Ei.Iiic 111011111:S Television Servicing High Fidelity

Special Full -Color Section: Color TV Adjustment MAY 1954

EI.IIIC 111011111:S TELEVISION SERVICING HIGH FIDELITY

In this issue:

Markers and Alignment Bugs

For Golden Ears i

Transistor Phono Oscillator

Using the V.T.V. M.

in TV Servicing

35 U. S. and CANADA Components for Color TV Receivers (See page 4) www.americanradiohistory.com draw a bead on quality...

IF YOU'RE IN TV SERVICE FOR KEEPS

Television service is big busi- 344 ness -one of the fastest growing in the nation. If you're shooting for all the marbles and aiming for the secure future TV service provides, remember today's service builds tomorrow's reputation. As in any big business, the strongest foundation for the future is a reputation built upon sound technical and business methods. In TV service, it's good business to back up your highly specialized workmanship with the highest quality replacement parts. You can depend on Du Mont quality picture tubes to do more for your service.

photo by Rob-lit R. Lou] - From PHOTOGRAPFY ANNUAL

Replacement Sales, Cathode Ray Tube Division

Allen B. Du Mont Laboratories, Inc., Clifton, N. J. PIONEER IN BIG PICTURE TUBS! ORIGINATOR OF THE FAMOUS BENT-GUN AND SELFOCUS 'T vd 3-Mark LEADER IN HIGH -RESOLUTION ^ M4JOR SRI.PPLIER TO MOST FINE TELEVISION RECEIVER MANUFACTURERS www.americanradiohistory.com 3

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I. E. MITI. Pt;fi)iresi Get Practical ll$IIdNSI kale IIIáiNde vsi l.os*a L C. has trained mom met Experience on Circuits for Redle- Teletisox than any other non Common to Radio & TV OUR 40TH TP/CR. Eva think HOW FAST F_.adie- Television Communications is chanFag. developing. arowivgt Have you considered what this amazing progress can mesa to you' Even without ' elevision he industry 4 bigger than ever before. C -er 115 million home and auto radios, 8014 radio stations, shout 200 TV sts ions wit! hundreds more being built. Expaiding use of Aviation and Relay. Two- onrt. hat i' Police Radio, Micro-Wave Operstae, buses, tais, etc. makes Radio Radayr. er as Way Radio for increases the value MEASURE current. opportunities for Comrntsdcations Tech- my course maSerniaes- YOU BUILD YOU operators. New of knowledge. and RF), ree nicians and FCC licensed your this Transmitter Powe- Supply voltage (AC, DC jobs more jobs for beginneisl Better jobs, impedance in cin used in the basic experiments in siatance and Imam pay for experienced men! Developments cuits wilt Electronic Multi. Includes New RF ant AF amplifiers,f-eauency now for faeti about my build. Slows how Television Is Today's Mail coupom multipliers, buffers. etc. tester you practical course in Radio-Televisian Com- basic transmitter circuits be- Good Job Maker Le: me send you my FREE munications. cf Parta I have; needed to maintain sta- Over 25 million television Beta are In use. book. See the rein big Kits to life" theory you learn, tion operation. Thousands more being ecli every week. send that "bring Good TV jobs o -/err Technicians; You get pracaizal experience by working Operators everywhere. The time to act is on circuits ommon to both Radio and NOW! Start learning Radk -TV communi- Television ; also lessons on TV arinciples. eatioae. Americas fast growing industry Read about the Transmitter you build and offers good pay, a bright future, security. operate. about the Electronic Multitester if you are a beginner, my course can help you get. All equipment is yours to keep, you get FCC Ltoenae. prepare for the job My graduates are filling jobs, making good money is both Radio and Television. NArI a successful career in YOU wit Remember, the way to PRACTICE setting up code, SERVICING TRAINING Television is titre+ugh experience in Radio. amplitude and frequency modu- YOU ALSO AVAILABLE lation circuits (put vent*. music. BUILD this Wá meter and Mail Coupon for Book FREE a -pay in Radio- signals" you use it to determine frequency If you prefer good job Send today! See what my Communies. etc., cn "carrier . . or your own make ether testa Televieion Servicing tions course ïe like. Find out bow I get produce). You learn how to of operation, money- making Radio-Television Sales future, better currents. you at home. you ready fer a brighter get best performance. en transmitter and Service Shcp, VII train more security in Radio-Televi. My famous Servicing Course also in- earnings, sion. Send con:-pon now in envelope or paste cludes many Kits of Pits. You use NO SALES- to PitACTICAL EXPERI- on postal. NO OBLIGATION, them get I sert to you Training Leads to Jobs Like These ENCE with circuits common to Radio MAN WILL ^_,ALL My book, to FREE, tells the full story. J. E. SMITH, COVERNMEINT AVIATION RADIO and Television. I also eh-m you how National BROADCASTING Plane 'Radio Operator make $10, $15 a week or more EXTRA President, Dept. 4EF, Chili Technician RADIO Washington 9, ID. Oap Chlor Operator Cperator in A.M. MONEY fixing neighbors' Radios Institute, Operator Power Monitor Navy, Marino Corn. while training. Full info-station in my 40th year. Roca-dine Operator Coast Guard TELEVISION Fd -wage book ... Mail coupon. Rem.te Control Operator Forestry Sella Pick -Up Operator HARBOR Dispatcher Voice Transmitter SHI? AND Airways Radii Operator Operator RADIO Technician Chia' Operator POLICE RADIO TV Operator Transmitter Rs LT al NAM #01V-80041FREE Radllotele0 ns Operate, Service Operator r Mt. J. E. SMITH, President, Dept.,,4EF, National Radio Institute, Washington 9, D. C. salesman I TRAINED THESE MEN NI lit me your 64 -page Book, FREE. (No am trchnleian at will! call. Please write plainly.) "My position asti WNBT i'. "I ,neineer on RTOP in Wallington and is video control much. DI.st the RCA color protect. I I like it very Name Age to of my radio knowledge orna owe a ext tad messes Brut your Warren from N.R.I ' -.lohn Deem, Malvern., N. Y. to, Hyatt stil é, J1d. Address "A former employer reem- Zone. State AVAILABLE 10 mended N.R.I. traintrg. City Now employee_ as transm.nt- write in date ter operator at W1{RO" VETERANS -Albert Herr. New Cum- VETS of discharge UNDER G.I. BULLS berland. Pa. L.

www.americanradiohistory.com 4 RADIO E LEI: I RINKS Formerly RADIO -CRAFT Incorporating SHORT WAVE CRAFT TELEVISION NEWS RADIO 8 TELEVISION Hugo Gernsback CONTENTS Editor and Publisher MAY 1954 M. Harvey Gernsback Editorial (Page 31) Editorial Director Atom Electronics Fred Shunaman ...by Hugo Gernsback 31 Managing Editor Television (Pages 32 Robert F. Scott -46) W2PWG, Technical Editor Markers and Alignment Bugs, Calibrating the marker generator; marker Jerome Kass injection; the zero -volt reference line Associate Editor by the Engineering Staff, Scala Radio Co. 32 I. Queen Reconditioning Picture Tubes Editorial Associate by John E. Ledbetter 34 Adjusting a Color TV Receiver Matthew Mandl 35 Color Receiver Components Television Consultant (Cover Story) . 39 Basic Color TV, Part IV Charles A. Phelps (continued) I and Q Signals; summary of the features and techniques Copy Editor of the NTSC system. by D. Newman and J. J. Roche Television 40 Angie Pascale -it's a Cinch (Tenth Conversation, 1st half -The composite video Production Manager signal) . by E. Aisberg 42 Wm. Lyon TV McLaughlin Service Clinic Conducted by Tech. Illustration Director Matthew Mandl 45 Sol Ehrlich Test Instruments (Pages 47 -57) Art Director VTVM Applications in TV Servicing by Robert U. Middleton 47 Sine and Square Wave Generator by P. N. Markantes 50 Lee Robinson Use a Phonic Signal Tracer General Manager ...... by Vergniaud H. Richard 52 Double -Beam Scope Switch John J. Lamson ...... by T. W. Dresser 54 Relative Field- Strength Sales Manager Meter by Hilton L. Remley 56 G. Aliquo Circulation Manager Audio -High Fidelity (Pages 58 -73) Adam J. Smith For Golden Ears Only Director, Newsstand by Monitor 58 Sales High -Quality Audio, Part Robert Fallath IX- Design factors of triode and pentode resistance- coupled amplifiers Promotion Manager by Richard H. Dorf 61 New Standard Record Curve Servicing High -Fidelity 63 Equipment, Part IV- Frequency test records; test instruments for audio work by Joseph Marshall 64 R -J Type 12 -Inch Speaker Enclosure r by J. W. Korte 68 Radio (Pages Member 74 -101) Transistor Phono Oscillator Magazine Publishers by Edwin Bohr 74 Association A Low -Cost CD Mobile Radio . ...by Eli Nannis (WIHKG) 78 M ultivibrators by Ed Bukstein 84 I.F.-R.F. Crystal Oscillator Uses Junction Transistor by I. Queen 92 Identifying Tube Types from Damaged ON THE COVER (More de- Etchings by Hector E. French 96 Radio 35 Years Ago tails on page 39) 101 Some of the more important New Design (Pages 104 -107) (and expensive) components New Tubes and Transistors which distinguish a color from 104 a black- and -white set. From left Departments to right-deflecting yoke, shad- The Radio ow mask (part of the picture Month 6 Question Box 18 Technotes Business .... 136 tube) and purity coil. At rear 12 Try This One 124 Correspondence With the 138 -for purposes of size compari- New Devices . 128 People Technician 142 son -model Sofia Fransella. 108 Radio- Electronic Electronic New Patents I 12 Circuits 132 Parts from RCA tube department, Literature . 145 Color original by Habershaw Studio Book Reviews 147 e

MEMBER Audit Bureau of Circulations Vol. XXV, No. 5

Average Paid Circulation over 169,000 RADIO- ELECTRONICS, May, 1954, Vol. XXV. No. 5. Published monthly at Erie Ave., Class matter September 27, 1948. at F to G Sts.. Philadelphia 32. Pa., Gernsback Publications, the Post Office at Philadelphia, Pa., under the Act of March 3, 1879. Inc.. Entered as Second must not lie reproduced without permission of copyright owners. Copyright 1954 by Gernsback Publications. Inc. Test and Illustrations EXECUTIVE. EDITORIAL and ADVERTISING OFFICES: 25 West Broadway, New York 7, N. President; M. Harvey Gernsback, Vice -President; Y. Telephone REctor 2 -8630. Gernsback Publications, Inc. Hugo SUBSCRIPTIONS: G. Alloua, Secretary. Gernsback, Address correspondence to Rarlto- Electronics, Subscription Dept.. Erie Avenue, F When ordering a change furnish to G Ste., Philadelphia 32, Pa., or 25 %Vest please an address stencil impression from a recent wrapper. Allow one Broadway, New York 7, N. Y. SUBSCRIPTION RATES: In U. S. month for change of address. and Canada, and in U. S. possessions, $3.50 for one year; $6.00 for two years; $8.00 $4.50 a year: $8.00 for two years; $11.00 for three years. for three years; single copies 35d. All other foreign countries BRANCH ADVERTISING OFFICES: Chicago: 7522 North Sheridan Road, Tel. Rogers Park 4 -8000. Los Angeles: Ralph W. Harker and Associates, 1127 Wilshire Blvd., Tel. Co.. Ltd.. London E.C.4. Australia: McGill 's eadeBladPressAtlas Agency, Melbourne. France: íß enano's l Parlo 2e IBelgium: Agence et Messageries International News Brussels.PublishingHolland: Tellectron, burg sMMiddle East: Stelmatzky Middle Natal. k3. East Agency, Jerusalem, India: Broadway News Centre,e Dadar, Bombay #19gß If undeliverable send form 3578 to: RADIO- ELECTUONIC8, 25 West Broadway, Pakistan: Paradise Stalle Karachi POSTMASTER: New York 7, N. Y. *Trademark registered U.S. Patent Office. RADIO -ELECTRONICS

www.americanradiohistory.com 5 LDVANCE! Raise your earning power-learn ADIO TELEVISION-0 ELECTR iJNICS by SHOP.METHOD. PHASES: 41.1.A Get Mosier anin9 c- N I No Es.obisledPo TR.AI N # *HOME on School f Il cal Resident Trann9 GOOD JOBS AWAIT THE -ts ; off 1.with SnSO TRAINED RADIO -TV TECHNICIAN -- almost tf1en There is a place for you in the great Radio- Television- StudiosTroinln5 AsnbitiousOlO{ ! National Electronics industry when you are trained as Laboratories, 1f t Schools will train you at home! Shops, Experience ` SavoD Trained technicians are in growing demand at good pay tiOss° communica- N° -in manufacturing, broadcasting, television, W e Bring .T. tions, radar, research laboratories, home Radio -TV service, and other branches of the field. National Schools Master Shop- Method Home Training, with newly added lessons and equipment, trains you in your spare time, right in your own home, for these fascinating opportunities. OUR METHOD IS PROVED BY THE SUCCESS OF NATIONAL SCHOOLS TRAINED MEN, ALL OVER THE WORLD, SINCE 1905. You also EARN WHILE receive this Many National students pay for all or part of their train- Multitester ing with spare time earnings. We'll show you how you can do the same! Early in your training, you receive "Spare - time Work" Lessons which will enable you to earn extra money servicing neighbors' and friends' Radio and Tele- vision receivers, appliances, etc.

Superheterodyne Receiver

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www.americanradiohistory.com THE RADIO MONTH

TRANSISTORIZED MICROPHONE HIGH COST OF TV broadcasting developed by the Army Signal Corps was seen in the recent rent increase eliminates the frying sound of the old proposed by the Empire carbon State Bldg. microphone, while fitting into Corp. to the seven New York television the plastic handle of the carbon model. stations. The rent increase, from $70; The Remler Co. is making a commercial 000 to $200,000 per year model per station, of similar design. would be for a five -year period begin- The transistor element, second from ning May 1, 1954. the right The renting pricf; in the foreground of the photo- carries only the right to use the build- graph, is extremely rugged and easy to ing's mast as a common assemble. transmitting Next to the transistor ampli- antenna site; floor space in the fier are the building handle switch and rubber for transmitter equipment, offices, etc., cover used in the old and new models. must be rented separately.

Public Address Loudspeaker System setting new standards No for modifications are necessary in ex- EIGHT NEW STATIONS have gone VOICE PENETRATION isting radio equipment to operate the on the air since our last report. These microphone. It can be plugged into any are: AND MUSICASTING in jack which a carbon mike was used. KSAN -TV San Francisco, Calif. .32 In addition to Greatly outperforms comparably sized the noise reduction fea- WINK -TV Fort Myers, Fla. 11 reentrant horns ture, the higher quality of reproduction KDAL -TV Duluth- Superior, Minn 3 Tremendous makes it easier penetrating power and for the listener to rec- WDSM -TV Duluth- Superior, Minn 6 coverage at very low unit energy cost ognize a familiar voice-an important WMUR -TV Manchester, N.H aid to 9 Exclusive E -V coaxial design and security in battle. WTRI Schenectady, N.Y 35 diffraction principle WAPA -TV San Juan, P.R. 4 Peak -free response 5 db to 10,000 cps KFBC -TV Cheyenne, Wyo. 15 KC 5 Delivers 2'/ octaves more musical range MODULATION of AM broad- Vermont is now the only cast stations is permitted state with- Weather -proof, blast -proof, splash -proof providing it out a TV Station, but Montpelier does not cause interference with now Virtually indestructible other has a construction permit for channel 3. stations, according to FCC Commis- Model 848 CDP. 25 watts. 16 ohms. Two more stations have gone off the air sioner George E. Sterling. Speaking be- List Price, $65.00 this month, WIFE, Dayton, Ohio, Net, $39.00 fore the Hi -Fi in chan- Fair Washington, he nel 22, and KFOR -TV, Lincoln, Neb., COMPARE pointed out the growing interest in high channel 10. POLAR PATTERN fidelity and stated that good reproduc- Sound distribution tion is "a challenge to the broadcaster." of CDP exceeds 120° Sterling stated the EAVESDROPPING at all frequencies up high cost of 15 -kc on rural telephone to 10,000 cps. intercity lines is the major obstacle to Party -line conversations may soon be- high -fidelity networking, come a thing of COMPARE and that he the past. Bell Tele- RESPONSE AND hoped listener pressure will force in- phone engineers are experimenting near EFFICIENCY creased use of better lines and terminal Americus, Ga. with a transistorized Note extended high equipment. telephone system that will permit sev- frequency range of eral conversations to CDP. Response is be carried over a smooth, peak single line without mixup. -free PIONEER ± 5 db to 10,000 cps. FM STATION CLOSES. The principle is already used on KE2XCC (formerly W2XMN), the first long- Write for Free distance telephone networks, but FM broadcast station in the U.S., shut until the transistor was Bulletin No. 197 down developed, it operations on March 6. Erected by was uneconomical on a local basis. the late Major Ellwin H. Armstrong, When a call is made, the conversation the station has been broadcasting music, will be transmitted without on the line at one SmieeZ- acz commercials, since 1938. The frequency. If a neighbor who shares station was completely financed 421 CARROL ST. BUCHANAN, by that line decides to call at that moment, MICHIGAN Major Armstrong and acted as the Export. 13 E. 40th St., New York 76, U. S. A. Cable: Arlab lab- her conversation will be carried on oratory for most of his experiments. another frequency. RADIO -ELECTRONICS

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MAY, 1954

www.americanradiohistory.com THE RADIO MONTH 81 BETTER BUSINESS BUREAUS PURE has throughout GERMANIUM been devel- the country have become oped by Bell Telephone Labs. Using a interested in "midget wonder" TV newly developed method, germanium (2.1147.4. "antennas" similar to those shown in has been refined to a purity in excess the photo. A report by the New York of 99.9999,/, . A substance this pure City bureau indicates that tests made may very well be the purest material by laymen are likely to be rather in existence. inconclusive, but that probably the The new method, known as zone - TUNÖ-SOL average user would get results of a melting, is based on the fact that im- somewhat similar nature with a piece purities are not equally soluble in the PICTURE TUBES of ordinary wire about the length of solid and liquid states of a substance; the lead on the new "antennas." usually, impurities are more soluble in Destructive tests by RADIO- ELECTRON- ICS on two of the dozen or so models advertised would tend to back up that conclusion. In one model (top one in photo) the wire was terminated inside a hard plastic hollow disc by being pushed loosely through (not soldered to) a small square of copper wire

Gun made of best grade non -magnetic the liquid. To take advantage of this, steel. a narrow molten zone is moved slowly along an ingot of relatively impure Glass bead type assembly is stronger material both mechanically and to "sweep" the impurities to electrically -gives one end of the ingot. greater protection against electrical leakage. The behavior of germanium transistors is affected critically by the pres- Rolled edges in gun minimize corona. ence of impurities; but the kind and amount Custom built stem with greater spacing of impurities must be rigidly controlled. By between leads assures minimum leakage. refining an ingot of germanium to a near -perfect state of pur- Lowresistance of outside conductive ity by the zone -melting process, its elec- coating minimizes radiation of horizontal trical properties can then be altered oscillator sweep frequency. to the desired degree by the controlled screening. A piece of soft plastic mate- Double cathode tab provides double addition of such impurities as arsenic rial or modelling clay held the screen and antimony. protection against cathode circuit failure. to the case. The other antenna (bot- Selected screen composition resists burn- tom in photo) was more elaborate. The disc -composed NEW KIND OF "TV" designed to help ing (X pattern). of a single molded nervous, tense people relax their piece of soft plastic- contained a small Rigid control of muscles and ease the strain on their internal conductive coat- hook of copper wire and a ing provides utmost ceramic hearts, has been developed by Dr. Ed- service reliability. .O1 -µf capacitor. Both leads of the ca- mund Jacobson of Chicago. The device Designed for use with single or double pacitor were apparently connected to- field ion trap designs. gether by the clamp which held the wire hook to the lead. One -piece construction of parts assures Barring the better alignment. remote possibility of some new discovery in radio propaga- Maximum dispersion of screen coating tion, it would seem reasonable to sup- assures uniform screen distribution. pose that these miracle antennas should work much like simple pieces of wire of similar dimensions. Tung -Sol makes All -Glass Sealed Beam Lamps, Miniature Lamps, Signal Flashers, STABLE TRANSISTORS and ger- Picture Tubes, Radio, TV and Special Pur- manium-silicon alloys pose Electron Tubes and Semiconductor that will permit Products. transistors to operate effectively at high heat levels have been announced TUNG -SOL ELECTRIC INC., Newark 4, by Sylvania. N. J. Sales Offices: Atlanta, Chicago, Columbus, Culver City (Los Angeles), Transistor stability was attained Dallas, Denver, Detroit, Newark, Seattle. through "stabilized germanium ", im- Photo courtesy Newsweek. and Chicago Photographers mune to the effects of surface moisture gives the patient a visible recording of which sometimes reduce greatly the am- the tension of his muscles plifying and nerves TU NG-SOL qualities of the transistor, or when he may think that he is relaxing. cause it to fail entirely. Later, when he really does relax his RADIO AND TV TUBES In discussing the new germanium - muscles, he can see the changes recorded silicon alloys, Sylvania stated that by the tension waves on the oscilloscope while a present -day transistor will not screen. operate efficiently when the germanium Dr. Jacobson's "TV" set consists of a crystal is heated to a point above 212° modified Fahrenheit, version of a standard electro- the new alloy will permit cardiograph connected to an oscilloscope You effective Can Build A Reputation On Tung -Sal Quality transistor action up to a to give his patients a dramatic view of temperature of about 350 °. muscular behavior. END RADIO -ELECTRONICS

www.americanradiohistory.com 9

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MAY, 1954

www.americanradiohistory.com NEW AY1HEo GUN WITH CROSSOVER CONTROL Helps RAYTHEON PICTURE TUB Set New Standards of Picture

Raytheon prepared suspension, quality controlled by standard diode method originally de- 8 contact points insure veloped by Raytheon, beam centering. guarantees perfect cathode performance. Molded powdered glass eliminates possibility of trapped air in bubbles. Long contact fingers keep internal coating away from strong field areas thus preventing stray emission.

"^.;. al&' New field design in cathode area creates Crossover Control for small spot of high current density. Redesign of focus lens structure stops arcing. Rolled edge of No. 2 grid prevents arcovers Flanged assembly with at this point. internal concentric ring allows perfect alignment of focused lens.

For crisp, clean, high definition pictures, you can't Picture beat Raytheon Tubes with the new Crossover Control Gun. This specially new gun has a shaped grid designed to keep the electrostatic field Emission from undisturbed. the center of the cathode is vastly improved eliminating slow electrons from the edges which overshoot and smear. These design improvements do away with tailings and halos, lines and spots won't blur even under highlight conditions. You owe it to your customers and yourself to replace Ask your with Raytheon. Raytheon Tube Distributor for complete information. RAYTHEON RAYTHEON MANUFACTURING COMPANY

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WE GUARANTEE IyFoRMA TO TRAIN AND COACH YOU AT HOME ll IN SPARE TIME UNTIL YOU GET TV Engineering INCL UDEO /N pUR 7-R4/1V/Mi ANO YOUR FCC Here is your guarantee C OACHWG- If you rail to pass your Commercial License exam after completing our course, we guarantee to continue your trainin8 without additional cost of any kind, until you LICENSE fully obtain your Commercial license, provided If you have had any practical your first sit for this examination within 90 days after experience Amateur. Army. completing your course. Navy, radio- repair, or experimenting.

EMPLOYERS MAKE JOB OFFERS LIKE THESE OUR AMAZINGLY EFFECTIVE JOB- FINDING AGT GRADUATES EVERY MONTH! SERVICE HELPS CIRE STUDENTS GET BET- TO OUR would TER JOBS. HERE ARE JUST A FEW RECENT Letter frotn nationally -known Airlines, "We also appreciate if you would place the follow- EXAMPLES OF JOB -FINDING RESULTS: ing additional advertisement in your bulletin- Superintendent of Communications . . . SERVICE JOB Wanted- GETS CIVIL Salary $666.66 per month." NOW! license, course I obtained my 2nd phone from nationally known airplane manufac- "Thanks to your Letter or and am now employed by Civil Service at Great Lakes turer, "We need men with electronic training Specialist." experience in radar maintenance to perform oper- Naval Training Station as an Equipment other electronics Fair Oaks, Mtd. Del., McHenry, Ill. ational check -out of radar and Kenneth R. Leiser, . . . amounting to systems . starting salary GETS STATE POLICE JOB $329.33 per month." Letter from nationally -known Airlines, "We are "1 have obtained my 1st class ticket (thanks to your school) an Airline Ground Radio all contemplating placing . .. and since receiving same I have held good lobs at Starting salary $385 per month. Kentucky Engineer." óet with the times. I am now Chief Radio Operator few of the examples of State Edwin Healy, 264 E. 3rd St., London, Ky. These are just a Police." the Job offers that come to our office GETS BROADCAST JOB periodically. Some licensed radioman filled each of these Jobs; it might have -Finding Service for the help in ALL3 "I wish to thank your Job been you! securing for me the position of transmitter operator here at WCAE, in Pittsburgh." Walter Koschik, 1442 Ridge Ave.. N. Braddock, Pa. Ours is the only home study FCC - JOB course which supplies FREE GETS AIRLINES type examinations with all "Due to your Job -Finding Service, I have been getting lessons and final tests. many offers from all over the country, and I have taken in Chicago, as a Radio a ¡ob with Capital Airlines You- FCC Ticket is required Mechanic." by nest employers at proof Harry Clare, 4537 S. Drexel Blvd., Chicago, III. of pur technical ability. HERE'S PROOF FCC LICENSES ARE OFTEN SECURED IN A FEW HOURS OF STUDY WITH OUR COACHING AT HOME IN SPARE TIME: Name and Address License Lessons Lee Worthy. 2nd Phone 16 of Radio Electronics 22101/2 Wilshire St., Bakersfield, Cal Cleveland Institute Desk RE -64 --4900 Euclid Bldg.. Cleveland 3, Ohio Clifford E. Vogt. delay) Phone 20 (Address to Desk No. to avoid Box 1016, Dania, Fla 1st my FCC Ticket in a mini- 1 want to know how I can get Francis X. Foerch, time. Send me your FREE booklet, "How to Pass 1st Phone 38 mum of 38 Beucler Pl., Bergenfield, N. J. FCC License Examinations" (does not cover exams for S /Sgt. Ben H. Davis. B Amateur License), as well as a sample FCC-type exam Phone 28 317 North Roosevelt, Lebanon. Ill 1st and the amazing new booklet, "Money- Making FCC License igfor- Albert Schoell, I mation.'' Cal 2nd Phone 23 about your Television Engineering Course 110 West I Ith St., Escondido, I Be sure to tell me Engineer. President Nome CARL E. SMITH, E.E. Ccnsulting I City Zone State ELECTRONICS Address CLEVELAND INSTITUTE OF RADIO 1 Paste on 2 cent postcard or send alp mai. Desk RE -64, 4900 Euclid Bldg., Cleveland 3, Ohio MAY, 1954

www.americanradiohistory.com 12 BUSINESS

Merchandising and Promotion lightning arrester. Ward Products Corp., division of Gabriel Co.;, Cleveland, introduced two new self -selling dealer display racks for its automobile antennas.

you're on my fro.f with PHOTOFACT TUBE PLACEMENT and TUBE FAILURE CHECK CHARTS serrins- Astatic Corp., Conneaut, Ohio, designed a new steel combination stock case and dispenser for parts distributors selling its line of pickup cartridges. CHARTS: included PLACEMENT TV TUBE PHOTOFACT in each and every and bottom views; Folder. Shows top as chassis would Alliance Mfg. Co., Alliance, Ohio, top view is positioned Shows in customer's home. was ranked in a 14th place tie among be viewed pin; gives locating key or blank the 26 top tube placement: in- national TV spot advertisers function, type and tube and circuit according to the current Rorabaugh fuse type, location cludes report. Alliance moved up from 16th protected. spot on the last report. Sprague Products Co., North Adams, Mass., designed a new ceramic capacitor kit for speeding service TUBE work on TV FAILURE CHECK CHART: each and in every PHOTOFACT TV Folder. Shows common trouble symptoms Erie Resistor Corp., lists and Erie, Pa., devel- tubes whose failure may be sponsible re- oped a new display carton for its for each type of trouble. type cludes In- 413 filter ceramicon. schematics of series filament strings for quicker reference. . Trio Manufacturing Co., Griggs - ville, Ill., purchased Falcon Electronics Co., Quincy, Ill., and its entire line of antennas. Roy Wade, formerly general manager of Falcon, is now general features sales manager for Trio. The entire Zother exclusive _ Falcon in every . operation will be moved to the consistently new Trio plant in Griggsville where Folder -the the PHOTOFACT faster, Falcon line will be manufactured. world's best data for All Falcon representatives have been more profitable servicing. retained and will work with Trio repre- V sentatives. The Trio plant t?ete f also added Vt1,nL a large tool room, a new laboratory, and a maintenance depot for its fleet yokes. With the new kit the proper of trucks. capacitance NOW! GET THE PROOF FOR YOURSELF! can be found easily, by DuKane Corp., St. Charles, Ill., has systematically bridging various capaci- produced a photo paste -up kit which We'll send you a Free tors in the kit across the yoke. its distributors Photofact may present to archi- FREE TV Folder - CBS-Hytrcn, Danvers, Mass., an- tects, engineers, electrical contractors, just ask us for it! nounced the winners in its Certified and others as an aid in visualizing Learn for yourself how PHOTOFACT pays for Quality Service contest for TV radio arrangements of console and panel as- itself by earning bigger profits for you! We'll service technicians. Martin H. Sable of semblies of a school sound system. send you the proof -a FREE specimen Mattapan, Mass., won the top award, PHOTOFACT TV Folder that shows all the fea- a Ford Shows and tures found consistently and exclusively oniv panel truck. Second prize of Conferences in PHOTOFACT. Send for your FREE specimen $1,000 in U.S. Savings Bonds went to NEDA described the first of its TV Folder now. Examine it. Compare it. Richard E. Reish of Marcellus, Mich. regional seminars held in New York You'll see why PHOTOFACT belongs in your RCA Tube Dept., Harrison, shop! And you'll want to ask your parts dis- N. J., City last March as an outstanding tributor about the pay -as -you- earn -plan. launched a spring promotional cam- success. Over 300 distributors and key Only $25 down brings you the entire paign on its portable radio batteries. personnel attended. The association PHOTOFACT Library. Write for FREE specimen National magazine, radio, and TV ad- indicated TV Folder -learn now how to earn more! that this successful debut vertising are being used together with would be a forerunner of similar meet- HOWARD W. SAMS & CO., INC. in -store displays and merchandising ings in other sections 22 Jv of the country. E. 46th St., Indianapolis 5, Ind. aids. The 1954 British Radio Components HOWARD W. SAMS 8 CO., INC. JFD Mfg. Co., Brooklyn, N. Y., de- Show was held in London in April. signed a display for its new LAD -11 The New York Sections of the AIEE RADIO -ELECTRONICS

www.americanradiohistory.com 13 Here comes opportunity

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Prepare now for the Ilelf Radio-TV- Electronics boom. Get in on VHF and I II F ... aviation and mobile radio . .. color TV ... binaural sound! The International Correspondence Schools can help you!

