedance, 8 ohms. Chassis size, 6x81/2x ing been recorded showing transmis- only $82.50 53/R ". Wt., lbs. sions of several thousands of miles. 851F001. Spe7 cial Price 21.50 Once this fact was established, our research were The Famous Regency G.I. 3 -SPEED CHANGER. Tone arm experts able to lay out uses crystal cartridge with single study programs for yielding an ex- Model DB -410 .002" needle to play both standard planation as to how this could Television and microgroove records. Size: 123/4 occur. Booster x12x5- 7/16 ". Requires 4- 1/16" above, New and relevant factors became Special Price! 31/7" below. Wt., 12 lbs. known. On short -waves, it was the $14.11 81E000. Special Price 17.88 Kennelly-Heaviside layer, first believed NEWARK 12" SPEAKER. Handles 10 Handsome mahogany watts of audio power. Has heavy to be a single layer and later found to plastic case, 51/4 x 41/8 x Alnico V magnet. 6 -8 ohms voice consist of several layers each of 33/8 ". All brand new, in coil. Wt.. 5 lbs. - original cartons. With 81F104. Special Price 6.95 which was responsible for a new set 616 tube. 6 lbs. COMPLETE FM -AM SYSTEM. Wt., 15 lbs. of radio communications ranges. On 90F150. Special ...1 4.1 1 81F010. Special Price 82.50 very -high frequencies, it was the dis- persion effect at the horizon plus natural wave guide paths resulting from FREE! CATALOG No. 51 223 W. MADISON ST. walls of buildings, sides of hills or jEWARKELECTRIC COMPANY CHICAGO 6, ILLINOIS mountains, walls of a canyon, or boundaries set by wayside wires and fences, etc. On microwaves, the possible range CUTHOLES'l :ïo37í" of operations is unlimited if the following conditions affecting propaga- IN RADIO CHASSIS tion through space are recognized. 1. Direct path communication within the unobstructed horizon. This is approximately equal (in miles) to 1.41 times the square root of the antenna height (in feet) above the intervening terrain plus the same conditions for EENLE , the second station. For example:

Station 1 Station 2 2300 ft. Height above intervening terrain 0 ft. (sea level) 200 ft. Antenna height 9 ft. NEW! 2500 ft. Total effective height 9 ft. WITH A GREENLEE Transformer Catalog and RADIO CHASSIS PUNCH Station 1 has a radio horizon of 1.41 TV Replacement Guide Save hours of work no reaming V 2500 = 1.41 X 50 or 70.5 miles while ... or Halldorson's new one-source catalog tedious filing. Punch cuts through chas- Station 2 has a radio horizon of 1.41 has the components you need, well sis quickly ... makes accurate, dean V 9 = 1.41 X 3 or 4.23 miles. The two classified for easy use. This highly active line has been holes for sockets, plugs, and other stations can thus intercommunicate super-charged receptacles. just turn with an over with 114 new items. ordinary a distance of 74.73 miles by direct Special attention is given to TV re- wrench. There's a GREENLEE Punch in path. placements. A self- contained guide sec- each of these sizes: W'; % "; "; % "; 1'; 2. Indirect path or reflected com- tion tells you where they are used. j Here's extra value, too. Halldorson 11,(6 "; 1W'; 16,6 "; 13,Ì6 "; 1'/4 "; 1h"; lie; munication. This type of transmis- 2/'. Write for complete facts. sion prices actually have been reduced, but Also get may exist either within the hori- Halldorson quality is even better than information on Knockout Punches and zon, beyond the horizon, or by a re- ever. Cutters for conduit and meter holes up flection within the horizon passing the Ask for a copy at your distributor, or write direct. to 3'-Ç. Greenlee Tool Co. 1888 Colum- energy on to another reflecting or bia Avenue, Rockford, Illinois. pickup point beyond the horizon of the The HALLDORSON COMPANY originating station. To understand 4500 N. Ravenswood Ave, Dept. ItN -R how this happens, one should consider Chicago, 40, ILL. the source signal as a beam of light and every solid object encountered en- GREENLEE route as a reflecting mirror. What- HCelldorson ever a mirror of such shape would do SINCE 1913 I August, 1952 i:11

www.americanradiohistory.com to light, a similar thing will happen with respect to microwaves. Reflec- tions will be more effective when ob- structions ehroute are substantially larger than the wavelength. This is quite likely to happen since microwaves are normally less than one foot long. Even dense cloud formations have reflective possibilities. At their greatest height, they can develop great RADIO ENGINEERING ranges, even for stations operating at sea level with very small unobstructed TELEVISION horizon. ELECTRONICS 3. Wave guide paths. Microwave Thorough training in all phases of radio and electronics, open to high school and junior college grad- energy may recognize the space be- uates. Old established school specializing in Radio wires as the equivalent of training exclusively. Modern laboratories and tween two courses. Enrollment limited. Approved for veterans. the two walls of a wave guide pipe. It VALPARAISO TECHNICAL INSTITUTE will treat one wire as if it were the Dept. RD Valparaiso, Ind. ionosphere, and the other the earth, and try to propagate sky -wave fashion FAMOUS SUN between such boundaries. The limit of N E V1/ ALL -TRIODE AMPL such a communications range is the 7:11NIONF

°" . SIZE The continuedand increasing de -' limit of the availability and existence POCKET of wire arrangements around Sun Radio's "Great All - suitable L °7] PICTURE TUBE mand for the country. Even the space between Triode Amplifier" has enabled us railroad tracks can serve as a wave (4- Reactivafor reduce prices in the face of tunnels, underpasses, -; A sturdy compact unit to as ' -` guide, can that effectively restores brilliance to most low rising costs. canyons, gorges, etc. emission tubes without re- 4. Atmospheric ducts. These are a moval from set. by us from a Two models engineered can make mi- GIVES NEW BRILLIANCE TO OLD TUBES by CONSUMERS' function of weather and design published crowaves a tremendously valuable tool For All Size Picture Tubes. Simple to Operate RESEARCH, INC., Washington, N.J. BIG MONEY MAKER FOR SERVICEMEN PEERLESS in weather forecasting. Microwave Adds extra months to tube life. First (Special BulletinNo.31). application pays for device. used throughout on propagation at great distances can be SOLD ON MONEY BACK GUARANTEE Only TRANSFORMERS Postpaid both models. Clear, rich, full, bril- tied in with weather conditions. Mi- UNION ELECTRONICS COMPANY o COD plus liant High Fidelity at low price. crowave energy recognizes the bound- 394 Metropolitan Ave., Bklyn 11, N. Y. Rostra. especially de- aries of a stratification of temperature Output transformers TRAIN FOR A SUPERVISORY POSITION IN signed for this amplifier. CR -10 uses or pressure aloft as a wave guide. It a standard quality "husk?' transform- also considers the adjacent boundaries from 30- 15,000 c.p.s:; ELECTRONICS er, response a wave guide. If signal CR -10Q uses the famous Peerless of two strata Thorough 2 -year course covers electrical circuits S240Q, 20 -20 line transformer, vacuum energy from a transmitter can enter and machinery, basic electronics and industrial re- electronics. Franklin Technical Institute graduates impregnated and moisture resistant, one of these atmospheric ducts or engineers for research 20- 20,000 c.p.s. are in demand as junior sponse from wave guides, the range of communica- and test work, sales engineering, supervisory work All triodes in this unique circuit em- on production lines and drafting room design ploying self bias. Seven tubes includ- tion can become very great -often up work. Other engineering and technical courses. ing rectifier. to thousands of miles. This fact has Coed. Day, evening. 44th year. Write for catalog. Harmonic distortion less than 2 %; hum output. been verified on many occasions and FRANKLIN TECHNICAL INSTITUTE level 60 to 70 db below rated Boston 16. Mass. Built in preamplifier for magnetic car- is undergoing continuing research by 46 Berkeley Street tridges, input for radio tuner, crystal governmental and subsidized institu- microphone or other signal source. Se- tions. In investigations of this type lector switch, volume control, bass the hams will be invaluable because PEN -OSCIL -LITE . and treble controls and power switch Extremely convenient test oscillator for all radio controls on the front panel. of their large groups, geographical dis- servicing; alignment Small as a pen Self are the powered Range from 400 cycles audio to over Kits supplied with punched chassis, tribution, and the number of hours 600 megacycles u.b.f. Output from zero to 125 finished in bronze hammertone, with on the air. The phenome- v. Low in cost Used by Signal Corps silk screened on they spend Write for information. control designations non is often missed by the professional the front panel; all necessary compo- GENERAL TEST EQUIPMENT nents; transformers and choke; tubes. groups working the modern 40 -hour Buffalo 22, N. Y. Easy to follow instruction book con- week. 38 Argyle taining step - by - step instructions, persons are schematic and`pidtoHial diagrams. Although thousands of $49.50 currently employed in the microwave SPEAKER RECONING Model CR -10 Kit expenditure of Model C R.1 OW wired & tested $76.50 industry involving the Complete line Cones, Spiders, Rings $59.50 billions of dollars, very few of these and Voice Coils. Custom Built Voice Model CR10QKit Coils. Low prices. Write for Parts Model C R -10QW wired &tested $86.50 persons and only a small portion of the List and Reconing information. total funds are actually used for prop- NOW AVAILABLE - most of the WESTERN ELECTRONICS CO. agation studies. Instead, 3164 Rest Colfax Denter 4. Colo. BASIC FOUNDATION KITS time and money has gone into the de- Contains all Peerless Transformers, sign and construction of complex and MODEL RC 80 punched chassis plus 12 page step - expensive radar and microwave relay by instructions. GARRAR -step systems. less cartridges $27.95 The author feels confident that when CR -10B .We 96a/a 3 Speeds the hams really get into microwaves ...fully CR -1OBQ $34.95 will a.zme1 automatic in sufficient number, the "CQ" call with yield just as interesting responses as automatic WRITE FOR SUN RADIO'S FREE those enjoyed now. Microwaves also stop "AUDIO EQUIPMENT HANDBOOK" offer infinite possibilities for a ham organization like the ARRL to live up

to name. Microwaves are an excel- a its Garrard Sales Corp. Dept. R lent medium for radio relaying and for 164 Duane St.. N. Y. 13. N. Y. I working out communications networks Can be Send GARRARD Feet Sheet. I & ELECTRONICS CO., INC. used echelons to with Name ST. NEW YORK 7, N. Y. with a wide selection of 122 -G DUANE during emergencies and your Address BArflay 7 -1840 communicate present City Zone State J civil defense operations. set. NEWS 132 11.%11111 TELEVISION