If you've ever thought about Radio or Television as a career . . . if you have the interest, but not the training ... if you're waiting for a good time to start ... NOW'S THE TIME! help No matter what your previous background, I.C.S. can you. If Radio -TV servicing is your hobby, I.C.S. can make it your business. If you're interested in the new develop- own profitable of ments in Electronics, I.C.S. can give you the basic courses training you need. If you have the job but want faster progress, I. C. S. can qualify you for promotions and pay raises. I.C.S. training is success -proved training. Hundreds of I.C.S. graduates hold top jobs with top firms like R.C.A.,G.E., DUMONT, ratings in military and I.T. & T. Hundreds of others have high of own. civil service. Still others have successful businesses their well With I.C.S., you get the rock -bottom basics and theory as You the all-important bench practice and experimentation. as or social learn in your spare time -no interference with business you wish. life. You set your own pace - progress as rapidly as the Free career guidance: Send today for the two free success books, catalog on the course you CHECK THESE SEVEN 36 -page "How to Succeed" and the informative coupon. With so much check below. No obligation. Just mark and mail the FAMOUS I. C. S. COURSES at stake, you owe it to yourself to act -and act fast! - ONE FOR YOU! I.C. S., Scranton 9, Penna. For Real Job Securil. -Cart LC. S. Training! PRACTICAL RADIO-TELEVISION SCHOOLS ;ICS' ENGINEERING - Foundation course INTERNATIONAL CORRESPONDENCE for rades- television career. Basic prim cipfes plus advanced framing. Radio 28814, SCRANTON 9. PENNA. which I hue marPOW Sound TV the booklet about the course BEFORE send me "HOW to SUCCEED" and Without cost o r obligation. Electrical Drafting ER TECHNICIAN -To CI Petroleum -Nat'l Gas Engineering TELEVISION Heating Power and Light tion O for high-level technical posi- Pulp and Paper Making O Electric qualify You ART Painting Contractor O Diesel-Electric Camera, studio, trans- Commercial Art O Plastics Light and Power tions in television. O Air Conditioning HIGH SCHOOL O Electric mitter techniques Manufacture. sale Magazine Illustrating CIVIL, STRUCTURAL Stationary Steam Engineering Fashion Illustrating Electrician School SublecSubjects and installation of TV equipment. 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MAY, 1954

www.americanradiohistory.com 14 BUSINESS

and IRE held a series of seven weekly at 75 North 11th St., Brooklyn, spring study groups on color television. N. Y. Business Briefs Calendar of Events . High Fidelity Institute of the Elec- 1954 Electronic Components Symposium, tronics Industries, was recently formed May 4- 6- Department of Interior Auditorium. in Washington, D. C. Chicago. Jerome J. Kahn, commis- 1954 Electronic sioner high style Parts Show, May 17-20 - of the Institute, stated that its Conrad Hilton Hotel, Chicago. immediate objective Western Electronic Show and Convention, is to dispel con- August 25-27--Pan Pacific Auditorium, Los sumer confuson about what high fidelity Angeles, Calif. is. High -Fidelity Show, September 30 - October dependable 2- Palmer House, Chicago. The Conference Co- ordinating Tenth Annual National Electronics Confer- Committee was ence, October 4 -6 -Hotel Sherman, Chicago. established by the six performance trade associations within the electronic industry to co- ordinate regional con- Production and Sales ferences run by the sales representa- RETMA reported that 28,468,818 TV tives. Russ Diethert, national president low price sets had been shipped to dealers in the of "The Representatives," was elected U.S. from 1946 through 1963. Over 62% chairman, and S. L. Baraf, United of the shipments were concentrated in Transformer, co- chairman. eight states each of which received RETMA's Board over 1,250,000 ... of Directors an- sets. nounced plans to facilitate the elimina- RETMA announced that 6,375,279 TV tion of radiated receivers interference in future and 7,064,485 radios, exclusive production of some TV sets; of automobile sets, to elimi- had been sold during nate or reduce the excise tax on TV 1953. The association also noted that sets; and to promote on C -4 stand 420,471 a research pro- TV sets and 871,981 radios were gram in educational TV. produced during January, 1954. This marked a drop both . Muntz TV, Chicago, and its two from December, wholly -owned subsidiaries, and from January of the previous year. were named in an involuntary petition for reorgani- New zation under Chapter X of the Bank- Plants and Expansions ruptcy Act. Sylvania Electric Products, New York City, dedicated . . . RETMA announced that 17 In design, its new Electronic De- new there is no compara- fense Laboratory in Mountain View, members have been admitted to the ble microphone that equals Calif. organization, bringing total registration Turner 80 styling and compact- Hallicrafters, Chicago, is building a to an all -time high of 373. New companies admitted ness. Styling that pleases the new $1,500,000 factory on an 8 -acre include: C -B -C eye site at Kostner Avenue and 45th Electronics Co., Inc., Philadelphia; and fits in with modern Street, Davis surroundings. which will be used for expanded TV Electronics Co., Burbank, Calif.; Compactness that Kay- Townes Antenna makes this manufacturing and warehousing and as Corp., Rome, microphone con- a central shipping point. Ga.; Litton Industries, Los Angeles; venient and easy to use. You Raytheon Manufacturing Co., Wal- Phen -O -Tron, Inc., New Rochelle, N. Y.; can cradle it in the palm of tham, Mass., has made tentative plans Plamondon Magnetics Co., Chicago; your hand. Actual size (not infor building a large electronics Telechrome Inc., Amityville, Long engi- Island, cluding C-4 stand) only 41/2" neering and research laboratory in N. Y. in length. Wayland, Mass. . . . Finney Co., Cleveland, antenna RCA dedicated a new office manufacturer, recently For PA, home recorder, dic- in Alex- held a dinner tating andria, Va., which will provide consult- meeting in Kalkaska, Mich., attended machine, office and fac- ing and engineering by over tory call systems and amateur services for the 50 of its dealers and distribu- uses, Armed Forces. It will be operated by tors from throughout the northern the Turner 80 perform- the Government Service Michigan area. ance is always dependable. Department of the RCA Service Co. Federal Federal Telephone and Radio Co., Sensitivity: Approx. 58 db Electric Corp. set up a new Clifton, N. J., is' planning to increase regional sales office below I volt/dyne /sq. cm. and warehouse at commercial production reaching more Response: 4056 West 80 to 7000 cps. Armitage Ave., Chicago, to and wider markets than now served. Weight: 5 oz. less service the Mid cable. -Western distributor Additional space for this expansion will Cable: 7 foot attached single market. be provided through the discontinuance conductor shielded. Antenna Specialists, Cleveland, man- of the manufacture of monocolor tele- C -4 stand gracefully matches ufacturer of radio communications an- vision picture tubes. the Turner tennas, recently expanded its facilities 80. Both are satin- ... Lion Mfg. Co., Chicago, has begun chrome plated. Stand won't tip and floor space. or Cannon Electric production on its remote -control tele- slide with weight of cord. Co., Los Angeles, vision sets. established a British affiliate, Cannon Turner 80 list price $15.95 Electric Co., Ltd., in London, to manu- Sylvania Electric Products, New facture, distribute, York City, in cooperation with C -4 stand list and license all Can- Stan- price $ 5.75 non Electric products for western ford University, formulated plans for Europe. an "Honors Co- operative Program in Telematic Industries, Brooklyn, N. Y., Electronics" to aid outstanding college opened a warehouse in Dallas, Texas, seniors interested in doing graduate to service the Southwestern market work in electrical engineering combined THE COMPANY with its antennas and accessories. with full -time electronics employment. 933 17th St., N.E. Wheatland Tube Co., Wheatland, Pa., . . . Telrex, Inc., Asbury Cedar Park, N. J., Rapids, Iowa is rapidly nearing completion of its antenna manufacturer, settled its suit plant expansion program which will for patent infringement against Cornell - EXPORT: Ad Auriemo, Inc., give the company an additional 40,000 Dubilier, South Plainfield, N. J., when 89 Broad St., New York 4 square feet of operating space. the latter company and its subsidiary, CANADA: Canadian Marconi Co., Jan Hardware, manufacturer of a Radiart Corp., Toronto, Ont., and agreed to pay royalties Branches complete line of electronic hardware to Telrex on all future sales of the components, moved to larger quarters patented conical antenna. RADIO -ELECTRONICS

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Model 808A Do -All TV- Radio-CR Tube Tester, Reactivator 8 VTVM Consists of RCP Model 324P SENSATIONAL MODEL 123 `tFLYBACKER" Tube Tester and a new CRT tester -reactivator, plus a Tests Flyback Transformers and VTVM. Checks all tubes including miniatures, anti- Yokes -Trouble Shoots Horizontal miniatures and magnetically TV Circuits in Shop or Home deflected TV picture tubes. Easy -to -read 4W meter. Has Now available for accurate fast- operating double Roll - index. 17 -range VTVM uses balanced bridge type push -pull and speedy testing. Extremely circuit. Input impedance of 25 mega for minimum current drain. sensitive -shows up a single Zero center scale for discriminator alignment. Ranges: AC and shorted turn in a flyback trans- DC volts, 0 -5 -25- 100 -250 -1000; resistance, 0.2 ohm to 1000 megohms in 5 ranges; db-20 to -62 in 5 ranges. Accuracy: former or yoke. Makes tests AC, 5 %; DC, 3 %. Also checks capacitors for shorts and leak- with components in place in ages. Oak carrying case, 12%x12 %x4 % ". With test leads, Checks all flyback FLYBACKER isolation probe and batteries. For 105 -125 volts, 60 cycle AC. the receiver. Shpg. wt., 12% lbs. 84 FX 333. Net $97.95 transformers and yokes for ,. Model HVMP -1. High Voltage Probe. Extends DC range of VTVM opens or shorts. Tests are ap- in Model 808A above, to 30,000 volts. 84 F 334. Net... $8.77 plicable to induction windings on any transformer, speaker .. Do -All Signal Generator ' Model 750 UHF -VHF choke, solenoid, relays, etc., New, combination signal, marker and where impedance is not rela- pattern generator. Covers all UHF -VHF tively low; acts virtually as a ,. channels for FM and TV receiver servicing. Checks and aligns front ends, sound proportional AC ohmmeter. ,.. IF's and picture traps, linearity, sync cir- Oscillator circuit operates at 1500 cycle frequen- cuits, sweep circuits, focus and deflection. Inductuner and special anti -backlash cy; interruption frequency 60 cycle. Slightest - drive assure accuracy of 0.5%. All VHF induction change caused by a shorted turn or frequencies covered on fundamental. intermittent effects shows up instantly on meter `` Ranges: 9 -11, 21 -47, 54 -220, 465 -690 and scale for 650 -900 mc. RF's and IF's clearly cali- as "Bad." Has 3 "Good -Bad" scales; brated on large etched dial. Provides yokes; direct -reading numbered scale; illumi- steady horizontal or vertical bars or cross- dial. In compact grey steel case with modulation: 360 cps nated meter hatch pattern on all channels. Internal 9 %x6x4 % ". Corn- and 141.75 kc. Also provides unmodulated carrier signal. Com- aluminum finish steel panel; plete with leads. Size, 10 4,x6 %x594. For 105 -125 volts, 60 plete with test leads. For 105 -125 volts, 60 cycle cycle AC. Shpg. wt., 10 lbs. 84 F 338. Net $77.91 AC. Shpg. wt., 8 lbs. 84 F 620. Net $39.15 Model 655 Do -All VTVM New, peak -to -peak type VTVM provides accurate measurements of complex ALL RCP INSTRUMENTS waveshapes. Reads RMS and peak to ALLIED STOCKS peak simultaneously of wave -forms in 84 FX 364. Model 8873A Servishop. Net $137.15 video, sync and deflection circuits. In- 84 FX 368. Model 324P Tube Tester. Net 77.91 dustrial applications include servicing of F 332. Model 730 "Signaligner" Signal Generator. Net 32.29 supplies and AC 84 vibrator type power 84 F 336. Model 740A VHF Signal Generator. Net 68.11 generators. 7 ranges on all functions. 303.80 Reads peak to peak AC from 0.2 to 2000 84 FX 365. Model 8020 FM -TV Servishop. Net volts; AC RMS 0.1 to 1500 volts; DC 84 FX 366. Model 8023 AM -FM -TV Servishop. Net 334.18 0.02 to 1500 volts. Measures resistances 84 FX 367. Model 324C Tube Tester. Net 68.55 from 0.2 ohms to 1000 megohms. High 84 F 335. Model 533M Midgetscope. Net 97.51 impedance input. Balanced bridge -type F 340. Model 453C Master Multitester. Net 35.77 result in 84 push -pull circuit and peak -to -peak rectification 84 F 274. Model 447B AC -DC Multitester. Net 17.59 absence of circuit loading, wave -form error and frequency distortion. Supplied with test leads. Size: 10x6x5 ". For 105 -125 All RCP instruments priced over $45, are available on Easy Payments: volt 50 =60 cycle. AC. Shpg. wt., 8 lbs. 84 F 324. Net. . $58.31 only 10% down, 12 months to pay. Write for details. 1 ALLIED RADIO CORP., Dept. 2-E-4 FREE 268 -PAGE BUYING GUIDE 100 N. Western Ave., Chicago 80, Ill. [11 Send FREE 1954 Allied Catalog. Make your selection from the world's LI Ship the following RCP instruments largest stocks of electronic tubes, g enclosed parts, test instruments, audio equip- Allied Radio ment, amateur gear, industrial components -get everything in electronics '1N Name at lowest prices. Send for your FREE copy today. Address

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www.americanradiohistory.com 16 I BUSINESS

THE 1954 ELECTRONIC PARTS SHOW The 1954 Electronic Parts Show will be held at the Conrad Hilton Hotel in Chicago, May 17 -20. The RA 277 exhibitors have reserved space in 397 booths and display rooms in the Conrad Hilton OtU Hotel. This year's Show promises to be the best attended yet. EXHIBITION DISPLAY HIGH COMPANY BOOTH OUTPUT Acro ( Products Co. 667 Advance Elect. & Relay Co 883 Aeroli1, Electronics Corp. THESE ASIATIC Aerovox 634A CRYSTAL Corporation 304 All PICKUP Channel Antenna 3 CARTRIDGES ARE Alliance Manufacturing Co Alpha 321 YOUR MOST BRILLIANT Metals Co. 887 PERFORMERS Alpha Wire Corp 416 Alprodeo, Inc. Altec 315 Lansing Corp. 204 607A American Microphone Co. American 671 Phenolic Corp. 207 560A -561A American Radio Hdwre. Co American 223 Screen Products 643 American Telev. & Radio 415 Amperite Co., Inc. 214 Anchor Radio Company 220 Argos Products Co., Inc. .. Astatic 530A Corporation 125 546A -548A Astron Corporation 888 Asiatic Atlantic Wire & Cable Co. 26 14, IS Asiatic L -12 -U Model, Atlas and 16L -3 Types, Sound Corp. 225 Dual -Output, Remov- Audio Devices, Extra High able Condenser Inc. 421 Output Series Harness, Universal Baker Manufacturing Co. 115 Type Barker & Williamson, Inc. 591 653A Baumker Manufacturing Co. 8 The most effective answers to a Belden Manufacturing host of high Co. 874 output requirements Bell Sound Systems 779 637A -638A are found among these examples Berlant Associates 609 of advanced Astatic engineering Blonder Tongue Lab. 783 precision David Bogen Co., Inc. 500 -501 and mass production. The Brach Manufacturing performance Corp 629A data for each appears British Industries Corp 408 507A -09A below. But these cold statistics Brook Electronics Division 789 662A Bud Radio, cannot cover the warm richness of Inc. 556A Burgess Battery Company tone, the smoothness of response 318 Bossmann Mfg. Co. 216 and other familiar Astatic qualities designed and built Cannon Electric Co. 885 into these units. Allen D. Cardwell If you have not Mfg. Co 872 already done so, Carter Motor Company 777 start adopting them now to the C -B -C Electronics 649 fullest possible extent in CBS -Hytron 218 your car- Centralab tridge replacement stocks. Higher Division 790 Channel Master Corp. 521 established quality of results is Chicago assured Std. Trans. Corp. 211 556 -557 with Astatic Crystal Car- Clarostat Manufacturing Co 586 tridges. Write today for full details Clear Beam TV Antenna 674 of crystal cartridges Cleveland Electronics, Inc. 668 replaced by Collins Radio those shown, other pertinent Co. 536 infor- Columbia Wire & Supply Co 404 mation. Conroe, Inc. 6.22 Continental Carbon, Inc. 6 Consolidated Wire 581 KNOWN THE WORLD OVER FOR HIGHEST Copperweld Steel Products . 121 Cornish Wire Company . 683 QUALITY AT LOWEST POSSIBLE COST Cowan Publishing Co.. . - 622A -623A Crescent Industries 309 Crestwood Recorder Division 9 641A -642A Minimum Output Crown Controls Company Voltage Frequency 604A Model List Price Needle Range WOO(1 c.p.c. Davis Electronics Co. 884 1.0 Meg. Load 'P.'. Delco Radio Division 625 Drake Electric Works S 7.00 10 gr. 2.811 222 2.4t 50 -4.000 Dukane Corporation 515A -517A 14L3-D 2.8tt Allen B. Dumont 8.50 10 gr. 50 -4,000 Labs., Inc 574 2.4t Duotone Company, Inc. 610A -611A 15L3-AG 7.00 10 gr. 4.0tt 3.5t 50-5,000 Easy -Up Tower Co. 628A 4.ott Hugh H. Eby Co. 782 151.3-D 8.50 10 gr. 50 -4,000 3.5t Eicor, Inc. 700 -701 6.2tt Elco Corporation 16L3 6.00 16 gr. 50 -5.000 788 4.0t Eldico of New York, Inc. 613A -614A L-12-U 5.50 1 oz. 1.25tt or 4.0 50 -5.000 Electronic Instrument Co. 202 "'AG' in model designation stands for ALL -GROOVE needle tip of Electronic Measurements special design and size to play 33.1/3, 45 and 78 RPM Records. t RCA 12- 5 -31.V Test Record or Equivalent. Corp. 112 }} Audio-tone 78 -1 Test Record. Electronic Publishing Co. 620 Electro Products Labs. 418 Electro- Voice, Inc. 104 550A -551A Electrovox Company 208 THE Equipto Division 672 Erie Resistor Corp. 314 616 Federal Tele. & Radio Corp 301 Feiler Engineering Co. 791 611 AST TIC CORPORATION Fenton Company 25 CONNEAUT, OH10 The Finney Company 880 632 a...o. UN,GUN,Sr,r,ttro ronoNro oNr,no Fisher Radio Corp. 639-640 Freed Elect. & Controls 633A EXPORT REPRESENTATIVE, 401 Broadway, Freed Transformer Co. 589 York, New N. Y. Cable Address: ASTATIC, New York Fretco, Incorporated 886 646A RADIO -ELECTRONICS

www.americanradiohistory.com 17

L. C. Lane, B.S., M.A. President: RadioTelevision Training Association Executive Di-ector: Pierce Schocl of Radio & Television

NO CIVILIANS! VETERANS! experience FOR A BRIGHTER FUTURE AS A TV TECHNICIAN PREPARE using the needed ... I'll Keep your present Iola while 1 prepare you AT HOME, same successful methods that have helped hundreds of men -many train you AT with no more than g-ammar school training - master television! YOUR HOME LABORATORY! HOME in your ENOUGH EQUIPMENT TO SET UP As part of your traini ig, I give you ALL the above equipment you SPARE TIME! need and more to prepare for a BETTER PAY TV job. You build and keep a professional GIANT SCREEN TV RECEIVER com- Earn while plete with big picture tube. takes any size up to 21 -inch ... also a Super -Het Radio Receiver, RF Signal Generator. Combination you learn! Voltmeter- Ammeter- Chmmeter, C -W Telephone Transmitter, Pub- lic Address System. AC -DC Power Supply. Everything supplied including all tubes' EXPERT FM -TV TECHNICIAN TRAINING! My FM-Tir Technician Course can save you months of training if you have previous Armed Forces or civ.lian radio experience' Train at home with kits of parts, plus equipment to build BIG SCREEN TV RE- CEIVER, and FREE FCC Coaching Course! ALL FURNISHED AT NO EXTRA CC ST' FULLY APPROVED TO TRAIN VETERANS MY SCHOOLS FCC COACHING COURSE! Important for BETTER PAY bill! If discharged after June 27, 1950 FREE under new G.I. JOBS License. get training AT -CHECK COUPON! Also approved for RESIDENT COST. Top V jobs go to FCC licensed in New York City at Pierce School of and AT aNOnEXTRA TRAINING technicians. Radio and Television .. qualifies you for full sub - . with allowance up to 5160 per month. Write NEW! PRACTICAL TV CAMERAMAN & STUDIO COURSE! For men sistence e at home for an for details. previous rato an training) train you exciting high pay job as the man behind the TV : amera. Work in TV studios or "on location" at remote pick -ups' with TV stars equip- A special one -week cpurse of practical work on TV studio ment at Pierce School of Radio & TV, our associate resident is upon your graduation. WARNING! school in New York Cit , offered ALL VETERANS DISCHARGED BEFORE AUGUST 20, 1952 I give you the latest principles and must be enrolled and IN TRAINING by August 20, 1954. practical training in TV COLOR! Otherwise you lose your G.I. rights to a free education under NEW G.I. BILL! Don't put it off . .. it takes several months to get your papers processed! RUSH COUPON BELOW. Tell your ex -G.1. friends!

MAIL THIS COUPON NOW! No Salesman Will Call! GOOD SPARE TIME EARNINGS' Almost from the very you can earn ext moneT while learning. repairing Mr. Leonard C. Lane, President start TRAINING ASSOCIATION Radio -TV sets for friends ano neighbors. Many of my RADIO -TELEVISION 52 East 19th Street, New York 3, N. Y.Dept. R -5B . . their entire students earn up to $25 a week pay FREE BOOK. start their own Dear Mr. Lane: Mail me your NEW training from spare time earnings ... SAMPLE LESSON, and FREE aids that will coupon and FREE profitable service business. .get now' Mail chow me how I can make BIG MONEY IN TELE- find out for yourself what a TV career can do for you! VISION. I understand I am under no obligation no will call. IN NEW YORK CITY and salesman OPTIONAL: TWO WEEKS TRAINING ( PLEASE PRINT PLAINLY) COST! get two weeks, 50 hours. of AT NO EXTRA You NAME AGE intensive Laboratory work on modern electronic equipment at our associated school in New York City - ADDRESS Pierce School of Radio and Television. And I give you CITY ZONE STATE after you all this AT NO EXTRA COST whatsoever, I AM INTERESTED IN: finish your home study tra ;ring in the Radio -FM -TV Radio FM -TV Technician VETERANS! Course and FM -TV Technician Course. Course here for NB Technician FM-TV Technician Course Training under Bill ASSOCIATION TV Cameraman & Studio NEW G.I. RADIO- TELEVISION TRAINING Course 52 EAST 19th STREET, NEW YORK 3, N. Y. Licensed by the State of New York Approved by the VA INM MENEII III II

MAY, 1 954 I.

www.americanradiohistory.com 18 I BUSINESS

Gabriel Electronics Div. 653A Gee Lar Manufacturing Co- 124 General Cement Mfg. Co. .. 320 General Electric Co. 209 General 520 Industries Co. 587 658 -659 General Instrument Corp. 778 G & H Wood Products Co. 879 Gonset Company 881 Gramer Transformer Groner) 537 Products , 5 Grayhill .... 105 Great Eastern Mfg. Co, 666A Guardian Electric Mfg. Co. 409 Halldorson Transformer Co. Hallicrafters 573 Company .... 575 6I9A -620A Hammarlund Mfg. Co. . Hardwick, 583 Hindle, Inc. ... 201 Harman- Kardon, Inc. 528A Haydon Products Co. ... 108 Hickok 649A -650A Elect. Instr. Co 873 524A -526A Hi -Lo TV Ant. Corp. Hy -Lite 111 Antenna 618 IE Manufacturing 24 Illinois Condenser Co. . 212 Imperial Radar & Wire 102 Industrial Television 118 Insuline Corp. of America 403 512 International Rectifier Corp 784 International Resistance Co 22 Jackson Electrical Instr. Co 322 James Vibrapower Company 302 J -B -T Instruments, Inc. . 580 Jensen Industries. Inc. 402 512A -513A Jensen Manufacturing Co. 504A -05A Jersey Specialty Co. 101 Jerrold Electronics Corp. 651A J. F. D. Manufacturing Co. 412 549 E. F. Johnson Company 681 Jontz Manufacturing Co. 875 655 Kay-Townes Antenna Co. .. 624 Rester Solder Company ... 119 K -G Electronics Co. 11 Kleer Vue Mfg. Co. 877 Kuehne Mfg. Co. 664 James B. Lansing Sound 652 Lapointe Electronics, Inc. 312 612A Leader Electronics 630A Lenz Electric Mfg. Co. 588 Littelfuse, Inc. 316 626A Lowell Manufacturing Co. 110 P. R. Mallory & Company 678 Master- Mobile Mounts 666 Merit Coil & Transf. Corp 689 James Millen Mfg. Co. 217 J. W. Miller Company .. 878 M. A. Miller Mfg. IS BRINGING OUT Co. .. . 313 Miller Television Co- 4 Model Eng. & Mfg., Inc. . 107 A NEW LINE Modern -Aire 81fg. Co. 621A Mosley Electronics .... 123 Don McGohan, Inc. 613 -614 National Carbon Co. 680 623 National Company 303 639A -640A National Electric Prods. Co 691 National ,Teletable Corp. 644 -645 National Union Radio Corp 406

National Video Corp. - .534A PRICE WISE Newcomb Audio Products 539 -553 Ohmite Manufacturing Co 41a PERFORMANCE Orradio Industries, Inc. 665 WISE Oxford Electric Corp. 113 557A Par-Metal Products Corp. 114 SALES WISE Peerless Products Div. 577 Penn Television Products 203 636 Pentron Corporation 870 520A -521A Perma -Power Company 579 Nothing Permoflux like it on the market. It's a sales Corporation . 578 532A -533A Permo, Inc. . 414 "natural ". Shown for first time Philmore Manufacturing Co 311 529 at the Pickering & Company . 523 Chicago Parts Show, May 17th thru 20th. Plastoid Corporation 787 Potter & Brumfield 131 612 Precise Development Corp. 130 CONRAD HILTON HOTEL ... DISPLAY ROOM Precision Apparatus Co. 413 507 602 -A Premier Metal Products, 10 Presto Recording_ 502 WEN Pyramid Electric mpany 417 PRODUCTS, INC. Quam -Nichols Company 401 5808 NORTHWEST HIGHWAY Q-Line Mfg. Corp. 617 CHICAGO 31, ILL. Quietrole Co. 648 Racon Electric Co. 310 Radelco Manufacturing Co 23 Radiart Corporation 213 Radio City Products Co. 210 657A Radio Corp. of America 305 628 -629 Radio Craftsmen, Inc. 605A RADIO -ELECTRONICS

www.americanradiohistory.com 1`l

face The Name SYLVANIA etched on the is assurance of RECOGNIZED QUALITY

"replace the face," show them this picture tube When your customers means leadership etched SYLVANIA! They know it's the name that and dependable performance! Make sure your customers of being offered the top Your customers will appreçiate the favor know all the facts about pic and, to most people, a new TV Picture value for their investment ... ture tubes. Ask your Sylvania is definitely an investment. Tube a free supply of by Nation -wide TV Show _ The story of Sylvania Picture Distributor for Rocked your and the facts about their winning exhaustive tests is these booklets to give to Tubes' quality ranking, weekly being told again and again to millions on the high- prospects. TV show, "Beat the Clock." Tube Distributor near you who offers There's a Sylvania Picture tubes. service, cooperation and a full range of available excellent Sylvania Distributor You'll find it profitable to do business with your and to push the full Sylvania line.

1740 Broadway, New York 19, N. Y. SYLVANIANÌSylvania Electric Products Inc., Dept.4R -3805, Montreal, P. Q. University Tower Bldg., St. Catherine Street, In Canada: Sylvania Electric (Canada) Ltd., E L E V I S I O N E L E C T R O N I C S T L I G H T I N G R A D I O

MAY, 1954

www.americanradiohistory.com Before you install another antenna take thls

Irving Rose, prominent Chicago designer and president of

Voice and Vision, noted television and high fidelity center,

takes the "look test" of fringe reception from Milwaukee.

using antenna A

1Four TV receivers of one brand, same Each receiver was tuned with infinite . model, same production run were set 3. care to the same channel to make cer- up. Technicians went over these sets tain the reception was as good as pos- to make sure they were identically sible. The picture is the proof -the re- aligned. sult can be immediately seen -the JFD Super Three other leading high gain TV an- JeT outperformed all others. 2 tennas were installed -each oriented The chart shows why the "Look- test" for maximum performance. Each an- 4. is your proof positive of sharper, clear- tenna was connected to a set by identi- er, more brilliant pictures ... in Black cal type lead -in. and White or Color on all channels present and future. JeT 213 (single Bay) $18.70 JeT 213S* (2 -Bay) $38.35 *complete with stacking transformer

www.americanradiohistory.com "look- test"

Here is your clinical proof that only the MD Super JeT

TV antenna Out-Performs all others on all channels

CHANNELS ANTENNA LIS I 11 12 13 2 3 4 5 6 1 8 9 10

11.5 11.7 11.0 11.5 11.6 Competitor A $42.36 4.5 4.3 7.3 7.0 7.0 10.00 10.75 Radar Screen with 3 dipoles (2 -bay) Partly Pre -Assembled 7.0 6.5 7.75 8.0 7.5 6.0 Competitor B $34.95 0.75 3.25 4.5 3.5 3.5 6.0

Radar Screen with . 2 dipoles (2 -bay) No't Assembled 5.25 6.0 5.25 7.25 9.25 6.5 7.0 Competitor C $55.00 4.0 5.0 7.0 6.25 5.0 Bedspring (4 -bay) Pre -Assembled 12.0 11.25 11.15 12.0 JFD Superjet $38.35 6.5 1.5 9.5 8.5 8.5 11.0 11.0 12.0 1,`' Modi UT 213 S (2 -bay) Company, Prr- Assembled JFD Manufacturing World's largest manufacturers of TV antennas and accessories Brooklyn 4, N.Y. Write for Bulletin ä290

www.americanradiohistory.com 22 I BUSINESS

RADIO -ELECTRONICS 633 Radio -Electronic Jobber News 651 Radio Materials Corp. 617A Radio Merchandise Sales 135 536A Radio,, -537A The FIRST STEP in Corporation 635A -636A Radio Receptor Co., Inc. 590 Radio & TV Journal 66M Radio & TV News 533 Radio & TV Weekly 661 Ram Electronics Co. 509 Rauland -Borg Corp. 542A-544A Raytheon Mfg. Co. 422 NIGH Recoton Corporation 221 Reeves Soundcraft Corp. 117 Regency Division 876 547 Rego Insulated Wire Co. 122 660A Rek -O -Kut Company 522 John F. Rider Publisher, Inc 317 River FIDELITY Edge Industries 785 561 Rockbar Corporation 205 Rohn Manufacturing Co. 14 616A Rytel Electronics Mfg. Co. 206 Howard W. Sams & Co. 407 San Fernando Elec. Mfg. Co. 27 Sangamo Electric Co. 776 553A Service Magazine 609A Service Management Mag 603 Shure Brothers, Inc. 215 516 Simpson Electric Co. 679 539A Mark Simpson Mfg. Co. 109 605 -607 Skyline Manufacturing Co 653 Herman H. Smith, Inc. 686 Snyder Manufacturing Co. 308 Sola Electric Co. 687 Sonar Radio Corp. 603A Sonotone Corp. 618A South River Metal Prods. Co 774 652A Spirling Products Co. 127 513 Sprague Products Co. 684 Standard Coil Products Co 604 Standard Electrical Prods 120 Stephens Manufacturing Co 890 664A Stevens Walden, Inc. 7 Stewart Warner Company 656 -657 Stromberg- Carlson Co. 600 Sutton Electronic Co. 660 Switchcraft, Inc. 126 Sylvania Elec. Products, Inc 676 647A-648A

Talk -A -Phone Company 129 601 -602 Sarkes Torsion, Inc. 626 Tech -Master Products 658A -659A Technical Appliance Corp. 21 Technician 535A Tel -A-Ray Enterprises 13 62M Telectrosonic Corp. 621 Tele -Ex -Pand Products TO N E 1 Tele -Matic Industries 682 Telex, Inc. 12 Telrex, Inc. 675 CERAMIC CARTRIDGE Thomas Electronics 133 Thordarson-Meissner 576 610 Transistor Products 786 There is no wiser investment a phonograph Triad Transformer Mfg. Co 572 656A owner can make than a Tricraft Products 677 TITONE ceramic cartridge. Trimm, Inc. 319 Trio Manufacturing Costing Co. 871 634 -635 no more than ordinary "replacement" cartridges, TITONE Triplett Electrical Instr. Co 585 gives a world of difference in results an Tung Sol Electric 106 - entirely new experience in TV Products 103 true high- fidelity sound, no matter what the make of phonograph. Turner Company 128 And only two models will replace most present -day installations! Ungar Electric Tools 405 United Catalog Pub. Inc. 571 United No other cartridge gives all these Transformer Co. 307 631A -632A features! University Loudspeakers 775 51M Utah Radio Products No preamplifier or equalizer needed Unaffected by moisture or tem- 2 560 perature Wide frequency range Outstanding response High sen- Vaco Products Co. 219 sitivity Low Van Cleef Brothers, Inc. 116 distortion High compliance No hum pickup Superior Vidaire Electronics 780 tracking ability Wide adaptability Proper groove fit Only needle V -M Corporation 584 rotates Simple to replace Waldom Electronics 582 619A -620A P. Wall Manufacturing Co 793 Walsco Electronics Corp. 685 Used Ward Leonard Electric Co 419 by America's foremost manufacturers of high -fidelity Ward Products Corp. phonographs, 411 637 -653A TITONE is an original discovery and devel- Webster- Chicago Corp. 534 opment of the Sonotone laboratories. Literature available. Webster Electric Co. 688 Weller Electric Corp. 306 Wen Products, Inc. 602A Westinghouse Electric Corp 781 ELECTRONIC 643A -644A APPLICATIONS DIVISION Weston Elect. Instr. Corp 420 615A Wilcox -Gay Corp. 673 G. F. Wright Steel Corp. 882 SONOTONE Wallace's Telaides CORPORATION 646 Elmsford, New York Xcelite, Inc. 592 END RADIO -ELECTRONICS

www.americanradiohistory.com 1,168 ServiceDealers Cashing in on CQS

SURVEY SHOWS 78% OF SERVICE- DEALERS TV Want Reliable TV REPLYING REPORT ENTHUSIASTIC and Radio SUPPORT OF CQS PLAN!* Repairs ... foircharges? Using the Certified Quality Service plan? If not, you may be losing business to your competitor across the street. If you are using the ' available to you, you're all set.. . CQS tags and all the sales aids Ceryifred' y-» QUALITY SERVICE CiSPI, e471aJ `Survey conducted January, 1954 "'°. á`m. ,2E2000DNghSP/

eeG ANDNE bout Your Tv., Your NATIONAL ADVERTISING continues to sell for you in LIFE during May and June.

TAGS BE SURE YOU HAVE YOUR CERTIFICATION dealers - for . cos Dealer Your national advertising says, "Ask your Service themselves Tag." Tie in. All you have to do is: help you sell this CQS ° c^^.rw rummy uevw CBS -Hytron colorful, multi -use CQS Tags to build w:w Mirror -Bock 1. Use your improved, and CTS - more business and greater customer confidence ... in you. Rated tubes. 2. Use your CQS signs, posters, decals, and other sales aids. Make it easy for customers to find you. CQS Tags are available: 250 for $2.25, 500 for $3.50, 1000 for $6.00, with your 3 -line imprint. Ask your distributor salesman for special offer ... or use coupon to order direct.

GET YOUR CQS CBS-STAR KIT Contains 6 smashing, big, colorful, magnetic CBS-Star streamers. Each CBS - HYTRON, Danvers, Mass. Benny features a different CBS-TV star: Please rush me: . Burns and Allen ... Gleason . . . Marie A CBS -Star Kit free with.... CQS Tags Godfrey ... Murrow ... and (quantity) shape. Wilson. Each is a different size and @ $2.25, 250; $3.50, 500; $6.00, 1000 Each sells the Star Performance of your new . Certified Quality Service. Kit also includes a A CBS-Star Kit only a Business Builder's inside /outside CQS decal and @ 250 (for handling and mailing) Catalog showing the many sales aids available to you. CBS -Star Kit is free with CQS Tags ... Kit alone, 25e. enclose to cover Tags and /or Kit. the Service- Dealer they read I $.... Let folks know you're check, m.o... no C.O. D.'s. ) about in the national magazines. Ask your distributor (Please send cash, salesman for special offer ... or use coupon. HERE IS MY 3 -LINE IMPRINT FOR TAGS Order your Tags and CBS-Star Kit today. (please print name and address) Name.

CBS - HYTRON Main Office: Danvers, Mass. Street City State Manufacturers of A Division of Columbia Broadcasting System, Inc. Receiving Tubes Since 1921 Television Signed A member of the CBS family: CBS Radio CBS and CBS -Hytron J Columbia Records, Inc. CBS Laboratories CBS -Columbia L MAY, 1954

www.americanradiohistory.com 24

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www.americanradiohistory.com ii: R E DEALERS INSI ALLING

CHANNEL MASTER'S CHAMPION THAN ANY OTHER ANTENNA IN TELEVISION HISTORY! model no, 325 -2 AM- channel reception: VHF & UHF

HORIZONTAL POLAR PATTERNS Relative Voltage ONLY THE CHAMPION enjoys this overwfielming acceptance: over 300.000 alread7 sold! ONLY THE CHAMPION is powered by the unique "Tri- Pole," the fringe arel triple- powered dipole system that provides fabulous VHF -UHF a flasi ! per`ormance. 100% zIuminum; rugged, exclusive al oy. Installs in 01-.27 gives you this four -stcr promotion program: Gain ONLY THE CHAMPION 'above tuned reference lipole) TV commercials FREE newspaper ads * FREE film literature -A FREE colorful display material * FREE consumer See your Channel Master distributor for Ml details.

The antenna America knows best! favorire Introduced to nillions through the editorial pages of their :C.L,It and newspapers, and on TV. W/I.-111101MNPVEN magazines RAIAMIMIE11:-^+='.7MI .rr,.YNINMEMM11\11WI\`1i ALKES" . . . .,t.,...... N=IMOIM...17R M. DON'T BE MISLED BY "LOOK- MEMINIIM_.r .110. THERE'S ONLY ONE REAL CHAMPION! .ZEIFILI®®®®® ..0 SD VI 3017 1190

Made) TO 325-6, Super Charnu Mcdel no 325. Single bey; Model n.. 3254. Four boy;

pySErr.BrF l ( ) f 1 t/ // "1L í pf[f p/7 11- s Y 1 1 1 E: N. -i /lr /. l// !i sfr:C .^ . . E l L 1 (`( L'/71 1l'!: ' Mosier :orp ÿl Antennas Cop yr,yht 1954 Channel The W nrld's largest 'danuf octal er of Television

www.americanradiohistory.com 26 $8000. -° PRIZES WESTINGHOUSE LEAGUE LEADERS AND DEALER AID CONTEST

208 MORE BIG PRIZES FOR TV SERVICE MEN

2nd PRIZE $700 in YOUR Choice of Merchandise 3rd PRIZE $400 in Merchandise YOU Select 4th PRIZE $300 YOU Select the Merchandise FIRST, SECOND, THIRD AND FOURTH PRIZE WINNERS WILL MEET MICKEY MANTLE OR STAN MUSIAL IN THE BIG PRIZE AWARD DINNER WESTINGHOUSE HAS PLANNED FOR YOU IN NEW YORK 5 Fifth Prizes of $140 Each in Merchandise How Would YOU Answer This Service Customer? 20 Sixth Prizes of $70 Each in Merchandise 30 Seventh Prizes Your solution to this cartoon -and your careful of $35 Each in Merchandise selection of 50 Eighth Prizes of $20 American and National League Leaders, as of August Each in Merchandise win 1, 1953 100 Ninth Prizes of $15 Each in Merchandise -can $1000.00 CASH for you. Send in your entry now, for one of the 209 big, valuable prizes in the Westinghouse League Leaders and Dealer Aid Contest. It's easy to qualify. Just buy 25 Westinghouse Receiving Tubes or 1 Westing- YOU CAN BE SURE... IF ITSWeStln house Picture Tube for each entry you submit. Winning house entries will be judged on the basis of correctness of team selec- i don, and aptness, originality and effectiveness solution. of cartoon Your Westinghouse distributor salesman will certify your RELIATRON® Entry Blank TUBES when he takes your tube order. Ask him for WESTINGHOUSE ELECTRIC additional Entry Blanks. CORPORATION ET-95031 Electronic Tube Division Box 284 Elmira, N. Y. USE THIS OFFICIAL LEAGUE LEADERS ENTRY BLANK 1 1. League Leaders on August 1st, 1953 were: 2. Here is what I would say to the Lady in the Cartoon: AMERICAN LEAGUE NATIONAL LEAGUE

MY NAME

SHOP NAME

STREET (Attach additional sheet of paper if necessary. 100 words maximum.) THIS SPACE FOR DISTRIBUTOR'S CITY SALESMAN'S CERTIFICATION STATE I certify this Entry Blank has been qualified by the purchase of ,25 house Receiving Westing Tubes; ,I Westinghouse Picture Tube) SEND ALL ENTRIES TO: Salesman's Signature WESTINGHOUSE TUBE CONTEST Company Name P. O. Box 610, Grand Central Station New York 17, New York City State L J RADIO -ELECTRONICS

www.americanradiohistory.com 27

... how its A Brief Survey complex character means job opportunity of COLOR TV for you

-by E. H. RIETZKE, President, Capitol Radio Engineering Institute

a very quick Since 1927 CREI has provided men cate-problems. That's leads run -down from the transmitter end. with the technical knowledge that Every step is a technical opportunity. to more job security -and more money. CREI starts with fundamentals and What about color receivers? They'll takes you along at your own speed, not be bigger -with roughly twice as many held back by a class, not pushed to receiver tubes as black- and -white. There keep up with others who have more is at least one more tuning knob -the experience. You master the funda- chroma control for color saturation. mentals, then get into more advanced Maintenance is complicated, to say the phases of electronics engineering prin- least, with three highly critical video ciples and practice. Finally you may channels to trouble -shoot instead of elect training at career level in highly one. Service contracts for color re- specialized applications of radio or ceivers will cost considerably more than television engineering, or aeronautical for black- and -white, according to highly radio. The coupon below, properly qualified sources -which should give filled out, will bring you -without cost complexity "Your Future 4 you an idea of servicing - -a fact -packed booklet, AGOOD MANY YEARS AGO, when he and earnings possibilities. So much for in the New World of Electronics," was a young fellow, my Dad was one transmission and reception. Manu- which includes outlines of courses of the country's fastest typesetters. He facture of color equipment is another offered, a resume of career opportuni- could go anywhere and get a highly field for trained technicians. ties, full details about the school, our newspaper in the Bureau (with more requests paid job with any sources agree Placement Then came the linotype ma- Most well -informed men currently on file than country. will be spread all for trained Before he knew it, my Dad's job that color television we can fill), and the names of some of chine! by 1956 at the latest. The was obsolete. He had to start all over in over the U.S. the organizations using CREI training years between now and then are crucial. Cables & Radio, another line of work. honest -to- (like All American If you are interested in an Canadian Broadcasting Corp., career in this booming part Inc., the age goodness Columbia Broadcasting System, RCA How will you get along in of the booming electronics industry, Lines, to has already arrived? Victor Division, United Air of Color TV that here's how you can step ahead of com- you your own have to start all over? Or name a few). I urge -for Will you petition, move up to a better job, earn send for this free booklet im- will you be prepared? The choice is a sure of a well - good -to more money, and be mediately. matter of black- and -white -or color. paid job: Study radiotelevision-elec- TV involves As you may know, color tronics via CREI. You don't have to be School instruc- much more NOTE: CREI also offers Resident handling an understandably a college graduate. You do have to be in Washington, D. C. New for black -and- tion, day or evening. complicated signal than willing to invest some of your spare classes start once a month. If you are a veteran must be in per- new GI white; the components time -at home. You can do it while discharged after June 27, 1960, let the fect balance; the margin for error is holding down a full -time job. Thou- Bill help you obtain resident (or home study) in- practically zero. Technical personnel sands have. struction. Check the coupon for more data. need new skills in working to closer tolerances. Microwave relays and coaxial cables require added equipment INSTITUTE Before a sta- CAPITOL RADIO ENGINEERING and special adjustments. Founded in 1927 tion can originate color it needs a An Accredited Technical Institute D. C. great deal of additional equipment, 3224 16th Street, N.W. Dept. 145 -A Washington 10, much more expensive and vastly more CHECK Practical Radio Engineering booklet "Your Future in Broadcast Radio Engineering (AM, FM, TV) than that for black -and- Send FIELD OF complicated of Electronics" Practical Television Engineering film equipment also the New World GREATEST TV, FM & Advanced AM Servicing white. Slide and Engineering require additional components and and course outline. INTEREST Aeronautical Radio maintenance. Color camera chains are more complex, requiring more Check : much 1 Name highly skilled adjustments and care. Residence Reports of network experiments indicate that live telecasting in color in- Street School creases technical man -hours required Veteran by 30 to 50 %. Lighting personnel need City Zone. .State more skill in handling new-and deli- L MAY, 1954

www.americanradiohistory.com 28

Your Own portable "Service Bench" for if -RF A1!gnrneni! PHILCO VISUAL ALIGNMENT GENERATOR Oscilloscope, Sweep and Marker Generator

gee z0f,

The Philco Model 7008 Visual Alignment Generator is a completely self- contained "service bench" for all alignment and trouble shooting problems in the field. It is specifically designed to permit rapid servicing of the IF amplifier and .e.. front end of TV and FM receivers. The sweep section furnishes a high too output signal with uniform sweep level throughout the FM and television bands, as well as the intermediate frequencies used. The marker system, with its associated crystal calibrator, has an accuracy of .005 %. The built -in oscilloscope greatly simplifies test set -up. Furnished complete with high frequency detector probe, output and input cables NEW! PHI LCO and AC cord. FIELD STRENGTH METER Look at these PHILCO features: Here's more than an antenna signal checker. 1. Only two external The new Philco Field Strength Meter pro- cable con- of RF output from a few micro- vides direct readings of RF signal level nections necessary... minimizes volts up to .1 volt. has built -in electronic sensitivity control. regeneration Signal levels above 100 microvolts are read and feed -back. 3. RF output directly on the calibrated dial. Read 10 to 100 increases with microvolt levels on the high sensitivity meter. 2. Shielded multiplier atten- frequency to offset the fall off High gain low noise TV tuner provides in gain which normally occurs exceptional wide range of sensitivity. Now. uator provides accurate control on the higher measure both strong and weak signals with frequencies. the Philco reference calibration method . it's the same type found in expensive laboratory equipment. MODEL M -8104. AVAILABLE THROUGH YOUR PHILCO DISTRIBUTOR ON A NEW SPECIAL PAYMENT PLAN

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RADIO -ELECTRONICS

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ATOM-ELECTRONIC s

... A fantastic new era is now in the making .. .

By Hugo Gernsback

appear- surrounds us on all sides. The sun, the stars, all are GRAVITY-CHAINED man, ever since his Without the sun's heat and on planet, has been a slave to all his energized by atomic power. ance this light no known form of life could exist. bodily work. Wherever he turns, he comes to atomic power relentless gravity which makes" all When we but realize that the actual grips with in a copper penny can drive an aircraft carrier work a drudge. "In the sweat of thy face shalt thou eat inherent is in ancestors. They across the Atlantic, we begin to understand what bread ", was the life-command of our by way of cheap and abundant themselves to death in their short life store for future mankind literally worked power. Electric power in the home for light, heat, and air - span of 30 to 40 years. from a small compact atomic gen- recent years, steam, electricity, and the internal conditioning will come In man's work erator in the basement. combustion engine have lightened modern will be solved, despite the opinion However, while lifting the gravity- chains in The shielding problem immensely. and of many skeptical scientists today. And, while powerful some measure, we have become enmeshed in other to man, we should chains: economic loads which atomic radiation is highly dangerous often more burdensome never lose sight of the fact that radiation is also energy- bear down on us as hard as gravity's weight. our present-day atomic not work as hard physically nowadays powerful energy. In shielding While we do still pay- energy piles, we lose most of the generated power. The and we live twice as long as our forefathers -we atomic energy directly into for our needs. Hardly anything that keeps pile, instead of converting exorbitantly without electric current, merely generates heat, which we use to you alive and comfortable nowadays is created steam then runs a steam form. And power is expensive, because make steam in a boiler. The power in some wasteful turbine, which now powers an electric generator! A con- practically all types of power are exceedingly wasteful, and inefficient as any another. traption as roundabout, in one way or are rapidly ever dreamed up in history! Moreover, our main sources of power supply makeshift because valuable present scale of spendthrift consumption, Shielding is a wasteful vanishing. At our water radiation- energy is uselessly absorbed either in thick con- coal and oil will be scarce 75 years from now. Even In this process the into electrical energy, is not an abun- crete blocks or heavy lead sheeting. power transformed becomes hot -with high unwanted heat that is a dant commodity in the U. S. It will always be expensive shielding high cost of key installations and distribution. total loss. due to the age of As I have said many times before: Why waste this Fortunately, the final emancipation of man-the not turn it into valuable now appearing above the horizon. It priceless radiation -energy? Why Power -Freedom -is as the electric power? This, I think, will be accomplished in is possible that this era will come to be known of materials will Age era that will pale into insig- time. Some material or a combination Atom- Electronic -the be found which absorb the deadly, powerful gamma radia- nificance the age of electricity and electronics. useful elec- made the beginning in our fabu- tion and turn it -as rapidly as created-into Very recently we have energy. This will not be accomplished tomorrow, lous atomic batteries, with which at last we can turn trical Neverthe- directly, without steam or nor next year -it lies as yet deep in the future. atomic energy into electricity problem will be solved, perhaps sooner than we heat or other wasteful intermediaries. The writer probably less, the phases, term. Atomic Battery, when, in expect. First the theoretical and experimental was the first to use the the elements for a reliable commercial December, 1945, he published the following fanciful pre- then practical diction: product. receiver, Berkeley Calitech- When the goal has been achieved, every radio 1950. Professor Andrew Lodge, will be powered atom -electronically. first basic, ATOMIC BATTERY, called every television set, nician, discovers as our portable radios are battery -powered today, so Atobat, whereby Plutonium -C generates electric Just any re- cost. Fin- in the future a tiny atomic cartridge will power current in vast quantities at infinitesimal a cost not much higher than a produces 10,000 kilowatt -hours for ceiver for years on end, at ger -sized Atobat single set of present -day batteries. less than 1/o cent. ulti- in 1951, the Bicycles, motorbikes, automobiles, airplanes, all As the first atomic battery was invented atom -electronically, as will all one year. The high output of power is mately will be powered writer erred by modes of transport. There will be a host of new atom - yet to be realized. But make no mistake -in the not -too- of today. sound picayune! We electronic developments undreamed distant future the 1945 prediction will Here are only a few that come to mind: High - this with conviction in view of the recently announced generators say electricity direct voltage (200,000 to 2,000,000 volt) cascade RCA atomic battery, which generates which operate without benefit of the usual transformers. from the atom in an entirely new and original manner- for various electronics. Self-powered X -ray emitters -adjustable a milestone in the new art of atomic- types of X -ray emissions. Banks of multiplex, self - We have now reached a parallel point in history com- or thousands of Faraday in the early powered transistors -where hundreds parable to the time when Michael transistors are required in a small space, such as in special 1830's demonstrated the first electric generator. It was a a desk. Auto -watches. a copper disc edgewise electronic computers for use at toy -like device in which he rotated Instead of present -day complex pocket watches powered between the poles of a horseshoe magnet. The weak elec- break, the atom -electronic watch by two contacts rubbing on by springs which often trical current was collected is self -nowered, has few wheels but instead a tiny elec- the edge and the shaft of the revolving disc. The current will be much cheaper, will need it could scarcely be demon- tric motor. Such watches generated was so weak that few repairs, will never have to be wound. Larger watches or strated from this most inefficient dynamo. Auto -fluorescents, skeptical man of science viewing clocks are made in a like manner. One unimaginative and self -powered table lamps or special -use lamps for home, a demonstration scoffed, "What possible good is this as they will do with, "What good is a office, or camp -an important innovation contraption ?" Faraday countered away with present-day connecting wires that clutter up newborn child ?" light is used. battery and its follower, homes and offices and other places where So it is with the newborn atomic This list can be extended endlessly as the new art the atomic generator. Curiously enough, man only dimly revolutionize our the fact that he would comes into full use. It is certain to and slowly becomes conscious of more than steam and electricity did in the past. not be here at all if it were not for atomic energy which lives far MAY, 1954

www.americanradiohistory.com 32 I TELEVISION

Calibrating the marker

generator; marker in jiection ; the zero -volt reference line

ENGINEERING STAFF. SC CO.

WE HAVE shown in the arti- of the S curve to cut the vertical line low hum cle "Killing Those Alignment of the level, or severe distortion of scope screen. the beat pattern may result. Bugs" (April issue) that Both primary and a bypass secondary ad- It is possible to use the internal marker injector justments of the discriminator trans- makes it possible to obtain a uniform amplifier of the bypass marker injector former are effective in shifting the S for this purpose. size marker at any point on the re- curve. But adjustment No distortion of the sponse curve of the tuned pattern is obtained under such circum- -along the base line, or coils also causes the curve in the traps. To to become stances, because the internal power refresh the reader's more or less symmetrical. The proper memory on this important point, supply of the unit is exceptionally well refer- adjustment is made when the curve is filtered. ence is made to Fig. 1. The height of symmetrical Circulating ground currents the as well as being centered which may cause a hum marker appears the same, whether on the scope screen. -voltage drop placed on top of the i.f. response to appear between various ground curve The time lost when a crystal de- points (Fig. 1 -a), at the bottom of the curve modulator along the chassis are avoided probe is used to locate the by proper layout of on the base line (Fig. 1 -b), on the marker point ground returns. hump on the scope base line of the after response ( Fig. 1 -c) , is a strong argument or in the for using a by- Observation of spurious markers bottom of the expanded trap pass marker injector in the busy (Fig. 1 -d). shop. Spurious markers are annoying to The the busy operator. Spurious experienced technician will rec- High accuracy required in marking markers ognize that this usually arise from beats between har- is a surprising type of Experienced technicians know display, normally that monics of the test signals which are in unobtainable with unless the 4.5 -mc marking frequency is older methods of beat-marker injection. use at the time. The annoyance is some- accurate, the sound output from the times so severe The marker display on the ratio -de- receiver will that technicians use be weak and distorted, or absorption markers, because an tector S curve is perhaps most sur- perhaps completely inaudible. absorp- prising of For this tion marker has no harmonics and all. The ratio -detector type reason, a method of calibrating of circuit is one the cannot cross -beat with harmonics of which is notoriously marker generator is an absolute neces- difficult to mark because of its the sweep signal. However, an absorp- AM sity. Fig. 4 shows how this is done tion marker always rejection (Fig. 2 -a) ; yet, with a bypass disappears near with the aid of a crystal demodulator the base of marker injector, a large marker is ob- probe. the curve. Furthermore, an absorption marker usually tained on the linear portion of the S The output appears in of the marker generator a misleading manner on curve (Fig. 2 -b) . is connected the steep side in parallel with the output of a response curve; the operator of a crystal oscillator, and Locating marker point on both signals usually judges the marker to be too low scope base line are demodulated by a crystal probe If a bypass marker and on the curve. injector is not applied to the input of the scope. The available, the technician can discon- It is possible to obtain clean markers scope is swept at a low frequency, and free from spurious indications, nect the sweep generator from the dis- a sine -wave beat pattern if the criminator, and appears on generators have good waveform; i.e.; feed the sweep and the scope screen. The marker dial will marker signals through a crystal the generators should have a sine -wav6 de- indicate zero -beat frequencies (seen as output, free from .., modulator probe to the scope. The a minimum harmonics. In gen- number of sine waves on eral, the more paid for a generator, marker will then become visible along the scope screen) when the the the scope base marker more nearly its output approaches a line. Set the marker frequency is an exact multiple of the generator to exactly 4.5 pure sine wave. Some sweep generators mc; then ad- crystal fundamental frequency. Any provide just the sweep generator to bring the a low -pass filter in the output crystal oscillator can be used, but the circuit for the express purpose marker to exact center screen, as shown technician will obtain the of sup- in Fig. greatest use pressing harmonics in the output. These 3. from 1 mc, 2 mc, and 4.5 -mc crystals. Now, the crystal demodulator will be found to develop fewer and less probe This type of calibrating arrangement noticeable spurious can be removed and the discriminator is markers. limited in the extent to which it can It must not be supposed reconnected. Although the marker may develop visible indications that spurious not of zero beats markers are always the result of har- be visible on the S curve, it is against higher harmonics of the known that at the cali- monic output from the generators. In center of the scope brating crystal. In order to use higher some screen is the 4.5 -mc marker point. cases, faults exist in the i.f. am- As harmonics of the crystal, a conven- plifier strip which causes the tuning adjustments of the dis- tional audio the generation amplifier can be placed of spurious markers in the i.f. amplifier criminator are varied, the S curve between the output of the crystal moves left or right along de- itself. One common cause of this is the the scope base modulator probe and the input termi- tendency of line. The proper adjustment, of course, the amplifier to break into nals of the scope. It is essential, how- oscillation when the stages is that which causes the center point ever, that the are incor- audio amplifier have a rectly peaked at frequencies too close RADIO -ELECTRONICS

www.americanradiohistory.com TELEVISION 33

SCOPE MARNER GEN. XTAL 05C.

Fig. 4- Calibrating a marker generator. la 3 together. As the amplifier breaks into oscillation, the response curve collapses, and spurious markers appear along the base line on the scope screen, as shown in Fig. 5. Obviously, if the marker signal does --+----_ not pass through the amplifier, any instability in the amplifier circuits can have no effect upon the marker indication. Hence, a bypass injector often avoids spurious marker indications lb 5 that appear when the conventional method is used. In conclusion, receiver manufacturers almost invariably indicate that the local oscillator in the r"'""uqll( receiver be disabled during i.f. alignment. If this is overlooked, spurious markers are certain to be generated which cannot be subsequently eliminated.

Width of marker depends on sweep width lc 6 The width of markers on response curves deserves serious consideration. It should not be supposed that it is always possible to obtain a sharp and narrow marker indication, as seen in Fig. 3. For example, Fig. 6 shows the same marker when displayed at a smaller sweep width. Since a discriminator has a smaller bandwidth than an i.f. amplifier, it makes the marker appear broader. Ac- 1 is la cordingly, the marker seen in Fig. ld narrower and sharper than the marker seen in Fig. 2. The marker on the ratio - discriminator curve requires particular observation; it is not pointed as in wide -band circuits, but is more or less uniform in width from one end of the display to the other. But if the technician looks carefully, he will observe that the marker is broken at one point, and that a dark line about 1/32 inch wide separates the marker into two parts, at the center of the S curve. This break in the marker is the exact zero -beat point, which is utilized in the procedure. 2a 7b alignment Displays with zero -volt reference A zero -volt reference line appears in the pattern shown in Fig. 6. The zero- Fig. 1- Marker maintains uniform size volt reference is a convenience in align- at all points of the i.f. response curve. ment procedures. Fig. 2- Marking a ratio -detector curve. Zero -volt reference lines are de- Fig. 3- 4.5 -mc marker on scope base by the sweep generator, or are line. veloped mark- provided automatically by d.c. scopes. Fig. 5- Appearance of spurious utilize a.c. ers along a collapsed i.f. response curve. Since most technicians Fig. 6- Appearance of marker when scopes, the zero reference must be ob- the generator sweep width is small. tained from the sweep generator, which Fig. 7 -Using zero -volt reference line. operates as a d.c. restorer during one - 2b half cycle of its operation. A detailed discussion on this subject is reserved for the next installment of this series. MAY, 1954

www.americanradiohistory.com 34 TELEVISION

RECONDITIONING PICTURE TUBES

By JOHN B. LEDBETTER

you ever try to burn out a the top portion cathode of the grid. (This is -to -heater or cathode -to- evidenced by the usually grid short in a picture tube? high- resis- D11) The tance readings and the fact that slight usual application of 117 volts element displacement would make con- a.c. or d.c. across the shorted elements tact more likely is satisfactory near the top of the in some cases. But it is elements. ) not very useful where the short is high - Fig. S -a -Zero -volt reference line aids resistance or is present only in FM discriminator under cer- alignment. tain thermal conditions. In addition, the high- current a.c. or d.c. source can damage the cathode coating or even the grid structure. The method to be described is extremely simple; it takes up a very small amount of time; and, so far as I am concerned, it has been 100% effective. And, what is just as important to the busy service technician, the entire procedure can be carried out without removing either the picture tube or the chassis **4 from the cabinet. obtaining high voltage from TV Unusual symptoms of trouble cci% r. re- Fig. 8 -b -Using zero -volt reference A common line to check antenna impedance. indication of a cathode - Removing to- heater short is full brightness, with the short the brightness control having no effect. The solution to the problem is to In some receivers (depending on the apply a high voltage, from a low -cur- particular circuit) the symptom may rent source, across the shorted elements. be a Such washed -out picture, while in still a voltage will produce a low - others the raster will be normal but current arc across the elements which with no picture. In a few sets, a shorted anneals or removes the burr without condition will cause a black- and -white disintegrating the cathode coating (and shading effect on the screen, with or without resembling an arc welder in without a picture. action). Such a voltage can be obtained Most picture tubes can be checked very easily, either from an r.f. oscilla- for cathode-grid or cathode-heater tor (amateur radio transmitter, etc.), shorts (or leakage) with a v.t.v.m. The or directly from the high -voltage power test should be made while the tube is supply of a TV receiver. The latter is still hot probably Fig. 9 -Hum voltage distorts S curve. and with the tube socket re- the simplest. moved. Use the highest resistance scale Usually, the shorted picture tube Fig. 7 -a shows typical narrow -band on the v.t.v.m. need not be removed from the cabinet. circuit response curves when The socket is removed (see diagram) displayed Analysis of trouble and the with zero -volt reference lines. It is ap- high voltage is applied directly parent that little advantage While at WKRC -TV, I received and to the shorted pins with well- insulated is gained test using a zero -volt reference unless processed a number of shorted C -R probes. In applying the high volt- a age, use wide -band circuit (Fig. 7 -b) is under tubes. In most of these, the short was care to prevent overloading alignment. In the latter case, consider- between cathode and grid and was the power supply. This can usually be able additional information is provided, usually high -resistance; between 250,- avoided by connecting one test lead since the operator would not 000 and 420,000 ohms. A few tubes (equipped with alligator clips) from know the otherwise where the base line of the showed a low -resistance or intermittent TV receiver chassis to the cathode curve is located. short between cathode and heater, some pin, and the other lead from the horizontal -output The zero reference level is also con- of which could be restored temporarily tube's plate cap. If this venient when aligning discriminators to normal operation by jarring or lead is touched rapidly several times in (Fig. 8 -a), or checking antenna thumping the neck or base of the tube. succession to the other shorted element, im- the short pedance characteristics, as shown in Experiments on these and other types can be cleared without undue Fig. 8 -b. of tubes gave rise to the theory that current drain from the horizontal out- The zero -volt reference should inter- such shorts were not the result of put transformer. In stubborn or inter- sect the S curve at the 4.5 -me point direct contact between elements (the mittent cases, the "annealing" or r.f.- when the circuits are in proper result of defective structure, displace- heating process can be aided by vibrat- align- ing ment. However, the technician must ment of elements from jarring, etc.), or jarring the neck or base of the guard against hum in the but were caused by contact between tube. As a precaution against possible discriminator recurrence, circuits, since hum voltage will raise the grid (or heater) element and the the process can be repeated, one of the S curves and lower the other spiral surface of the cathode. As the first from cathode to grid, then from (in the absence of the cathode expands and contracts during cathode to heater while the base is zero reference), vibrated as shown in Fig. 9. It is apparent that heating and cooling cycles, a small burr with the fingers. or flake In all tests if either of the traces seen in Fig. 9 of the oxide coating may work made, the shorts seemed is converted to a zero reference line itself loose and eventually make contact to clear almost instantaneously. As by the sweep generator, the intersection with the heater or grid element. In the each tube was returned to service, a case brief record of the reference line with the S curve of grid contact, the tip of the including the complaint, will be false. Accordingly, before align- cathode element seems to have made date, and condition were attached as a ment, the circuits should be checked contact through "oxidized" coating with means of evaluating the tests. To date, for hum. none of the tubes has given further END Engineericg Writer, Convair. trouble. END RADIO -ELECTRONICS

www.americanradiohistory.com TELEVISIONI 35

ADJUSTING A

service TV RECEIVER Bow would you install, adjust, or It has been a color television receiver? that on get useful information on can easily find information hard to HE service technician and put its get the color TV tube into place Thow to position. Two or it is almost impossible yoke and purifying coil into subject, because shield, come out with that three service sheets have already full - doubt see more before he the facts of color without information, and he will no to explain But little material is available handles his first TV tube. tube and adjustments to get the color and it is difficult on making the necessary impossible color illustrations, The reason is that it is almost working perfectly. without color illus- certain of the adjustments to print four -color illustrations to explain talk almost entirely about expensive trations. So we are going to adjustments. story (separately those was one book with complete in a magazine. This At the time of writing, there form. That is Practical Color color information in picture in the issue) shows Co., Camden, N. J., $2.00). printed and inserted Television, (RCA Service specialThe here are taken from that book, color illustrations Company, and y adjustments -or color faults arrangement with the RCA Service how correct The information given here - right by that organization. largely these illustrations -is also look on the TV screen. describing as it does that the instruc- - actually the same source, with the result taken from RCA color receivers, are especially applicable to tions receiver using the shadow - though useful for any color mask type of picture tube.

showing in the red picture. Fig. 2 -Color contamination purity control adjustment looks. Fig. 1 -How an incorrect MAY 1954

www.americanradiohistory.com 36I TELEVISION

It would be impossible to get a schematic available into the space (with CHROMA for this article. The references control turned down). A little matics are to the sche- picture won't color in the on pages 66 and 67 of the January, hurt, but linearity must be 1954, issue, or to high voltage right. Check the the large complete schematic in Practical with a v.t.v.m. and high -voltage Color Television. sure it probe, making Controls which are named in is around 20,000 at all settings those schematics are printed control. of the brightness in small capitals the first time they appear Correct the voltage by adjusting in this article. regulator control. the voltage - Preliminary adjusfmenfs Now we are ready to proceed with color adjustments. Once Turn the contrast the tube is in place, turn the set all the way down and the brightness usual adjustments on and make the well up. Then turn control to get a good black -and -white picture up the RED SCREEN control, while turning the GREEN SCREEN and BLUE SCREEN controls down. You should have a pure rich red raster. Screw the convergence magnets out the away from the neck of kinescope and slide the yoke back Then rotate as far as possible. the purifying coil -at the same the PURITY time adjusting CONTROL, until you get the most uniform the center of the screen. red in Use as little purifying coil current as possible. A wrong purifying coil adjustment, with best red toward the lower the left of the screen, is seen in Fig. Next adjust for most uniform 1. forward red by sliding the yoke till you get the best purity, making same time that sure at the there are no neck shadows. If there some purity contamination, is still as in Fig. 2, readjust the purifying coil and purity control. Convergence adjusfinenfs The converging electrode (grid 4) bends of the picture tube together the beams from the three guns them at the aperture and converges mask. This is d.c. convergence and will bring the beams together Fig. :S correctly in areas -Dot pattern out of convergence, center of the tube near the voltage low. screen. But, since the beams have farther to reach to travel the edges of the screen, the convergence voltage has to be varied according to the position of the spot. This is done by applying dynamic horizontal- and vertical -frequency convergence voltages. To adjust the convergence, a dot generator is used. down the HORIZONTAL Turn CONVERGENCE and VERTICAL GENCE controls CONVER- and the VERTICAL SHAPER control, screw convergence magnets the as far away from the neck of the picture tube as possible, and reduce convergence the voltage on the electrode by turning down the voltage control. convergence The screen pattern should look like Fig. 3. If it looks like Fig. 4, with the blue dot at the top instead of the bottom, convergence voltage is too high. Readjust. Adjust the three convergence magnets and vergence voltage, the d.c. con- watching the dots at the center of screen till they overlap the and become white (Fig. 5). Note well that it may be necessary to readjust during this the focus controls Fig. 4 -llots out of convergence process -several of the controls in with voltage too high. a color tube

Fig. 5 -D.c. convergence fairly good (see note in text). Fig. Horizontal 6- dynamic convergence voltage misphased. RADIO- ELECTRONICS

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and horizontal dynamic No color circuit affect each other. The vertical by operating the set as a them. Other faults can be found only convergence controls are among are properly adjusted, color receiver. No color is likely the d.c. convergence controls due suppressor of Once controls to Check the voltage suppliedto be vertical dynamic shape and amplitude oscillator. be about 5 volts adjust the of dots through "Q" demodulators. It should convergence along a vertical line the "I" and about 1.8 volts if obtain equal control should be signals are reaching them; of the screen. The vertical shape if oscillator may affect the the center and bottom in the BANDPASS AMPLIFIER also the color displacement on the top not. Defects adjusted to make adjusted to The vertical amplitude control is then color circuits. dots equal. entire line of dots the color displacement equal along the make of the d.c. convergence in the center. A slight readjustment from top to bottom. control will then converge the line convergence Repeat the operation with the horizontal converges and the other control. If one side of the pattern adjust the HORIZONTAL DYNAMIC PHASE does not (Fig. 6), magnets (When finally adjusted, the convergence control. or beam may not be too close to the tube neck, must n 7 (Actually A perfect pattern app ars focusg be distorted.) converged. The dots in Fig. 7 are ?lot perfectly the edge were still in the were taken while these tubes photos convergence" was not developmental stage, and "perfect then as good as is now possible.) adjustment White and CONTRAST away the dot generator, turn CHROMA Take to maximum. Adjust down and advance brightness controls a low brightness three -color screen controls to give the turn the contrast control white all over the screen. Then -white picture. Adjust due to the loss of color sync. halfway up and tune in a black- and Fig. 10 -A color picture gain controls till you get an uncon- the BLUE gain and GREEN brightness on the highlights. Then turn the taminated white controls to get and adjust the same BACKGROUND control down and lowlight white on lowlights. Repeat the highlight a good settings of the bright- adjustments till the white tracks at all ness and contrast controls. and you should color adjustments are now made, Your color test pattern. get a picture like Fig. 8 on a standard the color set Servicing by oper- faults in a color receiver can be located Many This shows up faults ating it as a black- and -white receiver. -white circuits, faults in in common color and black- and primary color fields, troubles in convergence producing pure uniform whites focus, and faults that prevent forming and produce a color field and grays. Primary color field troubles be cleared by repeating the over the whole picture and can Improper convergence makes a color purity adjustments. the high- picture look like Fig. 9. Color in black- and -white highlight and or lowlights is cleared by repeating on a black- and -white picture. lights Fig. 9 -Poor convergence lowlight adjustments.

'r.

bar pattern. Correct color adjustment on standard (see note in text). Fig. 8- Fig. 7- Properly converged dot pattern

MAY 1954

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Color sync problems are Loss of color sync looks like due to hum in the "Q" channel. Fig. 10. The colored bars Orange and bluish - move vertically. Loss of green bars would be caused color sync may be caused by defects by hum in the "I" channel. in the color phase -discriminator And finally, if all adjustments are tube circuit or in the reactance no correct, if there are circuit, or by the 3.58 -mc oscillator color -canceling reflections, if antenna If being off frequency. is a good broad- horizontal bars are few, frequency band job, and if the station is transmitting deviation is slight. the a perfect picture, result should look like Fig. 15. Phase adjustment problems END Incorrect phase relationship between the "I" and signals will produce improper "Q" colors. Before checking the quadrature circuits, check the manual phase control. A picture like Fig. 11 results when adjusted. the phase control is mis- If the "I" signal is missing entirely, will look like Fig. the picture 12, and a picture without the "Q" signal looks like Fig. 13. Narrow bands vertical of incorrect color at the edges of contrasting color and "Q" areas indicate that "I" signals are not exactly 90 degrees of the above, apart. For any check through the quadrature circuits "I" and "Q" demodulators. and the Other sources of trouble Troubles in circuits common to color can and black- and -white also cause color trouble. For example, ence signal the burst refer- could be prevented (by clipping circuits) from reaching in the i.f. the circuits in which it is compared with those from the local 3.58 -mc oscillator. This would cause sync trouble. Complete misregistration signal with the of the color fine detail ( "Y" channel) can usually Fig. 13- Failure of "Q" traced to trouble in be signal produces reddish picture. the delay line. Heater- cathode leakage can cause a picture like Fig. 19. The green and purple bars

Fig. l4- Heater -cathode leakage causes color hum bars. Fig. II- Picture due to incorrect phase control setting.

Fig. Fig. 15-What we have been working 12- Green -bluish cast is due to lack of "I" signal. for: a nornial picture.