www.americanradiohistory.com To utilize the microwave frequen- ..... _ .....jjjj-...- . cies, the radio ham has to become more .: of a mechanic than an electrician. He \ must get used to pipes called wave \.. eGGí:% guides and metallic structures having \ certain shapes, configurations, and di- AMPLIFIER 70241/141 AMPLIFI ER.,. e First Williamson Type Amplifier supplied with matching preamplifier mensions. He will use "cut- and -try" Uses Altee Lansing Peerless output transformer. methods and simple Practically distortionless - Harmonic and in. KIT arithmetic in his termodulation distortion both less than 1/2 of 1% at S watts output. computations. He will be required to e Frequency response ± 1 db from 10 cycles to 100 ke. perform simple sheet metal and ma- Output impedance 4, 8, or 16 ohms. The new Heathkit Williamson Type Amplifier kit Is chining operations in building his ap- the best obtainable in amplifiers today -the choice of the really discerning listener. You can hear the paratus but will probably purchase difference and measurements actually bear out the superb performance. Frequency response 4 1 db certain of his gear such as from 10 cycles to 100 kc allow you to )sear the the wave highs and lows with equal crispness and clarity. guide probes Harmonic and intemlodulation distortion both less and coaxial connectors, than 1/2 of 1% at 5 watts output eliminate the harsh and unpleasant qualities which contribute if they are readily available, other- to listening fatigue. The circuit is similar to the one published In wise he will build or improvise them Audio Engineering Magazine for November, 1949, and is considered by engineers throughout the from whatever is at hand. There is audio field as one of the best ever developed. The Main Amplifier (which may be purchased sepa- not one single thing connected rately) consists of a voltage amplifier and phase with splitter using a 8SN7, a driver stage using a 66N7, and a push -pull output Mage using a pair microwave operation on the ham bands of 807 tubes. The output transformer is manufac Lured by the Peerless Division of Alter Lansing. that cannot be built or improvised and is built to their highest standards. Output Impedances of 4, 8, and 16 ohms are available. The power supply uses very cheaply if the ham is willing to a separate chassis with husky Chicago Transformer power transformer and choke, and 700V Mallory filters for long experiment. Microwaves offer a real hum-free operation. A 5V4G rectifier is used. The main amplifier and power supply are each on a challenge to the alert ham chal- chassis measuring 7 high by 51/2 wide by 11 long. -a PREAMPLIFIER AND TONE CONTROL UNIT KIT lenge very few hams will be able to The preamplifier kit consists of: a 12AX7 (or 12AY7) dual triode first amplifier stage with a turn-over control for LP resist! or 78 record types, and a 12AU7 amplifier stage with individual bass and treble tone controls which each provide up to 15db of boost or attenuation. A switch on panel se- HF lects either magnetic, crystal, or tuner inputs. Preamplifier also is well suited to custom installations will operate in either - it vertical or horizontal position, and special Ws&1 An-plifiar kit - Combination 1 - notched shafts of the controls and switches allow a variety (Maia Amplifier and Power Supply) com- of shaft lengths to be selected, Dimensions: 21/4., high by \''' plete with WA -P1 Preampli MIXER /MASTER 1O1/4" wide by 71/4'ß deep. \ her kit. Total Ship. Wgt., CONTROL 34 Ihn. (Shipped. Express only) $69.50 WRITE WAA1 Amplifier kit only- Combination 4 - (Main Amplifier and Power Supply). By OLIVER BERLINER FOR Leas WA -PL Preamplifier. Total Ship. Wet.. 29 lbs. (Shipped Express only) $49.75 OFTEN in the design of audio mixing ?Tee CATALOG WA -P1 Preamplifier Kit Only. (less power equipment there is not enough supply) (Tubes included). To- space on the front panel to include a HEATH COMPANY tal Std/ Wgt., 7 lbs. (Shipped master gain control, or if a master gain 15, Expresa or Parcel Post) $19.75 is absolutely necessary, one of the mixer BENTON HARBOR positions must be sacrificed or the MICHIGAN panel parts layout becomes crowded and /or inefficient. '' N \\* Here is a single -wire \ \ block diagram of a mixer circuit designed for larger SELENIUM RECTIFIERS- FULL -WAVE BRIDGE TYPES consolettes but which can be adapted Current 18/14 36/28 54/42 130/100 (Continuous) Volts Volts Volts Volts to portable mixers. With this circuit, 1 -Electric Amp. 1.25 2.10 Tray 5 5 8 3.60 S 8.00 each and every one of the mixer gain 2 Amps. 2.20 3.60 6.50 10.50 controls can be used temporarily or 21/2 Amps. 13.00 miniature permanently 4 Amps_ 3.75 8.75 8.75 as the master gain con- _5 Amps. 4.95 7.9S 12.95 27.00 trol. In addition, the master gain con- 8 Amps. 5.50 9.00 14.00 38.00 Converter 10 Amps. 6.75 12.00 20.00_ 45.00 trol can, at any time, be eliminated Input 6 D.C. and 12 Amps. 8.50_ 18.00 _25.50 52.50 Volts - all mixers become gain controls, 20 Amps. 13.25 24.00 38.00 90.00 thus increasing the number of inputs 34 Amps _16.00 -31.00- 9.5 98.00 Output I IO V. 60 Cycle 40 Watts by one. 30 Amps. 18.50 36.00 As can be seen from the diagram, 36 Amps. 25.50 45.00 by 100,000 plates stocked for standard and special recti- patching any one of the "normalled" liers and testifier suppl es. Also XMFRS to Specs. A jacks to the "normalled" B jack, New, Selenium Rectifier Transformers that particular gain PRI: 115 V., 60 cycles In. 1 4 Ampo.....S 8.75 control becomes SEC: 9, 12, 18, 24, and 36 1) 12 Amps..... 16.75 volts. 24 Amps 35.75 the "Master Gain." Removing the 115V. PRI.-38V. 50 amp second XFMR 539.95 patch will return 115V. P5I. -SV. O 190 Amp. SEC $59.95 the associated jacks 30.5, 33.5, .50 to their normal positions and all the 36.5V 4 AMPS. Seem. ealetl5,sealed x6.nd controls again become CARTER DYNAMOTORS 6 V DC Input -400 VDC separate input Output O 375 MA. Only 7° x 4" x 3". gain controls. Brand New. Only $28.00.DL This system works AR- II- SUPERMET RCVR & 50 Watt XMTII w/ equally well with Built-tn Pwr supply. Only 12" x 9° x 5", for c20 both high and low impedance 40, & 80. A complete station for 550 circuits. only $99s7.7 ART-1-DE LUXE MOBILE 75 meter AM XMTR se/ vibrator supply -only 6" x 6 °. Close Out $18.85D 7 íJ Special hookup which permits mixer gain NC- 183-D-3 seta w /Spkra in stock in sealed National cartons. Write. controls to be used as the master gain. Standard Size- $15.95 Warranty TUBES 21/2"x21/2"z31Í2" List Price 0A2 $0.95 4032 ...522.40 717 -A ...$0.98 PROGRAM 052 1.10 4X150 -A. 35.00 805 2.00 Operates- AMPLIFIER 1L4 ....r .69 SFP7 .... 1.95 807 1.49 1521.5 .. 3.00 5U4 -G ... .59 829.8 11.00 Radios -Short and Broadcast Band CONNECTOR --a 1523 -A .. 2.00 5X4 -G ... .79 832 -A 7.95 O O O 1523 -B .. 3.10 tGAJS .... 1.20 872-A (GE) 3.25 Phono -Turntables O \O 1534 .. .62 OAKS .... .75 1618 .74 1534 -A .. .75 GANS .... 1.95 1625 .. .39 Small Dictating Machines 1544/ 6056 .... .65 5516 5.95 Test Equipment PRE -AMPLIFIER -- _ 400 -B .. 1.21 6C4 .49 5654 ... 1.95 - 1N45/ OJO .59 8008 ... 5.50 Electric Shavers 400 -C .. 1.39 7C30 85.00 8020 ... .90 Incandescent Lights 1554 .... .89 12A6 .85 9001 ... 1.35 2C43 12AÚ7 .69 9002 ... .95 MAKE /BREAK ....15.95 2E24 .... 3.00 104 -TH 7.75 9003 ... 1.50 JACK 2E30 .... 2.15 304-TL 7.75 9004 (RCA) .3S Just Plug in cigar Lighter 354 .90 408 -A (WE) 2.75 9006 ... .25 THOUSANDS IN USE MIXER GAIN CONTROL FLIIi Guaranteed ElE[TROI1I[5 [ORP. See Your Dealer or Jobber -or Write Direct 136 Liberty Street. N. Y. 6, N. Y. REctor 2-2563 Terms: 25°, with order. balance C.O.D. -Send a few postage -All merchandise guaranteed. F.O.B. TERADO CO . STBPÁUM8, MN. N.Y.C. Remember, you may order tubes not listed! A11J¡Il\t, Ifl.j:j 133

www.americanradiohistory.com SO IMPORTANT- it was Featured in Special Article in RADIO -TV

Jan. 28, 1952 FREE copy of article on request AIES ER ACTII 'UNIT Service Industry News TUBES TN PICTURE TV T.sts Electra n Small t°aMitiAdd a at Hom -Of Us* Mon SetYear or

3e. ted anort er T. L IMNNCDY ee, wan elettmmo detelevit,tion rin[ kta A omit of mmÑain -educed to. home blel tutwt In AS IBEIa/ItTIsD III' TRF. ti..PPiled dun an etNreherttwn, 9 In dotet mar ort[tnol cartone htnese. tun. is n roti. aema a[ pittura .el, rail iun[,d h lod e,crlbeid TECHNICIANS LECTURE BUREAU tub tmm the con ntc w to wniNh TELEVISION m4mmtr ( tubea d .wsd hri[htneea tits. ke Wkto t ci.ihpdero[.r toto. Ne .li 1Tt. sucn et pis an market an most m pnn putts LNew York nu' terthawurnnt aiut n..t time er t ye,,aln t O tod.r ée: tatuar sta. it d: id.t h Ntw pt tU,dtlwuti rbeeme+R WE ARE entering the season when to month in this type of operation that tile'n e {pmei.tartonT.ndtune: m[[t puc Y lfaebelo th ,i,Y ithourven i°od r. ueeÑl rU s a it is unable to take full advantage of nyoto tne vi= starts it neceM.ry. unta etanáara business normally pDmenttn,tmtnet áon:.i a tM eWUv^- peak periods of business and takes `e;tlrekt itve aapouná^lunch b t,exnká steady, uphill climb toward the Christ- the comMali 0Y .,tnt tmmt lh on tn at t ivi slumps. osU titile Nu ltimt^[ .d n otin[ This year, however, an undue loss during the %aura mtle ae mas season peak. rile. end ne't wdca.é the renewed activity of building new In contrast to this type of service service busi- Ow TV broadcasting stations and in business management, the he Alt changing channels and increasing pow- ness that employs "service selling" pro- eran nmleei is to level up its tub l er on others will probably usher in one grams regularly able for . van lwc of the swiftest periods of growth and volume by intensifying these programs Inc. mene is W. Pi< periods when business ea[ expansion this industry has ever expe- during the ors +á a Tr Records will probably reveal most needed. Television becomes N. pattu. rienced. eitt tint that starting in July, when the first of vital part of the family life in every .rre5 the two very important quadrennial home where a set is installed. Set steir owners feel the same need for good. n[ <. political conventions got underway, the etici radio -television blasiness has been ex- consistent performance from their TV periencing a better summer season receivers as they want from their auto- than it has in a couple of years. The mobiles. Auto manufacturers and deal- deep and extensive interest in the ers have sold car owners on the need Presidential candidates and in the isfor regular maintenance work to in- sues involved will, in itself, keep pub- sure dependable service from their lic interest in TV at a high level cars. Any television service operator CR TUBE throughout the late Summer and early who will institute a "TV set check -up" Fall. program on sets in the immediate area 1ii; of his shop will quickly discover that REACTIVATOR The continuing interest in getting TESTER- there are a lot of people who will wel- performs 2 vital functions: good television programs that these political campaigns will serve to main- come that kind of service. Tests Picture Tubes tain affords an excellent opportunity This type of maintenance service of for creating the "service sales promo- could include a regular chassis clean- Renews Brightness ing (a small, suction -type vacuum Dim Picture Tubes tional" programs that are needed so badly by TV service businesses in the cleaner as a part of the maintenance established TV areas. It is obvious technician's kit would be useful and It's a TESTER: that the "boom" days in the older ma- effective for this function), face wash- There is no ing, and an operational check. The set from set, you apply jor TV areas are past. Without removing picture tube now on the visible hori- owner's card carried by the technician this precise instrument to:- development in- zon that would impel large numbers of on these maintenance calls should Measure Cathode emission record of all radios, Locate shorts between elements set owners to discard their present re- clude a complete shorts or leakage new ones. There is no record players, and changers and any Locate high resistance ceivers and buy the as high as 3 megohms likelihood of a big upsurge in business other electronic equipment that when new u.h.f. stations go on the air. customer owns. A regular part of the It's a REACTIVATOR In short, the television service business maintenance call should be to inquire in areas has settled down to the about the condition of this other equip- those it if there is any Tubes regular maintenance of receivers and ment and to check for dim CR Picture question in the customer's mind about Revives dim TV Picture Tubes, without removal of accessory equipment now in use with tubes from sets. Reactivation works on tubes with the expansion possibilities tied to the whether or not it is operating properly. low light output, if there's no mechanical break in in set ownership that This method of business operational tube, 110 V-60 cycles. Weighs only 3 Iles. One normal increase to level up or two applications pays for instrument. be accomplished by good receiver planning will not only serve may business volume but SATISFACTION GUARANTEED ne merchandising. the periods of low S W dollars of or money refunded if you return A maintenance and service business it will also add many extra the instrument in 10 days in good NET in either of two ways. service income from replacement parts condition. may be managed radio equipment - -- -RUSH THIS COUPON - - --'f It can keep its identity known through and repairs on other TRANSVISION, INC. advertising in the hope that a certain that is normally neglected. DEPT. RN -8 NEW ROCHELLE,' N. Y. percentage of people who recognize ( ) Send me -CR Tube Tester- Reactivator(s). the need for service on their sets will New Channels -More Power C.O.D. effects of the renewed ( ) Enclosed find S- deposit. Balance call their number for that service. This The broadest television broadcast- ( ) find in full. Send prepaid. it may be called activity to expand Enclosed S- plan of operation -if will probably a plan- causes a business to suffer se- ing into unnerved areas Name slumps in con- be felt in the twenty -five current TV verely from seasonal are Address sumer calls for service. In fact, service areas in which present stations to change channels. In shift - I City State J volume fluctuates so much from month scheduled IIAIIO S TELEVISION NEWS 1:t t

www.americanradiohistory.com ing channels these stations are authorized to boost their power. This power boost will extend the range of each of HERE IS THE BIGGEST these stations by a number of miles, BARGAIN YOU EVER SAW! bringing new sections into their fringe areas. These newly opened fringe areas will create new markets for TV receiv- World's Finest 630 DX Chassis ers and antenna installations while the New CASCODE tuner assures best re- increase in power, ,and the channel ception in fringe areas without a booster. Handles all Cathode Ray changes will develop a large spot mar- tubes from 16" to 24". Improved 30- 50 ket for touch -up realignments and set tube super- quality TV receiver (including 3 rectifiers) mfd. under license adjustments throughout the affected by RCA. Complete, Less Picture Tube. areas. The kind of "boom" that can hit a fringe area city when a station ex- With Hi -Gain standard coil STANDARD tends its range through an increase in tuner and R.C.A. Hi -Fi 12" Vl Individually BRAND TUBES % Speaker, complete with knobs 50 Boxed (Manu(, of tubes and Guaranteed effective radiated power was dramati- and hardware. Complete with tion name refuses permission FAIR because tubes to men- cally demonstrated in Indianapolis, Fed. Taxes Paid. Less Cathode TRADE) are FAR BE Indiana, last Spring. Station WTTV Ray Tube 1 ,47 ...$0.89 6BH6 86 12AT7, .99 All Mahogany IHS... ,71 6BQ71.15 12417. in Bloomington, fifty miles distant CABINET 86 1R5 124X7. 1.19 from Indianapolis, put a new high -gain Most beautiful ., 79 6C4 console made. .. ,5q 128X7 99 IT4 .. 71 antenna in service when it increased Solid 3/4" mahog- .79 12BÉ6. .69 any wood includ- IU5 .,. .78 B6 2,39 1254 I 661656 7, ,99 its power on Channel 10. This put its ing panels. Meas- X2A , .94 54 1211(7. 3Q4 ,89 ures 31" W. x 6K6 .94 1251(7, signal into Indianapolis with sufficient D. x 39" II. 3Q5 ... ,66 .77 24" 3V4 .89 6K7... 12SN7. 8q E9uipped with .., -J3 GSA7 .74 strength to give good pictures wher- 504 .., .64 20" mask. ,63 Ì44Q7 , 5V4 .., ,97 64 14BG ,84 ever a satisfactory antenna system was 5y3 6SJ77 94 $95.00 47 6SK7 . installed. GAC7 . .94 , ,72 25Lfi S' 1;29 20CP4A Pig GAGS 79 6S6SL7., .74 Tube -$32.00 6AH6 25W4 . Indianapolis had a Channel 6 station, . 1.29 -(Not a rebuilt) 6A Q7 25Z6 K5 . 1,29 ., .64 ., 67 Guar, one year 6AL5 618 yg 35L6 WFBM -TV, for several years which . .68 . .86 35W4 6W4 T; 64 , 52 most set owners were receiving satis- 6AT6 , 64 35Z5 Special Offer! 6AU6 .68 ., , .69 5045 factorily with built -in or indoor an- Chassis, Picture 6646 7C5 .. .74 .. .96 Tube and Cabi- 66C5 69 7F7 5065 was no . .74 74 ., .79 tennas. Since there effective E6 7K7 I.09 5005 ó 7N7 66 service association in existence in net$239.50 68G6 76 .; SOL6 In- 172114(F/T6:2AT6 "I'141 .64 (with 630DX Above partial 1723.. dianapolis there was no planned public chassis $249.50) listing .64 complete Send for relations campaign to educate the set Send for Latest Catalog owning public about the long-range economy in having Channel 10 antenna STEVE -EL ELECTRONICS CORP. VISIT OUR systems installed by experts. Set re- NEW STORE tailers ran ads tieing in Channel 10 an- Dept. 4211 61 Reade St., New York 7, N. Y. COrtlandt 7 -0086 tenna installations in a "package" to sell sets, but there was no real program directed to the thousands of set owners who would be in the market for antenna system installations and perhaps a touch -up alignment of their sets on Channel 10. The result was that a large percentage of this new an- Radio Handbook. Giant 13th Edition. A one -volume tenna installation work was done library of radio information with extensive, simplified theory. Detailed how -to- build -it data on dozens of either by the set owners themselves or items of practical radio equipment. 734 pages. by the host of fringe installers who Orderigook No. E&E-RH13 $6.00* jumped into the business to make a Radio Handbook. 12th Edition. Selected constructional quick buck. items only. English Edition: THE FINEST IN If the established service businesses Order Book No. ESE -RH12 $3.00* Spanish Edition: HIGH FIDELITY in the Indianapolis area had gotten to- Order Book No. EBE- RHSP12 $4.00* gether and pooled their resources to Antenna Manual. A practical, comprehensive book on RECORDING put on a public educational program antennas, for everyone interested in transmission and on the reasons why experienced TV in- reception. Over 300 pages. stallation companies should be em- Order Book No. EBE -AMI $3.50* ployed to up Better TV Reception (in fringe and low- signal areas). put antennas and make The standard guide for installation technicians. A the necessary set adjustments, it would popular text for all TV enthusiasts. have prevented a lot of confusion and Order Boot No. EBE -TRI $2.50* LOW I would have helped to build public ac- Radiotelephone License Manual. Typical study ques- Cast. tions with concise answers for any commercial U.S.A. ceptance of the importance of employ- radiotelephone operators license. ing competent service companies if Order Body No E&E-RL1 $3.756 they want to get top performance from World's Radio Pubes. (Brans' Vade Mecum,) Lists their TV receivers. over 15,000 tubes from every tube making country. Printed in 16 languages. New 9th Edition. DEALERSHIPS AVAILABLE NOW! Effects of Order Book No. E&E-VM9 $5.00* Power Increases MAIL COUPON FOR INFORMATION TODAY! In areas where stations have in- Surplus Radio Conversion Manual. Volume 1. Prac- creased their effective radiated power tical conversions. Write for list of contents. t. Order Boot No. EBE -SM1 $2.50* 1 11 three new reception problems have DUKANE CORP, Dept. RTN -82, St. Charles,111.1 arisen. These are: (1) the added pow- Surplus Radio Conversion Manual. Volume 2 Com- panion to Volume 1. Please send information on the 1 er put too much signal in the area Order Book No. EBE -SM2, $2.50* DuKane Magnetic Tape Recorder. 1 close to the transmitter; (2) it extend- Plus any tax. 1 1 am interested in a dealership. ed the co- channel interference belts; 1 and (3) it increased the possibility of BUY FROM YOUR DISTRIBUTOR Nome 1 adjacent channel spillover. ADD 10% ON DIRECT MAIL ORDERS TO Address i Tremendous signal levels put a EDITORS AND ENGINEERS, LTD. City State 1 strain on even the more modern a.g.c. BOX 689A, SANTA BARBARA, CALIF. 1 ESTABLISHED AS OPERADIO 1922 Bookstore; order from BAKER & TAYLOR, Hills de, N.J systems and particularly if the a.g.c. 1 August, 1952 13 :;

www.americanradiohistory.com must be set to receive a relatively them about what they may expect in weak signal as well as a strong one. the way of reception troubles when the The best solution for this condition in station changes its channel and what many cases is to use a resistor atten- to do about it if it occurs. MATTISON uator pad to drop the signal level be- These campaigns should be put in SILVER ROCKET fore it reaches the antenna terminals. effect in advance of the change in chan- Set owners, however, do not under- nels. When set owners understand the 630 CHASSIS with these technicalities that are pe- reasons why service may be needed stand will TUNEABLE culiar to television. The average set when the change is made they owner knows only that the picture on most likely arrange with an estab- handle the BUILT -IN BOOSTER his receiver is good or bad; if it is bad lished service company to he wants the trouble corrected as adjustments on their receivers if they for Better DX Reception cheaply as possible. are necessary. A planned program of The co- channel interference problem this kind will do much to eliminate the Featuring NEW CASCODE TUNER ', too confusion that causes many set users made for UHF interchangeable is a difficult one. The familiar "venetian blind" effect is prevalent to turn to the first technician who tuning strips and 70° COSINE YOKE offers his services when unexpected Tube throughout the flat Midwestern states Complement: and extends into most sections of the troubles occur. 28 tubes country on nights of abnormal refrac- 3 rectifiers Immediate Effect of New Stsitions 1 hot, humid nights). CRT tion (often during will get the A highly directional antenna (strictly The new stations that 32 uni-directional pattern) and careful "go ahead" as the Federal Communi- orientation will help to minimize the cations Commission proceeds with its interference. program of granting channel assign- is ments and issuing station construction Here again, though, the set owner on ignorant of a serious condition that permits will have a sectional effect may affect the quality of the picture the TV business. The priority sched- , ule recently released by the FCC shows on his receiver. When these stations will be boost their powers many set owners that sections of eighteen states d affected in the first twenty -five cities may suddenly find that the quality of their the picture they get on the new chan- to be considered for new-and All Channel) Booster nel is inferior to what it had been on first -telecasting stations. Of these 25 cities, five have channel Broad band single knob control pre -amplifier the former channel. And, unless they As- built in to eliminate long leads which may about what allocations only in the u.h.f. band. cause regeneration and attenuation of signal. are informed in advance are may happen, there will be a lot of consuming that construction permits ONLY THE MATTISON 630 CHASSIS will be extremely dif- granted for u.h.f. stations in these HAS AN ALL CHANNEL TUNEABLE fusion and it an of ficult job to advise them about the cities they will become the center BUILT -IN BOOSTER THAT INCREASES of all segments of the indus- IO trouble attention SIGNAL STRENGTH UP TO TIMES. causes of the trouble after the be the "prov- WILL OUT-PER- try. They will probably THE SILVER ROCKET starts. u.h.f. receivers, equip- FORM ANY CHASSIS MADE AND IS When there is an increase in effec- ing ground" for PRICED RIGHT TO SELL FAST WITH the adjacent chan- ment and accessories. tive radiated power, -Holyoke, Mass., area AN EXTRAORDINARY MARGIN OF nel picture and sound levels are cor- The Springfield PROFIT FOR YOU. WRITE FOR CON- a tops the u.h.f. priority list with Chan- respondingly higher. This becomes to broadcast FIDENTIAL PRICE SCHEDULE. particularly t r o u b l e so me problem nels 55 and 61 available Mattison tratares a complete line of cabinets station applicants. Youngstown, O., is MADE IN MATTISON'S OWN CABINET FAC- when strong and weak signals fall on TORY. :hi breathtaking designs that blend per- second with Channels 27, 33, and 73 in setting, or modern. channels. Technicians must f.rtly any traditional adjacent assigned to that area; then follows be instructed to align traps carefully - 21, preferably when spillover is observed Fort Wayne, Ind., with Channels DEALERS! 27, and 33; Scranton, Pa., with Chan- on the screen. and South Bend, SERVICE -DEALERS! An antenna with a pattern that can nels 16, 22, and 73, Ind., to which Channels 34, 40, and 46 Here is YOUR opportunity to become be oriented in the direction of the de- s the "important" TV Dealer in your the have been assigned. sired weak station and away from the Youngstown, area for THE FINEST CUSTOM -BUILT interfering strong station will be of Of these five areas RECEIVERS. provide LINE OF TELEVISION substantial help. The added selectiv- Ohio, section will undoubtedly desired some of the most useful information FREE! Write for MATTISON'S : ity of a booster can make the limitations of recep- signal dominate adjacent channel in- on the extent and merchandising portfolio explaining: tion in the u.h.f. band. terference to a greater extent. the "THE MATTISON reception prob- It is quite possible that some of In addition to these service contractors UNASSEMBLED PLAN" lems may occur in every one of major television that will set up small branches in the first and the areas where channel changes and first- few of the u.h.f. areas in order to acquire "THE MATTISON power boosts are scheduled, with the problems of sets now in service will produce the hand experience s SI,000,000 FLOOR PLAN" without installation, alignment, and servicing best picture they can deliver by propagation at least a touch -up alignment for max- that will be created at these higher frequencies. SALESMEN- AGENTS imum response at the new frequency. entire list TV set owners think of Denver, Colo., heads the Choice Territories Available. Become a Since most consideration for in TV stations as being about of cities for priority Prefer men tuning With Channels 2, Factory Sales Representative. the same as switching stations on their station assignments. with experience selling direct to dealers. 4, 6, 7, and 9 in the v.h.f. region and old push- button radios, there may be a lower end of among set owners Channels 20 and 26 in the lot of consternation allocated to that city, When you buy front who are not familiar with the need for the u.h.f. band Mattison you need " will experience lively activity . only one source of when they tune in these sta- Denver alignment ,, supply! You can buy TV construction and receiver yeas, a Mattison Chassis. tions on their new channels. in station a Mattison Cabinet or and legiti- sales and installations. Portland, Ore., h +TTIf O a complete Mattison Both parts distributors Tv Set: follows with v.h.f. Channels 6, 8, 10, Manufactured with integrity mate TV service businessmen in these twenty -five areas which are slated for and 12 and u.h.f. Channels 21 and 27 :Mattison Television &Radio Corp.: channel changes should pool their ef- available for stations. Other cities priority consideration 893 Broadway, Dept. R8, N. Y. 3, N. Y. forts in conducting educational pro- on the list for grams for TV set owners, advising of v.h.f. applications include Tampa - I1.11110 & TELEVISION NEWS I :16