RADIO -ELECTRONICS

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COLOR RECEIVER COMPONENTS 15GP22 color TV picture tube circuits require specially designed components

high -voltage rectifier supplying the d.c. voltage to the focusing electrode of the 15GP22. Voltage for the converging electrode is taken from a bleeder resistor in the high -voltage supply. In typical operation the transformer can supply 4 kv to the foc king electrode, and 10 kv to the converging electrode. The vertical dynamic- converging and dynamic- focusing transformer has a tapped secondary winding for coupling the vertical- dynamic output of the convergence amplifier to both the converging electrode (grid 4) and the focusing electrode (grid 3) of the 15GP22. This transformer supplies vertical dynamic correcting voltages for combining with those supplied by the horizontal dynamic converging and dynamic con- focusing transformer. for the 15GP22 deflection, high voltage, and focus and dynamic correcting RCA components is the deflecting yoke, These combined vergence circuits. In the background from left to right are superimposed on the d.c. coil, vertical dynamic focusing transformer; in the fore- voltages shadow mask, purifying isolation inductor, hori- voltages for grids 3 and 4 to provide ground, vertical deflection output transformer, vertical fields which focusing transformer, and horizontal output transformer. changing electrostatic zontal dynamic maintain proper focus and convergence of the beams as they pass over the flat of the de- common axis of the beams, so that it shadow mask of the picture tube. FOR the proper operation the picture dynamic- converging high -voltage, dynamic fo- coincides with the axis of The horizontal flection, the beams are focused, focusing transformer per- cus, and convergence circuits used tube. Thus, when and dynamic converged, and deflected, they approach forms essentially the same function as with the tricolor tube 15GP22, the it couples TV compo- each hole in the shadow mask at its counterpart, except that several specially designed the centers of dynamic output of the been developed, some of proper angle to strike the horizontal nents have color dots -producing amplifier to the converging which -deflecting yoke, purifying coil, their appropriate convergence color purity. and focusing electrode of the 15GP22. and horizontal output transformer, to- at the hori- from the kine- The beam -positioning magnets are Designed for operation gether with shadow -mask correspond frequency, an adjust- shown on the front cover. spaced at 120° intervals to zontal scanning scope -are of the kinescope guns. able ferrite core permits tuning to the, The most striking feature of the de- with the positions size as com- The magnets are threaded and slotted, scanning frequency. flecting yoke is its physical deflection output trans- yokes. Having a with a red dot indicating the north The vertical pared to conventional on the of standard design, and will deflection angle of 45 °, the pole. The effect of the magnet former is horizontal be reversed by insert- operate with one -half of a 6BL7 -GT horizontal and vertical coils produce beam position can ing the opposite end of the magnet into as the driver. The transformer pro- the necessary magnetic fields for simul- ample de- beams. the shield. vides good sweep linearity, taneous deflection of the three coupling between placed nearest the The magnetic shield isolates the flection, and efficient The end of the yoke through driver tube and the vertical coils of tube funnel is widely flared to provide beams passing at low velocity the c tube from deflecting yoke. the proper flux distribution for opti- the neck section of the -r the effects of extraneous magnetic An especially interesting component mum convergence. A polyethylene liner the a 2- the fields. is the vertical isolation inductor, is used to prevent arcing between to operate as the coating on The horizontal- output high -voltage section coil designed yoke coils and the grounded element in the filter network tube. The outside diameter transformer is conventional in appear- inductive the picture between the vertical deflection circuit of the deflecting yoke is 7i(; inches; ance. Electrically, it is extremely an output of 20 kv and the vertical centering circuit. The the inside diameter 2.2 inches. rugged, supplying a high im- is purify- at 750 µa when driven by a single filter network represents Of particular interest the between the respective obtaining multibeam align- 6CD6 -G operating from a 400 -volt sup- pedance inserted ing coil for circuits to isolate the a.c. component in ment. It consists of three magnets for ply. ground. This beams, and The transformer has a multi- tapped the vertical coils from positioning the individual the a.c. component reduces is designed for auto -transformer winding and four isolation of a magnetic shield. It capacitance between the vertical on the neck section of the tri- isolated windings. The auto -transformer the mounting voltage and and horizontal coils which results in color tube. winding supplies the high the connections to deflecting yoke reduction of capacitance between The purifying coil produces a trans- provides ground. Thus, ad- damper tube, driver tube, and width horizontal coils and verse magnetic field which can be retrace time is obtained for the the coil and changing control. Other taps supply pulses for shorter justed by rotating horizontal deflection circuit, END the current through it, to align the keyed a.g.c. circuits and voltage for a MAY, 1954

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BASIC COLOR TV

411, Part IV (continued) -I and Q signals; summary of the features and techniques of the NTSC system

By D. NEWMAN* and J. J. ROCHE*

IN earlier installments, we mentioned a two -color system of reproduction. primary that the eye does not colors for all video frequencies appreciate blue The primaries we are using are reddish - up to in picture details which approximately 600 kc. Above 600 correspond magenta and greenish-cyan. kc it is to video frequencies above approxi- advantageous to shift to the For many years, experiments have preferred two -color system mately 600 kc. Remembering that the been conducted to primaries, green determine the best orange and cyan. color- difference signal is derived primary colors to use in a two -color at the receiver from To operate along the orange -cyan the red and blue reproduction system. Results of this axis above color signals, we can see that the ac- 600 kc, we must shift the wide -band color-difference curacy of the green GR EN components color- difference sig- 33° nal depends on the presence ahead of the ER - E axis. of the red The methods and blue signals. Therefore, it would used in the NTSC sys- be desirable to transmit tem to do this are illustrated in Fig. 2, the blue color - which shows difference signal for all color the original Ea' - Er' and video EB' Ep components frequencies, to maintain the accuracy COLOR WHEN SCANN - in quadrature, and of the green color BLUE their phase relationship to the refer- component which is ence burst. recovered in the receiver -even though The resultant chrominance PREFERRED signal E, produced by these the eye may not appreciate ORANGE compon- part of the -CYAN ents blue signal. AXIS is also shown. The wide -band In our previous discussion, we learned color difference component which is substituted for ER that the blue color channel is limited BLUE - Er', in RED to provide improved color reproduction bandwidth to approximately 600 kc. COLOR WH N SCANNING REO COLOR WHEN SCANNING above 600 kc, is shown Let us see what this means in terms of YELLOW as a dotted line the actual colors being Fig. Colors leading EB' - E, by 33 °. A narrow -band transmitted and 1- reproduced above 600 kc, color- difference received, at frequencies above approxi- when scanning red, blue, and yellow. component is substi- mately tuted for EB' - Er', and is placed in 600 kc. Above 600 kc, the action experience of the low -pass have shown that the two quadrature with the new wide -band filter, in the blue color - colors which color- difference channel, removes give the best results are difference. As a result, the new all the a slightly orange red narrow -band color -modulating components produced and a greenish component leads EB - E by blue (cyan). by 33 °. the blue camera. Because we are These preferred using a suppressed- carrier primaries have been We can retain the identical phase and type of used successfully in amplitude of modulator, the EB' - Er' two -color photog- the original chrominance component raphy. One example you signal below completely disappears in the absence of may be famil- 600 kc, by adjusting the modulation. iar with is the Cinecolor motion -picture process which This means that only results in pleasant color the EB - Er' reproduction, even though modulation components are present at it cannot re- frequencies produce all colors correctly. above approximately 600 kc. Possibly the Since the EB' - Er' component most noticeable improve- has van- ment gained by using the ished, and is no longer acting in quad orange and - cyan primaries -in preference to the rature with the EB' - Er' component, the reddish- phase of the resulting magenta and greenish-cyan pri- chrominance sig- maries-is in the reproduction nal is now controlled by only one volt- of flesh age (Es' tones. Since the eye can detect rela- - Er'), instead of two. tively small errors If we plot the colors that in the reproduction are repro- of skin tones, use of the preferred duced above 600 kc on a color triangle, orange as shown in -cyan primaries above 600 kc re- Fig. 1, we find that we have sults in a straight line running a perceptible improvement. This from reddish - is approached in magenta to greenish -cyan. the NTSC system. In other words, for frequencies above Modifying the I and Q signals 600 kc, we are using what is essentially As we have seen, Fig. 2 -Phase relationship between the it is desirable to I and Q wide Allen B. DuMont Laboratories. Inc. use the original red, green, -band color- difference sig- and blue as nals, and the color- reference burst. RADIO -ELECTRONICS

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Note: EÍ and EQ can also be specified rQUÁL Ey...30ER +.59 EG +.11 E B'= WMINANCE SIG as fixed proportions of Er' - E and ER ZAT ION - Er' as described earlier in this article. RED passed g' W PASS The I and Q signals are E Iti-28E¿+.60 E R'-.32E MOD.I bandwidths 1.5C ÌZÁTÓN through filters to limit their N according to the following specifica- I SUBCARRIER tions: BLUE BAL. LO Q-channel bandwidth EQ-52EG'+2I ER+.31EB' FL 1, 0-600KC at 400 kc less than 2 db down at 500 kc less than 6 db down 1C7HROMINANCE SIGNAL MATRIX UNIT Q SUBCARRIER kc least 6 db down WOW OF PHASE COMPLETE COLOR PIX SIGNAL at 600 at channel bandwidth basic operation of NTSC color television transmitter. I- Fig. 3- Diagram shows at 1.3 mc less than 2 db down at 3.6 mc at least 20 db down Eyi DELAY PROM VIDEO DET EQUAL- television signal IZATION 4. The transmitted color Q are used to mod- IBAND MSS FILTER 2-42MC I The I and signals PISS DELAY I DET LO ulate two subcarriers of the same fre- FILTER --- EQUAL- 0-1.5MC IZATION quency (3.579545 mc) but 90° out of phase with each other. Carrier suppres- I REFERENCE sion is used and the output of the I and Q DET LO PASS a FILTER Q modulators is combined to form 0-600KC chrominance signal which varies in T MATRIX UNIT phase and amplitude according to the Q REFERENCE of the color being 90' OUT OF PHASE hue and saturation in NTSC system. Fig. Diagram shows basic operation of color TV receiver transmitted. 4- The chrominance and brightness signals are combined and used to modulate the transmitter. ER' are the red, green, the color- detector cir- of the new color- difference corn - where ER' E' and To synchronize lengths signal voltages respec- accurately, a burst ponents, as shown in Fig. 2. This is and blue color cuits in the receiver makeup of the tively. of approximately 9 cycles of a 3.579545 done by modifying the resem- on The new color - This brightness signal closely mc reference signal is transmitted color -difference signals. black - sync called EÍ and E,'. bles the video signal in regular the back porch of every horizontal difference signals are and is trans- E,', the wide -band color- difference and -white transmissions pulse. in essentially the same manner. is made up as follows: mitted 5. Recovering the transmitted signals signal, the color signal can be received in E,' = -.27 (Es' - Er') + .74 (ER' - Er') Thus At the receiver the brightness signal and -white by existing monochrome de- EQ designates the narrow -band color- black- is detected in a conventional video difference signal and is formed by: receivers. tector. The I and Q signals are recov- Er') + .48 (ER' -E,') 3. The I and Q signals ered in separate color detectors. The EQ = .41 (ER - combined receiver the phase of the local- The three color signals are required reference voltage for each At the amplifier, in fixed ly generated reference signals supplied in a special matrixing synchronous detector is obtained from is shifted proportions and polarities, to form two synchronized by the to the synchronous detectors re- a local oscillator these new EÍ and EQ modified color- difference signals, color burst. 33° to recover The proportions From these signals, the nec- ferred to as I and Q. original color signals signals. used are stated in the 6. Recovering the essary ER' - E,' and ER' - Er' (and and polarities The three original color signals, ER', E6' Er') color- difference signals are formulas below: E,' are recovered by combining - ER- .32 EB ER and derived. EÍ = -.28 E0' +.59 (E,'), E,' and EQ signals EG' +.21 ER' +.31 ER the brightness The use of E,' and E0' provides im- EQ = -.53 in a special matrixing amplifier in fixed proved color reproduction above approx- proportions and polarities. The values 600 kc, without impairing the RADIO -ELECTRONICS expects soon the formulas below: imately dealing are stated in below this frequency. to begin a series of articles + 1.00 Er' + .96 E,' color fidelity from the view- ER' = .63 Eá along with color television + .28 E; Above 600 kc, we now operate Each of the circuits E0' _ .64 E0' 1.00 Er' - -cyan axis as point of circuitry. +1.00 E,' -1.11 EÍ the preferred orange which make up the color part of a TV E8' =1.72 Eú shown in Fig. 1. will be discussed in turn. We picture discussed receiver 7. Recreating the color Up to this point we have will -of course -also run articles on The three original color signals are individually the important features and various special aspects and subjects tube, recreat- in addi- applied to a color picture techniques used in the NTSC system. in the field of color television ing the original televised scene in color. Now we can summarize how these tech- tion to the circuitry series. END niques are used to transmit color television signals (Fig. 3) and recreate the original color picture at the receiver (Fig. 4).

1. The three -color signals At the transmitter, a special color camera produces three separate signals, representing the red, green, and blue color content of the scene being televised.

2. The brightness signal Fixed proportions of the red, green, and blue color signals are added together in a special matrixing amplifier brightness or luminance to form the E. Cohn, Chicog°. Ill. (Y) signal, as stated in the formula e, AEA II Suggested by Charles below: "Now I know why they call them flyback supplies!" E, = .30 ER' + .59 Eó + .11 ER MAY, 1954

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TELEVISION...

it's a cinch

By E. AISBERG Tenth conversation, first half: a discussion of the composite video signal

From the original "La Télévision? . Mais c'est trés simple!" Translated from the French by Fred Shunaman. All North American rights reserved. No extract may be printed without the permission of RADIO- ELECTRONICS and the author. i

A fransmiffer in boxes KEN -What do you expect to do with that big piece of white paper, Will? Surely we're not going to paint posters today? CAMERA WILL -No, I'm looking ahead a bit, that's all. And I think we'll make a lot more progress if you draw me a complete schematic of a TV transmitter. KEN-Thanks for the compliment, Will! But even if I could draw you a complete TV transmitter diagram right off the cuff, it would only confuse you. What you need to know VI PEO is what kind of signals the transmitter puts out. Here, let me draw your AMP diagram -in one corner of the paper. Is this schematic enough for you? WILL -- That's what I call an apple -box diagram. You VERTICAL have a complicated assembly hid in every one of those little SWEEP boxes. But maybe a diagram like that could give a person an idea of a whole system and how its parts are tied together. KEN -Well, this bunch of apple boxes does HORIZONTAL r.f make up a television transmitter. It's a little simplified, I admit. I've SWEEP AMP. f left out all the power supplies, including the camera tube's. -4ti By the way, the camera is nearer to a true schematic than any other part MASTER of the diagram. But maybe I should have made it a pictorial, so we could show the electronic view- OSC. finder. WILL -And what would that be? KEN -The TV equivalent of the optical viewfinder on your camera. It lets the operator frame and focus the scene correctly. Imagine a little TV receiver (with a 5 -inch tube) minus front end and pix i.f. amplifier sitting right on top of the camera, and you have it. The operator looks at the image on the picture tube of this sawed -off receiver, and can tell exactly how the televised scene is being viewed by millions of other spectators. So he frames his picture and varies the stop and focus to give the audience (and himself) the clearest picture. WILL -I see that the vertical and horizontal sweep of the camera are connected to a pulse generator. Is that where we get the sync pulses? KEN -Yes. They come from a pulse or sync generator. But don't get the idea that this generator is a simple little gadget. The pulses it produces are the very ones that keep RADIO -ELECTRONICS

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with the picture at the station and in your receiver in step It gives us the horizontal and vertical sync each other. signals that pulses and the equalizing pulses and blanking television signal ready are needed to make the complete HORIZONTAL vERrio1l for transmission. 1 sync? I suppose it WILL -Both horizontal and vertical SWEEP SP/HP has to have two oscillators -one for each frequency? generally. The most common method is to use KEN -Not second. one oscillator whose frequency is 31,500 cycles per frequency is divided to get the horizontal pulses Then this gives and the much lower vertical sync frequency. That stable system -you're sure the vertical and you a more other. horizontal signals can't get out of step with each plain apple box marked "Pulse Gen- WILL -H'm -m -that full of erator" begins to look more like the "black box" like to talk about! tricks the engineers It KEN -Don't forget this is a very important generator. the whole synchronizing part of the transmitted supplies synchro- television signal, and so keeps all the receivers PUISE nized with the transmitter. suppose that this "mixer" you show just after WILL -I synchro- the generator is the equipment that combines the CENERATDR nizing and video part into the complete TV signal? And it also includes an amplifier for the KEN -Exactly. can be video signal, as well as a monitor receiver (which an ordinary TV receiver, because it has its simpler than receiver video signal already detected for it). The monitor the voltage of the sync pulses so that is used to adjust the they're in proportion to the video signal. And after CAMERA PI/1ff this mixer, we can handle it just like signal gets through it the audio frequency in a radiophone transmitter -feed GENERATOR stage. There, it varies the amplitude of the to a modulator oscillator. r.f. oscillations produced by a very stable master through a power amplifier, the modu- Finally, after going radiated lated ri. currents are sent to the antenna and into space. More light, less power we follow that example! Let's leave the WILL -Suppose to go to the receiver. We're going to have transmitter and and work with receivers rather than transmitters anyway, like to put in my time learning about them. 'MIXER I I'd in space for KEN-You'll be better off to hang around the transmitting and receiving antennas a while -between signal -while we learn more about the composite television the waves are carrying. we already know that the signal is "corn - WILL -Don't values of the modulation which interprets the light -AN* posed the picture "? of the successively scanned elements of That's the video signal. We have to include the KEN- TV signal. sync signals in the complete, or composite, course! And I've been doing quite a lot of WILL-Of I can't thinking about synchronization. But some things - --75%- example, how can the receiver distinguish figure out. For how video and sync signals? And, if it can do that, between and vertical does it know the difference between horizontal sync pulses? is a matter of amplitude. Voltages la KEN -The difference -.i ¡4.-sync of the maximum are used for the video signal. below 75% of signal. Sig- The 75% level is black; white is the absence those two levels appear as halftones, or grays, nals between this drawing. on the picture tube of your receiver. Look at black and white, WILL -So we get these grays, as well as this video signal and applying it to the grid by detecting strongest signal of the picture tube. Hut why should the you the weakest light, and vice versa? give II is a matter of choice. I KEN negative transmission I -Our vi obp Signa I I I use positive transmission, and their England and France I 30% of total amplitude TI region is between 1 synchronizing the sync signals Sere daretiow and zero. Hut we think it's better to have are less likely to o/ one fine ' ¡ up near the maximum power level, so they with than the weaker ones of positive trans- be interfered don't have mission systems. Incidentally, the video signals the receiver's picture tube. They to be applied to the grid of Heiri2ontD/ SweC ¡rofra,e to the cathode in some receivers. pplied don't get to LL hope those powerful sync signals -I They would grid -or cathode -of the picture tube. Y, 1954 11) www.americanradiohistory.com 44 I TELEVISION

drive the spot beyond zero light level -make it blacker than black, you might say. KEN -"Blacker than black" is just what they do say! And I have bad news for you: The sync signals are applied to the control grid of the picture tube. What harm can you see in it? On the contrary, it's a great advantage to have the spot invisible while the sync signals are being received! WILL -I don't see why. KEN-You're not as bright as usual today ... Just sort of follow in your mind the track the spot would make during the sync period. WILL-Let's see AVEE P -the sync signals start the spot on its return journey, both at the ends of lines and the end of C/RCU/T,J' fields.... Oh, I see it now! Of course it's a great advantage to blank out the spot so the return movement won't be seen on the screen. So that's why they make the signals "blacker than black" and even follow them with a little step just at the black level, as you show in your little drawing. KEN- That's not the only reason. The difference in strength makes it possible to separate the sync from the video signals and send them to the proper sweep circuits. WILL -Now I'm beginning to see light than in this blacker- -black subject. The composite signal is applied to the grid (or whichever is the control element) of the picture tube to vary the brightness of the spot during the scanning time and to blank it out during its flyback periods. And the sync signals are separated from the others because they are stronger. Then they go their own way to keep the and vertical horizontal 15% synchronizing signals perfectly timed. Horizontal sync signals WILT. -Now, another important point. How much time do these sync signals take up? KEN- Including the "pedestal" at the black and level (b to c d to e in the figure) they have to extend just a little beyond the time it takes for the spot beginning to get back to the of its trace, so that it will be blanked out the whole during trip. Under our standards, the horizontal sync signal takes up just a little less than 20% takes of the time it to trace a line. When we talk about a 525 -line system, the time taken by each line (including the horizontal ing blank- I l pulse) is 63.5 microseconds. About 55 , microseconds that is of -+06),(6 the scanning trace, and around 8 is spent on the return trip. And the whole time IMMOM, alloted to the sync signal (between its two black-level steps) is about 10 microseconds. WILL -Then the horizontal sync signal is a pulse about 10 microseconds long? KEN -Go easy, Will! The pulse itself is only about 6 microseconds long. But it has those two black -level we've steps been talking about-one ahead of it and one behind it. WILL -Just a second! Give me a hand straight to get myself on this. I want to follow a line from beginning to end. First of all, during about 80% or more of the have time, we the video signal (points a to b on your figure). This signal varies from a low level to about 75% of maximum signal. During this time, the horizontal sweep circuits of both the transmitter and receiver are producing the rising part of the sawtooth wave. Then for a microsecond or two (b to e) the signal stays at the black level (75 %) with the spot still going from left to right toward the end of the line. Then the pulse itself comes along, and the transmitter signal rises to 100% of full output. This sudden jump (e) discharges the sweep oscillator (as we learned a long time ago) and its sudden drop in voltage sends the spot back toward the left side of the screen. It gets there just about the time the pulse drops to the 75% level (d). Then we have a little safety zone (d to e) in which the spot remains invisible as it starts out to start tracing another line. KEN -I see that you've got more help from my drawing than from my explanations! WILL -And how is it at the transmitter? Do they apply the same type of signals to the TV cameras to blank out the spot during return traces? KEN -Of course. Otherwise the scanning beam would set up charges on the photosensitive element during the return trace. That would mess up the picture -you'd have retract lines in it. (TO BE CONTINUE RADIO- ELECTRONI

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Overall IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIpIIIIpIIIIpppIIIIIIIIIIIIIIIIIIIIIIIIII IIIIIIIIIIIIIIIIIIIIIIIIIIIIIII antenna length (in inches) Channel (Corrected for Reflector Director TV Number end- effect) (inches) (inches) Antenna dimensions. Arrows indi- 2 97.2 102 93.3 cate similarity in SERVICE reflector and direc- 88 92.31 84.4 tor lengths on CLINIC 3 adjacent channels. Conducted by 4 80 84.377 MATTHEW MANDL* 5 70 73.6 67.3 IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII II III IIIIIIIIIIIINIIIIIIIIIIIIIIII 111111111111111111111111111119 6 65.2 68.2 fl 62.5

with the best signal -to-noise Spring clip arcing SERVICE shops are often called the one ratio can be chosen. Many boosters 16R50 receiver upon to minimize radio interfer- with cas- In a Traveler model by nearby -television will not function properly there is considerable sparking between ence caused tuners. In the latter, noise receivers. The best procedures code type the spring clips on the high -voltage of- reduction is over 35% greater than -tube coating. I consist of liberal shielding of the a con- cage and the picture with older type tuners. When the worn conductive coat- fending receivers. r.f. stage is used in have recoated foil-kitchen- ventional pentode ing on the picture tube but this did not Ordinary aluminum will introduce considerable be used for lining the inside a booster, it help. The cage is making good contact type -can noise and nullify the high signal -to- much ap- of the, television cabinet. It can be to the chassis. I would very noise ratio obtained with the cascode D. B., Green- stapled to the cabinet or applied with have preciate any suggestions. metal cabinets). At- tuner. Some manufacturers field, Ohio. plastic tape (on boosters which will func- section of the foil shield brought out tach one tion properly with the cascode -type Since you have recoated the picture to the chassis. should also clean the spring of transmission line tuners. tube, you The short section contacts so they will make good elec- connecting the tuner to the antenna interference sure they interference Adjacent- channel trical connection. Also make terminals often picks up for loose and corroded con- their radiation by trying to correct interference are tight, signals and causes I am tacts will aggravate the arcing. the antenna system. This section of on channel 3 in our area in an installa- persists it may loosely Yagi antenna If the condition still ribbon lead should be wrapped tion using a 5- element an internal leak within foil and the foil should oriented. Channel 2 be caused by with aluminum which is carefully the picture tube. The outer coating acts grounded to the chassis by a short can be received on the reverse side of be ad- as a second filter capacitor and can length of wire. If the foil is wrapped this Yagi. I would appreciate some since enough for E. C., usually be dispensed with too tightly some signal attenuation vice as to what remedies to try. exists for filtering. may occur. circuit capacitance higher -channel stations Long Bottom, Ohio. can bend the spring clips away leads which run from the chassis fact that you get channel 2 from You The The that from the outer coating and thus pro- to the picture tube can also be wrapped the rear of this antenna indicates of the defective foil and is acting as a long the usefulness loosely with the aluminum the channel 3 reflector picture tube. the latter grounded. A tight wrapping channel 2 director. This will aggravate some of the higher - -channel interference as here may attenuate upper adjacent squeal frequency video signal components be- you detailed. You can try adjusting the High- frequency the the re- cause of the capacitive effects of upper adjacent -channel trap in a high -frequency squeal the i.f. alignment There is shield. ceiver and retouch from a Stewart - Warner model 9200 -A The leads from the chassis to the for a sharper response. Another solu- on. Dur- of receiver when it is first turned yoke should also be shielded to mini- tion would be to increase the length is also some horizon- 3 Yagi ing this time there mize radiation. the reflector rod on the channel and interference bars. 1 of the receiver This will pre- tal instability The drive control antenna to 102 inches. have checked all tubes, as well as re- also be adjusted below the point vent the latter from acting as a director with- should the sistors, capacitors, and voltages, where left -hand stretch or center com- for channel 2 and will decrease success. K. H., Seattle, Excessive drive not mentioned. This would out appreciable pression occurs. interference you Wash. only will shorten the life of the tubes mean, however, that you would no in the horizontal and high -voltage sec- longer be able to receive channel 2 as These symptoms are probably caused tions, but also will increase pulse ampli- well from the rear of the antenna and by the cumulative circuit conditions tudes and aggravate interference to would have to have an additional an- during warmup which permit spurious radios. tenna for the reception of channel 2. oscillations to build up in the horizon- Another topic which has been the As shown in the table, a reflector for tal scanning multivibrator. Since you of several letters lately is snow 3 has almost the same dimen- have checked tubes and component subject channel given effect in boosters, in spite of a good sions as a director for channel 2. The parts, the following suggestions signal reading from the antenna. The same holds true for a channel 4 re- by the manufacturer will help remedy fault usually lies with the first r.f. flector which has virtually the same the condition. in the booster. If tube noises are dimensions as a channel 3 director. A tube a 1. Change the capacitor connected to excessive in an r.f. stage, they will be channel 6 reflector will also act as scan- and also, one plate of the horizontal amplified by subsequent circuits director for channel 5. Directors, pin 2 of the Often, sev- for the next higher ning multivibrator, will appear as snow effect. will act as reflectors from 470 µµf to 390 should be tried so that the dimensions are almost 6SN7 -GT, eral r.f. tubes channel when µµf, as shown in Fig. 1. identical. Author: Mandl's Television Servicing. MAY, 1954

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Wlllllllllllllllllllllllllllllllllllllllllllmllllllllllllllllllllllllllllll"" 'l' 6SN7-GT cA4E To got IIIIPIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIg is applied to the bottom of the 18,000 - 014f MORIZ OSC ADD 2701( ohm cathode ISOV resistor, while plus 200 volts is applied to the screen and to TO MORII OUT the 5,600 -ohm plate FARM resistor. If these voltage relationships NASE CET are upset it will affect brilliancy as well 3.90 as contrast, ICOK 330K-CHANGE TO 6800 since the contrast control is in the cathode of the 6AQ5. Also check the brilliancy- control switch (on the contrast control) , *ONCE T0 3.311 for this may be defective. 8t Fig. 1- Stewart- Warner model 9200 -A Buzz in Admiral IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII horizontal scanning multivibrator. IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII In an Admiral 24D1 I get a 60 -cycle buzz. It seems to come from the vertical section of the 2. Reduce the resistor receiver because when I connected to wire line to the ribbon lead by remov- pull any of the vertical tubes the same point from 3,900 the buzz ohms ing the insulating spacers for 100 inches stops. I have replaced the vertical block- to 3,300 ohms. from the end. Now ing- oscillator 3. Increase taper the spacing transformer and a num- the resistor connected to of the 100 -inch section to meet ber of resistors the other plate that of and capacitors without of the same stage the 300 -ohm lead spacing. This tapered success. S. S., Red Lion, Pa. -pin 5 of the 6SN7 -from 330,000 line section will give a It is to 680,000 fairly uniform evident that the buzz is being ohms. match for all channels. picked up from the vertical 4. Add a 270,000 -ohm, -watt section as 1 re- you surmised. The Admiral service sistor, connecting one end to the Yoke arcing notes plate (pin recommend that a shield be added 5) and the other end In a Hallicrafter model 1004 the between the vertical -oscillator to any 150 -volt supply point. tube and raster flicks off and on every few sec- the audio.output tube to minimize the Yoke removal onds when the receiver is first turned 60 -cycle pickup. This shield is Admiral on. After warmup, the part I would appreciate condition occurs 15B625, and holes are available in any information less frequently. The yoke clicks the earlier 24D1 on getting loose a deflection each receivers to accom- yoke that time the raster disappears. I've tried modate two No. 8 -32 self -tapping screws is stuck to the neck of the picture tube. new tubes F. in the entire horizontal sys- for mounting the shield. K., East Pittsburgh, Pa. tem and have checked resistors If the ground Generally, when and lead from the volume the deflection yoke capacitors. D. D., Hobart, Ohio. control is connected to the grounded sticks to the neck of the picture tube, The click heater technicians in the yoke when the raster pin of the first audio tube it apply to it a voltage of disappears indicates should be sufficient amplitude an arc in the hori- transferred to the grounded to heat the unit. zontal deflection coils which shorts out cathode pin 7. It is also possible that This can be done with a vari- the high voltage. the able voltage This trouble some- a.c. power leads to the switch on transformer. The trans- times occurs in that part of the volume control former is adjusted the yoke run too close to the to a voltage output housing which contains the shunting grid circuit (pin 1) of which will make the yoke this stage. They fairly warm resistors and capacitor, particularly should be moved away. Also make sure after a few minutes. This usually during warmup before the .01 -µf loosens the full load drops coupling capacitor between sealing compound sufficient- peak voltages to lower values. the volume control and the ly so that the yoke Arcing grid has the can be removed. can overheat soldered connections or outside foil connected to the volume If the yoke is already damaged and components and cause intermittent control. must be removed, acetone or speaker operation. Check this by removing the cement solvent can be used. This should yoke and inspecting the Intermittent vertical centering be permitted section con- to run into the yoke in the taining the aforementioned In an Admiral 20T1 area which encircles parts. If receiver the the picture tube the arcing is taking place inside the picture changes position vertically, leav- neck. Such solvent usually affects the windings, a new ing a dark insulation yoke will have to be area at the bottom. This of the yoke windings and installed. occurs only once every several should not be hours used except on a yoke and returns to normal almost immedi- which is to be discarded. Contrast in Magnavox ately. 1 have tried tube changes but this I am did Open -wire line having difficulty locating the not help. When the antenna is dis- trouble in a Magnavox connected, the same I find CT297 chassis. thing happens to it necessary to run a transmis- In order to get proper contrast, the raster. T. C., Philadelphia, sion line for 1,000 feet. the Pa. I am now using control must be advanced fully and this If centering disturbance in a vertical a polyethylene -insulated No. 16 wire, is accompanied by unstable plane is the only symptom, but do not horizontal it could be have the correct spacing for sync. I have checked all tubes from caused by a variation in J00 ohms. My spacing the the voltage is about 2% tuner through the video i.f. stages, and applied to the vertical deflection inches and 1 coils. have the line twisted at the those in the horizontal sweep system. Initially, check entrance to the house. the low- voltage power All voltages and resistors check all supply feed to the vertical deflection My signal strength is down and the right against the schematic except at coils. Then check for defective com- snow effect is bad at times. How can I the cathode of the 6AQ5 improve the installation? video -output ponents in the vertical output circuit, C. W., Poca- tube. This reads minus 6 instead hontas, Va. of particularly the voltage feed to the minus 20 volts. I have tried a new The severe mismatch between your cathode oscillator and output tube. Also check -bias resistor without improve - the vertical- present line and the 300 -ohm input at inent. Y., New York, size -control potentiometer the M. N. Y. for an receiver contributes to your trou- As you have checked all tubes, intermittent- contact condition bles. It is impractical volt- or change in value. to try smaller ages, and components, the trouble may spacings for the open -wire lines to get be caused by poor tuner tracking The B plus for the vertical oscillator a 300 or -ohm impedance, because capaci- video -i.f. alignment. It is possible, and output tube is derived from the tive losses increase. how- Install the regular ever, that you have overlooked the voltage boost system in the 6W4 -GT open -wire line available at your whole- 1N60 crystal video detector. This .damper. Any voltage change sale jobber and may in the run this from the an- be causing the poor contrast. Also damper (or a change in the horizontal tenna to the place where the line is to check all the circuits associated with circuit flyback characteristics) will enter the home. From here on in you the in- 6AQ5 video -output stage to ascer- fluence the vertical circuit. Try a new can use the standard 300 -ohm lead for tain why the cathode convenient voltage is in- damper; if this doesn't help, check the installation. Match the open- correct. In this stage, minus 100 volts parts in the voltage boost system. END RADIO -ELECTRONICS

www.americanradiohistory.com TEST INSTRUMENTS 147

Fig. 2 -a. The shielded cable eliminates the pickup of stray fields about the test bench, which would otherwise disturb the high- impedance input circuit of the v.t.v.m., and cause inaccurate indication. The isolating resistance prevents the shielded cable from acting as a capacitive shunt across tuned and high - impedance circuits, such as the local - oscillator in a receiver. The equivalent circuit in Fig. 2 -b pplications in shows that the cable capacitance C is isolated from the probe tip by the 1- megohm resistor, which cuts down the effective value of C to approximately 1 or 2 µµf. This is a large reduction, as compared with the approximately 75 µµf of cable capacitance. Hence, the TVservicing.... d.c. probe can be applied across a local - the self- The Simpson model 303 oscillator circuit to measure vacuum tube voltmeter. bias on the oscillator grid, without disturbing circuit operation. The equivalent circuit is also a low - pass filter. This is an essential feature, since d.c. voltages at the grids and plates of tubes often must be measured By ROBERT G. MIDDLETON* in the presence of large a.c. voltages. If the probe permitted a.c. voltages to d.c. voltages in i.f. be impressed on the v.t.v.m. tube with TV SERVICE technicians use a used to measure when the meter indi- d.c. voltage, highly inaccurate indi- wide variety of test instruments amplifier circuits; the cation varies as the test leads are the operation of antennas, CABLE to check that lead resonance ,SHIELDED lead -ins, front ends, i.f. amplifiers, moved, it indicates rVti 0 into oscillation. V.LV.M sweep has thrown the stage DC VOLTAGE IN video amplifiers, sync circuits, T- o circuits, high -voltage circuits, and over -all performance. The minimum Vacuum -tube voltmeters requirements of a one -man shop include The d.c. voltage system of a typical C signal generator, oscillo- v.t.v.m. is shown in Fig. 1. When d.c. T a v.t.v.m., 6 scope, and sweep generator; most tech- voltages higher than 1,200 are under nicians also have a tube tester. Many test, a high -voltage multiplier probe is Fig. 2- Diagram of d.c. probe shows shops regard additional instruments as used ahead of the instrument. When shielded cable and equivalent circuit. essential, such as audio oscillators, high- frequency voltages are to be frequency me- a half -wave peak rectifier or cations would result. As a matter of square -wave generators, measured, another ters, field- strength meters, pattern gen- a peak -to -peak rectifier is used ahead fact, v.t.v.m. design includes -dip meters, capacitor of the instrument. Calibration control A low -pass filter at the grid of the v.t.v.m. erators, grid voltage is checkers, sensitivity checkers, etc. determines the full -scale deflection, and tube to insure that no a.c. Nevertheless, the v.t.v.m. is the key control B determines the linearity of applied to the grid. layout. To measure the second -anode voltage instrument in the deflection. types Vacuum -tube voltmeters have under- A v.t.v.m. is called upon to make of a picture tube, and for other development during of d.c. voltages from less of tests which will be described, the gone considerable measurements shown the past several years. Copper -oxide than 1 to as high as 25,000; to measure isolating resistor arrangement which are applicable only at resistances from less than 1 ohm to in Fig. 2 is changed to form a high - rectifiers high -voltage low frequencies in low-impedance cir- several thousand megohms; to measure voltage d.c. probe. The 3, and is cuits, and which can measure only ri. and i.f. voltages from a fraction of d.c. probe is shown in Fig. r.m.s. values, have given way to diode a volt to 25 or 30; to measure the peak - indicating arrangements. voltages of complex video, sync, peak -to -peak to -peak ---NN`' o ----- TO V.T.VAI. from and to measure IN D.c. scale ranges now extend and sweep waveforms; DC VOLTAGE 0 1 to 30,000 volts, full scale. direct current throughout the milliam- to Using a voltmeter might appear pere range. Fig. 3 -The d.c. high -voltage probe. be an elementary matter, but the pecu- To meet this wide range of require- liarities of television circuits frequently ments, the v.t.v.m. is used with various usually designed to multiply each range complicate it. For example, the test external probes. For example, d.c. volt- of the v.t.v.m. by 100. This multiplying leads of a volt- ohm- milliammeter occa- age measurements from 0 to 1,000 are factor is of considerable use in other sionally operate as resonant stubs when made with a shielded cable terminated types of tests such as measuring low resistor, as shown in in the presence of high - Electric Co. with an isolating d.c. voltages +` *Field engineer, Simpson voltage a.c. pulses. thought that a high - 40V It is generally -I- voltage d.c. probe can be used with a Note: The 1.2 v tap at right end of voltage divider should read "1.2 kv." scope for the investigation of complex un- 500 B a.c. waveforms -this is largely an o ADJ CALI. misconception. When such a (SERVICE fortunate 1.2V 12V . 12V . 60V 300V ADJ.) probe is used with a scope, the attenua- IMEG 12.5K _ tion is not constant; i.e., the attenuation 4.5MEG 400K 80K 15K 5K different DC PROBE 4MEG found at 60 c.p.s. will be very -60V 4 mc. Hence, K from the attenuation at CALIBRATION peak -to -peak voltages cannot be meas- GND (SERVICE ADJ) ured when the probe is misused in this 2008A 650n manner. Also, stray fields often affect the distorted waveform, to further Fig.1- Diagram shows basic d.c.voltage circuit of the Simpson model 303 v.t.v.m. MAY, 1954