www.americanradiohistory.com St. Petersburg, Fla., with Channels 3, 8, and 13 available; Wichita, Kans., where Channels 3 and 10 are open; 1V/tat is 11usicaI Prefrreiíce? Flint, Mich., due for a Channel 10 sta- Vour tion; Spokane, Wash., for Channels 2, 4, and 6; Duluth, Minn., Channels 3, 6, Classic symphonies - Chamber Music and 8; and Sacramento, Cal., with Channels 3, 6, and 10 allocated. Red-Hot Jazz Band? Assn. Distributor Cooperation one or all in natural, little affected .. One city that has been a by television service racketeers is Co- lifelike reproduction with lumbus, Ohio. A strong, aggressive r service association, the Associated Ra- Available in 10 or 30 watt models, featuring: f> dio- Television Service Dealers of Co- ALL TRIODE HIGH QUALITY lumbus, has been functioning in that All triodes. Attractive, remote -control pre -amplifier with AUDIO AMPLIFIER city for many years. It started origi- inputs for tuner, TV and phono; or single -chassis nally as a radio service association but units. made a quick transition to cover tele- Exclusive BROOK 8- position stepped bass & in treble control circuits. vision when telecasting started that BROOK-designed transformers and "transient area. However, even with such a peak" circuits. strong association of conscientious Harmonic distortion and intermodulation re- service businessmen cooperating with duced to vanishing point. the Better Business Bureau, the Co- lumbus newspapers and the parts and set distributors, once in a while a service "sharpie" managed to edge his way into the business. It required a high order of cooperation between the better business elements to weed out those slick operators who managed to work themselves into the business. One of the major reasons for the suc- Write for technical data, free booklet, - cettes .44tutK9- and name of cess of the ARTSD in keeping the local dealer. Dept. RH -2. service industry free from racketeering has been the cooperation they have had from all set and parts distributors in the city. The focal point of this program of cooperation is the quarter- annual dinner meetings which bring Association members together with distributors for discussions of mutual PH OTO CO N SALES problems. Activities of common inter- 417 N. Foothill Blvd. SYcamore 2 -4131 est are discussed at these meetings, Pasadena 8, Calif. RYan I -6751 gripes are aired, and points of conten- tion are freely discussed in an atmos- FREE 24 -PAGE SUMMER SURPLUS phere of mutual respect and coopera- SALES CATALOG tion. Because of this cooperative WANTED new or clean used electronic surplus. Please state exact description of the comfit loo activity the citizens of Columbus are and details of modification. Include lu'., , assured of efficient, reliable service un- price in first letter.

excelled in any other city. T5.12 Test Set for X -Band Box I & 2 complete Pu R. In attending a recent joint meeting Audio Oscillator Hewlett- Packard 20 BR 20- 20,000 c.p.s. . Exc. $110.00 of the ARTSD with their distributors, 4286 Kelvin Bridge Ohmmeter, Leeds & Northrup. .0001 -11 ohms Exc. 100.00 the editor of this department was able 804LX -1 Signal Generator UHF 8- 330mc Exc. 425.00 TS -13 /AP X -Band Signal Generator, Wave 00,AMT to observe at first -hand why this pro- Meter, Watt Meter PUR All/ I.96A Signal Generator SCR -522 Test IM6 llOtár, gram has worked so successfully. The Equipment . Like New 350.00 LM & BC -221 Frequency Meter with cal. Ain ; meeting, which was presided over by book, crystal, and tubes Exc 99.50 TS -352/U Weston Test Set Exc. 150.00 Fred C. Colton, dynamic president of TS -174/U Frequency Meter 20-280 mc with cal. book, and crystal Exc. 450.00 ARTSD and the originator of many TS- 173/UR Frequency Meter 90 -450 me. AIM Complete with crystal, cal. book, & 115 Wra fine technical training ideas now used VAC. Power Supply Like New 600.00 *NM P141111:-- TS- 146/UP X-Band Signal Generator. by a number of organizations, was at- like New PUR TS -34 /AP Portable Oscilloscope Exc. 350.00 WITHOUT, tended by a representative of the Co- Industrial Circuit Tester Weston Model 785. Like New 125.00 lumbus Better Business Bureau, a local Electronic Analyzer Weston 769...Like New 225.00 level APR -4 Search Receiver. PUR ., newspaper columnist, top execu- Tuning Units for APR-4 Receiver. of and set distributing New & Like New PUR. 1 w tives the parts BC -348. BC -312. BC -342 Receivers. and members of the As- New & Like New PURR organizations, Communication Receivers-made by Halli - crafters. National, & Hammarlund. Many sociation. models . Prices start 79.50 The BBB representative discussed T-47 /ART-13 Transmitter PUR+ Measurements Corp. Signal Generator Model the type of complaints they were re- 84 300- 1000mc. Erse PUR> PU -14 Inverter Input 24 VDC. Output 115 ceiving, how they were being handled, V., 3 Phase. 400 C.P.S. 5 amps ....Exc. UR`, T -17 Hand Microphone with cord and PL -OS. analysis of the results. He Exc. 4.50 and gave an HS -25 8000 ohm Used $2.95. New 5.95 HS -18 8000 ohm Used 1.75. New 2.25 also outlined the actions that had been HS -33 600 ohm Used 3.50. New 6.95 HS -38 600 ohm Used 1.75. New 2.25 instituted to keep the last of the local FOR A FEW CENTS MORE YOU PUR-Price upon request. service racketeers under control. Rep- CAN GET THE ORIGINAL AND MOST NOTE: One of the largest and most complete electronic resentatives of the various organiza- surplus stocks in the country. We have thousands of RELIABLE PRODUCT OF ITS TYPE. tubes, capacitors. plugs, accessories, transmitters-re - WHY RISK YOUR REPUTATION TO SAVE A tions were invited to voice their opin- ceivers, test equipment. etc. Send us your require - ions on any subject of common interest ments. FEW PENNIES? TERMS: Prices F.O.B. Pasadena. California. 25% on ORDER FROM and the parts distributors reported on all C.O.D. orders. Californians add 3 %a Sales Tax. YOUR D;STRIBUTOR new equipment shown at the annual Prices subject to change without notice. august. 1952 137

www.americanradiohistory.com Electronics Parts and Equipment Show Back Again By Popular Request! in Chicago. TELEPHONE Chassis The speaker for the evening's meet- Special Purchase FM Radio ing was Paul H. Wendel, managing di- EQUIPMENT & PARTS New TS9 Handsets with butterfly switch $6.50 88 -108 MC rector of the Television Technicians Rebuilt TS9 Handsets with new shell Each 4.95 Complete with 6 Lecture Bureau, who discussed "Areas Rebuilt Solid Type Handset with new 3 con- tubes. Built -in An- ductor cords Each 4.95 tenna and Speaker. of Cooperation Between Parts Distrib- New Western Electric Handsets with rubber Product of Famous utors and Servicing Organizations." He cord & PL47 ping Each 7.50 Radio & TV Manu- New Receiver & Transmitter Elements inter- facturer whose name pointed out that the industry is stand- changeable with W.E. Elements Fl & HAl. we promised not to Each 1.00 mention. ing on the threshold of the period that Reconditioned Upright Desk Telephones (for in- TUBE LINEUP I 2.95 Regularly $29.95 will witness its greatest expansion. tercoms, extensions. etc Each 1 -12BA7 1 -1288 W.E. 202 Desk Telephones Each 8.50 Brand New 2 -12BA6 1 -35W4 While attention has been focused on New 6 -Foot Rubber Cords with Alligator clips. 1 -35B5 television for home entertainment, Each .60 also be used as an FM New Weatherproof Cook Commando type Pole May in Jacks . Each 1.00 Tuner by picking signal off great strides have been made the detector. $16.95 development of television for industrial New W.E. UA 38 Relays Each 2.50 New, unused R.C.A. Amplifiera -90 Watt, 50 -60 Cycles, and commercial applications and the 105.125 Volts, with spare part kits. Maroon Plastic Cabinet for above $5.95 entire field of industrial electronics Terms: Check with Order-F.0.8. Brooklyn, New York will open up vast new opportunities EASTERN TELEPHONE CO. for parts distributors and competent 321 Vanderbilt Ave. Brooklyn 5. N. Y. HERE'S independent service companies. A Taking the specific subject of indus- REAL trial television, the speaker described BUY the work that has been accomplished YOU GET 2 by the Lecture Bureau staff in devel- ABSOLUTELY THE GREATEST CABINET BUY TV unit IN YEARS. oping an industrial camera 101 uses for this sturdy, handsome, black plastic so low that it could cabinet. Can be used that could be priced for TV boosters, re- be sold for use in a myriad of applica- mote control units, Two Station Intercom System tions. He cited the following as just a meters, etc. Less than half the original price. P Built for America's leading dept few of these possibilities : 1. Window A genuine bargain store chain, whose name we cannot you can't afford to mention because of this low price. BRAND 2. Consists of master station,n, advertising displays; Store -room miss. ation and 20 ft. 3 conductor NEW wire. Can be used as a private or pick -up of customers as they enter For only non -private system. 115V AC or shop; 3. Monitoring of small plant op- 2 $3 DC. Brand now only ditinl wire, per ft., Sise Postpaid anywhere VARIABLE CONDENSERS erations; 4. Store -room advertising s1/4" a sn x 31/4" In the United States From SCR -5.22 or 2 -GANG 25 MMF r± displays; 5. Use in service shops as a No C.O.D. Send cheek money order. Per Section $1.29 3 -GANG 2S MMF $11.95 piece of test equipment. Also use as MANUEL KLEIN CO. Per Section $1.59 94 -N CHAMBERS ST. NEW YORK 7, N. Y. Brand New with Concentric Air Trimmers a source of signal to check receiver performance; 6. Estate and farm ap- SPECIAL PURCHASE Record Changer plications; 7. Remote observation of 8. Gen. Instruments 3 -speed Automatic recording instruments; Applications in various departments of local gov- Reg. $34.95 ernments; 9. Novelty and other appli- TUBES 50ç Brand New g. cations at night clubs, carnivals, fairs, A REPEAT OFFER 10. 5Ú4G 6AU6 6AL5 6806 auditoriums, etc.; and Television ALL AMERICAN SERIES-$2.50 $19.97 operations studies for radio amateurs, 12SA7 12SK7 12507 3525 50L6 Our Flyer contain. a terrific Fltkb: BONUS - With all purpose car- students, and experimenters. srnd for your copy today tridge & needle. Plays Since every installation will have to THIS MONTH'S SPECIAL 33V3-45 RPM records auto- be to accomplish a specific No. 807 -2 for $2.50 matically. tailored CROWN TELEVISION purpose, industrial television will re- P. 0. Box 194 Hicksville, N. Y. quire the services of competent instal- Manufacturer's Closeout! lation and maintenance organizations. EVERY READER KNOWS THIS FAMOUS MAKER TV OF WIRE WOUND FIXED AND VARIABLE RESIS- It is a natural field for independent TORS. MARKED GENERAL ELECTRIC. service organizations. We've bought up a tremendous supply of these and now you can buy them below manufacturer's 5000 The speaker pointed out, however, lot prices. 10 WATT FIXED 10 WATT ADJ. that servicing organizations should be HIGH SPEED WITHOUT 1 -1000 List....$ .75 1.1000 _es List 51.47 1100- 5000 .... .80 1250- 5000 1.53 studying industrial television now in NERVOUS TENSION 6000-10,000 .... .92 6000. 10,000 .. 1.63 REVEALING 11,000- 20.000 .... 1.03 Your Cost. Each .39 to be prepared and equipped to shows a ck. 22,500-25,000 .... 1.08 order operators develop high 30,000 -50,000 .. 1.22 20 WATT FIXED business quickly when speed and proficiency. Your Cost. Each .24 5 -1000 .-. List 5 95 move into the Learn code for Ama- 1200- 5000 .97 teur or Commercial 25 WATT ADJ. 6000- 10,000 1.12 it starts to develop. 1.1000 List 51.87 12,500- 20,000 1.20 censse0, or1improve your 1250- 5000 1.88 25,000- 40,000 1.37 Readers of this department who are sending and receiving 6000 -10,000 2.03 45,000- 60,000 1.58 I with the Candler System which develops ra- 12,000. 20,000 2.08 65,000- 80.000 1.83 interested in the subject of industrial I dio- telegraph champions. FREE 23K 2.2.28 85.000-100,000 2.11 exper sSYSTEMde Cost. Each Cost OOEach .36 television may obtain a copy of a bul- Box 928. Dept. 2 -1, Denver, Colo. BOOK I TT on it by sending a stamped, ad- ______- 1- 1000... List... 52.37 1 -1000 List... 3.58 letin 1250- 5000 ... 2.47 1500- 5000 . 3.67 6000. 10,000 ... 2.63 10.000 .. . . 3.87 dressed envelope to : The Service News 12,000-20.000 ... 2.83 15.000.20;00.0 4.12 WALKIE TALKIES $4.99 Set of 2 25,000 -40.000 ... 3.08 25.000. 40,000 4.37 Editor, RADIO & TELEVISION NEws, 366 -ELECTRONIC VOICE POWERED 50.000-60.000 ... 3.30 50,000 4.53 POCKET SIZE No tubes, batteries, adjustments, 80,000 . 3.67 75,01)0 4.75 Madison Ave., New York 17, N. Y. 30 license or permit needed! 100,000 3.92 100,000 4.95 up to Four Cost. Each .69 flour Cost. Each .79 Guaranteed to work anywhere U4 milee with rs et Deduct 10 -t.nts of 100 or more. Deduct 20%- garage to house, Your own Lots of 1000/ to 10,000. Minimum Order-$2.00. ae, talk- listen phone. Not war surplus. Brand new. Solid Alu- minum Case. Two complete units with wire-READY TO USE! SEND Attention Prospective Novice Hams', ONLY $1.00 deposit and pay post- man $3.99 C.O.D. or send $4.99 for Code Oscillator Kits -All Parts -Phones oc PP delivery. Sold only by mail from: MIDWAY CO., Dept. WRT -9, KEARNEY, Key- Battery -Instructions.. Complete $T BUJ.7J NEBRASKA, TERMS: All items F.O.R., Washington, D. C. All orders $30.00 or less, rash with order. Above $30.00. 25 per cent .th order, balance C.O.D. Foreign orders, cash with orders. plus exchange rate. RADIOS K I. 2 6 3 band Electric andior battery K TELEVISION AC/DC Operate, VUN RADIO 1' TEST INSTRUMENTS T Write for FREE Cototog "Will whoever has the remo e control S A R K AY -Radio Kits, Inc. S 938 FSTREET. N. W. WASH. 4. D. C. gadget stop playing with the channels!" 120 Cedar St., New York 6. N. Y. 138 II:111I0 .t 'l'ELE1"ISI11\ VIEW`

www.americanradiohistory.com few new tubes combine two or more of The TV I'iclure Tube these features. (Continued from page 50) Practically all picture tubes use the from now on . . . same 6.3 volt, 0.6 amp. filament, which permits us to neglect this item in any current, and the proper type of ion changes of picture tubes. trap for each tube. If it is desired to On studying the tube chart on the replace a tube with a similar type be "Data- Print" it appears that some of sure that all values given in the "Data - the more recent large- screen tubes are Print" for both tubes are almost'iden- identical although different numbers tical. A variation of 2 kv. in second are assigned them. In most cases the anode voltage, 5 ma. in focusing cur- differences are in gun structure, ex- rent and 1/4 inch in length will not ternal conductive coating, and other affect the tube's operation, but larger minor variations which do not affect deviations will often require circuit the function of the tube. If a tube hav- modifications. When a metal shell ing an external coating is used, some tube is used be sure to obtain the cor- means of grounding this coating must rect plastic insulating frame and be provided and almost all TV sets nothing is beyond apron. Another frequent source of diffi- have a ground spring, clip, or other culty is the variation in high -voltage contact for that purpose. terminals used for the second anode. It would be impossible to mention all your control! When the new tube requires a different the details and different features of type of terminal it is best to purchase the host of TV tubes now in use, but the correct mating part rather than the chart will answer all pertinent use a makeshift arrangement which questions which arise in either replace- the quality will later produce arcing or corona. ment or conversion work. Just be sure The controll,ng factor in Picture tube screens come clear, to check every one of the columns for of your home music system . . . with a filter glass, or etched. The latter both the new and old tube and make a two type screens are designed to re- note of the differences. Then it can be duce glare. A third type of glare -redu- determined whether these differences cing tube has recently been introduced. can be overcome and how, or if a differ- It has a cylindrical outer face to re- ent tube type offers some advantages. duce reflections from incident light. A i

spaced. Electronic timers control such Industrial Elect reenies complex sequences with precision and (Continued from page 64) reliability. The sequence con- timer The CRAFTSMEN sists of two or more time delay circuits -Preamplifier connected in cascade. Fig. 4 shows the Equalizer on the negative alternations. In this diagram of a sequence timer made up complete one Combines ie one central panel equalization, manner, relay chattering is prevented of four circuits like thdt of Fig. 1. To compensation, phonograph switching. even though an alternating voltage is start the timing sequence, switch 1 is and control of oll audio channel supply used on the plate of the tube. opened. After an interval of time Completely self -contained power with any audio The potentiometer to which the grid relay 1 is energized. This relay has permits flexibility tor use is connected serves a power amplifier. as voltage di- normally- closed contacts which serve variable loudness control Continuously lis- vider across the power lines, and de- as the switch for the second timing compensated at different correctly to low termines the voltage to which the con- circuit. In this manner, when relay 1 tening levels for loss of response denser charges. Since a larger volt- is energized it initiates and high audio frequencies. the timing infor all popular age will longer Preamplifier exactlyetly take to discharge, the terval in the second circuit; when the phono cartridges, compensated potentiometer serves to control the du- second relay closes, it initiates the for all types of recordings. continu- Bass and treble tone controls, ration of the timing interval, time delay in the third circuit, etc. to boost ously variable from attenuation Sequence Timing The relay in the last circuit may be -fiat clearly marked. reduction of In many applications, resistance connected back to the first in order to Two 4- position filters: for for reduc- welding for instance, power is noise- and record scratch ... alter- repeat the same timing sequence over hum. tion of turntable rumble and nately applied and disconnected. The and over. Additional contacts on each ex- Cathode follower output permits "power on" IOU intervals may be of the relay serve to apply or disconnect the tremely remote installations without same or different durations, and they power of the associated equipment. of response. may be The first preamplifier performance - uniformly or irregularly 500 Ultra - matched to the Craftsmen F.delity audio amplifier. Fig. 4. The sequence timer consists of several time delay circuits connected in cascade. The contacts of each relay serve as the switch for following circuit. HAVE YOU WEAR!) the C.500? Wiliam- Son all -triode circuit. It's 95.99°ó -free! AI 4 distortion " Write today for information THE RADIO era tsmen INC. Ave. Dept. R- 8,440 N. Rav Inswaod e O 9 Chicago 40,

f,ugue.l. 1952 139

www.americanradiohistory.com ,RADIO Surplus Buys INDEX eZ//ej.e./t AUG. 1952 500 KC CRYSTALS Of 500 KC Crystals in FT 211 -:A holders with 1/2" pin spc. While every precaution is taken to insure accuracy, we cannot guarantee against ONLY LIMITED the possibility of an occasional change or omission in the preparation of this index. %, QUANTITY AVAILABLE N.UIE PAGE NAME PAGE %corn Electronics Corporation 92 Land-Air, Inc. 10.2 TUNER FROM irex Radio Corporation 105 La Pointe Plaseamold Corporation, The 6 A i r -O- Tronics 123 Leotone Radio Corp 141 NAVY "BN" Allied Radio Corporation 9 Luther, Otto 140 Aluminum Products Corporation 121) EQUIPMENT Alvaradio Supply Company 116 McConnell'. 116 Simply modified into 2 -me- American Phenolic Corporation 80 McGee Radio Company 82, 83 ter converter for car or com- American Television & Radio Co. 24 McGraw -Hill Book Company 100 receiver. Uses munications Amplifier Corporation of America 12:5 Mallory & Company, P. R. 29, Fourth Cover 1-6J6, 1 -6SH7, 1 -9006, 1-6J5 (Not Furnished). Arkay -Radio Kits, Inc. 138 Mattison Television Company 136 Slug is tuned from 157 to 187 Megacycles. Inchiil - Arrow Electronics, Inc, 88 Merit Coil & Transformer Corporation 84 schematic diagram for "BN" equipment. Arrow Sales, Inc. 103 Midway Company 106 Now-A New LOW Price $4.95 Ashe Radio Company, Walter 97 Miles Reproducer Company, Inc. 130 Astatic Corporation 26 \lilwaukee School of Engineering 110 Astron Corporation, The 96 3lodern Science Labs 106 SENSITIVE ALTIMETERS Atlas Sound Corporation 100 Moody Machine Products Co., Inc. 85 Mosley Electronics 119 Pioneer Sensitive Altimeters. Range Barry Corp. 133 0.35,000 ft., calibrated in 100's of Electronics Moss Electronic Distr. Co., Inc 81 Iret. Barometric setting adjustment. Bell Telephone Laboratories, Inc. 20 117 No hook -up required . mounts Bendix Radio National Electronics of Cleveland 126 sally in auto or air - $ 1 2 95 Rerlant. Associates 122 National Radio Institute 3 .-raft. Used. Good.Each v1 L 3a/ Brook Electronics, Inc. 137 Postpaid National Schools 11 Brush Development Company, The 18 Newark Electric Company, Inc. 131 Newark Surplus Materials Co. 88 C & H Sales Company 140 Newcomb Audio Products Company 16 ALTIMETER, AIRCRAFT Candee-Airco 123 U. S. Navy surplus Altimeters, range Candler System Company 138 0- 10,000 feet. Adjusts to sea level Capitol Radio Engineering Institute 69 Offenbach & Reimus Company 118 setting of terrain. Simply installed, Olson Radio Warehouse 90, 91 requires no hook -up . . . for auto or Centraiab, Inc. 22. 23 aircraft Channel Master Corporation 17 Olympic Electronics Supply 124 BRAND NE \Nation. Each $7e95 Chicago Transformer Company 109 Postpaid Cleveland Institute of Radio Electronics 77 Park Electronics 128 Collins Audio Products 19 Peak Electronics 130 Columbia Electronic Sales 116 Phototon Sales 137 CONTACT Commissioned Electronics Company 128 Pickering and Company, Inc. 88 Communications Equipment Company. 111 Platt Electronics Corp. 114 MIKE ASSEMBLY Consolidated Radio 140 Precision Electronics Inc. 102 BRAND NEW! Coyne Electrical School 127 Premier Radio Tube Company 99 Crest Laboratories, Inc. 96 Progressive Electronics Company 105 Complete Contact Alike As- Crown Television 138 Pyramid Electric Company 30 sembly includes: Two microphones, on-off switch, ampli- fying transformer, batteries, Davis Electronics 112 Quiet role Company 137 battery case. Connector to at- DeForest's Training, Inc 5 tach to any radio, AC. DC or battery portable. Amplifica- Delco Radio Parts 87 RCA Institutes, Inc. 27, 106 tion up to full volume output Del Tronics 86 RW Electronics 121 of radio or sound system used. Dow Radio, Inc. 112 Radcom Engineering Company 121 FB for watch or clock repair, Diesel eurtin. Q q cm 135 injector adjustment, gas engine diagno..r -, 42.41J Dukane Corporation Radio & Television News 95 etc. Specially Priced at Postpaid Dumont Electric Corporation 123 Radio Corporation of America Second Cover, 107 ALL EQUIPMENT F.O.B. PASADENA UNLESS Eastern Telephone Company 138 Radio Craftsmen, Inc 1.39 OTHERWISE SPECIFIED. PLEASE ENCLOSE Editors & Engineers, Ltd. 135 Rad -Tel Tube Company 123 FULL AMOUNT WITH ORDER Edlie Electronics, Inc. 78 Bauland Corporation, The 79 Electronics Institute 130 Raytheon Manufacturing Company 53 Electronic Instrument Co., Inc. Third Cover Rider Publishers Inc., John F. 28 C & H SALES CO. Engineering Associates 128 Rytel Electronics Mfg. Co. 84 Equipto 127 BOX 356 -AT East Pasadena Station, Pasadena 8, Calif. Esege Sales 130 Sams & Company, Inc., Howard W...92, 102 Sankt, Bob 130 Fair Radio Sales 12:5 Simpson Electric Company- Fisher Radio Corporation 122 South River Metal Products Co., Inc 141 Franklin Technical Institute 132 Sprague Products Company S9 Sprayberry Academy of Radio 21 G. L. Electronics 104, 106 Stan Burn Radio & Electronics 106 Garrard Sales Corporation 132 Star Electronic Distr., Inc. 122 General Electric Company 12, 13 Steve -El Electronics Corporation 13:5 General Test Equipment 132 Stevens -Walden, Inc. 116 Gonset ('onipuny 10 Sun Radio & Electronics Co., Inc. 132 Good Inc., Don 113 Sun Radio of Washington D. C. 138 Goodheart, R. E. 128 Supreme, Incorporated 108 Greenlee Tool Company 131 Sylvania Electric Products Inc. 25 Halldorson Company 131 TA It 142 Hallicrafters Company, The 7 T. \. Installation Equipment Co. 96 Harvey Radio Company 120 Tries i.ion l'omntunications Institute. .. 115 Heath Company, The 70 Own 75, 133 Television Materials Corporation 106 Henry Radio Stores 141 Telrts, Inc. 119 133 7334 North Clark Street Hollywood Technical Institute 9'L Terado Company, The Hytron Radio & Electronics Co 15 Transvision, Inc. 101, 134 Triad Transformer Mfg. l'o. 128 Indiana Technical College 85 'Fri-State College 112 Instructograph Company 100 Tung -Sol Electric, Inc 94 J.F.D. Manufacturing Company 8 Ungar Electric Tool Company, Inc. 111 CET in on the fun of operating your J.S.H. Sales Company 125 Union Electronics Company 132 own licensed transmitter. I guar- Jensen Industries Inc. 128 antee you will memorize the Inter- Jersey Specialty Company 113 Valparaiso Technical Institute 132 national Morse Code alphabet within Jones & Laughlin Steel Corporation 93 two hours by my simple picture Electronics, Inc. 127 TWO DOTS within Waldom method, or return method Wells Sales, Inc. 76 MAKE THE five days and I will refund your Klein Company, Manuel 138 Krylon, Inc. 98 Western Electronics Company 132 LETTER money. Wholesale Radio Parts, Inc. 115 COMPLETE COURSE ONLY $1 Corporation 14 World Radio Laboratories, Inc. 117 NOTHING ELSE TO BUY! Lafayette Radio i OTTO LUTHER, NEW PRESTON, CONN. RADIO 6: TELEVISION NEVI'S