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confuse the technician. v.t.v.m. These fall into three general eral considerations as have The measurement of high d.c. volt- classes, been noted based upon voltage -handling for the half -wave type of probe. The ages, such as the second anode voltage capability and the type of indication of a picture tube will withstand much higher tube, with a v.t.v.m. and they provide. Fig. 4 shows a tube type voltages high -voltage d.c. probe are than the crystal diode. rather well rectifier probe, which will handle mod- In some cases, understood. Less understood is the erately the peak -to -peak indi- high voltages, and provide cating arrangement is built into the measurement of relatively low d.c. volt- negative -peak voltage indication. The ages v.t.v.m. This raises the input capaci- in the presence of high a.c. pulse 0.01 -µf capacitor charges up to the tance voltages, such as the plate voltage at of the arrangement, but also pro- negative -peak value of the applied a.c. vides a much greater voltage -handling the horizontal-output tube. Receiver waveform. R is an isolating manufacturers and cali- capability, since a compensated multi- commonly insert a tech- brating resistor; in its absence the plier nical note in their service data, then precedes the rectifying tubes, warn- cable capacitance would shunt down and will usually raise the ing against attempts to measure the the top range of diode and bypass the a.c. signal. peak -to -peak voltage measurement to d.c. plate voltage of the horizontal out- The value of R must be properly put tube. This 1,000. Such a range will accommodate is because the approxi- selected to provide the desired scale the majority mately 350 volts d.c. is accompanied by of complex a.c. waveforms indication -usually to indicate the encountered in a TV chassis. an approximately 6,000 volt kickback r.m.s. voltage of a sine wave. The pulse. The pulse is an a.c. voltage and 10- megohm resistor is a bleeder, and is does not show PROBE A5 534 itself on the d.c. scales used to avoid undue lag in return of UTH of a v.t.v.m. Nevertheless, this high the meter pointer ~= R to zero. If very low o pulse voltage draws a heavy pulse cur- CA' TH frequencies are to be accommodated, ~J TO V.T.V.M. rent through the input -ND circuit of a the value of the 0.01 -0 capacitor must 1.05 o v.t.v.m. or volt- ohmmeter, and quickly be increased correspondingly. Fig. 6- Peak -to -peak indicating probe. ruins the instrument. A similar crystal -diode type of rec- Recalling that a high -voltage d.c. tifier probe is illustrated in Fig. 5; When a demodulator probe probe will provide is used on a high degree of low- such a probe is commonly rated to the d.c. ranges of a v.t.v.m., the indi- pass filter action, it can be seen that approximately 20 volts, and provides cation is proportional the high-voltage to the amplitude d.c. probe makes this peak indication. The characteristics of of the r.f. carrier in a modulated wave, type of measurement possible. For ex- a typical probe of this type are given but when ample, the used on the a.c. ranges of a v.t.v.m. can be set to its in Table I, which shows that the input v.t.v.m. (having peak -to -peak facilities 6 -volt range, and when used with a impedance may not always be suffi- built high -voltage in), the indication is proportional d.c. probe having a 100 -to- ciently high to avoid throwing i.f. to the peak value of the modulating 1 attenuation factor will indicate the stages into oscillation. However, vari- waveform. 350 volts d.c. at approximately half - ous expedients can often be used in The ohmmeter range scale of the v.t.v.m.; of a v.t.v.m. at the same time, case of difficulty, which we plan to (Fig. 7) is used to check both linear and the low -pass filter action of - the high discuss in future articles. TO DCV INPUT OF voltage d.c. probe effectively protects It might be supposed that a rectifier the v.t.v.m. against the 6,000 -volt a.c. probe and a v.t.v.m. could be used to PROBE pulse. signal -trace the i.f. circuits of a TV IX Kf OMEG receiver, but the low signal level in the I.5V early stages limits this. The full gain o t PROBE TIP of a 3 -stage i.f. amplifier is about IO MEG 5,000; so Fig. 7- Simpson v.t.v.m. ohmmeter cir- TO V.T.V.M. with a 2 volt peak -to -peak input to the video detector, the corre- cuit. ¡ND sponding input to the first i.f. grid --o will nonlinear resistance Fig. 4 -A tube type rectifier probe. be 0.0004 volts peak -to -peak. Since a values of compo- v.t.v.m. does not satisfactorily indicate nents in the TV chassis. Some of these Some v.t.v.m.'s have zero -center indi- voltages below approximately 0.1, a applications are not as well understood cation, while others do not; still other serious signal- tracing limitation is as they should be. Not only does the v.t.v.m.'s provide a choice of zero -left, imposed. question often arise concerning what or zero -center indication on d.c. ranges. The peak -to -peak type of probe used measured value of a nonlinear resist- The zero- center feature is convenient to measure peak -to -peak voltages of ance is acceptable, but there is also when adjusting discriminators, where complex a.c. waveforms, is shown in the dan, ar of damage to the component the output voltage swings through both when such measurements are made on positive and negative values during 27oppt R u.h.f. mixer crystals or the filament circuit adjustment. 22K - resistance of small tubes. TO V.T.V.M. The ohmmeter is useful to measure The high- frequency voltage-measur- I548CATH 1205 ing section of a the front -to -back ratio of a video detec- v.t.v.m. is useful in Fig. checking the operation of a.c. circuits. 5- Crystal diode rectifier probe. tor crystal, to determine whether it is This is a field in satisfactory operating condition. of servicing which has Fig. 6. Tubes been the subject and crystal diodes are The front -to -back ratio will depend of extremely rapid used commercially, with the changes in the last few years. Not long same gen- upon which ranges of the ohmmeter ago all a.c. measurements were carried out upon the basis of sine -wave indications, and this approach is still basic in TABLE radio receiver servicing. However, with I- CHARACTERISTICS OF FIG. 5 PROBE the arrival of television, the technician Frequency capability: is faced with the necessity of measur- Carrier frequency 500 kc to 200 me ing peak -to -peak voltages of complex Modulation envelope frequency 30 c.p.s. to 5 kc a.c. waveforms. In some cases, the Input capacitance peak -to -peak values must be further 2 5 µµf broken down into positive -peak values, Input resistance: negative -peak values, and component At 1 me 25,000 ohms values, to pinpoint various circuit At 10 me 20,000 ohms faults. At 50 me 10,000 ohms To meet these requirements, various At 100 me 5,000 ohms instrument manufacturers provide ac- At 200 me 2,500 ohms cessory rectifier probes for use with a RADIO -ELECTRONICS

www.americanradiohistory.com TEST INSTRUMENTS 49

are used, and upon the voltage of the TABLE II- V.T.V.M. APPLICATIONS AND LIMITATIONS internal batteries of the ohmmeter. feature Applications Misapplications These complications are based upon of a crystal D.c. voltage measure- Checking values of plate, Attempted measurement the nonlinear resistance nient, with high input screen, and grid volt- of plate voltage of hori- diode. Since resistance is the ratio of impedance, even on the ages; tracing progress zontal- output tube; high - voltage to current when the resistance tow -voltage ranges. of signal by measure- voltage a.c. pulse darn - resistance (Measurements made ment of self -bias (only ages v.t.v.m. Attempted is nonlinear, the apparent using shielded cable ter- in circuits using over- measurement of grid will measure different values at various urinated with 1- megohm drive grid bias) ; check- bias in vertical blocking Voltages are applied to the insolating resistor.) ing local -oscillator oper- oscillator circuit when voltages. ation by measurement grid leak has very high crystal diode on various ranges of the of self -bias; checking resistance; v.t.v.m. will ohmmeter, and hence various resistance for amplifier distortion load circuit seriously. At- in terms of shift of oper- tempted measurement of values are obtained. sting point with applied pulsating d.c. voltage A crystal diode in good operating a.c. signal; measurement values; v.t.v.m. indicates condition may have a front -to -back of voltages in high re- only the average value. when meas- sistance circuits such as ratio of 1,000 to 1, or more, a.g.e. systems, etc. ured on the R x i ranee in the low - Checking peak -to -peak Attempted signal tracing resistance direction, and on the R x A.c. voltage measure- rela- ment, in peak -to -peak voltages of most of the in tuned circuits; 10,000 range in the high- resistance values, using built in complex a.c. waveforms tively high input capaci- of v.t.v.m. serious- direction. However, an ohmmeter using peak -to -peak indicating found in the sync and tance sweep sections of the TV ly disturbs circuit opera - 11/2-volt internal battery will indicate circuit and low -capaci- voltages less a tance a.c. test cable.' chassis. Also, checking tion, and a lower front -to -back ratio than an line voltage and power- than 0.1 volt cannot be with certainty. using a 3- or 41/2 -volt bat- transformer voltages, be- measured ohmmeter ing certain to convert Attempted conclusions tery. When checking u.h.f. mixer crys- from peak -to -peak to concerning waveshapes tals, not more than 11/2 volts should be r.m.s. values of sine or frequency components the crystal; hence, to waves. Checking most of complex a.c. wave- applied across al. voltages. forms; no information of avoid damage to the crystal if the ohm- this sort is provided by meter uses internal battery voltages a peak -to -peak v.t.v.m. higher than 11/2 volts, the resistance A.c. voltage measure- Checking line voltages Attempted checking of measurement should not be made on the ments, in r.m.s. values, and power- transformer complex waveform volt- using voltages, and checking ages in sync and sweep R x 1 range. Instead, the measurement with instruments built -in copper -oxide con- the lower audio -frequen- circuits; indication is al- should be made on a higher resistance tact rectifier. Prequency cy voltages in relatively ways erroneous (peak - the voltage ap- are same as low-impedance circuits. to -peak values can be range which will limit limitations for sine the u.h.f. mixer crystal to v.o.m. with similar recti- Checking heater voltages. determined only plied across fier. waves). Attempted sig- 11/2 volts, or less. nal tracing in tuned of small battery - circuits; no indication The filaments obtained. operated tubes sometimes can be damaged by excessive ohmmeter voltage. A.c. voltage measure - Checking peak voltages Attempted checking of ments, in peak values, of some oscillator cir- complex waveform volt - The filaments are nonlinear resistors, using external diode cuits.Checkingsine -wave ages in sync and sweep and will measure correct (rated) probe. audio -frequency voltages. circuits; indication is only when the Checking line voltages, peak value (peak -to -peak values of resistance power- transformer, and value can be determined rated voltage is applied across the fila- heater voltages, being only for sine waves). At- ment (typically 11/4 volts). Meter certain to convert from tempted measurement of be damaged by peak to r.m.s. values of voltage values exceeding movements can easily sine waves. input rating of probe. ohmmeters. The correct method of Attempted r.f. or i.f. measuring the internal resistance of a signal tracing. meter is the half -scale method, dis- A.c. voltage measure- Checking of peak -to- Attempted measurement cussed in many standard technical merits, in peak -to -peak peak values of many of of a.c. voltage values ex- values, using external the complex a.c. wave- ceeding input rating of texts. peak-to-peak diode probe. forms encountered in the probe. Attempted meas- Although a v.t.v.m. can be used to (Provides higher input sync and sweep sections urements in high- imped- measure current, such measurements impedance than built -in of the TV chassis. Check- ance circuits, such as volt- peak -to -peak indicating ing a.f. voltages. Check- ratio -detector circuits. are seldom necessary, because the circuit, but input voltage ing line voltages, power- Attempted signal trac- age drop across a known resistor indi- rating is usually less.) transformer, and heater ing of r.f. and i.f. tuned flow (Ohm's law). voltages, being certain to circuits. cates the current convert from peak -to- peak to r.m.s. values. Conclusion Resistance measu re- Measurement of forward Attempted measurement Although a v.t.v.m. provides a wealth ments, when internal and back resistance, and of high resistance val- ohmmeter battery volt- front -to -back ratios of ues, such as the leakage of information, there are various fields all crystal diodes, includ- resistance of paper or age is higher than 1.5 (unless of testing which are closed to the in- pro- ing u.h.f. mixer crystals. mica capacitors (Some ohmmeters of most re- high driving voltage is ( see Table II) . For example, volt- Measurement strument vide a low driving sistance values encoun- provided on the high-re- although a v.t.v.m. provides informa- age on the tow -resistance tered in TV chassis. sistance ranges). At- tion concerning peak -to -peak voltages, ranges, and a high driv-ree tempted measurement of of the volt- ing voltage on the high- resistance values in hot the instrument tells nothing resistance ranges.) circuits, or in circuits ? age waveshape. In many cases the wave - with capacitors retain shape is even more important than the ing residual charge. voltage value. This type of information Resistance measure - Measurement of forward Attempted measurement with the oscilloscope. and back resistance of of the filament resistance must be obtained ments, when internal battery -oper- There are times when a peak -to -peak ohmmeter battery volt- Picture- detector crystals, of small age is higher than 1.5 but not of u.h.f. crystals ated tubes. Attempted indicating v.t.v.m. gives erroneous (on low ranges). (except on higher ranges, measurement of the inter - -to -peak voltages because of exces- to limit terminal voltage nal resistance of meter peak to 1.5). Measurement of movements. Attempted sive circuit loading; such a situation all resistances found in measurement of resist - may be encountered at the grid of a TV chassis, with excep- once values in hot cir- blocking oscillator, in ratio - Don of leakage resist- cuits, or in circuits with vertical ance of small capacitors. capacitors retaining re- detector circuits, or in self- excited sidual charge. sweep circuits. However, in such cases can be used to obtain Note: The high- voltage d.c. probe which is usual y available for use with other instruments service v.t.v.m.'s, is unsuitable for use on the a.c. voltage ranges of the v.t.v.m. the needed information. Attempted use of the probe to measure high a.c. voltage values, such as the (TO BE CONTINUED) pulse voltage at the plate of the horizontal output tube results only in failure.

MAY, 1954

www.americanradiohistory.com 50 I TEST INSTRUMENTS

Sine and Square Wave Generator Tite Eico model 377 ranges from 20 to 200,000 cycles per second

By P. N. MARKANTES

M AST ráe:s UNTIL a few years ago, square - e ét9 e wave generators and precision audio oscillators were considered laboratory equipment rather than repair bench adjuncts. With the increasing use of wide - range audio amplifiers in high -fidelity systems and modern receivers, audio test equipment ..- that can perform a KATßA AUDIO &t. number of functions has become im- sssa ae portant in servicing. sae uw In the Eico model 377 generator (Fig. 1) the production of pure sine and square waves in the audio range has been combined in a single Fig. 1 -The model unit that 377 generator. can perform wide variety of tests for TV and radio servicing. The generator is available in kit form (model 377K) for those who like to assemble their voltage drop across LM and thus in- results in grid limiting because positive own. creased degeneration in Vl. Thus, the alternations The audio of the input signal cause generator portion of the amplitude of oscillations is auto- grid- current flow. When instrument consists of a precision this occurs, R -C matically limited and voltage variations the grid -to- cathode (Rg_k) impedance oscillator which produces sine waves at the input to V1 remain fairly con- within the tube drops to extremely low from 20 cycles to 200 kc. By covering stant throughout the operating range values. this spectrum Effectively therefore, the in- in four bands as follows, of the oscillator, thus providing linear put voltage is applied a long scale is available: to a voltage operation and pure waveform. divider consisting of R4 in series band A: 20 -200 c.p.s. with E. also appears across the left -hand Rg_k, and since Rg_k is a band B: 200 -2000 but fraction c.p.s. arm of the bridge (1 -4 -2) with the of R4, only a portion of the positive band C: 2000 -20,000 c.p.s. portion between (4) and (2) applied half of the input band D: 20,000- appears across the 200,000 c.p.s. to the grid of Vl. Since this voltage input of V3 as indicated in Fig. An auxiliary 0-100 linear 5. The scale is pro- is in phase with the original voltage negative half of the input is of course vided for reference. variations, it is a regenerative voltage. Harmonic unaffected by R4. distortion is below 0.5 %, In this case, however, the magnitude Two factors act to produce providing a pure sine -wave the wave- output. of the regenerative voltage depends form shown at the plate of V3 -a. First, The audio generator (Fig. 2) con- upon the frequency of E. as deter- the negative alternations sists of of the input a two- stage, high -gain, un- mined by the settings of Cl and C2. voltages are sufficient to drive tuned amplifier and a frequency- the tube deter- At the desired frequency, f °, the re- beyond cutoff and thus round off the mining network consisting of a Wien generative voltage is maximum and top bridge, of the negative alternation; second, shown in detail in Fig. 3. The frequencies on either side of resonance since the tube is over -all operation being driven to satura- of the oscillator can produce voltages which quickly fall tion as well as cutoff, operation occurs be seen in the block diagram (Fig. 4). off from the maximum value. over nonlinear portions When voltage of the tube's is first applied to the R2 is adjusted so that the negative characteristic, thus accounting for the oscillator ( Fig. , 3) a signal voltage feedback voltage is just smaller than increased "squareness ". appears and is amplified. From the the positive feedback at resonance. At plate The output of V3 -a is fed directly to of V2, a portion of this voltage, all other frequencies, negative feed- V3 -b where it is amplified and further E °, is fed through C3 to point (1) of back predominates and thus eliminates squared by operation over nonlinear the Wien bridge where it appears be- any undesired frequency. portions of the tween (1) and characteristic curve. (2). Strictly speaking, the term Wien The d.c. component is then In the right -hand removed arm (1 -3 -2) this bridge as applied to this oscillator is a and a symmetrical wave can be fed voltage appears across R2 and the slight misnomer since the true Wien to V4. lamp, with the portion across the lamp bridge oscillator uses frequency selec- Both sine- applied and square -wave outputs to the cathode of VI. Inasmuch tive negative feedback and untuned are available from a conventional as the voltage which originally ap- positive feedback. At resonance the cathode follower, peared at V4, which provides the grid of Vl undergoes a output of the bridge, and thus the the voltages (shown in table) at all phase shift of 180° in Vl and another degenerative voltage, is zero. frequencies. 180° in V2, E. is in phase with the grid voltage Square -wave output AUDIO -GENERATOR OUTPUT VOLTAGE of V1. However, that por- Load impedance tion of E. which appears Voltage output across the Square -wave output is obtained by 10,000 ohms or higher 14 volts lamp (Ed) is applied to the cathode using the audio oscillator as a timing 1,000 ohms IO volts of Vl. In other words, R2 and lamp generator and applying its output to 500 ohms 8 volts LM constitute a degenerative network. the shaping circuit of V3. Rated power output Is 100 milliwatts Moreover, since LM possesses a posi- The first half of V3 consists of an tive into a 1,000 -ohm resistive load. temperature coefficient, any in unbiased amplifier. A 600,000 -ohm re- Hum level crease in E. results is less than 0.4% of rated in an increased sistor (R4) In series with the grid output, or 0.04 volt. In test applications RADIO -ELECTRONICS

www.americanradiohistory.com TEST INSTRUMENTS I 51

INE

WAVEFORM C3 +/SQUARE 6.2C1 RI e 25 6SN7-GT T+ 5MEG 9501 95K 9.5K 2 9CV v3 S

CI-btCl-5'920ppf

Ia _41 500K. 2.7K 16 OCppt r IOOV + 120

OUT e

_ IOK RS E2-a-1-C2- L 95MEG 9519 9.519 92410

IK 20 + 6X5 550V V. V5 511 Fig. 2- Complete schematic of the sine and square wave generator.

RI =IKOR MORE TO V2 PLATE RItR2 TO V2 GRID MODEL 371 Cl OUT AUDIO GEN. R2

Fig. 6 -An external voltage divider. requiring small signal voltages at very high signal -to-noise ratios, the desired voltage may be obtained by leaving the attenuator at maximum and tapping down the output with an external volt- 6. 45 90 age divider as shown in Fig. /000\a Applications Fig. 7- Patterns indicate null points. For laboratory measurements, the an excellent sig- 4:1 377 generator provides Diagram of Wien bridge circuit. nal source for the operation of a num- Fig. 3- ber of bridge circuits for measuring inductance, capacitance, etc. VI -92 FLAT AMPLIFIER An unknown frequency is easily determined by beating the unknown signal against the generator output and tuning the generator to a null, as indi- IDEGEN. FEEDBACK:FLAT I:3 I :4 cated by headphones or a scope. In the 1 :2 latter method, the output of the generator is applied to the horizontal plates of the scope, and the unknown fre- IREGEN. FEEDBACK :FRED. SELECTIVE quency to the vertical plates. (Both should be adjusted to produce voltages Fig. Over -all action of Wien bridge. roughly equal deflection.) The null 4- 4 e f the unknown frequency is point where Fig. Making use of Lissajous figures. equal to the frequency setting of the 8- generator is indicated by one of several patterns, depending upon the phase difference between the voltages (see Fig. '7). I C Frequencies outside the range of the R generator can be measured by Lissajous EIN as shown in Fig. 8. figures, I 1 - Thus, in Fig. 8 -b, if the generator dial reads 190 kc, the unknown signal is 570 kc. useful application lies in the R -C coupling network. A most of a square wave. Fig. 9- Typical field of square -wave testing. Scope pat- Fig. 5- Formation the passage of a -b. Thus the terns resulting from square wave should ap- shape shown in Fig. 11 wave through equipment can network, the distortion is to tilt the square in Fig. 10 -b. effect of phase considerable information in a pear as the square wave. yield An increase in X, would cause the edges of minimum of time. as in Fig. Fig. 11 -b indicates that the first consider Fig. 9, a fundamental to be decreased frequency distor- As an example, the square wave would ap- visible effects of low- R -C coupling network. 10 -c, and largely to phase distortion typical as in Fig. 10 -d. tion are due Since low -frequency response is de- pear than amplitude distortion. A decrease in X, would cause the rather termined largely by C, any change in If other types of coupling are used, in low -fre- fundamental to be increased as in Fig. the value of C will result wave would have phase distortion may occur when E0 10 -e, and the square the square wave quency distortion. shown in Fig. 10-f. lags E1, in which case normal conditions, the rela- the shape as in Fig. 11 -c. Under Let us consider phase distortion. If will appear tion between X, (reactance of C) and two The good accuracy and long effective frequency (fre- E0 leads E10, and if we plot these R at the fundamental the square wave, we scale of the 377 generator make it setting of the generator) are voltages against the instrument as an quency get the graph shown in Fig. 11 -a. The possible to use such that the square wave and the emergency bar generator for the adjust- as in Fig. 10 -a. square wave, after passing through fundamental appear network will have the ment of TV receiver vertical and hori- After passage through the coupling the coupling MAY, 1954

www.americanradiohistory.com 52 I TEST INSTRUMENTS

zontal linearity. Ideally, of course, the output of a true bar generator is applied to the antenna input terminals, and since the output consists of a high (video carrier) frequency modulated by the test signal, an over -all receiver check is made. In the absence of a bar generator, USE A PHONIC rough checks and adjustments are possible by setting the frequency of the 377 generator at 1,200 (20 X 60) cycles and the selector for square -wave output. This output is fed to the plate A receiver of the first video amplifier through a being checked becomes blocking capacitor, thus resulting in 20 horizontal bars on the face of the pic- an important test instrument when ture -tube screen. Vertical nonlinearity is indicated by nonuniform spacing of properly used with headphones the bars. By VERGNIAUD H. RICHARD

THE most modern radio service signal at this point shows shops that the usually boast a signal tracer trouble is in the following stage or among their various testers. The speaker. Connecting the phones technician and who does not have such blocking capacitor from ground to the an instrument, may none the less enjoy following plate soon tells its the tale. Dis- many advantages thanks to the tortion at this point indicates that the phonic signal tracing system. trouble lies INCREASED between the plates of the %, Many technicians are averse to using first and second audio stages. ,...... e., headphones in the plate circuits of detector r and audio tubes as a service aid. Checking the Like most systems, signal tracing with r.f. circuits phones has its limitations. Those of us If the detector and audio sections are DECREASED X, who have used this method to track in the clear, we can proceed right away to locate the fault in the stages ahead Fig. 10- Effects of reactance variations. down such audio troubles as motorboat - ing, hum, and distortion agree that the of the detector. Now here is the most advantages greatly outweigh the dis- interesting part. Phones do not respond rs- advantages. Of course, it is usually use- to r.f. signals -so what will we use for less in a receiver whose only trouble is a demodulator? low volume. Yet, as a help to enable us The technician will be surprised to 4 f find to criticize the signal quality, it is most out that the demodulator (detec- useful, especially in audio servicing, or tor) he needs so badly is furnished by cases where the trouble is distortion. the receiver itself. True enough, having made sure that the c First, we check the audio section audio section is with O.K., we the phones to make sure that it is free are going to use it along with Fig. 11- Effects of phase distortion. of the particular the detector to do the signal tracing job. trouble involved. Since Referring neither headphones nor the human ear again to Fig. 1, break the Similarly, horizontal linearity is connections of the r.f. transformer at checked by setting the frequency respond to the frequencies in the r.f., to oscillator, and i.f. stages; we point A and do the same thing for the 189,000 (12 X 15,750) to give 12 verti- then proceed to signal -trace the higher-fre- last i.f. transformer at point B. Using cal bars. a jumper with alligator clips at both These are but a quency stages by using the receiver it- few of the many self as a ends, join the disconnected lead of the potential uses of the generator. As signal- tracing detector. the Suppose r.f. transformer to the plate of the user becomes familiar with the instru- a set is brought in to be diode detector. serviced and the complaint is Presto! Chango! The re- ment, many others will suggest them- distortion. sulting circuit, a t.r.f. as Now, the technician knows that this is shown in Fig. selves and thus make the 377 a valuable 2, has taken the place of the more elab- part of a well -equipped service or labo- a trouble that may originate in the r.f., orate mixer, oscillator, detector, superheterodyne of Fig. 1. So far ratory bench. or audio cir- so good, but what about the test? A very common cuits. Tracking it down usually involves application of the Turn on the set and tune in a station, audio generator is in measuring the fre- a series of tests which consume an appreciable amount of time. preferably a local one, the oscillator quency response of an audio amplifier. tube being removed. The When a combina- simplest method is to connect a tion mixer -oscillator tube is used, the vacuum tube voltmeter across the out- Signal tracing audio stages oscillator portion should put of be made inop- the audio amplifier, and connect For rapid location of the trouble, it is erative. Check the output of the loud- the generator to the amplifier input. By preferable to start at the output of the speaker to see if the observing old trouble has the variation in the v.t.v.m. detector, for we will then know whether reappeared. If it has, our search is lim- readings as the audio generator passes the defect is before or after it. Fig. 1 ited to the r.f. transformer, the pre- through a range of frequencies, a rough shows the simplified circuit of a typical selector (r.f. amplifier) tube and its frequency response check is obtained. superhet receiver. Connect the phones circuits. Loudspeaker volume More may be accurate results can be ob- and a .02 -µf capacitor in series across very low from the speaker, so connect tained if there was some means of the detector load resistor R1 or across the headset in the output tube plate switching the vacuum tube voltmeter the volume control. If the signal is clear circuit. This enables us to better judge from generator output to amplifier out- the trouble lies between this point and quality by cutting out outside put for noises. each new setting of the genera- the speaker. Connect one lead of the Having decided that the trouble is tor. By doing this, the generator would phones to the plate of the first audio elsewhere, we proceed to the secondary be monitored for constant output, and amplifier and the other to ground of the first i.f. transformer and more precise results obtained. break END through the .02 -µf capacitor. A clear its connection at C. Use the jumper as RADIO -ELECTRONICS

www.americanradiohistory.com TEST INSTRUMENTS 53

sider it just plain drudgery, you can call the old analyzer to the rescue. One can be put together for everyday use by using a combination of tip jacks, sockets, toggle switches, etc. The cable can be made of flexible wire or just ordinary lamp cord. Old tube bases will come in very handy as plugs and TRACER adapters. In using the analyzer, you SIGNAL will probably experience some trouble by interaction caused by wire capacitances. It may not prevent you from discriminating between the trouble that you are chasing and the one you are creating. On the other hand, you may invite in some squeals, whistles, or motorboating which are most confusing. So, it is safer to stick to the old phones, however toilsome is the process, and spare yourself additional headaches. The technician is confronted by some troubles in the service business which in sheer desperation make him use the kinks. Any re- dure is a combination troubleshooting most rudimentary hints and before to hook it to the detector, despite the inconveniences to same time to repair and alignment method. You are able to method- membering at the the which it may put him-is welcome, pro- A. Restore the oscillator criticize the signal quality and at the break at the different vided it brings the solution to the prob- to operation. As a result of this, the same time manipulate mi- trimmers to bring signal strength to lem at hand. superheterodyne circuit reappears student of the old school usually of i.f. Faulty operation normal. Considered from the alignment The nus one stage unorthodox. frowns on any other form of signal points to the mixer -oscillator circuits angle the procedure is most we break the rules by tracing except that with his trusted and first i.f. transformer as harboring Right away some- using the output of the second detector signal generator. However, he the culprit. If there is no trouble, we to the actual in- (in as our starting point. Disconnect the times wants to listen turn to the second i.f. transformer and signals through the different in a receiver) testing thus signal source from the antenna post telligible case of three it on stages of the receiver. The purpose of the first i.f. tube circuit and the i.f. -ignoring the preselector -clip mixer grid. Now, discon- this system is to provide him with an transformer. directly to the troubles nect the primary of the first i.f. trans- inexpensive means of checking Ground the a.v.c. line and repeat the quality. the a.v.c. former and feed the plate across the related to signal tests outlined above. Ground systems have their limitations and of a few thou- phones instead. Disable the oscillator, All line through a resistor the trim- this one follows the general rule. Its sand ohms if each grid circuit connects tune in a signal, and adjust for maximum output. This done, purpose is to isolate the defective stages directly to the line, or ground it direct- mers The operator must resistors are used. reconnect the signal source to the anin troubleshooting. ly if a.v.c. decoupling increase not expect it to point unerringly to the trouble is still not found after all tenna post. There should be an If the the pre - faulty resistor, capacitor, tube, coil, or these tests, the a.v.c. is certainly defec- in signal strength. Peaking selector (r.f.) trimmers should produce transformer causing the disturbance. tive. wants to cut servicing the mixer can be additional volume. The man who The preselector and leads time to a minimum will find this system as possible causes of troubles If this business of disconnecting checked may con- a great help. END on stubborn alignment jobs. The proce- does not appeal to you who

JUMPERS I.F.AMPL. R.F.AMPL. MIX.

PIqNES IST I.F.T. TNL TRANS

.Ó2

superheterodyne Fig. 1 -Top, simplified diagram of typical receiver. Some sets have two or more i.f. amplifier stages.

OEL d IST A.F. A.F. OUT

Fig. 2- Right, a t.r.f. circuit develops when the mixer and i.f. are bypassed.

MAY, 1954

www.americanradiohistory.com 54 I TEST INSTRUMENTS

DOUBLE -BEAM SCOPE SWITCH By T. W. DRESSER

An electric switch for obtaining two traces -ideal for comparing signals

TODAY an oscilloscope is a standard item of equipment in many service shops. Larger numbers of technicians -and amateurs too-- are finding them useful things to have around for trouble shooting, checking alignment, and a variety of other purposes. But unfortunately only one trace at a time can be observed on most scopes. This imposes serious limitations on their use, and can be a strong source of annoyance when trying to locate distortion or, say, spotting the cause of a drop in signal strength between two stages. A double -beam scope, in Front panel view such circumstances, would probably of the scope indicate , the location ')f the trouble switch. straightaway and save much time.