www.americanradiohistory.com What Do You Want to Rate 50c per word. Mini Trade In on a New RADIO ENGINEERING COMPLETE radio, electronics theory & practice: ; ma- television ; broadcasting ; servicing aviation, rine, police radio. 12 or 18 months. Catalog. Val- paraiso Technical Institute, Dept. N, Valparaiso, Ind. hallicrafters? Hallicrafters receivers and transmitters. We will give you SALE I have a complete stock of the best doggone trade -in in the world because we need used receivers badly for leading makes; tape, wire, blanks, RECORDERS, me about it. I give you prompt delivery, 90 -day largest discounts. Commissioned Electronics, 2405 our trade. What do you have? Write 18th St., N.W., Washington, D. C. FREE service and the world's lowest credit terms. Write, wire, phone, or visit either store today for the best deal. Export orders solicited. PO HEARING aids, used. Zeniths, less accessories, WrARA $7. One -piece Nationals, $10. One -piece over - hauled, with accessories, $20.00. Shelby Instru- ment, 321 W. 7th St., Long Beach, Calif. DIAGRAMS Radio, Record Changers, Recorders, 75c; Television with Service Data, $1.25 up. State manufacturer and model number. Kramer's Radio Service, Dept. N8, 36 Columbus Ave., New York 23, N. Y. TUBES and equipment bought, sold, and ex- changed. For action and a fair deal, write B. N. Gensler, W2LNI, 136 Liberty, N. Y. 6, N. Y. ENJOY television with a 3 color filter screen. Thirty seconds to attach. Reduces glare, blur, and snow. Send only $1. Mention screen size. Zingo Pro- Popular Double -IF Model SX -71 All -Wave Receiver Model SX -62 ducts, Dept. B, Johnstown, N. Y. A double superheterodyne circuit receiver at Covers 540 kc to 109 mc- including AM, FM, modest cost. Built-in narrow band FM reception. and SW broadcasts. Six bands: 540 -1620 kc, TV Yagi Beams. Aluminum Tubing, FIVE element 15 mc, 27 -56 etc. \'rite for prices. Willard Radcliff, Fostoria, Temperature compensated, voltage regulated. 1620 kc- 4.9mc, 4.9 me -15 mc, -32 Ohio. 5 position band selector for 538 -1650 kc, 1600- mc (AM -FM), 54 -109 mc (AM -FM). Only $289.50. 4800 kc, 4.6 -13.5 mc, 12.5 -35 mc, 46 -56 mc. Other popular Hallicrafters models: S -76, Manuals 1 thru 15 in eleven volumes. Like RIDERS rectifier. $169.50; S -40B, $99.95; S -72, $109.95; new. Best offer. Ivan Beal, 3913 Oakland Ave., 11 tubes plus voltage regulator and S S $49.50. So. Minneapolis, Minn. Only $ 1 99.50 S-72L, $119.95; -81, $49.50; -82,

TELEVISION Towers direct from factory. Write 11140 Olympie Blvd. Youngstown Steel Towers Co., Youngstown 8, Ohio. LOS ANGELES 25 But ler2,Missouri CALIF. SENSATIONAL bargains! Standard brand tubes, HENRY RADIO STORES bought, sold. Free list. Mark, P.O. 14, New York City 72. "WORLD'S LARGEST DISTRIBUTORS OF SHORT WAVE RECEIVERS" SURPLUS Electronic material, tubes, Ham gear. Arnold, Box 706, Amarillo, Tex. Free list. Albert AN -130A WHIP ANTENNA 34 ", gnoseneck 50.98 19 FT. WHIP ANTENNA . . 6 steel screw secta 2.96 FM Yagi, Conical, Bow-Tie. CRYSTAL HEADPHONES (Brush) . 50.000 TV and Antennas. imped. With adjust. band & tipped cord 4.95 Mounts, accessories. Lowest prices. Wholesale TUBES!! TUBES!! , individual unsealed car- Supply Co., Dept. H. Lunenburg, Mass. ton; 90 DAY GUARAN. TEE. Standard brands. irme.ili a24, 26. 27. 34. 39. WANTED 41, 42, 6K7, 1114, 1556, or 1J6 ...... ea. $0.39 #46, 55, 77, 78, 85. 89. 11.4, 5Y3. 5Y4, 6B7, 6F5, 6.15, 605, 6K8. 68A7. 65D7, 6S117. WANTED: AN /TRC -1 equipments, T14 transmit- 6SK7, 6R7, 6C5, 81)7 or 7B6 ...... ea. .59 ters, R19 receivers, TS32 test oscillators. Any con- 11 27AC67. * *NEWS ** 6C717A7, 7AG7, 7C6. 7Y4 orA57 .ea. .79 or quantity. Box 525, Radio & Television dition BC -604 10 CHANNEL PUSH BUTTON TUNER News, 185 N. Wabash, Chicago 1, Ill. ASSEMBLY. Brand n ew $5.95 8S-30 HEADSET ear -plug type 2.49 River MATCHING05-30 G TRANSFORMER fEr NITS...... 59 South AN /APR -4, other "APR -," "ARR -," "TS -," 555-30 REPLACEMENTR PHONE UNITS lesslees "IE -" ARC -1, ARC-3, ART -13, everything sur- e ea. .59 Replacement Banding 20' SPEAKER EXT. CORDS tip-lug.. . .88 plus ; Tubes, Manuals, Laboratory equipment. De- PORTABLE METAL UTILITY BOX (8x8x6a/q ^) scribe, price in first letter. Engineering Asso- eneILO k hinged lid. Wcr strap. 69e: 3/1.98 Kits Now Available 69. PILOT . 9, BULBS min, screw 10/39c; 100/3.49 ciates, 434 Patterson Rd., Dayton Ohio. 5" C.R. TUBE FRONT BEZEL . . black crackle. .89 R" SCOPE VISOR eyepiece.. .98 KIT A: (Consists of) RADIO HARDWARE TREASURE FU eL LB. CORRESPONDENCE COURSE of: Nuts, curia, Screws. Washers. etc, in 2 -12' 3/4" GALV. STEEL STRAPS hinged lid n 89e; 3 lbs. /2.49 with eyebolts attached USED Correspondence Courses and Books sold 32MFD -450V cELECTROLYTICS. can 2^x4" ea. 49e; 6/2.49 2- Eyebolts Unattached and rented. Money back guarantee. Catalog free. 4-Nuts to Fit Eyebolts (Courses bought.) Lee Mountain, Pisgah, Ala. A REAL BUY 2-KWIK KLIP Strapping Fasteners FCC LEARN Code, theory for amateur, commercial 1/20 M.P. GE MOTOR , . 1725 KIT B: exams. Free information. American Electronics, VÍ RPM, 110V. DC. .1 Amp. Dble. 1451 Wilkins, Dept. ItN -8, N. Y. C. 59. Ws" shaft. 43/4^ O.D.x51/2" $2.95 Similar to KIT A, except furnished with 1/1" width stainless steel banding CABINET DRAW SLIDES .. silent. ball- bearing and special plated hardware. .. 13" (9^ t.) $2.10 pr.: 15" (li" ext ) MISCELLANEOUS $2.25; 160/ " (121/2" ext.) 2.39 Heavy duty, all- steel 1619^ (121/2 ^). .... 3.25 SPEAKERS repaired, wholesale prices, guaranteed "HOOK -UP WIRE SPECIAL" .. Solid. stranded KIT C: colors; ends stripped & tinned. 3" to 10" KIT B, except furnished workmanship. Amprite Speaker Service, 70 Vesey Igths 3 lbs. /1.98 Similar to St., New York City 7. 100W -50 or 75 OHM W.W. RESISTORS. with 3/4" width stainless steel band- ea. 59e; 4/1.98 MIDGET PLUG & JACK (P).201!.JK -481 39c; 6,1.98 ing. CRYSTAL HAND MIKE . HI- FIDELITY. High impedance. Moulded bakelite case. 5l/2 ft. NOTE: ALL SOUTH RIVER CHIM- cable .... 3.95 ARE NOW AVAILABLE DYNAMIC HEADSET & N AND MIKE rpressto- NEY MOUNTS STEEL STRAPPING. talk ...... 3.49 WITH STAINLESS 6V.AC -DC PLUNGER SOLENOID (11/2x "2,, 3/a" PILOTO CREDITS action .89 South River Antenna Mounting Acces- EXPERIMENTAL TUBES .. for Test. Research, leading TV etc. Fit. tested. 40 asstd. rove, types 1.98 sories are carded by every Page Credit Parts Jobber from coast to coast. I "ALNICO MAGNETS" .. "U" type, 2 "x s/g". Poles: /b 31, 32 (Fig. 3), 33 1Fig. 5) De Mornay Budd Ii/ç 1/4 "xs $1.25 I catalog mailed to all Dealers FLAT BAR . 1T /$ ^x7 x5 /16'... ea. 79e; 6/4.25 New ROUND BAR 2'x3 " O.q. .. ea. 59e; 10 /5.50 I and Service Men. 33 (FIg. 6) Sperry Gyroscope Co. I BLOCK MAGNET .7 -I. x :

www.americanradiohistory.com TV PICTURE TUBES RECTIFIERS 10-in. Rnd ..514.95 17 -in. Rect.. $24.85 30Vin 26Vout /150Ma Selen 12.ín. Rod.. 17.95 19 -in. Rnd .. 28.50 w /mtg 11:11u.t. 2 unhs C.,n Con - 14 -in. Rect.. 20.95 20 -in. Rect.. 29.95 et C. T. for Full Wave, 16 -in. Rnd.. 22.95 21 -in. Rect.. 30.45 Unit. i36c;2for 60c:4 for $1.00 16 -in. Rect.. 23.85 24 -in. Metal. 67.00 Full Wave Bridge Selen for re- Your old pact tube is worth money. Write "TAB" ¡net 115 to Ors lays or Pwr, 130 for trade-in allowance on RMA coded and ac; Outpt il5vdc /4OMa. 49e Stack dated tubes with one year guarantee. Ship THAT'S A BUY Current 18/14 26/18 3 15000 your defective picture tubes prepaid only. volts v When Ordering Metal Tube, Defective (Cont) volts 116667 POWER TRANSFORMERS 2 amps 2.20 .1 120000 Metal Tube Is Requrred. 2500V for Cet 6.3V /.6A, 2.5V/ 4 amps 3.75 t b.JO 130000 TUBE SPECIALS 1.75 Hvins 4/ 5 amps 4.95 - 18380 135000 WITH BROKEN KEYS t 7 98 10 amps 6.75 9.98 12 J 18500 140000 ELECTRICALLY TESTED PERFECT 132mní1V & 375TVCsd /llama, 5V/ 12 amps 8.50 16 00 18800 141000 1B3, 6116. 6K6GT, 6V6GT. 6SN7GT. 3A, 2.5V/3.25A, 6.3V/ 20 amps 13.25 16.20 245, 4000 19000 145000 12SN7GT. Ea. 50e; 5 for $2.00 2.75A Held Hvins. ..59.98 24 amps 16.00 31.0, 4030 19500 147000 ...... 4 4200 20000 150000 6BG6G, 13/3Q6, 12Sß7 19BG6G, 6L6G. 1000VCT /200MÁ 18V /.55A. 30 amps 18.50 24.30- 36.00- , ..0 6a. 79e; 3 for $2.00 6.3V /5A. 5V/6A....56.98 36 amos 25.50 45.00 N 40 4220 20441 155000 1000VCT /45MA, 795vct /80ma, 300 CT Rectifiers 100 amp- 10- O.10V..1N, 1646 4280 20500 160000 OIL CAPACITORS vet/55ma, 355V /3A, 6.3vct /IA 80 Amp 18 -0 -18V 2b. .6 1650 4300 21000 165000 6.3vct -.3A end Hvins can be used 80 Amp 36.O -36V O 1670 4314 21500 166750 Mfd Each Mfd Each 2x tin Raytheon Hypernil Core. 4.98 Full Wave Selen Rect & Trans. with Ageing 475 1680 4440 22000 167000 900V/35MA, 2x2.5V/2A, /mint 1800 Taps, in Kit form. All 115V/60cy inputs. c 380 1710 4444 22500 169200 31000wvdO9 12000 cantle V'tlblr two 2x2 fil. wndgs held... 3.49 up to 16VDC at 12 amps $23.98 389 1712 4500 22990 175000 Mtd Each .45 .79 .02 4.98 840VCT/110MA, S30vct/21ma, 2x5 u to 28VOC at 12 7 390 1740 4720 23000 180000 SOwvde 1.69 V /3A 6.3vrt /1A, 6.3vct /.3A...... 4.98 up to 28VDC at 48 amps 149.50 7.8 400 1770 4750 23150 180600 4 5 8 770VCT /85MA, 5V /2A, 6.3V /3.5A up to 20VDC at 6 amps...... 12.98 7.9 410 1800 4850 23325 185530 150w9vdc 150Owvdc .0016 9.98 Throe' 3.98 Ñ This 6 amp supply has no ageing taps. 8 414.3 1818 4885 23400 186600 1.1.3 -5 .98 750VCT /200MA, 6.3V/5A, SV /4amp 5.95 specialize power supplies to your 10.38 418.8 1830 4900 23500 190003 250wvde .75 1.69 2mvde 720VCT/115MA 28.3V/.6A, 5.05V/ specifications. 11.25 425 1850 5000 24000 198003 7.49 3.95 13.52 426.9 1865 5100 24600 200000 2x.25 .35 I 1.79 .00025 2A. 6.3V/3.82,03.3V/.6A, 14.2 427 1892 5210 25000 201000 400wvde 5 700VVCT /120MA, 2x6.3V/3A. 6.3V/ RECTIFIER XFMRS 14.5 430 1894 5235 25200 205000 .1 .49 6 3.98 1AC RATED 3.98 18.8. 19.2 -20.4 -21.4 Volts 12 Amp..514.98 15 .5 .59 .05 .79 225vae/ 600VCT /100MÁ, Tapp d 35Ovct. 6.3 31.32 440 1895 5270 25400 210000 630dc Wndg -34.36 Volts /12 amp 2Kvins.. 16.49 16 450 1896 5300 25833 215000 1 .69 2000wvdc V/34. 2.5V/3A Isolation 115 18- 12- 9- CT- 9 -12 -18 Volts /4A 8.75 17 452 1897 5500 26000 220000 4 1.69 .1 1.49 3.3 .79 V /.45p 3.25 18- 12- 9- -18 Volts ..... /15ORIADC. 6.3 V /5A 3.49 CT- 9 -12 /12A .... 16.75 19.2 460 1898 5600 26500 225000 6 8.1 55OVCT 5V/3A. 36VCT- 18V . 49 2 630d / Hsld 2.98 24V- /24Amp 35.75 18.5 470 1899 5730 26600 229000 2 1 1.89 1.29 500VCT /60MA, 6.3V/4A 20 475 1900 5770 27000 230000 10 2.89 2 Infrared Snooperscope 22 478 1901 5910 27500 2x.1 .75 .69 330vac/ FILAMENT TRANSFORMERS 235500 2x.5 .94 OOd 2X12V /2A or 24V/2A 2Kvins $3.89 Image -Converter Tube HiSensi- 23 480 1902 6000 28000 238000 .91 simplified design 2" dia. 24 487 1903 6100 28430 240000 3x.1 82500vwde9 1.25 6.3vct /4A (god 6.5Á1 H'Sid Hvins 2.69 tivity 25 500 1904 6125 28500 245000 30.25 .99 .25 2.29 1.5 .89 6.3vet /1A $1.98; 6.3v/6A 1.98 Willemite screen-Resolution up 26 510 1905 6140 29000 250000 600wvdc 3000wvdc 1.75 2.5v/2A. //9c; 7.Svet /í2A 15Kvins 10.98 to 350 lines /In. Complete data 28 520 1906 6200 29500 .49 I.ó3 . 1.98 & tube, each 2 for $9.49 265000 .034 .1 2.49 2.5 1.09 24v/6a cad. $4.98: 240/1.25 end. $4.98; 30 525 1907 6300 29990 268000 S 2.98 2.8 2.5vct /10Amp. 5Kvins, $3.59; 2x12 .25 .61 1.15 V 2 3.89 SNOOPERSCOPE PWR SUPPLY 31.5 540 1908 6495 30000 270000 6.98 3 1.19 /2A or 24V/2A Kvins 1NPT 115V /60CY. Outpt 1800VDC 37 550 1909 6500 31000 275000 .65 3 6.98 /35MA 48 560 1910 6800 1 .75 1.29 using Voltage DOLE Circuit Incl. Trans.. 31500 294000 1.49 SELENIUM POWER Rectifiera, Sockets, Resistors. 50 575 1911 6840 32000 300000 2 5 Condensers 51.78 580 1912 6990 3 1.08 44000wvde8 15 3.98 SUPPLY Diagram $6.95 33000 307500 4 1.89 2 8.98 55 588 1913 7000 35000 311000 3000wvdc 25 , PÒ w. 0.12 VDC /2amps. Un- 56.7 600 1914 7320 36000 314000 5 1.98 4050äe49/ cased DYNAMOTORS 60 612 1915 6 2.69 2 4.49 120040 ))))BlIY" & completely -1115 DM4 12 &24V out 225V/100ma, 7500 37000 316000 7 2.89 2 10.98 440V/200ma ...$11.98 63 620 1916 7700 38140 325000 4 19.98 1 BOOva1.29 VAC input. Usable for lab, filament DC, 68 625 1917 7717 38500 330000 10 Plating, batt charging model railroad. In- DA3A 28V/10.5A out 300 VDC /260ma, 74 633 1918 7800 39000 333500 2x.1 3.29.79 7000wvdc 1800de control /center 150VDC /1Oma, 14.5 /vdc S 6.75 1.69 16 6.98 cludes voltage speed w ... 75 640 1919 7930 39500 350000 2x,25 .85 .002 off reversing witch. Ideal for two HO" PE94 W /DYNA DA3A. (S 522)... 8.98 80 641 1922 7950 40000 28.5 .90 .0075 1.98 660vae/ locomotives. Special $10.95; 2 for $20.00 Inet 6V outpt 200V /1OOMA 3.75 353500 2x1 1.19 .1 4.98 2000de Inpt 28VDC /60MA 3.95 81.4 645 1924 8000 41400 375000 5 449 outpt 250V 88 649 1926 8094 42000 380000 2.98 CABLE 95 650 1960 8200 43000 390000 2x8 3.49 .03500w 6 4.98 CONNECTORS AND SELSYNS 100 38.05 .89 05 3.49 10 6.98 UG9 /1./ ..$1.90 Uß27 /U $1.25 657 1980 8250 43000 400000 10000 mode 7.98 ',II7 2JIHI GE 9ele2n. 101 665 2000 8500 47000 402000 3x.22 .98 16 UG19 /U .. 2.20 UG106 /U .14 2 for 103.2 670 2045 8700 47500 420000 2M1D /330VAC /1000WVDC "CD" END CAN 1.1021 /U .. 1.20 UG254 /AU 3.40 2J1F3 GE Brand 105 673 2080 8770 48000 422000 3 for $1.00 12 for $3.50 UG22 /U .. 1.60 CW123U .55 400cy ea. 9.75 105.7 675 2095 9000 48660 425000 9MFD /220VAC /600VDC $1.00: 12 for $10 ÚG24 /U . 1.50 M359A . 75 C78249 'yue.Diff, 115V /6Oey. .2 for 25.00 107 680 2141 9100 49000 430000 Quantity Users. Write for Special Price 831R/S0299 Receptacle, 50e; 10 for 3.90 C78248 rang 115V/6OCy.2 for 29.95 110 681 2142 9445 50000 450000 831SPN /PL259A Plug ..65e; 10 for 5.50 Synchro RepeaterRepea ter 115V /605y Type 120 684 2145 9500 51000 458000 MODEL HF -I OSCILLOSCOPE 831SP/PL259 Plug 50e; 10 for 4.75 11-4 Brand New @ $32.50; 2 for 59.50 121.2 689 2150 9710 52000 470000 Laboratory Features, 5 M C 83- 1J /PL258 Junction .95 Rendis Autnsyn AYl & ÁY5...2 for 4.95 125 697 2160 9800 55000 472000 Bandwidth, 1OMV Sena PP CD307A w /JK26 & PL55, 5 Ft 1.09 C69405.2 Trans Type 1 -1 130 699 2180 9900 56000 478000 Morie & Vert Amp., Cathode RG /SU Coaxial Cable. Per Ft .12 New 527.50; 2 for $5.00 135 700 2187 9902 57065 500000 Coupled Multi VII) Swp, Int R659Ú Cable...Per Ft. /.08; 1O0 Ft 7.00 147.5 711 2195 10000 58333 510000 Retrace, Cathode Flwr Inpt 300 Ohm Twincx; Durable Hvy Web 150 733 2200 10430 60000 520000 1 Write for Vert & Hurls Amp, Non -Freq 100 Ft. 51.80: \1 II_ 16.00 TAB OGRAMBaroain Sheet 160 740 2250 10500 61430 521000 Dlscrim Gain Cntrl, Cal Com- 165 750 2300 10600 62000 525000 pensated tt "TAB" TESTED 725A 170 800 2400 10900 64000 543000 g I ror Extrnl c In- 726A 175 806 2450 10936 65000 550000 built Cathode F'Iwr for Sig & GUARANTEED 7268 . . . 59.95 179 820 2463 11000 66600 560000 Tracing with Phones, Tech. 726C ...69.95 180 850 2485 11400 66650 570000 Manual. 13 Tube. I. Me up. 800 1.85 182 854 2490 11500 Write for Complete .45 67500 575000 3 -6(14. 4-6465. 2 -it \G7, 8O1A .. 182.4 899 2500 11690 68000 600000 13 Tubes, Listing. (Prices Sub. 803 3.89 All Data Diagrams. jest to Change) 200 900 2525 12000 70000 620000 Including 38P1 Cray Tube. . TUBES 804 11.50 209.4 910 2600 12500 72000 650000 805 3.90 210 917 2625 12800 0A2 .98 6AB7 /1853 1.39 65F5 . . .89 F123A 7.90 807 1.65 73500 654000 A "TAB" SPECIAL only $99.50 0A3-VR75 1.23 6ACSGT 1.09 65F7 . .89 T125 . . 12.49 216 946 2635 13100 75000 660000 .. .. F127A 19.98 808 2.98 220 978 2700 13500 80000 680000 0A4G 1.45 6AC6G ... 