N N °1 IN N°2 PLATE LOAD OUT

3Y = NEG 81,5 t

Fig. 1- Fundamental electronic switch. Before going on to describe a straightforward practical beam splitter, perhaps some idea of what is involved will help in understanding the gear. Fig. 1 shows the diagram of an elec- Underchassis tronic switch reduced to its bare essen- view shows selec- tials. The tubes shown are triodes (for tor switch. simplicity) and are biased to cutoff. When switches S1 and S2 are open there will be no output at the common plate connection. Closing Sl. will apply a positive signal to the grid of the first tube, and during the period the switch remains closed this tube will conduct. Opening Sl and closing S2 will cause VI to cease conducting and V2 to start doing so. If the two switches were operated alternately, there would be two different traces on the scope screen. In other words, we should have an electronic switch -a crude one, because the two traces would be far from simultaneous and they would be superimposed on one another, but a switch all the same. Two things are necessary to convert Double -beam this arrangement scope switch. into a practical in- 6K8's may be strument for use with a standard scope: used in place of One, a means of separating the traces the European and, two, a method of speeding up the tubes. switching, as manual operation is far RADIO -ELECTRONICS

www.americanradiohistory.com TEST INSTRUMENTS 155

directly coupled to the hexode through amplifier gain controls (at the right too slow to give the appearance of switching fre- The :first require- its grid, there is no need for coupling and left respectively) simultaneous traces. quency switch, and separation control. is simple to obtain capacitors. The hexodes are biased to ment comparatively when once the latter has been decided upon. cutoff; this condition changes This is where the gating circuit comes the multivibrator comes into action. Ports for double -beam switch. Each switching grid in turn then be- 22,000, into the picture: it will give us the Resistors: 2 -330, I- 1,000, 2- 15,000, 2- 2- other, ohms, 6-1 meqohm, 1/2 watt; I- 10,000 ohms, necessary switching speeds and do it comes positive with respect to the 33,000 and each hexode conducts until the 2 watt; 2- 20,000, I- 25,000 ohms, potentiometer. shows the basic 1 2 1 automatically. Fig. Capacitors: I-50, I -100, 1 -200, -500 ,uf, -.001, changes over to the 400 volts; 2-0.1, 2-0.2 uf, paper, circuit. The tube shown, a pentode, is multivibrator I -.02 uf, mica, I -20 uf, 450 volts, other tube. This is determined by the 400 volts; I -10 -10 uf, 450 volts, -20 electrolytic. switching speed. The traces are sepa- ct, Miscellaneous: I -power transformer, 600 volts rated by varying the screen voltage on 40 ma; 6.3 volts, 2 amp; I- 6X5 -GT, 2- -6AK5, 2-6KB, one of the hexodes. tubes; I- switch, 2 -gang, 6- position; 3- jacks; I- 7 x 5 x 21/2 -inch chassis. The electronic switch in the photos was constructed around two European the unit ECH42's, but 6K8's are When first put into service triode -hexodes, low -frequency switch- can be used with- should be used on identical to them and the technician becomes accus- out making any circuit changes. ing until tomed to the instrument. After that, Fig. 2 -Basic type gating circuit. The unit can be used as is -that is, any higher frequency can be chosen by the signal can be fed into the grids of switching in smaller capacitors. The up off by the heavy negative the hexodes without any preamplifica- ranges covered are from 25 cycles normally cut input in this bias on the suppressor grid and will tion. But, as the minimum to 10 kc in six steps. conduct when a square -wave pulse case is approximately 0.1 volt, anything hundreds of appli- only a trace of suffi- There are literally positive polarity is applied to this less may not provide beam switch, and once a of although some gain is cations for the grid. We use two such tubes controlled cient amplitude, technician has used it he is unlikely to secured from the hexodes. An amplifier by a multivibrator. Presenting a posi- go back to the single -beam instrument. tube in was added before each hexode, but they tive square wave pulse to each the oper- we want fast are not absolutely necessary. The addi- The formula for determining turn will give us what -a a free running whose speed we can tion of these extra tubes made little ating frequency of switching circuit, of the is as follows: control. difference to the compactness multivibrator unit, which is built on a 7 x 5 x 2.5- 1 From there on the practical work is bent from lightweight F inch chassis = R1C3 +R2C2 relatively easy, although there are still aluminum. On the front of the chassis some problems to be solved, such as are the four controls: first and second R is in megohms, and C is in tif. END whether or not time -base synchronizing should be used, whether or not a buffer stage should be inserted, and what the switching speed should be. It depends on the application. Fig. 3 shows how sawtooth traces will appear on the scope when the electronic switch is set for different switching rates. Note that the traces are in the form of dashes whose length depends on the switching rate. At a the switching rate is close to the frequency of the signal being observed. At this low rate neither trace is sufficiently a 6 c to be useful. Increasing the complete will increase detail. switching rate as at b and c, greatly Fig. 3- Switching traces. Increasing switching rate increases the detail in each trace. -1SwITCnING FREO CONT IN N°2 ALTERNATE IN N°2 When the switching rate is sufficiently ALTERNATE 0--)1- .02 I-o ¡A/ IN N1 o [-o '. fast the dashes are so short and close e 6K8 0-11-.--001-- 8K8 that the traces appear as together a"Ìl-'-50OVpt' I 6AK5 continuous lines. These are traces ob- o 1F--,2oWu ° 0 tainable under the ideal condition of o-0.-100MIt E-o instantaneous change -over, a condition 0-41-*-- WWI k-o not likely to be attained, and the real NAG IMEG performance therefore falls rather EG short of this, though not enough to SEPARATOR 130 matter. Both high- and low- switching speeds have advantages and disadvan- 20K tages, and provision is made for both, though there is not much doubt but GAIN (INN 2) that for most of his work the tech- frequency switch- nician will use low- OUT TO ing. For those who would like to juggle SCOPE with their switching speeds, the formula for working it out is given at the ARE NOT USED end of this article. ALTERNATE INPUTS If MKS PREAMPLIFIERS óo0v CT 6X5 010~ Modern multielectrode tubes simplify 450v the construction of an electronic switch IOK O 401ÁA (Fig. 4). Two triode -hexodes take the 0 2w place of the two triodes (the multi - IITVAC vibrator) and the two amplifiers. The 6.3V FILS sections are coupled together as triode All values are shown. a multivibrator, and, as the triode is Fig. 4- Schematic of the double -beam scope switch. MAY, 1954

www.americanradiohistory.com 56 I TEST INSTRUMENTS

Relative Field- Strength Meter

By HILTON L. REMLEY

9 x 7 -inch chassis. The tuning controls plitude- modulated project through carrier and gives us the front panel of a all the information necessary. By standard 8 x 10 feed- x 7 -inch utility box. ing a signal of 25.75 mc into The tuner output feeds the mixer The relative field- strength meter both a 25.75 (with the oscillator disabled) and ad- simplifies antenna installations. mc i.f. to a video i.f. amplifier and a justing each i.f. tuned circuit 21.25 mc i.f. for the for maxi- sound i.f. channel. mum output on the meter, we have WE have often needed a field - We do not need the sound i.f., our so we unit tuned! Actually, the unit can be strength meter in our instal- use only the 25.75 mc signal which lation work; is tuned without a signal generator, mak- but were always fed to the grid of the first i.f. amplifier, ing use, brought up short by instead, of a signal from a the high a 6BC5 mounted as close to the output television station. cost of such equipment. Yet we noted of the This might be diffi- tuner as possible. The grid is cult if the coils are not somewhat that the most expensive commercial peaked at the i.f. by a near slug-tuned coil. resonance, but later retouching of instruments-costing perhaps several This stage also has a slug -tuned the hundred dollars coil in circuit can be done at any time by this -had the advantage of the plate circuit, peaked at the i.f., method. only slightly greater accuracy than ap- thereby providing considerable paratus which, gain. Some tuners will have sufficient re- while cheaper, was still This stage feeds a 6AÚ6, mounted close sponse beyond the limits of our at the audio -carrier frequency pocketbook. to the first stage, which is also slug- Possibly a simple, inexpensive that, combining with the nonlinearity of instru- tuned and peaked at 25.75 mc. With the detector, the ment-which would still be quite ade- these two sound signal will be stages peaked at 25.75 mc heard. Since this is a quate for our purposes -could be con- we have sufficient frequency -modu- structed. gain to drive the de- lated signal, we are not interested in tector. All the i.f. tuned circuits it. We thought it over are The video carrier is always identified and came to the standard slug -tuned transformers, by the peculiar conclusion that we could do our job buzz due to the presence which may be purchased, or, as in this of synchronizing and just as well, and reduce the cost con- case, removed from blanking pulses siderably, a junked television present. if we used a relative field - chassis. The detector is a germanium strength meter. Calibration of the meter scale does In this case we are not diode that feeds a filter circuit. From not concerned so much with an become a problem as long as we absolute there the signal goes to the meter cir- remember we have measurement as we are with a relative cuit only a relative read- and a 6A U6 amplifier which drives ing instrument. In our measurement; a comparison of one sig- the monitor headphones. case we made nal up a linear reading scale, reading from with another. We thus do away The meter circuit is conventional with the expensive up 0 to 100. Later, if desired, this dial and troublesome to the multiplier. Here we have used problem of calibration. In could be calibrated in any units found other words, a s.p.d.t. switch to insert either of two to be useful. we are not so interested in measuring potentiometers in series exactly with the 100 - The meter has proved to be quite how many microvolts -per-meter microampere meter. We thus make exist at a given location our useful in a number of applications. as we are in meter a high- resistance voltmeter, con- First, determining if a signal is it has been very handy, in con- satisfactory nected through the filter and across the junction with or unsatisfactory. With this require- diode a length of a.c. cord, in load resistor. The double -throw setting up and orienting television ment in mind, we set out to construct switch allows one or an- the other of the tennas for maximum signal. We have a simple meter which would easily read variable resistors to be such signals. adjusted so as found that the average television tech- to multiply the scale reading by say 10 Since our main nician who makes these installations concern was for or 20 in one position over that in the has all checking TV signals, our first thought too often only a vague idea of other. If desired, a tap switch could be topography and direction. was to insert a meter in the detector used in this position A surpris- and other values of ingly large percentage of antennas have circuit of a standard television receiver, resistance added to extend thus allowing the scale been found oriented in very odd direc- us to read the signal multiplication for strong -signal areas. tions, strength as the set is operated having nothing whatever in com- as a The series multipliers may be changed mon with maximum signal. regular receiver. While this would allow to lowresistance shunts It has also both if high sensi- been found that a very large number of sound and picture identification, tivity is not necessary. installations even a small 7 -inch set proved may be improved by relo- too bulky No provision is made to alter the cating the antenna. and was not sufficiently shielded. As a plate voltage We don't mean to result, as the range switch is move the antenna any great distance, we set out to build a simple, moved, because we are using a relative small, portable meter. but one must remember a move of only reading instrument where such changes one -half wavelength, horizontal The first item to be considered was in gain are or ver- unnecessary. If a trans- tical, could mean the difference between the tuner, or "front end" of the meter. former with a 5 -volt winding is avail- maximum and minimum signal. If we A quick glance through the spare parts able, a 5Y3 or some similar tube bin produced may be move the antenna around the positions a complete television -tuner used in place of the 6X5: this tube was available assembly, covering all 12 v.h.f. for mounting, observing sig- chan- a happy choice only because the trans- nal strength on all nels. This happened to be an RCA type former at hand channels, we will when the unit was built finally find a position where we 206E3 tuner assembly, but nearly any had a 6 -volt winding. get of the nearly maximum signal from all sta- tuners which are on the market After construction of the unit has as surplus or replacement units tions in the area. may be been completed, alignment is the next Second, in fringe area installations, used. The tuner thus takes care of the order of business. This a is not difficult great deal of time and effort may be input radio frequency stage, the oscil- since we wish to peak the i.f. amplifiers lator and the mixer stage, saved by use of the meter. The first step all in one for maximum response at the video here is to determine neat unit, being mounted on a standard what relative field carrier frequency only. This is an am- strength will give a satisfactory picture RADIO -ELECTRONICS

www.americanradiohistory.com TEST INSTRUMENTS 57

Above -Top view. Potentiometers are conven- iently mounted behind the meter movement. Left -Underchassis view shows layout of components. The tuner is RCA v.h.f. type 206E3. leak from vent holes, cable entrances, on the particular receiver chosen by the the customer purchases his receiver, thereby increasing customer good will around the edges of doors, near hinges, customer. This can be done by connect- meters on through a variable and saving the technician's time and and even around the edges of ing the receiver, panels. Any small hole in the metal pad, to an antenna system, along with money. the Another use for the meter was re- seems to be a potential trouble spot, the meter, and observing the received that may pass picture as attenuation is added to the cently turned up when an amateur radio along with any cable received signal until we reach the mini- operator was discussing some of the through the metal structure. the meter measures he had taken to insure his Still another use for the instrument mum signal. A reading of radiation from then tells us the minimum signal usable transmitter against interfering with his is in tracking down r.f. heating equipment. This type of loo pf lOppf 6BC5 P 8AU6 equipment is composed of the same es- 5 661( sential components and often follows CATH EA TUNER (206E3) .002

IN46 TO ANr(3004 4104 .002 SA Parts for field strength meter 68,000, .--) Resistors: 1 -150, 3- 1,000, 5,000, 1- 1- 002 I- 100,000, 1- 220,000, 1- 270,000, 3- 470,000, V/2 watt; -4 1-500, I- 1,500, 2 watt; I- 100,000, 1 -500,000, potentiometers. 2 -500 uµf, 8- 0-100 pA Capacitors: I -10 µµf, 2-100 µµf, 10 -IO -10 Isf, 002 µf, 1 -.05 µf, mica or ceramic; I- 450 volts, electrolytic. LO Miscellaneous: I -6BC5, 2 -6AU6, I- 6X5 -GT, tubes; -100 µa PL z 6AU8 I -IN48 germanium diode, and holder; I-0 480 volts meter; I -TV tuner I -power transformer, LSK ct, 60 ma, 6.3 volts, 2 amps (Halldorson P- 2067); I and 1-on -off switch; 1 -line cord; -pilot light 2A 6.30 TO FILS assembly; I -phone jack; I- s.p.d.t. switch; 2 -input x 10 x 7 -inch utility jacks; 1 -9 x 7 -inch chassis; 1-8 4705 to R7VAC Soopp 46OVCT box; 3- slug -tuned i.t. transformers (matched tuner). °T 3 BOW PITONES 6X5 -GT construction methods relative reading television field strength meter. the same general Schematic diagram of the as amateur equipment. friend has suggested such a receiver. This value must neighbors' television reception. He had Our amateur with might be of assistance if be on all channels, as both found that actual detection and location one item that obtained is to be used extensively for field and sensitivity vary on of troublesome interference was the the unit strength a .re- to the cus- first difficulty. After the source was interference work. Addition of all. We can then proceed side of the a.c. tomer's home and, using a temporary located, it was much easier to correct section filter on each determine whether the trouble. We suggested use of the line at the point where it enters the antenna installation, any signal from the signals will be satisfactory. Here signal- strength meter and it turned out chassis will prevent about from to be a useful tool for him. entering the meter via the a.c. line. This again, moving the antenna that indica- one spot to another will be a great help. For this type of work, a short length will add some assurance ob- of line is connected to the input of the tions on the meter are only from radia- Often a usable signal cannot be not a booster. We can insert meter, with a small tuned pickup loop tions picked up by the probe and tained without on the the booster and then once more measure on the far end. Then, with the trans- something entering the meter the signal to determine whether it has mitter in operation, and the meter set a.c. line. to provide to the interfering signal, it is an easy With continued use, the owner of been sufficiently amplified which the necessary input to the receiver. All matter to completely explore the trans- such a meter should find uses much more quickly mitter installation and find exactly have not been covered, thus increasing this may be done times. with the field -strength meter, giving a where radiation is taking place. It has the value of the instrument many complete story of the possibilities before been found that radiation can, and will, END MAY, 1954

www.americanradiohistory.com SR I AUDIO-HIGH FIDELITY

FOR GOeE11 CADS ONLY This is the first appearance of a feature which will appear from time to time as the conditions in the world of audio warrant. All subjects which may interest the audiophile will be discussed in these columns By MONITOR

THE high -fidelity addict has no ob- showed no signs of special treatment. for its specifications. jections to having a system which I made my checks without disturbing Although consists designed primarily for of several units and pos- the factory settings of balance and bias home use, it occurs to sesses lots of controls. He a controls. me that the gets The IM distortion as meas- Golden Knight would be an especially great deal of pleasure operating the ured on a Heathkit IM analyzer was good choice for high -fidelity controls. The ordinary consumer, on the well installa- below 1% for all levels under 10 tions in smaller restaurants, schools, other hand, accustomed to automatic - watts and remained under 2% at the etc. The high -power drive automobiles, capacity would automatic washers, 20 -watt level. The frequency response preserve a sufficient, safe reserve and even automatic frying pans, has was of flat to 40,000 cycles until 20 watts power for good reproduction of peaks little patience with complication. What of output where it fell off slightly at even at the high he is average output levels wants simple assembly and easy the extremes but was still within 1 db necessary to override operation. conversation ro Now that high -fidelity is within 20- 20,000 cycles. The hum level sound absorption of heavily populated finding an increasing market with was as specified also, with no adjust- rooms. users who know little about audio and ment of the hum control. Now let us see how this high per- want only results, the dealer and in- I used the amplifier in my home for formance is achieved staller are faced with the problem at such a low of some weeks with various loudspeakers: price. There is nothing tricky about the meeting the customer's desire for my infinite -baffle wall- mounted combi- circuit ( Fig. 5) . simplicity. The high output power nation of 5 speakers plus a bass -coupler is obtained by using 6L6's as tetrodes Most of the manufacturers of high - built into the floor; the Kingdom Lorenz with very high plate fidelity equipment have and screen volt- taken notice of combination; and the same speakers in ages (465 and 420 respectively). With this and are now offering simplified, a corner horn enclosure. such high operating voltages, more compact units combining phono- the tubes I have no complaints to make of the ara being driven to only a fraction of preamplifiers, control units, program performance of the Golden Knight with maximum possible output selectors, power amplifier, and power and operate any of these speaker systems. It also on the flat portion of their curves. A supply -all on one chassis. I have just behaved almost flawlessly with my col- special output transformer with grain - tested one of these -the Golden Knight lection of special test records. Since oriented core and interleaved (Fig. 1), produced and sold by Allied windings high -quality amplifiers, like high -qual- no doubt accounts for the clean per- Radio, in the medium price range at ity musical instruments, often possess formance at the extremes $79.50. of the fre- a character of their own, highly criti- quency range and at high power out- cal ears may have a certain amount of put. What appears to be about 20 db Golden Knight amplifier preference for slight differences in the of feedback is applied to the three The specifications of the Golden tonal qualities of several amplifiers stages of the power amplifier. Finally, Knight (Table) are above those of the which otherwise are electrically similar. the amplifier has potentiometers for medium price range high -fidelity equip- The Golden Knight is no exception. But adjusting the bias voltage on the out- ment and, indeed, fall into the de luxe only the most sophisticated of Golden put tubes, and the rest of the output category. The rated power output is Ears will find much to quibble with in tubes. These do much to correct the 24 watts at less than 1% harmonic and its performance; and in comparison 2% IM distortion (Fig. 2, 3) ; and the tests it will hold its own against the GOLDEN KNIGHT SPECIFICATIONS frequency response is specified to be flat field. Rated power within less than 1 db over 20 to 40,000 As for the general consumer (for output 24 watts cycles Frequency response 0.75 db, 20- 40,000 at full output (Fig. 4). When it whom- rather than the high -fidelity c.p.s. at rated output is considered that in addition the am- crank -it was designed) I doubt that, Harmonic distortion Less than I% at rated plifier includes a two -stage phono pre- given the same program material and output amplifier- equalizer, a two -stage tone speakers, Intermodulation Les than 2% at rated as many as 1% could discern distortion output (60 and 7,000 control and program selector, and also any difference between the Golden c.p.s. tones; 4:1) claims an over-all hum level of -80 db, Knight and the cost- is -no- object ampli- Hum level 80 db below rated out- one can be excused for being skeptical. fiers. It represents a successful put (inaudible) attempt Gain (high -level inputs) 0.5 volt for rated out- I can say that the specifications are to produce fidelity acceptable to 99% put not exaggerated. The unit I received of the market, with simplified controls Gain (low -level inputs) .02 volt for rated out- was in its factory-sealed package and and at a price well below the average put RADIO -ELECTRONICS

www.americanradiohistory.com AUDIO -HIGH FIDELITY 59

vide a range adequate for most uses. Any simplification of controls involves compromises; but the Golden Knight appears to have struck these in a way which should make the average user happy. In short, the Golden Knight is a successful attempt to provide very high quality at low cost. Baruch -Lang loudspeaker system Recently when assembling a compact low -cost high -fidelity system I had occasion to use and test the Baruch -Lang loudspeaker system. This system consists of four inexpensive 5 -inch speakers in a very small enclosure of rather tricky but effective design. I found it surprisingly good. There Fig. 1 Golden Knight 24 -watt high -fidelity amplifier. -The is very little if any response below 50 cycles, and the high- frequency slope

30 is rapid beyond about 11,000 cycles; WATTS but the reproduction between 60 and 25 10,000 cycles is excellent. The efficiency SK 10K 40K 20 50 100 500 IK FREQ. C.P.S. is surprisingly high despite the small magnets used in the speakers and the Fig. 2 -The power output of amplifier at 1% harmonic distortion. small enclosure. The loss of the octave between 25 and 50 cycles is to be course; any good system 2 mourned of sounds better and more real with it PERCENT HARMONIC than without it. But there will be very DISTORTION o little loss, if any, of the musical con- music is written 22 24 26 . 28 30 tent since very little 2 4 6 8 10 12 14 IB IB 20 OUTPUT- WATTS in that octave and even less is found in and recordings. Besides, the c.p.s. radio Fig. 3 -Graph shows percentage of harmonic distortion at 400 second octave is well and cleanly reproduced, and since the ear has the

MA %.TREBLE BOOST of imagining it hears MAX.BASS BOOST RESPONSE AT FULL POWER curious property the fundamental when it hears only the absence of the notes 4 .ii:!uIr_.NuIuuuIUIfi!ii harmonics, the ..111111 a.IIlllloa illlmuI below 50 cycles is noticeable only to those who are thoroughly accustomed 30 moluniiiegiummemmuumm to their presence. In any case, you OB ABOVE 1M ..uuiu.píi11 Suu11 can't expect to buy reproduction of the 20 111111111111MMIII111M\5111111111111111111 lowest octave for anywhere near the 1111111!!!>RN111111I1111UI1i!III11111U11 $30 price tag this outfit carries. The transient response is fair and iiiIIlI .II111111111NIu111M1ua -especially when 111111R11uI1111111111111uI111111t UU the over -all quality a 5K 10K 406 is mounted in a corner 50 100 500 IK the enclosure - FREQ. C.P.S. MAX.TREBLE ATTENUATE MAX. BASS ATTENUATE is superior to that of some much larger systems. It probably pro- frequency response and bass and treble ranges. and costlier Fig. 4- Amplifier vides about all the bass a small room or apartment can stand. The treble tolerances of tubes, components, and meter; or, if the filament winding has response is smooth and adequate. assembly, and to insure that individual a center -tap, just returning the center - One could not compare the Baruch - units will meet specifications and main- tap to the output -tube cathodes. Lang with the best available speaker tain them with changes of tubes and The only other notable point about systems; but it certainly represents a ageing. These controls should make the amplifier is the simplicity of the lot of quality -per -dollar. Moreover, its servicing a simpler matter than is various control circuits. Three phono- compactness, the freedom of placement allowed for by most amplifiers. playback curves are provided: a 500 - which its small size and design makes The hum level is kept low partly by a cycle turnover and flat treble, the AES possible, and the variation in bass re- balanced heater -biasing circuit with a curve, and the NARTB curve (Fig. 6). sponse that can be had by placing it in hum -balancing control mounted on the The NARTB curve works well with LP either of several positions, combine ` chassis. Incidentally, all three controls recordings, and the AES does well to make it a nearly ideal low -cost sys- are protected against accidental mis- with Ortho discs. Although this tem. One of the speakers would be adjustment or monkey- business by choice does not provide complete or an excellent choice to use with a porta- youngsters, with screw -down caps. Ob- exact equalization for all recordings, it ble tape recorder for monitoring and taining and applying the heater -biasing is sufficient for the average user. A playback. Two or more could be used voltage is very simple. The slider of slide switch provides a change of input also with small public- address systems the heater -balancing potentiometer resistance for G -E or Pickering car- or guitar amplifiers. I recommend it (hum- balancing control) is returned to tridges. There is an input for low -level strongly where every dollar and foot the cathodes of the output tubes, which mikes. High -level crystal or ceramic of space counts. are at a positive potential of 37 volts, cartridges can be fed into the auxiliary an excellent value for biasing. This input. Magnetic cartridges with ex- New recordings equalizers could be accommo- method saves a couple of resistors or ternal from time to time be applied dated through the microphone channel. I will comment a voltage divider. It could new or recent records which are any cathode biased amplifier The bass and treble controls are smooth, on to almost pro- either: unusually striking examples of by adding a 100- to 1,000 -ohm potentio- are approximately calibrated, and MAY, 1954

www.americanradiohistory.com 60 I AUDIO -HIGH FIDELITY

33K TPPt

2W-WW

0056/200V

BOOST 250 IOW

BASS} 50011 47 AUX. BIAS 100 2W-WW

TUNER

22K PICK. G.E.

320V 6 POSITION SW.:- +470V MAG 7 SW. VEWED FROM KNOB END IN AUX. POSITION C.C.W.. POS.1 -WV. ;2TUNE R ;3- MIKE; 4- MAO. FLAT ; 5-MAG. AES; 6- MAG. NART B +440 ..3D/SOOv TT T 10/450V 7.1 450V AC RECEPTACLES

WAFER N.I FRONT

Fig. 5- Schematic diagram of the 5U4 -G Golden Knight high- fidelity amplifier.

stimulating, and could be tolerated in 30 the shop or store for days on end. The DB ABM MW MAG.FIAT same cannot be said of many of the 2 recordings used for high -fidelity dem-

MAO. NARTB onstrations.

MAG. AES e Third symphony Aaron Copland. (Minneapolis Symphony Orch.) MERCURY MG 50018 020 50 loo 500 IK 5K 10K 4011 FRED: G.P.S. Until the arrival of LP records, Cop - Fig. 6- Amplifier response -preamp in FLAT, AES, and NARTB positions. land's El Salon Mexico was my favorite test record. Copland is especially clever high -fidelity recording; the expression standing presence, and there are sev- in approaching (though never quite of a new recording technique; suitable eral interjections of voices, solo, and in rer.ching) outright dissonance. Such for testing various qualities of high - chorus, which furthers the realism. The sections provide a wonderful check of fidelity equipment; or useful for dem- recording is not up to the standard of system distortion because even a little onstration of high-fidelity equipment. today's best, but is sufficiently good to distortion will throw the music over I shall not be concerned with the present a fair test. The music itself is the edge into extremely unpleasant musical content or the interpretation - interesting and this is the only com- dissonance. merely the technical aspects. plete version of the score available. He is also fond of using several brasses playing in unison or The three cornered hat American concert -band exquisitely masterpieces close harmony. On Manuel De Falla MERCURY MG 40006 a system of poor (Paris definition the result sounds like one Opera Comique Orch.) One of the URANIA URLP 7034 very best recordings for badly muted horn; but on a good system high- fidelity demonstration; but Here is an excellent also it is actually possible to count the horns. record for listen- useful in portions for testing. For in- His ing tests of high- fidelity equipment. It deep bass rhythms and more or less stance, the bass drums, cymbals, and onomatopoetic (sounds resembling nat- has plenty of prominent bass for check- tyn.pani provide a very ing severe test of ural sounds like gunfire, dancing feet) the bass response of speaker sys- dynamic range, transient response, and tems; a good deal of high passages are excellent measures of frequencies loudspeaker damping. The contrapuntal transient response. including those contributed by the typi- writing of some passages, with cally Spanish percussives; several In this version of the Third Sym- several high - instruments running rings around each phony we have volume bursts of rather dissonant cre- all this and a superlative other, is good for checking definition, example of high -fidelity recording at scendos, excellent for checking distor- since in the good system the separate its tion and overload; excellent transients, best with plenty of realism but no instruments will be clearly discernible. artificial high -fidelity effects. The re- and offers many opportunities for check- The whole effect is calculated ing to make cording is good enough so you can safely intermodulation when a prominent the good system sound very real and assume bass accompanies high that any serious aberration in trable passages. attractive even to the complete layman. the output of your speaker The recording has good, but not out- is the fault In addition, the music itself is pleasant, of your system, not the record. END RADIO -ELECTRONICS

www.americanradiohistory.com AUDIO-HIGH FIDELITY 61

Part IX- Design factors of triode and pentode resistance- coupled amplifiers

By RICHARD H. DORF*

Typical high -quality audio amplifier -in- clades a phono pre - amp. NIGH -QUALITY AUDIO

SO FAR we have burned the audio of the various parts of a single wave. technician. The knowledge necessary candle at both ends, talking about It must not create waveforms that did for the purpose is not hard to acquire. loudspeaker systems and sound not exist at the input, nor fail to For that reason we shall go into the sources. Now we come to the mid- duplicate waveforms that did exist. It subject rather thoroughly. dle -the heart of every sound system- should, in short, act like a magnifying We can divide our analysis of ampli- the amplifier. glass through which an object appears fiers into five parts: voltage amplifiers, amplifiers, feed- most important exactly as it would if viewed directly, phase splitters, power The amplifier is the back, and power supplies. This is made a home music system. We except for over -all size. component of clearer by the block diagram of Fig. 2 said at one point that the audio chain Fig. 1 is a diagram of a very simple link amplifier. It has the necessary gain for which shows the essential parts of an is no stronger than the weakest - amplifier. Everything shown in Fig. 2 is and we still agree with this statement. a home music system and furnishes enough power output (4.5 watts) for present in a high -quality amplifier, But it is reasonable to place special which even though ordinary listening. The power supply is except the positive feedback may emphasis on the amplifier or may not be provided. it cannot neutralize the effects of a transformer -operated. Anyone can design such an amplifier in about ten poor speaker, a bad tuner or pickup, or Voltage amplifiers record. minutes with the aid of the tube hand- a defective am- The output of a phonograph pre- T1:3 amplifier is usually the most book. Why do home- music -system is on the order expensive part of a system and there- plifiers have to be more complex than amplifier or radio tuner 1 this signal appears fore the one least likely to be replaced. this? One answer is that this amplifier of volt. Normally due a ; therefore there is It is the most complex element of the has about 12% harmonic distortion, across resistor more different mainly to the output stage. Another some current flow through the resistor system, since it performs in it. The tasks and contains more parts than answer is that the effective output and some power dissipated any other. Most other components, if impedance is high, giving rise to resistance value is kept very high so built in one transient distortion. Still another is that current is at a minimum and the correctly designed and to respect, perform well. An amplifier may that a single -ended amplifier does not signal source is not loaded enough and other poor allow sufficient power output to take reduce the voltage. Until the signal have one good portion where ones; all must be good if the amplifier care of peaks, and both reduces and actually reaches the power stage, is to be good. varies the inductance of the trans- it will be used to control the power *. former primary so that low- frequency output, we are interested only in am- What does it do? performance is restricted and non - plifying the signal voltage so that it linearity distortion is high at all will be great enough to drive the power - An amplifier's main function is made stage grids. The stage or stages which its name; it amplifies. Its frequencies. clear by Basically, designing amplifiers to give do this are voltage amplifiers. The secondary function -but the one that contains only to trans- high -quality reproduction is simply a phonograph preamplifier causes the most trouble -is which raise the low - into power matter of observing rules which have voltage amplifiers form voltage variations years, using good level output of the pickup to something variations. been known for many components (especially a good output between 0.5 and 2 volts. The phono- The amplifier must amplify without graph, tuner, and other sources reach is, changing the char- transformer), and incorporating a very distorting -that important ingredient, negative (and the input to the main amplifier at this acter of-the signals. It should not voltage level. levels of the various sometimes also positive) feedback. change the relative -amplifiers may be resistance -, frequencies, or the relative amplitudes Unlike many other components, am- Voltage plifiers can be constructed and serviced transformer -, or impedance-coupled, but home music system amplifiers it is *Audio Consultant, New York City.. by the individual enthusiast or service in MAY. 1454

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unusual to find anything but resistance coupling. The reason is -aside from the cost and weight of transformers and inductors -that resistors make ideal loads because they are not frequency- sensi- tive in the audio range. Transformers and inductors, on the other hand, must have sufficient inductance to maintain a - the necessary impedance down to the Fig. 3- Diagram of two of the most commonly used resistance coupled amplifier lowest frequencies; may be self -reso- circuits, &iode and pentode. Design tables for them have become standardized. nant at certain frequencies; and have problems like leakage reactance (fre- screen voltage thus depends on the of the v.t.v.m. is sufficient to lower it quency- sensitive reactive couplings be- value of Rg2. Screen current passes substantially. tween windings). In most amplifiers through Rg2 to Ebb. C. smooths out the The value of Rk is far from critical, use of an output transformer is Un- audio -frequency variations so that the even for high -quality work, and this is avoidable, but in earlier stages trans- d.c. voltage applied to the screen is one of the advantages of cathode bias formers are avoided. steady. If it were allowed to vary at for voltage -amplifier stages; it makes Resistance- coupled (R- C- coupled) am- the audio rate, the gain of the stage the entire operating condition of the plifier stages are generally standard- would be greatly reduced. This is be- tube more or less self- compensating. If ized. These are shown in Fig. 3, with cause the screen voltage would always Rk is a little too large, it creates a 3 -a the triode and 3 -b the pentode am- be 180° out of phase with the control higher bias voltage, which lowers tube plifier. The components and voltage grid, thus tending to cancel a.f. plate - plate current, which in turn lowers the source are marked to conform with the current variations. Rk voltage drop. For a given value of The design of voltage -amplifier com- Rb, changes in static plate current due 8J5 6V8 ponent values is a straightforward to any of a number of causes are com- process which anyone can carry out by pensated by the resultant changes in a using the resistance- coupled amplifier bias voltage which tend to restore plate tables found in the back pages of the current to its design value. RCA RC -16 Receiving Tube Manual or Selection of all the capacitor values comparable tables in other tube hand- follows the principle that capacitive books. These tables are widely used, reactance must be negligible by com- because resistance -coupled audio -fre- parison with the associated resistor. quency voltage amplifiers provide essen- Thus the reactance of C at the lowest tially uniform amplification over a wide frequency to be dealt with must be no frequency range. greater than about one -tenth the re- The first step is to determine the gain sistance of the following Rg to which needed and the maximum peak output it is connected. The series C and shunt voltage the tube will have to furnish. R make up a high -pass filter, cutoff A suitable tube is easily selected from frequency of which (frequency of 3 -db 6.3V FILS the last two columns of the tables, attenuation) is that at which X° is which show these characteristics. A equal to R. If X, and R were Fig. 1 -A basic 3 -tube audio amplifier. equal tube should always be chosen whose at, say, 30 cycles, the 3 -db drop at that output voltage capabilities frequency symbols used in the RCA resistance- are well would not be serious in itsel f, above those necessary, since distortion but the resulting coupled amplifier tables. In Fig. 3 -a, phase shift would the signal is fed to the control grid. rises sharply near and at maximum. give trouble if, as is usual, negative Current passing through the tube from Output capability of a stage is de- feedback loops are included in the ground (B minus) termined principally by the supply stage. to B plus (Ebb) is voltage and varied in intensity by the grid. The secondarily by the value The values of Ck and C, should be variations of current of R,; available output being higher as high enough so that their X, is less than through load re- each of these is increased. sistor R,, produce audio -frequency The maxi- one -tenth the resistance of Rk and Rg2, volt- mum grid voltage age variations across R,, which peak for the stage is respectively. A parallel resistor and are of course the maximum output divided coupled to the next stage through d.c. capacitor are also a high -pass filter, blocking capacitor by the voltage gain. The figure obtained since the capacitor bypasses more effec- C. This capacitor is is also usually value of large enough value to offer negligible the correct of bias tively those frequencies at which X, is a.f. voltage, since maximum output is that smaller. Here again, the more audio impedance. Bias is obtained from at which the net grid- current passing through cathode cathode voltage current flowing through Rk and Rg2, the re- swings to zero on the positive alterna- sistor Rk. Since the grid is more degeneration sets in. For flat fre- at ground tion. This fact is useful in potential for d.c., the grid is negative service quency response and adequate phase checking to see if bias is correct. response, the capacitor with respect to cathode. Ck is of large should be practically a short -circuit for audio down value and filters the audio variations Resistor and capacitor values which would otherwise appear across to a frequency much lower than the In the tables the value Rg Rk. of shown is lowest audio frequency to be passed. that for the following stage's grid re- The resistance-coupled amplifier 'N. sistor. Rg is effectively in parallel with tables in the manual specify the R,, at audio frequencies, and the net capacitor values for a response drop parallel value of resistance is the a.c. of about 3 db at 100 cycles. For home - IN FROM VOLTAGE P-P PWR TO load resistance of the stage. Lowering music- system amplifiers the values of PREAMPL AMPL. -1SPLTITER AMPL "SPKIT the value of Rg lowers the undistorted TUNER,ETC. 1 - the capacitors should be increased by at output of the stage. least 5 to 10 times. The vdlues of Its The cathode Rk is L___ resistor chosen so shown in the tables are minimum FÉÉ BACK --J that the current through it produces values. For smaller distortion with an a voltage drop equal to the desired bias. audio voltage level, Rg 1 should be kept AC PWR SUPPLY I In a few very-low -level stages where as high as possible, though values in Fig. 2- Essential parts of an amplifier. the cathode is grounded, a 5- to 10- excess of 1 megohm may give trouble megohm grid resistor provides contact because of unwanted contact -bias. The pentode circuit in Fig. 3 -b is bias as the result of small gas currents Next month we shall conclude our similar, with the addition of Rg2 and flowing through the resistor from grid discussion of voltage amplifiers and Cg2. Screen current passes through Rg2, to ground. Measurement of this contact pass on to phase splitters. causing a voltage drop across Rg2. The bias is impractical since the resistance (TO BE CONTINUED) RADIO -ELECTRONICS

www.americanradiohistory.com AUDIO -HIGH FIDELITY 163 25 MI:a.N roll 20 . 1111 S. 111 15 :`~ 11 ----- .. 11I H/.\ NI 1111 .I 11 DB N...... III .. ' PLAYBACK RESPONSE CURVES In