1.49 65G7 .. . 1.39 809 2.43 220.4 1000 2750 13550 82000 690000 UHF ANTENNA 082 1.37 6AC7 .... .99 6587 .. . .99 VT127A 3.90 810 9.95 225 13B3/VR90 1.09 6A1360 .98 65J7 . .89 CV148 4.98 1030 2850 13600 84000 700000 UHF ANTENNA 12" /30CM AT5 /ARR1 Us- .. FG166 49.00 811 2.90 230 1056 2860 14000 85000 750000 & Ham Band Ins Coax Term Silo 0C3/VR105 1.19 6A070 ... 1.49 65K7GT . .89 235 1059 2870 14250 able Cit.= OD3/VR150 .98 6AF6G ... 1.33 65L7GT . .89 FG172 . 31.50 813 12á9 85750 761300 PI Cont Wpf Cask & H'ware Mobile Mtg. 183/8016. .83 6AG5 .89 6SN7GT 79 250TH 22.25 814 240 1067 2900 14400 88000 800000 New 39c; 4 for $1.00 .... 6SN7WGT. 2.25 25071 18.50 245 1100 3000 14500 80000 813000 PL259 for above .65 6AG7 .... 1.99 13 2.98 245.4 1110 3100 14550 91000 820000 185/255 . .99 6AH5G . . 1.49 6SQ7GT . .79 HK254 14.49 1.07 MICROWAVE ANT AS125 /APR. 1000 to 1B7GT .99 304TH 8.90 816/866Jr 250 1150 3163 14600 93000 850000 340011c w /UG58U Term InBUtit HiPass 6AH6 .... 1.99 6587 .95 260 1155 3259 15000 93300 860000 1821 471A 2.85 6AJ5 ... 1.40 557 .... 1.12 8.90 829 11.49 3290 16000 110 Flange Mtg Intl H'ware $5.98 . . 313CL 2.98 270 1162 95000 900000 1.98 1822 2.20 6AK5 .90 6577 1.33 8296 12.45 271 1200 3300 16500 100000 910000 ANT AN130B, 33" Whip 1823 9.90 6AK5W .. 2.98 6Su7GTY . 3.37 GL434A . 29.95 830B . 275 1225 3333 16800 110000 930000 Sectional Antennas 1824 17.49 6AK6 .... 1.49 6V6 2.25 446A . 1.05 832 7.65 51549.52, /.2 . . 950000 121 ft. $1.69 1626 2.45 6AL5 . .69 6V6GT .69 446B 3.89 832A 9.65 MS49 -53, 16 ft. 2.49 450TH . 44.00 Any Size Above, Each035e; Ten for $3.29 1827 14.98 6AL7GT ,. 1.29 6W4GT .69 833A 39.45 MEGOHMS BASES: MP22, $3.88; MP47, MP48 3.85 1832/532A 3.90 6AN5 .... 2.90 6X5GT .75 450TL . 52.00 834 5.95 1835 10.98 6AQ5 .59 6Y6G 1.27 460/ 4.75 1. 1.579 2.7 4 6.7 10 HF200 15.95 836 1.1 1.65 2.75 4.23 7 11.55 RHEOSTATS 1837 . 6AQ5W .. 3.98 12AH7GT 1.45 837 3.45 1.2 1.75 2.8 4.25 29.95 12AK5 1.98 WL468 . 13.95 838 3.98 7.5 12 GL471A . 2.69 1.25 1.8 2.855 4.5 7.62 12.83 6AQ7GT .. 1 19 12AK5W. 2.98 843 .39 1.3 3 18841 49.95 6885 .79 12AL5 1.11 GL530 . 22.00 5.95 1.9 5 7.74 13 ... . 845 1.35 2 3.3 5.1 8 13.85 1842 18.00 6AR6 .... 2.98 12AT6 . .59 CK501X 1.26 849 29.45 1B46 12877 .93 CKSOIAX 1.26 852 19.98 1.39 2.11 3.5 5.5 8.02 30 1B53 12AU6 . .89 GL502A 1.79 4.90 1.4 2.2 3.673 6 8.5 51 49.95 61156 .... 2.79 CK502AX 1.79 860 1.5 2.25 3.75 6.5 9.05 1656 . 38.50 6A570 ... 4.35 12AU7 . .74 861 23.95 2.5 3.9 2 ohm 50W Ohmite S2.59 1E158 ..350.00 6AT6 12AV6 .69 CK503AX 1.79 864 .39 6.6 1.98 .2 1.35 CK505AX 1.79 Any? Size Above, Each 70c: TenSfar $6.49 6 ohm 25W Ohmite 1860 69.75 6AU5GT .. 1.49 12AV7 CK506AX 1.79 865 1.29 15 ohm 25W Ward L 1.98 1863 50.00 12AW6 . 1.79 866A 1.50 NEW THRIFT -LITE 15 ohm 75W Ohmite 3.74 1863A 75.00 6AVSGT 1.29 I2AX4GT . 1.20 RH507 9.98 868/CE1C 3.49 --" 2.35 .. CK509AX 1.26 20 ohm 50W Ohmite 2K25 39.95 6AV6 .59 12AX7 CK512AX 3.15 869 36.95 Lifetime Photo -Flash 60 ohm 50W Ward L 2.69 2K25/ 6AW6 . 1.89 12AY7 . 2.95 872A 3.29 Not a kit. Inc! Pwr pck 2.25 12AZ7 . 1.49 CK522AX 2.49 1.39 100 ohm 50W Ohmite 723613 39.00 6AX416U4. .79 CK525AX 3.15 874 Life gtd Lamp. Rfletr & 151 200 ohm 25W Model D 1.98 2K28 32.00 6AX5GT .. .79 12BA6 . .79 878 1.95 cord 1 /1000 Sec flash every 5.00 12BA7 7 9 CK526AX 3.95 1.80 250 ohm 25W ea. $1.39; 4 for 21(29 23.95 684G . 1.59 CK528AX 2.39 884/6ß5G 7 sec. True daylite color. 300 Ohm, 200W Model 5.49 21133 12006 . 1.75 885 1.45 [i Usable cameras Oper P...... 300.00 128E6 89 CK529AX 2.98 5.98 all 350. 500, 5000 ohm Slotted shaft 2K43/8 ...118.00 6BA7 . 1.27 CK531DX 1.98 5516 . 1I5VAC w /lite Type AC40 25 Watt 79c; 3 for 2.00 2C3 6BC5 .. .69 128E6 . .85 531 6.98 5517 . 3.39 1.,1111 $41.98 1000 ohm Type J Ohmite 2.19 RX233A. 3.49 68C7 . 1.23 1281.17 . 1.29 Complete Outfit for AC & Battery ogre Intl CK532DX 1.98 . 5.95 7500 ohm 50W Model J 2.59 2C34/RK34. .69 68DSGT .. 1.65 12BY7 . 1.35 WL532 3.98 5608A AC4O&BP25 p rpakm & all ac s for KO- 2C39 33.98 6BD6 .89 12BZ7 . 1.25 CK533A1( 1.39 5637 7.15 MPUR Shutters Complete. ,569.95 68E6 .79 FG17 . 3.95 5638 for Complete Data END EQUIPMENT BUYS 1.79 CKS34AX .89 Write TG5 Keyer. New $ 5.98 2C40 JAN 19.90 69E5 .. 1.06 1980631 . .89 51 . 13.05 Boosts Est liter, Units for Focal . . 1.09 CKS36AX . 2.95 NEW 12.98 2C43 26.75 613F8 .. 1.49 1978 5654 plane shutters. hutters & accessories. RM29 Control Unit. BRAND CK537AX 4.98 . 6.90 R59 /TPS3 Good, As Is, Less Tubes 29.98 2C43/464A 9.49 6BF7 .. 2.55 CK5380X .89 5656 2C44 1.20 68060 1.65 238Q6GT . 1.19 5663 . 1.85 TAB "SUN- FLASH" LAMPS 1 -81 Compass Indicator, Like New 7.95 ... CK539DX 1.98 5.98 1.82 Compass Indicator. Like New 4.95 25L6GT CK541DX 1.98 5670 "Tab" W -Sec. 2C51 6.45 BBHB 1 89 2525 .79 CK5672 2.29 No. Replaces Each PE97 Plate Supply Unit, Less Tubes 9.98 ... 2526GT 99 CK542DX .98 CK5676 2.29 Max. 1 -108 Range Calibrator. Metal Case. 29.98 . . CK543DX .98 2.45 U10 GE FT114 100 5 9.98 1.198 Sig. Gen, Good Cond, Less 4823 16.98 6BK7 . 2.1 5 FG27A 8.70 CK544DX CK5678 ,1I No. I AMGI.O 5804X 100 10.98 . 14.98 Tubes 14.95 6BL7GT.. 1.45 HV27 .10.95 CK546DX 1.98 5684 . 23ST GE FT210 200 10.98 As 1.98 4C25/HK54 5.98 6BN6 .... 1.49 RK28A . . 4.89 5686 . 3.90 53GT GE FT403 500 16.98 BC456 Less Tubes, Dyn, ls 59.00 2807 ,. . 1.39 CK547DX 1.98 5687 5.75 SCR595 IFF, Less Tubes. As Is 3.98 4C33 FG32/ CK571AX/ 5692 7.69 VA SYLV. 4330 200 11.98 BC605 Amp. Less Tubes, As Is. 3.98 4C35 27.00 6BQ6GT .. 1.29 5886 4.98 7.69 23MT FT214 250 10.98 BC906 Freq. Mtr., exc. coud 29.95 687 .... 5558 .13.85 CKS73AX/ 5693 . 225T FT110 200 10.98 4E27/257 14.50 68V5G . , 1.45 3SL6GT .79 5694 3.65 A Sig Gen, 115V/60 Cy 125.00 . 6029 4.45 5.98 353GTQ FT503 5000 54.98 4J22 ....148.50 ELBC ....16.98 3SZSGT .59 . CK5697 EC221 Sig Gen. Exc. Cond 125.00 455/VT52. .65 WL676 39.95 CK5702 7.45 V454 /0400 200 12.98 SCR522A Less /Xtals w 69.95 4J31 95.00 6C21 ....29.45 W L686 . . 35.00 Power Packs External Light and Complete /Tubes 4J34 ...194.00 45Z3 . .8 9 CK5703 .98 of 707A CK5704 . 4.39 Line Accessories. Write for Data. 4J47 ..260.00 6CD6G . . 2.49 45Z5GT .89 RK48A 5718 .. .10.15 STORAGE BATTERIES 4J47C .198.00 71011/80i1 17.95 .12.75 PHOTOFLASH CAPACITORS Volt WII.I.ARD -BRAND NEWS Port- 4J52 350.00 C6J/5C21 . 6.95 50L6GT . .69 5719 .. 36 Mint 80 .69 713A .... .98 4.39 2x.36MFD Total 72MFD Per Unit. 30 able Equip Models 98c; 4 for $3.00 5C21/C6J. 6.95 6J4 7.65 NL714 ... 5.95 Units 21.6MFD 1800VDC /38.8 W. 2V /20AH Willard PLUS 2V. Vibrator. 2.39 5C22 .52.50 6J5GT .59 1.69 714AY ... 5.90 5744/ 6.49 95 6V /6AH Willard NT6 /BB214U 1.98 5C30/CS11. 3.95 6.16 V18 16 3.90 CK619CX 82 1.19 715A .... 6.45 5749 . .. 3.39 Units 21.6MF1/3000VDC 30 64.8 W. 6V /40AH Willard 6.98 5021 27.45 6J7 1.09 715B .... 8.90 5751 5.45 7.95 Battery Acid. ;It -Lxp) I pt. 59e; 2 pts .98 51323/ 618G 1.19 82V 1.39 715C ....29.85 .... Save on Replacements, Details 1.06 1.24 Sp Gray 1.98 36.50 1.45 5763 ... 1.70 Write far Hydrometer to RK65 61(4A 6.45 21, 1.79 717A .... 1.49 CK5783.. 6.69 15MFD /330VAC /1500VDC Intermit.. 3.98 Spec Gray Ind & Mere. Thermoitt .98 5J29 12.40 6L6 7188Y ...48.45 .. 7.40 25MFD /330VAC 6.49 5R4GY 1.80 LG 1.69 84/6Z4 . .99 CK5784 /1500VDC Intermit.. VR92 . .25 718CY ...48.45 16MFD /600VAC /2800VDC Intermit.. 6.95 5R4WGV 1.75 6L6GA . 1.69 7196 ....49.95 16MFD /660VAC /3000VDC Intermit.. 7.95 1.59 2.29 Fß95/ . 5814 PLATE TRANSFORMERS 6A3 6L6GAY 5560 721A 2.49 750VCT/650MA W /SOOV TAP 6A4 1.89 65A7GT . .89 .24.85 722A/287. 2.45 CK5829 PHOTOFLASH PWR SUPP KIT . Fß98 . .19.95 Hmsld $10.95 6A5G 2.39 6SA7GTY 3.37 1800 VDC at 35MA, using oltage Dblr 1100VCT /212MA PRI. 115 or 6A8GT 1.09 6587Y 1.19 100TH . . 8.89 7236/8 ..25.00 CK5851 .. 4.98 Circuit. Trans., Rectifiers, Sockets. Reaiet- 8.50 . 230V Cad 6494 .79 6SC7 1.39 Fß104 .37.98 724A .... 3.95 CK5875 .. 1.98 Condensera, W/Diagra & Flash Tube 15000 AS V'dblr WE. SIG Fß105 . 18.98 385629 /7500V /35MA 19.95 6A65/685 1.33 65D7GT .99 7249 .... 3.45 5881 .... 2.89 V IX4, X400. Inpt 115V/ 60/T. $31.98 3000V /10MA Cad WE161913 Hvins 8.95 Money Back Guarantee 5500VCT /6SOMA USN Wstghs TTHAT'S (Cost of Mdse Only) 69.95 THAT'S 55 Min. Order FOB Csd NYC. Add Sheg Charges 866A KIT AND XFMR BUY 6 25% Dee. Tubes 2 Tubes. Sekts & Xfmr 115V BOry BUY "T A B Old. via R-Exp. only. Sept. Output 2.5VCT 10/imp iii. CORNER CHURCH 8 LIBERTY STS. Prices Nnt DEPT. 8RN, 200 Without Photos Volta Insulation $6.98 SIX CHURCH ST. NEW YORK 6, N .Y., U.S.A.. ROOM REctor 2.6245. 142 PRINTED I` U.S.A. BABIO & TELEVISION NEWS

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