Low High 111 Curve , end \`_ A A Old Std. Columbia LP ' hilltaWS. IM . LP A E London ffrr III B B Cld AES , - C D Cid RCA D D RIRA Std., NARTB ' 5 Ill New AES, RCA ORTHO ,, 111 n ' n ti ,IQK , 3û 5') FREQ: C.P.S. curve: used by leading record manufacturers in the United States. I -Graph illustrates various recording

NEW STANDARD RECORD CURVE Phonograph record manufacturers agree llt sl(u(1nr(1 recording (r!(1 playback curve shown in Fig. 2. 2 -a is a triode electri- ica, Inc., and has also been recom- circuits, FTER nearly 30 years of 2 -b a pentode circuit. of mended by the Audio Engineering circuit and cal recording and 5 years When designing other circuits the leading phonograph Society to replace the original AES LP's, the curve is tabulation below may be useful for record manufacturers have at playback curve. The new on an identical with the Orthophonie curve testing. last gotten together and agreed NARTB -ORTHO recording and play- which RCA Victor adopted in the fall NEW RIAA -AES- industry standard adopted PLAYBACK CHARACTERISTIC curve. If all manufacturers of 1952 and with the recently back transcription curve. It is shown Frequency Response switch over to it, it will no longer be NARTB (c.p.s.) (db) 1. Comparison with the necessary (at least as far as new at D in Fig. 15.000 -17.17 concerned) to adjust older LP curves in Fig. 1 shows that 14,000 -16.64 recordings are between 13,000 -15.95 controls at the high end it is midway -15.28 phono preamplifier equalizer old 12,000 when playing the original LP curve (A) and the 11,000 -14.55 to different settings curve is also -13.75 of different makes. The lis- AES curve (B). The new 10,000 records the high end (above 1,000 9,000 -12.88 will merely use the normal tone identical at 8,000 -11.91 tener Icsec pre- emphasis controls (if any) on his equipment to c.p.s.) with the 75 7,000 -10.85 used in FM broadcasting. At the 6.000 -9.62 adjust balance for his particular listen- curve 8.23 500- c.p.s. crossover is used 5,000 - ing room, equipment and loudness level, low end, a 4,000 - 6.64 flattening at 50 4.76 the same as he now does on a radio together with a 3 -db 3,000 - c.p.s. The original LP curve had greater 2,000 - 2.61 program. A in Fig. 1. 1,000 o recording and bass flattening as shown at + 1.23 The new standard adopted this 700 playback curve was adcpted by the At the time that RCA 400 + 3.81 of Amer- curve it released 2 suggested equalizing 300 + 5.53 Record Industry Association 200 + 8.22 100 +13.11 Bt 70 +15.31 1001N 50 +16.96 .1 470C 30 +18.61 Decca and MGM 156 So far, Columbia, 2 (in addition to RCA) have indicated T0035 new curve. 02 5 4t 680n that they will use the old AES curve B- Several others use the which is within the ±2 db tolerance of L cycles. END a Pentode equalizing circuit. the new curve above 40 Fig. 2- a- Triade equalizing circuit. Fig. 2- b- MAY, 954

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SERVICING

HIGH -FIDELITY

EQUIPMENT

Part IV- Frequency test records; FREQUENCY - test instruments for audio work Fig. 1-Pattern of Cook frequency and intermodulation test record, series 10. By JOSEPH MARSHALL

AUDIO generator can be used For example, if the test record with a grooves. A comparison of the response to test the preamplifying stages 6 -db- per -octave slope below 500 cycles of the same pickup with of record playing the two needles systems; but is played through an equalizer for in the same bands of the Cook record A the pickup, turntable, etc., can European 78- r.p.m. records whose play- will be helpful in determining the con- be tested only by using suitable record- back curve calls for a crossover of 250- dition of the needle. ings. There is a wide and most useful 350 cycles, the frequency run will show Measurement of IM distortion range of test is very recordings available. a rise in response in the region between important and therefore a record which The comments applying to signal 250 and 500 cycles instead of giving permits testing generators the IM of a system is apply equally to test records, a nice straight line. However, by plot- valuable. The same Cook record pro- but relatively few records meet audio ting both the playback and the record- vides, generator on side 2, 100- and 7,000 -cycle standards. Most records do ing curves of each of the two types of tones in the usual 4 -1 not deliver -to ratio. There any useful signal material recordings, we can interpret the de- are two IM bands; one has an IM dis- below 50 or above 10,000 cycles. One gree to which we do or do not duplicate tortion level of not over very conspicuous 4% and the exception is the Cook what we want. other not over 2% -when new, of Laboratories series 10 (or 10 LP) which The flatness of a test record can course. The output of covers the equipment the range from 30 to 20,000 easily be determined by examining its under test can be fed to cycles. the analyzer light pattern. This should be done when portion of an IM analyzer and the IM Recording problems require that the purchasing one. Examine the record measured. Clarkstan has a special low IM portion of the spectrum be attenu- under a bright light, tilting it this way test record, the model 101, which is ated; the high portion may be boosted. and that until the pattern appears. The equally good. Manufacturers of commercial records more closely the sides of the pattern Cook Laboratories now offers an ex- provide test records made to the same approach straight lines, the flatter the tremely simple means of checking IM curves used for their musical record- response. Good test records will be distortion by ear with their AN Inter- ings. If played back on a properly flat to 1 db or better 'and the points modulation Test record (series 50). equalized system they will be ade- at which the recording departs from This recording ingeniously applies the quately flat. The most useful test rec- linearity are plainly evident when ex- N -A system used in radio range- finding, ords, however, for servicing and amining the light pattern. Fig. 1 is so that when the IM exceeds 2 %, there development work are those recorded an actual photograph of the pattern of is an audible change in the signal. This with a 6 -db slope below 500 cycles and the Cook series 10 test record. Although is an extremely useful record and might flat above 500 cycles. Such a record this record does not vary in response well be included in the tool kit for permits the running of frequency -re- by more than 1 db from the recording initial diagnosis and troubleshooting sponse curves of various equalizers curve, the points where it does depart (see Fig. 2). with relative simplicity. The resulting are plainly visible. The record contains two high -fre- curve above 500 cycles can be compared It is easier to obtain a smooth wide quency tones which sweep gradually directly with the playback curves of range at 78 r.p.m. and with needles of downward, always maintaining a 1,000 - various makes of recordings and de- large radius (and wide groove spacing) cycle difference. If the reproduction partures will be quickly spotted. The than at 33 r.p.m., with narrow groove were perfect, only the original fre- curve below 500 cycles will need more spacing and with a needle of small quencies would pass through the car- care in interpretation. But in general, radius. Some microgroove needles may tridge and amplifier. However, if cross - when the test record is played back fall off in response above 10 or 12 kc, modulation distortion is present, the through an equalizer designed for a even though the pickup itself is flat 1,000 -cycle difference tone will be heard. given playback curve, the response be- beyond this point. This effect is also In the form of a repeated dot -dash, low 500 cycles will also indicate the produced by a worn needle. Therefore, a 1,000 -cycle 2% distortion signal is degree to which the desired playback the measurement of the loss at high recorded on the disc. If this signal is curve is reproduced. frequencies may offer a clue to the louder than the distortion due to track- The most serious exceptions occur condition of the needle. The Cook series ing, only the dot -dash (A) will be when the turnover point of the desired 10 records are recorded with a V groove heard. At frequencies where the cross - curve is higher or lower than 500 cycles. which can accommodate either the large modulation distortion of the cartridge In this case the comparison is not direct needles used for wide -space 78- r.p.m. and amplifier is louder than 2 %, the A but will require some interpretation, and 33- r.p.m. broadcast transcription, will be lost, and an N (dash -dot) will especially around the crossover region. or the 1 -mil needle used for micro- be heard instead. RADIO -ELECTRONICS

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re- tests of the damping of a scopes have more than adequate For rapid frequency runs and the are really -frequency end, but system -are valuable diagnostic tools. sponse at the high simplest adjustment of tone -control not all are adequate in low- frequency records are It is difficult to find acceptable sources circuits, sweep -frequency especially response. We are rapidly improving extremely valuable and time saving. and standards of transients, and with phono systems. The Cook our ability to record, transmit, These records sweep the whole range for use lowest octave of sound 20 White Noise record offers such reproduce the from 50 to 10,000 cycles, and when series up. Also, the behavior a signal and can be most useful. from 16 cycles properly presented to a scope will pro- system at these low frequencies showing Thermal noise is nothing but transients of a duce on the screen a pattern and affects the behavior of the whole sys- frequency response of the and covers the entire audible band the over -all presents a care- tem- especially from the point of view system from record to output. Pips more. The Cook record any other proportioned series of thermal of distortion -more than indicate various reference frequencies fully the spectrum. This is partly curve noises in switch bands, in which the portion of so that departures from a desired because these low- frequency compo- roughly and then ex- high-frequency and low -frequency com- can be spotted are progressively nents are of high amplitude and are amined in detail with normal frequency ponents of the noise to make out. By comparing the sound usually boosted in amplifiers runs, using steady -state records, or an filtered for attenuation in transmission or Clarkstan offers a of the noise output of a system as the up audio generator. these switch bands, deficiencies in loudspeakers. The result whole series of these, including one record goes through system is first a quick idea of the transient all too often is that the with a response to 15,000 cycles, for we obtain region. Since a high - response and transient cut offs of the overloaded in this both 78- r.p.m. and 33- r.p.m. Walsco system is very flat above this No. 726, in its system. The record is useful for listen- fidelity offers a similar record, more region, any distortion produced there inexpensive test records. ing tests and can also be used for series of a scope. With is passed easily to the output, whereas Needle wear is a very serious item subtle diagnosis with may not skill, it is possible to distortion at high frequencies in high- fidelity reproduction. Serious experience and response, not only transient response be audible at all because the wear can be spotted with the naked eye estimate slopes rapidly be- but also bandwidth, distortion, hang- at least of speakers, and even by feeling with a sensitive kc. Finally, when these wear, sufficient to over or ringing, and even pickup track- yond 12 or 15 finger tip. Moderate low frequencies occur in music, the produce serious distortion and record ing.' most nearly re- to dis- resultant waveform damage, is sometimes difficult a square wave, and it is in a microscope. The Oscilloscope sembles cern even through value this region therefore that square -wave simplest test is by the new Audak Oscilloscopes first proved their them we owe testing is most significant. Stylus -Disc, recorded with special in audio work and it is to itself does we know today about Obviously if the scope grooves so that needle condition can be most of what behavior with low -fre- the needle waveforms and the behavior of not have good determined by the damage audio square waves, it is going to be grooves. A single such waves in amplifiers. The oscillo- quency causes in clean much more difficult to use square -wave -Disc will permit scores of checks scope is an indispensable diagnostic Stylus for some testing methods. So it is necessary that and will quickly repay the investment tool and furnishes an indicator least a 60- types of measurement; the scope be able to pass at in profits from new needles. most important wave, and preferably a rumble can be it can make possible extremely rapid cycle square Wow and turntable 20 -cycle square wave, without sig- quickly with the Walsco 727 and highly convenient testing routines. checked a scope nificant deformation. Direct -coupled and 728 records. They can also be For high- fidelity servicing very much not necessary for amplifiers are therefore checked with IM test records since an needs some qualities which is to be increase work. Most of today's worthwhile in a scope excess of either will greatly TV, or radio fidelity work. There are Emory used for high- the IM distortion. 'See "White Noise Testing Methods." by of such scopes, although they response -which Cook. Audio Engineering, March. 1950. a number Tests of transient aie expensive. Good scopes are avail- considerably lower - (A) able in kit form, at 2% SYNTHETIC PILOT TONE tl cost. The high- frequency response is less modern scopes N2 (20,000 - of a problem since most D CARRIER WV4 rrYYYr I11 INN are flat at least to 500 kc. The distortion level of the scope should be very low, and for this reason a scope with STEAM WIRIER NI (19,000' is preferable. High ) tI\ V'YrYrYY`rrYYr` push -pull amplifiers sensitivity is also very important. Often, serious trouble occurs in low - RESULT I DISTORTION TONE MORE it a scope TWIN 2% level stages, and to trace L -PILOT TONE should be able to give an acceptable test record Fig. 2- Diagram shows principle of Cook series 50 N -A beam

Left -The Eico model 125 oscilloscope. Above-The Heath intermodulation analyzer. Right -RCP model 655 vacuum -tube voltmeter. '.IAY, 1954

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trace with input levels at least as low Audio wattmeter low frequency and as 100 mv and preferably 10 a choice of either mv. Ot her The power 3,000- or 7,000 -cycle audio indicators are usually calibra ted output of audio equip - high frequency. ment can be calculated The ratio can be set in r.m.s. volts and measure the effect ive by measuring for any figure the between 1 value of the voltage drop across a specified load -1 and 10 -1; including of signal. A scope can in di- resistance course the cate and measure the peak and using Ohm's law. This is standard 4-1. The IM of the -to -p eak a clumsy and time -consuming instrument itself value, and therefore a means e opera - is-at least in my of ali- tion, and an audio own instrument brating the scope for peak -to wattmeter, such as -in the order of 0.2 %. -pe ak the Heath -1, Fractional levels reading in volts is very helpful. AW is very convenient. can be read easily and The instrument makes without much error. The A little item which is also very he possible direct range of IM 1P- reading of power output readings ranges from ful is a reticule (grid) marked off in from 5 milli - this fraction to watts to 50 watts across normal 30 %. The accuracy is well a square, over the scope tube fa e. loads. within the The loads are provided by the instru- needs of production and general Used with the phase -shift meth od ment servicing which we shall discuss itself and meter multipliers are work. in the n ext switched simultaneously The IM analyzer article, this square offers a convenie so that no works thus: The nt translation of any sort mixed 60 -cycle and and accurate means of observing a nd is necessary. It 3,000 -cycle (or interpreting is fiat from 10 to 250,000 cycles and its 7,000 -cycle) signal is fed to the input the behavior of the signal accuracy of the as it goes through an amplifier. is well within permissible equipment under test. The output limits for production of the equipment is fed It is also desirable that a scope p er- testing and to the analyzer mit push-pull servicing. section. Here it passes through a 2- as well as single -end ed stage amplifier input. A large part of the quality As I alreadyY pointed out, power out - which also acts as a high -fidelity put measurement is a helpful step in high -pass filter and eliminates (for all equipment is due to t he practical purposes) use of push -pull configuration in diagnosing troubles and adjusting the 60 -cycle com- ou t- power ponent. The remaining put and driver stages. Some equipme nt, amplifiers. One of the watt - signal, now con- like meter's most practical jobs is that of sisting of the high-frequency tone plus the Golden Ear, Powertron, et the intermodulation, may be push -pull e'' indicating the improvement made by a is passed into an for several stag es. change infinite impedance The ability to observe the push-p ull g in tubes. It can pay for itself detector which de- very quickly modulates it. The 3,000 behavior of such equipment is ve ry in this way. -cycle compo- helpful. The most significant rating of com- nent is eliminated in the low-pass filter If a scope is to mercial high -fidelity equipment is in which follows, and the IM prod- be purchased f or ucts only combination audio-TV -radio terms of IM distortion at various out - are fed to a v.t.v.m. which use, the measures them and special qualities needed for high -fideli P ut levels. The quickest way to check reads directly in ty amplifier terms of percent IM. measurement should always be kept in performance is to check the mind. IM level at maximum rated output. The entire operation is very simple This should be a routine shop procedure and fast, and can be performed by A.c. vacuum -tube voltmeter at the conclusion of repairs and adjust- almost anyone. The analyzer portion can be used As I pointed out in discussing scope ment and will save much time and with other signal sources, it is desirable s' argument. After all, a service tech - as for instance IM test records -the to measure the sign al filters of the in low-level stages. On rare occasion nician is not expected to do more than analyzer section being s, restore completely suited to the it may be desirable to have an instr u the equipment to its original frequencies ment specifications. No customer can gripe used on such records. that will read voltages as low a s The signal output 10 mv. Lacking such an instrumen t, when shown by measurement that the of the analyzer equipment is as good as new. Of course, can also be used for signal tracing. The you can use the scope with a linea r device grid over not all manufacturers are, shall we has no means for turning off the face of the C -R tub either the high- with an oscilloscope calibrator. e' say, conservative in their rating and it frequency or low - sometimes frequency generators; so the A general- purpose v.t.v.m. with a happens that the equipment output will not meet the IM specs will always be a mixed signal. This, low range of 3 volts (preferably 1 even when brand -new. Obviously, if the shop also however, is by no means a disadvan- will be suitable for tracing and measur tage. ing a.c. - handles the sale of high -fidelity equip- On the contrary, if the 60- and voltages in most amplifier 7,000 -cycle tones Most have a.c. input impedances rangs' ment, the above check is a prudent test be used, we have a - of whether tracing signal which gives some ing from 200,000 to 500,000 ohms. If yo the manufacturer is meeting indi- u his specifications. cation of both the low- and the high - need a v.t.v.m. for general -purpose a.c frequency response d.c., and It is also significant to know just how as well as distor- r.f. measurements, you migh tion. Finally, the voltmeter consider one of the several models hay much the frequency response varies itself is with the output level. A frequency run available for measuring audio frequen- ing an a.c. input impedance of about 2. 5 cies in three megohms. at maximum rated output, as well as ranges, 0 -3, 0 -10, 0 -30 one at normal volts full scale. So the instrument is by If you plan to do a large volume f output, can be very o instructive. no means a special -purpose tool but ex- audio servicing, you may need one o f So, although perhaps less essential than the other instruments tremely versatile and a nearly ideal the amplifier- rectifier type of audio single diagnostic tool. vacuum -tube voltmeters, with a full discussed, the wattmeter is often very useful. The IM analyzer portion is very sen- scale deflection of around .01 volt on sitive. An input the lowest range. of only 50 mv is sufficient to permit accurate IM I find mine all but indispensable. Intermodulation analyzer measure- The ment. The instrument can be used lowest scale is .01 volt, but good read- Rivaling both the scope and genera- at tor in usefulness, the output of an initial amplifier stage, ings can be made down to 100 micro- and perhaps even even the phono preamp; and volts; even the output more important in diagnosing and re- it might, of many micro- with a suitable test record. be used phones can be measured directly with storing a high -fidelity system to proper directly operation, is the IM at the output of a Pickering it. The accuracy and linearity, though analyzer. Aside pickup. In tracing distortion, not up from outright inoperation, caused by the ana- to laboratory standards, is more a lyzer input can be moved from stage to than good enough for service work. The tube or component failure, a large percentage of complaints stage, beginning with the first one. This instrument is fiat from 20 to 50,000 will involve is an extremely helpful means of cycles, which is adequate for most higher- than -normal distortion. Distor- diagnosis. needs. The regular shop v.t.v.m. can be tion is not too easy to trace. To make matters The next part of the series will dis- used to measure output -if a watt- worse, high -fidelity addicts are cuss actual measurement likely to and testing, meter is not available or can't be be hypercritical. A means of with special attention to routines which afforded -while the a.c. v.t.v.m. moni- checking distortion is therefore almost have proved to be fast in diagnosing tors the generator output and measures absolutely essential. equipment faults. voltages and gain, stage by stage. An IM analyzer provides a 60 -cycle (TO BE CONTINUED) RADIO -ELECTRONICS

www.americanradiohistory.com 67

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www.americanradiohistory.com 68 I AUDIO-HIGH FIDELITY

R-i TYPE 12'' SPEAKER ENCLOSURE

Get nutxi,une bass in ntini- By J. W. KORTE mum space with a l2-inch speaker and a R-J type en- ciosure

Photo of a combination cabinet with the 12 -inch 1. -.1 type speaker enclosure.

NIAANY audio enthusiasts would like to have good bass re- Fig. 1- Construction detaik of an It -.1 type enclosure for 12 -inch loudspeakers. sponse from their living -room radio -phonos. A large bass - :efl ex cabinet will do the job but it is usually too bulky for the smaller home of today. I tried to improve my open - backed radio -phono cabinet by incorporating various labyrinths, columns between the wall and cabinet, reflexes, and infinite baffles. Invariably the insufficient volume caused either high bass-frequency resonances with vented enclosures, or excessive speaker damping and loss of bass response with closed enclosures. Finally an R -J type enclosure was tried with almost unbelievable results. I found that the free -air resonance of a 12 -inch speaker could be lowered from about 70 to 55 cycles by slotting the corrugated suspension edges of the cone radially at about one -inch intervals. Good speaker -to -air coupling in the R -J type enclosure permits this speaker modification which could not be used wits an open -back cabinet, for instance. This same speaker has a new resonance of about 45 cycles in the enclosure, and does a good job down to 35 cycles with a 10 -watt push -pull 6B4 amplifier. Rear -view photos with the airtight back removed to show insides. Left -hand Resonance may be easily checked by photo shows the normal position (Continued of the Ozite strips. The right -hand photo has on page 73) the strips pushed aside to show how the speaker mounting hoard is positioned. RAD 0- ELECTRONICS

www.americanradiohistory.com 69

®Save by ordering direct from manufacturer. OAll high quality standard brand components. OIncreased knowledge through actual construction. ®Sound engineering insures excellent performance. TEST INSTRUMENTS AMPLIFIERS OKit construction is fascinating and enjoyable. RECEIVERS, etc.

qeeatidat MODEL O -9 OSCILLOSCOPE KIT New features unheard of in a kit oscilloscope have been added to the already popular Heathkit series. All top quality components are used including a brand new RCA 5UP1 CRT. Ten other first line tubes complete the lineup. Voltage regulation provides a rock steady pattern regardless of normal line voltage variations. A built -in blanking amplifier eliminates the retrace line entirely. Other important advantages are a phasing control, Z axis input, direct connections to the deflection plates, 1 volt peak -to -peak calibration voltage and a calibrated grid screen. Wiring is simplified by the use of the harness technique which also results in a neat professional appearance. Extremely wide vertical bandwidth allows accurate reproduction of even a 500 KC square wave. Excellent focusing characteristics are made possible by the use of the new RCA 5ÚP1 CRT and a spot shape control. One of the most versatile of test instruments, the Heathkit 0 -9 Oscilloscope will be invaluable in the radio and 'IN service shop. as a work project in schools and for all types of circuit investigation work in the laboratory. Its new features make Model O -9 comparable in every way to many commercially built oscilloscopes selling for as much as $400. Don't pass up this opportunity to add a really fine instrument to your service or experimental lab.

Wear.liZet VOLTAGE CALIBRATOR KIT ELECTRONIC SWITCH KIT

Switch Kit . MODEL The use of a Voltage Calibrator will greatly The Heathkit Electronic will further extend scope usefulness S -2 increase oscilloscope usefulness. Provides a by permitting observa- convenient method of making peak to peak simultaneous by establishing a rela- tion of two individually controlled $ 50 voltage measurements t variable switch- tionship between the unknown wave shape MODEL VC -2 races. Continuously 23 the Voltage Calibrator. Voltage ranges ing rates 10 cps to 2,000 cps in three and ranges. Will also serve as a square Shipping .01-100 volts peak to peak. The Voltage Cali- $1150 wave generator over the range of brator features direct reading scales and a Wt. 11 lbs. regulated power supply system. switching frequencies. Shipping Wt. 4 lbs

Tecte., 6:t VACUUM TUBE VOLTMETER KIT \\ The beautiful new 1953 Heathkit Model V -6 VTVM, the world's most popular kit 444. instrument, now offers many outstanding new features in addition to retaining all of the refinements developed and proven through the production of over 70,000 VTVM kits. The Heathkit VTVM now features extended voltage ranges with 50% greater coverage on the DC range. New 1'4a volt low scale provides well over 21/3 inches of scale length per volt permitting faster measurements with greater accuracy. AC and DC ranges are 0- 1.5-5- 15-50- 150- 500 -1500 volts (1,000 volts maximum on AC). Ohmmeter ranges are Xl, X10, X100, X1,000, XIOK, X100K Xl meg. Measures .1 ohm to 1,000 megohms. Other features are db scale, center scale zero adjpst and polarity reversal switch. High 11 megohm input resistance virtually eliminates circuit loading. The low anti -inflation price of this tremendously popular kit includes all tubes, nec- .osary constructional material, test leads and the construction manual.

qleaddit AC VACUUM TUBE r'eaelcliít VOLTMETER KIT HANDITESTER KIT A new amplifier type AC VTVM that makes possible those sentitive The ever popular Handitester is MODEL AV -2 measurements so essential in now supplied with a Simpson 400 laboratory or audio work. Ten MODEL M -1 microampere meter movement. voltage ranges covering from 01 Provides AC and DC voltage $2910 RMS full scale to 300 volta RMS $1450 ranges 0- 10-30- 300 -1,000 -5,000 full scale. Input impedance 1 volts. Ohmmeter ranges 0-3,000 Shipping; megohm with frequency response and 0- 300,000 ohms. DC current wt. 5 Ibg. 20- 50,000 cycles. Ten DB ranges Shipping measurements 0-10 and 0 -100 from -52 to +52 DB. Four diodes Wt. 3 lbs. milliamperes. A completely self in meter bridge circuit for maxi- contained portable instrument. mum linearity.

MAY, 1954

www.americanradiohistory.com 70 HEATHKITS for the ENGINEER ee¿t eaeirZet VISUAL AURAL RESISTANCE SUBSTITUTION SIGNAL TRACER KIT BOX KIT MODEL RS -1 .. Choice of 36 switch Ship. Wt. $ C 5O Designed especially for selected resistance 21bs. r service applications in AM- values 15 ohms to 10 SW-FM-TV repair work. megohms. All stand- RF and audio two channel ard RTMA 1 watt input. More than adequate 10% resistors. Buy sensitivity -new noise lo- several for NEW cator circuit -calibrated those lab Mate at wattmeter -substitut ion and service speaker -visual signal applications. 20,000 OHMS PER VOLT indication. Can be used with scope and VTVM, checks phono cartridges, MULTIMETER phono mechanisms, micro- KIT phones, tuners, etc. Let the Here is the solution to all service Heathkit Visual Aural Sig- problems requiring a portable nal Tracer help you. measuring device of high accuracy. 20,000 ohms/volt sensitivity on DC and 5000 ohms /volt on AC. Full scale e voltage ranges of 1.5, 5, 50, 150, 500, sTeatile 1500 and 5000. DC current ranges of CONDENSER CHECKER KIT 150 microamperes; 15, 150 and 500 milliamperes; and 15 amperes. Re- sistances An instrument designed solely are measured from .2 ohms for its particular job. Not a to 20 megohms in 3 ranges and deci- "sideline ' or a multiple function bels from -10 to +65 db. instrument. Measures value and Model MM -1 uses standard quality of unknown condensers and commercially available batteries resistors. Capacity range and is .00001 mfd to 1,000 mfd. Resist- not affected by strong RF ance range 100 ohms to 5 meg- fields as encountered in and near ohms. Sensitive electron beam transmitting equipment. 1% pre- indicator -five polarizing test cision resistors on a very easily wired voltages -safety spring re- ring turn type range switch and a highly leakage test switch. accurate Simpson An amazingly accurate in- 50 microampere strument at this low price. meter fully qualifies the Heathkit Multi- meter for close tolerance laboratory and MODEL MM -1 service work. The meter movement is placed in a recessed position for maximum non -glare readability. The kit $2650 GRID DIP METER includes the attractive black bake- KIT lite cabinet, 2 color meter scales, Ship. Wt. 6 lbs. One hand operation. 5 test leads, batteries and' all other pre-wound coils cover necessary 2 -250 MC. Controlled components. Overall cabinet size is 5 °2' sensitivity. Usable wide x 4' deep x 754' high. as an oscillator or an absorption '%CacL wave meter. ál Extra low frequency TUBE CHECKER KIT e : Ship. Wt. 8 lbs. coils avail- Checks qiCcitlife LABORATORY The able. overall tube quality, t !l. standard filament continuity, and in- . service .44 instru- dividual elements for shorts GENERATOR KIT ment for align- and opens. Features ment work. .1 volts chart illumination, output from 160 KC to 110 harness MC. Calibrated harmonics up to type wiring, and large 3 -color 220 MC. Internal (400 CPS) and meter external modulation. Pre-calibrat- scale. ed coils for all 5 bands. G sta- Portable .., . , Model TC -2P at $34.50. Wt. included. 14 lbs. No. 91 -8 Cab- di?t inet only at .$7.50. « Wt. 7 lbs. No. 355 TV MODEL LG -1 MODEL TC -2 Picture Tube Adapt- Ship. Wt. geetialefit LABORATORY REGULATED er at $4.50. Wt. 1 lb $ 2950 16 lbs. $3950 A professional laborat -.> POWER SUPPLY KIT Shipping Wt. 12 lbs. instrument desiard for extreme accu.acy in frequency and output level. A regulated variable 160- Colpitts r,acillator operates 450 volt DC output power q eatltle t in 5 ranges from 150 KC to supply for the lab or serv- 30 MC. Panel meter cali- ice shop. Accurate voltage AUDIO WATTMETER KIT brated in output voltage and current measurements Measure output power levels di- and percent of modulation. with large Simpson meter. rectly with the Heathkit Audio Output in excess of .1 volts. AC supply 6.3 volts at 4 Wattmeter. Flat response to fre- Features complete shield- amperes -standby switch quencies from 10 CPS to 250 KC. ing of oscillator, buffer and eliminates warmup time. Full scale ranges of 5 MW, 50 MW, attenuator sections; regu- Low hum content -5 tube 500 MW, 5 W and 50 W. Db cali- lated power supply and 50 ohm output cable. Com- circuit. AC and DC output MODEL bration from -10 to voltages isolated from panel +48. Uses non -inductive parable instruments priced for maximum operational AW -1 built -in load resistors pro - many times higher than the flexibility. cost of this new kit. Ship. Wt. viding impedances of 4,1 50 8, 16 and 600 ohms. Q 6 lbs. . Meter bridge uses 4 germanium diodes.

0-ELECTRONICS

www.americanradiohistory.com SERVIC NAMATEURSTUDENT eeatlt t IMPEDANCE BRIDGE KIT AUDIO OSCILLATOR KIT Modern design with eae4it MODEL AO -1 built -in 1 KC generator for AC meas- COMMUNICATIONS RECEIVER KIT $245° urements. A choice Full coverage from 550 KC to 35 MC on 4 bands, of the Wheatstone, and Ship. Wt. Maxwell, Hay or with good sensitivity I1 lbs. capacitance com- selectivity. Features ele- parison bridges for trical bandspread, BFO, Reaturea sine _# measuring resist- headphone jack, slide or square ance, capacitance, induc- rule dial with ham band wave coverage from tance, dissipation factor identification, RF gain 20- 20,000 cycles in 3 MODEL IB -2 and storage factor. Si % control, noise limiter and ranges. Variable 10 volt output level resistors and precision mica phone -standby -CW at 600 ohms impedance. Thermistor condensers provide maxi - switch. Top quality, high gain controlled linearity- precision multi- $5950 Completely components used through- plier resistors distortion less than mum accuracy. coils in a - value Ship. Wt. 15 lbs. AC operated. MODEL AR -2 out. Pre -wound .G An outstanding instrument 2 shielded turret assembly and at this amazing low price. 50 a transformer operated power "4"12 lbs. 41t. $2550 supply assure trouble -free (Less Cabinet) performance. DECADE Cabinet available separately. No. 91 -10. Shipping RESISTANCE KIT wt. 5 lbs. Price $4.50. 'eetrideit AMATEUR í.:. MODEL DR -1 TRANSMITTER KIT $1950 Q METER KIT in- Power input up to 35 watts on A typical Heathkit 80, 40, 20,15,11 and 10 meters. vasion of the laboratory excited. Ship. Wt. instrument field. Here Can be crystal or VFO 4 lbs. Complete with modulator in- is the first successful put socket and VFO power out - low priced Q meter ever desirable offered in kit form. Os- put provisions. Other RF in features are good shielding, AC cillator supplies line filter, key click filter, stand- Individual switch selec- the range of 150 KC to coaxial Reads Q directly by switch and a 52 ohm tion of twenty 1% pre- 18 mc. output. Model AT -1 is AC op- MODEL AT -1 cision resistors in 1 ohm on calibrated meter exciter scales. Measures Q of erated and is suitable as an steps from 1 to 99,999 for a higher powered rig. Complete ohms. Sturdy ceramic condensers, RF resistance and distributed with full instructions for construc- $2950 wafer switches featur- tion and use. ing silver plated con- capacity of coils. Cali- Ship. Wt. 16 lbs. tacts and smooth,posi- brate capacitor with tive detent action. Ship. Wt. range of 40 mmf $4450 14 lbs. to 450 mmf with vernier ±3 mmf. All measurements DECADE sTeaticáit made at the oper- KIT ating frequency. CONDENSER KIT AUDIO GENERATOR A new extended Switch selected 1% range 18 cycles T l FVISION SWEEP silver mica preci- 4;y,.. -1 megacycle www.americanradiohistory.comIIÏI - .l i r inatru_ "Weiatl>lt F M TUNER KIT NEW HEATHKIT WILLIAMSON TYPE s'íßdearlf4 t AMPLIFIER ECONOMY ó WATT MODEL KIT FM-2 The ideal amplifier for custom high fidelity AMPLIFIER KIT Tops audio installations. in performance, value and flexibility of operation. Either MODEL A -78 $1Z5ó Altec Lansing Peerless or Acrosound output -* available. Frequency transformers response ±1 db 10 CPS to 100 KC, $1550 negligible hum and noise levels and plenty Shipping Wt. 9 lbs. of reserve power for complete listening Ship. Wt. 10 lbs. pleasure. First Williamson Type Amplifier Sensitive transformer operated supplied with matching preamplifier. Dual inputs - 8 tube circuit. Frequency cov- separate bass and erage 88 -108. r treble mc. Pre- assem- PRICES OF VARIOUS COMBINATIONS: tore con- bled and tuned "front end." trols- output impedances Vernier tuning with slide rule W -2 Amplifier Kit (Includes of 4, 8, and 15 ohms. Perform- type (liai. Main Amplifier with Peerless ance far beyond that normally Output Transformer, Power Sup- expected for the price. ply and WA -P2 Preamplifier.) $1( 50 A-7C: Includes preamplifier for Shipping weight 38 lbs. Shipped low level input express only j`j//\ `yU/i devices. Price $17.50 NEW r?featlrlit W -2M Amplifier Kit (Includes Main Amplifier with Peerless BROADCAST BAND Output Transformer und Power Supply.) Shipping weight 30 15 lbs. Shipped express c RECEIVER only 49 HIGH FIDELITY 20 WATT KIT W -3 Amplifier Kit (Includes Main Amplifier with Aerosound AMPLIFIER Output Transformer, Power Sup- KIT ply and WA -P2 Preamplifier.) MODEL BR -2 Shipping weight 38 lbs. Shipped S 50 MODEL A -9B $1750 express only W -3M Amplifier Kit (Includes Main Amplifier with Aerosound (Less Cabinet) Output Transformer and Power ( $3550 Ship. Wt. Supply.) Shipping weight 30 15 I1,, tilii,r..,1 Shipping 11 lbs. express onl- Wt. 23 lbs. Complete receiver with chassis mounted 51-i ' PM Speaker and HEATHKIT HIGH FIDELITY new rod type antenna. Covers LOW PRICEDSÙg94UNIT the full Outstanding features of the broadcast band (550 WiLLIAMSON TYPE PREAMPLIFIER KC -1600 KC) with excellent KIT Heathkit 20 Watt Amplifier sensitivity include a frequency response and selectivity. MODEL WA- P2 --:_ +1db Operates as a receiver, AMPLIFIER KIT of from 20 CPS to 20 tuner or a phono ampli- KC, less than I% harmonic fier, MODEL $1975 distortion at rated output, High gain miniature W -4M 1) A tubes and IF trans- k separate (boost and cut) formers. Easy tuning $3975 Ship. Wt. 7 lbs. bass and treble tone controls, with direct plane- Complete compensationforl.l'. \i; I'll, 4 selected in- tary drive. AES put jacks, hunt balanc- Ship. Wt. 28 lbs. and early 78 recording character- ing Cabinet control and output . avail - istics. An ideal control unit for the custom a Lae separately. The famous Heathkit Williamson Type Ampli- Hi-Fi system. impedances of 4, 8. 16 5 individually controlled and Part No. 91 -9. fier is now available in a single chassis. Includes inputs, 4 500 ohms. Flex- Power turnover and roll -off switch ibility is Ship. wt. 5 supply and power amplifier. Enjoy the positions, 3 twin empnasizr lbs. Price same high triodo tubes, cathode ed in the inpt.t quality reproduction at less cost by follower outpput, monitored recorder cir- $4.50. eliminating the second output, cuits with built - chassis, connecting shock mounted tube chassis and proper shield- cables, etc. Size 15 t4 °wide -- r' high deep. ing. All condensers in preamplifier Model W -4 includes -9' are of the molded plastic and proper W -4M and preamplifier WA- type. Critical input circuits feature l'2. Shipping weight 35 tbs. Price low noise equalization. $59.50. deposited carbon resistors. Use it with any conventional high fidelity amplifier.

www.americanradiohistory.com providing capacity ," ment at a re- 1 ;' 100 ¡: range of markably low 4 GENERATOR KIT mmf. to 0.111 price. Five con- t mfd. in steps of tinuously vari- MODEL TS -3 100 mmf. able output ran -. MODEL DC -1 ges -600 ohm output impedance - AG -8 low distortion MODEL $4450 figure, less than Shipping$ Wt.O 4 lbs. .4% from 100 cps $29° through audible Ship. Wt. 18 lbs. range. Ship. W. 1 lbs

Simplify your TV alignment jobs with the new Heathkit TS-3. Full coverage on fundamentals from 4 MC to 220 MC at anrout- BAR GENERATOR KIT put of well over 100,000 microvolts ... Automatic Small, compact and easy to blanking and wide range use, Model BG-1 supplies hori- phasing. A triple marker system ranges zontal or vertical bars. for TV from 19 MC to 180 MC using a Colpitts linearity adjustments. Output MC crystal con- cable clips directly to the TV oscillator plus the 4.5 antenna terminals. trolled oscillator for check points (crystal receiver Provisions are also made for using an external marker. furnished). con- MODEL BG -1 Featured is the new sweep system, using an *INCREDUCTOR trollable inductor. Sweep width is variable from 0 tci 12 MC at the lower Ship. Wt. the highest Other $14" RF frequencies and increases to 0 -50 MC at ... BATTERY 6 tbs. advantages are power supply regulation, constant RF output level, independent marker and RF output control circuits, low impedance ELIMINATOR KIT output and properly terminated output cables. The construction and with a reasonable amount of 6 or 12 volt opera- manual is complete in all detail tion with current and WRITE FOR 72e-C-1 care, Model TS -3 will serve faithfully for many years to come. voltage constantly monitored. Double pro- CATALOG *Trademark, C.G.S. Laboratories, tection with a fused Stamford, Connecticut auto- New 40 page 1954 Cat- transformer and alog lista all kits, speci- MODEL matic overload relay. Well fil- fications, schematics tered output and all heavy duty and latest price infor- Ship. Wt. $ 5O components. Designed for auto radio repair and as a storage mation. 18 lbs. 31 battery charger.

HEATH COMPANY Benton Harbor 20, Mich.

MAY, 1954

www.americanradiohistory.com SHIP VIA Parcel Post Express Freight Best Way

QUANTITY (PLEASE PRINT) ITEM MODEL NO. PRICE

Enclosed find ( ) check ( ) money order for Please ship C.O.D. ( ) postage enclosed for On Express orders do not include transportation pounds. charges -they will be collected the express agency at time of delivery. by ON PARCEL POST ORDERS insure postage for weight shown. ORDERS FROM CANADA and APO's must include full remittance.

RADIO -ELECTRONICS

www.americanradiohistory.com ," AUDIO -HIGH FIDELITY

(Continued from page 68) adding a resistance in series with the speaker voice coil to decrease electrical damping and measuring voice -coil voltages at various frequencies, higher voltages indicating resonances. Take care when slotting the cone AGAIN and AGAIN suspension so that rattle and distortion are not added from excess flexibility. Most of the commercial speakers are quite stiff because they must be suit- 15 times be factor, experts to provide .ind insure able for nearly any type baffle. An ex- (insistent HIGH FIDELITY PERFORAIANCIì ample of the slotted edges can be seen in the Permoflux line of speakers. Figs. 1 and 2 may be used generally so that the enclosure can be built into practically any shape as long as the crattsrrEn volume is 4,500 cubic inches. enclosed rf ornr It should be constructed of a/a -inch or does this ... each ant ever)' Inner mast p heavier plywood with an airtight back with less than 1/2% interrnodulation distortion absorbent and a lining of 1 -inch sound 9"r. frequency modulation when tested the front at 100 on all inside surfaces except antrum to audio output. and speaker baffle panels. A % x 3 -inch strip of Ozite or equivalent is looped from top to bottom to fill the inside volume of the box with about 10 irregu- larly spaced vertical strips. They damp out the box resonance which is in the vicinity of 125 cycles.

New! C 810 FM -AM Tuner

A new basic High Fidelit Tuner with flat audi output response. Featuring: Sensitive FM, tpv for 3(1 db quieting. Automatic Frequency FM simplifies tuning. Fig. Details of the lemon- shaped Control (no drift) on 2- It- 1/2db, 20 tr 20,0(N) cps. opening in the center of the panel. Frequency response, Distortion - FM, t/3% at 100% modulation Various dimensions were tried' for Cathode- follower audio output for remote the lemon -shaped opening in the front installations. panel. None were critical. I settled for the dimensions and shape shown in New C 800A FM -AM Tuner Fig. 2. The shape was obtained by con- in the center (same as C 810 structing a parallelogram with additional features) of the front panel and rounding off the corners to give the desired shape. The record equalizer. factor seemed Built -in phono preamplifier and greatest single benefiting Front-panel selected equalization for AES, LP to be the suspended Ozite strips. or EURopean. recording characteristics. Double- If the dimensions shown are changed, shadow tuning eye. Bass and treble controls it may be desirable to vary the s/4 -inch continuously variable up to 15 db attenuation spacing between the front panel and or boost. speaker baffle. Placing the baffle tight against the front panel (reducing the space to zero) increases acoustical capacitance in the system to effectively WetITEM stiffen the cone and decrease the low - Craftsmen CAI Assembly -a complete HiFi frequency response. The speaker and home music system. Ready to install with all enclosure capacitances should be bal- cables, hardware, escutcheons and detailed anced out with a like amount of acous- plans. $275 net. tical inductance which is variable by on High changing the $/4 -inch spacing. When Get new booklet the acoustical á Fidelity by DEEMS TAYLOR. correctly balanced out, or write to resistance remaining loads the speaker Ask your Supplier advantage us ... enclose 10c to cover cone to the air to the best handling and mailing. and the resonances are minimized. Very little has been said concerning the workmanship of the construction, Department G5 but it is important that all the cutting and fitting be done with care. Heavy n should be used, and spaced close screws THE 6AOIf It sme1I INCORPORATED enough to give a very strong bond, the craftsmen back should be especially tight, etc. 4445 North Ravenswood Ave., Chicago 40, III. These extras make a difference. END MAY. 1954

www.americanradiohistory.com 74 I RADIO

TRANSISTOR

PHONO

OSCILLATOR

By EDWIN BOHR

3A-TER" L=ADS R4

The small transistor phono oscillator in actual operation.

MUSIC and conversation can be AUDIO broadcast over short distances LEAS 1 with this tiny transistor oscillator. The basic circuit uses one transistor plus a few inexpensive components. An extra audio stage may be added for more amplification. The idea that junction transistors are useful only at audio and low radio frequencies is fading away. Practically CI 22 Sft_t.ET all CK722 transistors will oscillate in the broadcast band. Some will go as far Despite small size. there is ample room for wiring. as 3 megacycles. All of the transistors I've been able to get my hands on have BATTERY LADS worked in the phono oscillator circuit. The first experimental circuits with transistor phono oscillators used a sep- FFC arate transistor amplifier to collector - modulate another transistor oscillator. At least two transistors were necessary plus some sort of modulation transformer. The circuit evolved into a simpler one- transistor layout that performed better than the two -transistor circuit. The circuit makes a single transistor do double duty as audio amplifier and A.F. INPUT LEADS oscillator. The oscillator is grounded base and the audio amplifier is grounded emitter. Let us see how it works. UNING TUNING COIL CAPACITORS 390ppf

C*:;22 CI C2 Fig. I -The basic oscillator circuit. All major components are neatly laid out for maximum compactness. RADIO -ELECTRONICS

www.americanradiohistory.com 75

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THE PRODUCTS CORP, DIVISION OF THE GABRIEL COMPANY 1148 Euclid Ave., Cleveland 15, Ohio Canadian Distributor: ATLAS RADIO CO., LTD, TORONTO, CANADA

MAY. 19r:

www.americanradiohistory.com 76 I RADIO

Circuit ing range. The iron core in the tuning and distorts easily on loud sounds. A Fig. 1 shows the oscillator alone. Ex- coil is pushed in and out to adjust the 3 -inch speaker connected through an cept for resistors Rl, R2, and R3 which carrier frequency. This way the oscil- output transformer to the oscillator stabilize the d.c. operating points of the lator can be tuned from about 600 kc makes a better microphone. Carbon transistor, the circuit is a simple type to over 1 mc. microphones are suitable and much where feedback is tapped from the tun- The transistor plugs into a hearing - more sensitive. Carbon mikes must have ing capacitors rather than the coil. This aid tube socket. It is made into a three - a coupling transformer. A small fila- is a matter of convenience so perme- pin socket by pushing out two of the ment transformer will do. Fig. 3 shows ability tuning can be used. Capacitors contacts. CARBON MIKE FIL TRANS Cl and C2 bypass the r.f. around the Some shopping of the mail -order battery and base resistor. catalogs was necessary to find the 6V SEC 117V PRI 10 AUDIO IN To also function as an audio ampli- smallest inexpensive capacitors. Capac- fier and modulator a few extra compo- itors Cl and C2 are 200 -volt miniature } I.5V nents are necessary. units made by Aerovox (type P83Z). (See Fig. 2.) The Fig. 3- Circuit for carbon mike input. microphone is connected in the base cir- They cost about the same as regular cuit from the bias resistor R2. This re- capacitors. The electrolytics are Cornell - how it is connected. The 6 -volt side goes sistor-and also Rl -must be bypassed Dubilier BBR tubulars. to the microphone and battery and the with electrolytics to prevent audio de- A few precautions are necessary. 110 -volt winding goes to the transistor. generation. Since R1 must be bypassed Most of the transistor circuit polarities Clarkstan or Pickering VR cartridges for audio, we must keep the r.f. feed- are just opposite to those of vacuum can be connected directly to the oscilla- back from going to ground too. The tubes. Note that positive sides of the tor, but the modulation will be very choke labeled RFC prevents this. electrolytics and battery go to ground. low. A G -E cartridge, because of its Resistor R4 stops a periodic blocking Disconnect the battery before the lower output, can just barely be heard. of the r.f. oscillator by the voltage de- transistor is removed from its socket. Crystal pickups are not satisfactory, veloped across Rl, C3. Two hundred One end of the socket for the tran- even with matching transformers. ohms for R4 kills instability for all sistor has a raised identifying dot. The transistors, but 100 ohms is usually socket pin nearest the dot is wired to enough. The lowest value that prevents the collector circuit. This corresponds motorboating of the carrier is the most with the red dot on the transistor case. desirable since high values of R4 It certainly will not do the transistor reduce audio gain. any good to plug it in backward. The antenna is a whip type, two feet ANT long, mounted 100P5T1C]( by a bananna plug and CK722 jack. Antennas this short can be con- i5 C o 6 nected directly to the collector. Longer Fig. 4- Schematic of audio amplifier t E AUDIO IN antennas must be connected for the transistor phono t o to the col- oscillator. g F C C274.01 lector through a 30 -µµf trimmer. With- out this trimmer, long antennas load Before the battery voltage is turned á the circuit so heavily it will not on, the microphone should be connected, R45100 R2 47K C4$25 R3/100K or a shorting jumper jjjj tleV oscillate. should be placed The complete phono oscillator-bat- across the "audio input" terminals. RI 25 teries and all -is mounted in a 1% x +IBV + 2% x 2s/4 -inch aluminum case. Parts for phono oscillator Resistors: I -100, I- 8,200, 1 -47,000, I- 100,000 27x5-3CÑ ohms, 1/2 watt. QÇ o Operation Capacitors: 2 -390 uuf, ceramic; 2 -.01 uf, 200 volts, Fg. Diagram paper (Aerovox P83Z); 2 -25 uf, 6 volts, 2- of transistor phono To test, connect an earphone to the electrolytic (Cornell oscillator showing component -Dubilier BBR). values. audio input and slide the iron core Miscellaneous: I -CK722 transistor; 2- Ferri -Loop- stick; I- socket for transistor; I-on -off switch; about halfway into the tuning coil. battery Some of the battery voltage is lost in Next I- (22.5.to 30 volts); I -1% x 21/8 x 234 -inch aluminum I the stabilizing place a radio within a few feet of the case; -fiber board; I -2 -foot whip an- resistors. I So, up to 30 oscillator and tune tenna; -jack for antenna. volts can be used without exceeding the across the broadcast band. A "shwoosh" or "shistle" Parts for amplifier transistor ratings. Thirty volts Resistors: 1- 8,200, 1- 47,000, 1- 100,000 ohms, of will be heard watt. V2 course gives the greatest power output, as the transistor carrier is passed over. If a whistle is Capacitors: 2-25 uf, 6 volts, electrolytic. but the heard, Miseell : I circuit oscillates down to 15 the carrier -CK722 transistor and socket; volts (subject to variations in individ- is heterodyning with a I- plate -to -line transformer, primary impedance broadcast station. 10,000, 25,000 ohms, primary current 3, 1.5 ma, ual transistors). To cure this, find a secondary impedance quiet spot on the dial and tune the 200, 500 ohms (UTC SO-3). Construction transistor oscillator to that frequency by moving the core. The oscillator will Amplifier The oscillator chassis is a 2 x 1% x drift for the 1hs first few minutes, so let Once the oscillator is built you may -inch piece of insulating board. The it operate a while before the frequency components are mounted want to add an extra stage of audio by pulling is set. amplification. This gives satisfactory their leads through holes drilled in the If the carrier motorboats, increase operation board. As shown in the photographs, with VR cartridges. An am- the value of R4. To get an idea of the plifier is shown in Fig. 4. the electrolytics and coils take up Like the oscil- the tuning range of the oscillator, follow lator, the amplifier is d.c. stabilized. greatest room. the carrier with the radio The tuning dial as the There is no need to make any circuit coil and choke are both tuning slug is moved in and out of the adjustments for individual cut -down Ferri -Loopstick units. Take transistors. coil. The two 390 -µµf tuning capacitors The output of the amplifier is connected off the cardboard sleeve over the loop - may be changed to other values. If each directly to the audio input terminals of stick winding and cut off the mounting capacitor is changed to 100 µµf, bracket plus most the the oscillator. of the form. The os- oscillator will tune from 1 me to about cillator coil and choke are then mounted 1.8 mc. Conclusions to the chassis by pushing them into a Tap on or talk into the earphone and block of fiber The phono oscillator makes a very board. The block has a the sound should come through the good hole drilled in it experimental transistor project. the same size as the radio. There will be feedback squeal if The range is limited outside of the coil form. because of the low the microphone is too close to the power, yet it can transmit a signal Push the iron core all the way into speaker of the radio. The earphone from room the choke, otherwise the oscillator to room. Except for the may gives a pretty good impedance match to transistor itself, standard low -cost not work at the lowest end of the tun- the com- transistor input, but it overloads ponents are used in the circuit. END RADIO -ELECTRONICS

www.americanradiohistory.com 77

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Photo A -Civil Defense mobile radio station operated by the Malden Amateur Radio Asso- By ELI NANNIS (W1HKG)* dation under the auspices of the Malden Emergency Corps. MANY units of the Civil De- fense Radio Emergency Corps want a mobile radio station as part of their equipment, but the budget cannot stand the expense. Howeyer, it can be done on a small budget if you have the co- opera- tion of your city and Civil Defense office. It is not necessary to buy expensive commercial equipment and large super -duper trucks to carry it. Let the big companies beat the drums to buy their units at prices untouchable by the average American city. Your city can have a mobile radio station without breaking the budget. We did it in Malden, Mass., and we are quite proud of the results. Our city, 5 miles north of Boston, has a population of about 60,000 and a CD budget about average for a city of our size. Approximately two years ago we organized the Malden Emer- gency Corps, and a short time later the Malden Amateur Radio Association was organized. We had no mobile equipment of any type. To save money, we built our own mobile transmitter and converters and distributed them among Photo B- Inside of the radio the members of our net. We soon had truck. The officer is Sgt. Orin a first -class mobile net in operation. Hood (W 1 LD) of the Malden police. * Radio Officer and Emergency Coordinator, City Author is at the mike. of Malden, Maas. RADIO -ELECTRONICS

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Our main station was located in the basement of a school. Through our communications officer, Sergeant Orin D. Hood (WILD) of the Malden Po- lice, we found out that the old 1939 Studebaker patrol wagon was to be pensioned off. This wagon was not used very often and was in good condition. We talked it over with the Civil De- fense Director Edward J. Hoffman and Assistant Director Joseph V. O'Donnell. We explained why we wanted the wagon and what we could do with it. They thought it was a good idea and with the cooperation of the City Gov- ernment the wagon was transferred to the CD office. Thus we had procured what would be the most expensive item of a mobile radio station without a penny coming out of the CD budget. Cities are always buying new vehicles. Grab one of the old ones the way we did. We also obtained the power supply without cost. The police station had a new 15 -kw emergency power plant installed. An 1,800 -watt 110 -volt a.c. gasoline generator which they used on rare occasions was now surplus and this was also turned over to us. After shopping around a while, we were able to buy a used 2 -wheel trailer at a reasonable price. All the work of converting the wagon to a mobile radio station was done by the members of the emergency corps. Truck and trailer are shown in Photo A. By careful buying we kept the cost of the radio equipment to a minimum. Esquire Our spare transmitter and receiver was installed in the wagon, and since we use the same type of transmitter and receiver in our main station we can and Squire interchange this equipment in case of failure. The transmitter shown on the table Now you can have perfect companion at the front of the truck (see Photo B) pieces in which to house your complete is the popular Harvey -Wells TBS -50C. high fidelity system -the Squire and It operates on all amateur frequencies Esquire ESQUIRE -two beautiful consoles which from 80 through 2 meters. Besidé the will complement and grace any Mahogany -Model HF 800 M decor. transmitter is a National NC -183 re- Complete with two -way, four The Esquire--a console with a Utah ceiver. Next on the table is an auto- speaker system. Audiophile two -way, four speaker system designed mobile receiver and a converter in- Net $89 -95. to give you matchless high fidelity sound. stalled in a home -built cabinet. On top of the cabinet not clearly shown in The Squire beautiful, the -a perfectly photograph is a 10 -watt transmitter. matching console which will house in one complete unit, This complete unit (the same as we your AM -FM tuner, use in high fidelity amplifier, standard record our mobiles) operates on the changer or a professional three -speed net frequency of 29,540 kc. This is an turntable and pick -up arm. emergency unit which obtains its power from Both of these consoles have a beauty, the truck battery so in case of style and grace that glows with the failure of our gasoline generator we splendor and lustre of fine woods - can stay on the air. Next and very blonde korina, genuine mahogany or prominently shown in the photograph rich pioneer cherry-hand rubbed to a is a 40 -watt Silvertone PA system con- rich patina of the highest quality sisting of the amplifier, furniture. a dynamic microphone, turntable, and two Univer- The Squire and Esquire are truly master sity 25 -watt horns, all procured for a achievements in the art of sound little over $100. The horns are shown SQUIRE engineering and woodworking. on top of the truck and are mounted on Mahogany -Model HF 700 M See and hear the Squire and Esquire Complete with pull -out and - swivels so that they may be turned in all the other models in the Utah any direction. changer drawer and tilt -ouf Personality Series -at your local Hi Fi The last two units on the tuner compartment. Audio. Headquarters. table are walkie- talkjes. The one at the phile Net $79.95. end of the table operates on the net frequency and was home -built at a cost of $35. The other is a commercial RADIO PRODUCTS CO., INC. unit made by Motorola and it operates on the Malden 1250 WASHINGTON STREET Police and Fire fre- HUNTINGTON, quency of 156.21 mc. This unit does not INDIANA have a speaker, so we use a Police RADIO -ELECTRONICS

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Alarm unit for receiving on the police frequency. Below this receiver is a CO2 fire extinguisher (not visible OuThrkrrm thorn in the photo). The power supply for the transmitter, an 8- drawer metal cabinet and a tool box are under the table. There are both 6- and 110 -volt fr lights inside the truck. On the right in moisture resistance side of the truck (not shown in the photograph) is a first -aid kit and an in high temperature a electric fan. Two plywood panels are attached to the bottom of the table so operation they can be pulled out to form tables to write or work on. in holding rated There are three antennas on the truck. The capacity main antenna is mounted on the front of the truck (Photo A). It was purchased from a mail -order in long troublefree house and consists of a heavy-duty life spring base and eight 3 -foot rods which go up more than 20 feet. It cost only $10. On the other side of the truck is an 8 -foot whip for the emergency unit and on the top rear is the small police tyne wh'n antenna.

sqN ns the Sangamo

Mobile unit at scene of tornado. MOLDED Decals are used for the lettering on PAPER TUBULAR CAPACITOR the truck. A spotlight is located in front of the cab and beside it is a flashing red light The Telechief which is used to in- will outlast all other tubulars! MIL -C -91A dicate that it is an emergency vehicle. tests prove that Telechiefs There is also a powerful siren mounted have a final insulation resist- under the hood. It was donated by one ance value 10 to 15 times of our members who services burglar greater than paper tubulars alarms. molded in any other material. That's because they're Other equipment not shown in the molded in HUMIDITITE! photographs are a 150 -foot extension cord for feeding 117 -volt commercial power into the truck if available; 100 YOU GET EXTRA VALUE AT NO EXTRA feet of No. 12 wire for running power COST! from This amazing the gasoline generator; two 300 - new capacitor -that meets specifications watt floodlights which can be mounted so tough that no previously on top of the truck if need be; and existing paper tubular could 100 feet approach of telephone cable for con- them -is a premium tubular at the price necting the two phones contained in of the truck. an ordinary one. See your Sangamo Distributor today ! The members of our emergency corps willingly gave their time to put this mobile radio station together and they did a splendid job. David Smith (W1HOH), a radio engineer for the National Ade wh-Zr.ove. clraw/affirmo- Co., designed our home -built equipment. He also keeps our equip- .... ment in tiptop shape. Find a "Dave Smith" in your net and take good care of him. Our mobile radio station has already taken part in a real. emergency. After SANGAMO ELECTRIC a tornado struck Worcester, Mass., our COMPANY truck did its part in 'providing communications MARION, ILLINOIS and lighting for several seaa.e days. END RADIO- ELECTRONICS

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* SEND FOR FREE BOOKLET -Mail the coupon -today. Study Get complete information on the RCA INSTITUTES Home conducts a resident school in New of RCA Institutes Course in Television Servicing. Booklet gives you a general outline and evening courses in trains York City offering day the course by units. See how this practical home study course and Radio card. Radio and TV Servicing, Radio Code you quickly. easily. Mail coupon in envelope or paste on postal Operating, Radio Broadcasting, Advanced Tech- Write for free catalog on resident courses. nology. * RCA INSTITUTES, INC., Hume Study Dept. RE554 350 West Fourth Street, New York 14, N. Y. "RCA INSTITUTE. Without obligation on my part, please send me copy of booklet will call.) Home Study Course in TELEVISION SERVICING." (No salesman

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Increasing use of MULTIVIBRATORS square and sawtooth waves ..EO.,,,.E, . has elevated the multivibrator circuit to one of prime importance

THERE was a time when the radio capacitors or the grid resistors. and electronics technician A selec- 7. The IR drop across could tor switch and several different values Rl drives VI afford to ignore multivibrator cir- of coupling beyond cutoff. cuits. This capacitors will permit a 8. is no longer the case. choice of frequency When C2 has completed its dis- Today, the multivibrator range. Within each charge, and its many range, the frequency can VI is no longer cut off. close relatives have found their be varied by 9. V1 begins way a dual potentiometer used as the grid to conduct plate cur- into almost every type of electronics resistors. rent, and the cycle repeats. apparatus, from television equipment From to The operation of the circuit of this analysis, it is obvious that automatic computers. Variations of the Fig. 1 conduction in GRID VOLTAGE either tube causes basic multivibrator WAVEFORM the have become so other tube to be driven to cutoff. The numerous and diversified in applica- 0 length of time each tion that accurate tube remains cut classification of mul- off depends upon the R -C time -constant tivibrators requires such adjectives as of the grid circuit. When symmetrical, CUT(SFT the time - asymmetrical, cathode - constants of both grid circuits are coupled, delay, one -shot, made etc. equal, each tube remains cut off for the Symmetrical multivibrator sane length of time -hence the name symmetrical multivibrator. The The grid symmetrical multivibrator -the resistors are sometimes returned to basic circuit from which many varia- E plus rather than to ground. tions The are derived -consists of two advantage of this arrangement is stages, the that plate of each being 1 2 the frequency coupled 3 456 stability is increased to SYNCHRONIZING the grid of the other (Fig. 1). With PULSES with respect to supply -voltage Fig. 3- Multivibrator synchronized at variations. submultiple of input pulse frequency. Synchronization can be analyzed most easily by assum- ing the plate current of D PLATE WAVEFORM V1 is in- In many applications, frequency sta- creasing, and noting the consequent bility is not changes a primary consideration which occur in the circuit: and the multivibrator is operated 1. As the plate current as a GRID WAVEFORM of VI in- free -running circuit. When required, creases, the IR drop across the 70K its frequency of a multivibrator can be plate -load resistor increases, and held constant by synchronizing Fig. 1 -The symmetrical multivibrator. the it with voltage at the plate decreases. an external signal. The synchronizing this arrangement, one 2. As the plate voltage of V1 de- signal can be applied tube conducts creases, to either of the while the other is cut off. This capacitor Cl loses some of grids or the cathodes condition its charge. of the multi- reverses periodically. The discharge current vibrator. Although many types of One application of the multivibrator flows to ground through R2. waveforms may be used as synchroniz- 3. The IR drop is as a square -wave generator. Since across R2 makes the ing signals, the pulse waveform is each tube of the multivibrator grid of V2 negative with respect most widely used. is alter- to nately cut off and conductive, ground, and V2 is driven to Fig. 2 illustrates the the plate cutoff. synchronization voltages alternately increase and de- of a multivibrator by positive pulses 4. When Cl has completed crease, producing a square -wave out- its dis- applied to one of its grids. The period charge (to a value equal to the of VOLTAGE the multivibrator in its free- running GRID WAVEFORM plate voltage o of Vi at saturation), state should be slightly longer than the no further discharge current flows period of the desired through synchronized fre- R2. quency. Fig. 2 shows the effect of the 5. With the grid of V2 no longer positive pulse in driving the tube from negative, this tube conducts plate cutoff to conduction. The pulse thus SYNCHRONIZING current, PULSES and its plate voltage initiates the switching action of the Fig. 2- Multivibrator synchronization. decreases. circuit, by causing the grid to go sud- 6. Capacitor C2 now begins to dis- denly more positive, and put. The resistors the frequency marked Rg in Fig. 1 charge through RI, producing an is locked in with that of the input improve the quality of the output IR drop across this resistor. pulses. square wave. If these resistors are 100K C MULTIVIB. omitted, the square wave has a rounded OKC MULTMB. 71SC MULTIVIB. corner on its leading edge. This is due to the loss of the high harmonic content of the square wave as a result of the --91 -- bypassing effect of C2 through the grid -to- cathode resistance of Vl. The TO I MC %TA L OSC grid resistors increase the plate -to- ground impedance and decrease the attenuation of high -order harmonics. R) The operating frequency of the circuit of Fig. 1 can be controlled by changing the values of the coupling

IMC OUT aoKC Northwestern Vocational Institute, Minneapolis, OUT 10KC OUT !KC OUT Minnesota Fig. 4- Diagram illustrates application of multivibrator as frequency divider. RADIO- ELECTRONICS

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Negative pulses may also be used for synchronization. The action in this case TO THE is very similar, since the negative pulse applied to the grid of the conducting E. E. tube is amplified and appears as a positive pulse at the grid of the non- OR conducting tube. A multivibrator can also be made to PHYSICS lock in at a submultiple of the pulse frequency (Fig. 3). Pulse 1 drives the GRADUATE tube to conduction and switches the circuit. Pulses 2 and 3 have no effect WITH EXPERIENCE IN Electric -Motor since they are applied to the grid at a RADAR time when the tube is already conduct- Battery -Operated ing. Pulses 4 and 5 produce no change OR in the circuit since they reach the grid Portable Recorder at a time when it is far below cutoff. At ELECTRONICS the time pulse 6 comes along, the grid The ideal recorder for newspaper reporting, re- of the cording lectures, telephone monitoring, field re- tube is approaching the cutoff ports traveling secretary, on- the -spot interviews, threshold, and the pulse is sufficient to reference recording, customer interviews, salesmen HUGHES reports and secret recordings. RESEARCH AND Combines, for the first time, ease and of operation efficiency DEVELOPMENT 6SN7-GT with maximum reduction of weight. LABORA- Bt Performs anywhere, producing professional re- 71( sults under adverse conditions. TORIES ARE Fly -ball governor - ENGAGED IN controlled electric motor plus triple shielding assures constant A CONTINUING PROGRAM -11---11- V speed and freedom from hash. o , n Weather -tight, satin -finished, aluminum alloy FOR DESIGN AND VI PLATE WAVEFORM 2 PLATE WAVEFORM case gives complete protection to recorder. Three MANU- models available in speeds of 15/16, 1v/a and 31/4 ips. FACTURE OF ADVANCED Check these unusual features: RADAR AND FIRE CONTROL * Records for 4 full hours (Model 310 -A) SYSTEMS IN MILITARY * Operates from self -contained dry cells ALL -WEATHER FIGHTERS Fig. 5-The asymmetrical multivibrator. * Immediate playback *Size: 51/2 x 9 AND INTERCEPTORS. x 12 inches * Weight: only 8 pounds start conduction in the tube. Since every fifth pulse initiates switching Write for complete technical literature THE GREATEST advancements in action in the circuit, the multivibrator and direct factory prices to Dept. RE electronics are being made in this synchronizes at a frequency equal to one AMPLIFIER sphere because of military emphasis. -fifth of the pulse frequency. CORP. of AMERICA The use of the multivibrator 396 Broadway. N. Y. 13. Men now under 35 years of age as a N. Y. will 1 M. Reg U S frequency divider is illustrated Pot OR find this activity in can fit them for Fig. 4. A crystal -controlled oscillator is future application ofhighly advanced used to drive a chain of multivibrator NOW! . YOU'LL electronic equipment. circuits, each of which is synchronized' to a submultiple of YOU WILL serve the frequency of REALLY as technical ad- the preceding circuit in the fashion of visor in the field to companies and Fig. 3. The output of the 1 -mc crystal - government agencies using Hughes controlled oscillator is used to syn- KNOW HOW equipment. chronize the 100 -kc multivibrator. The square -wave output of TO USE TO BROADEN this circuit is your field of expe- differentiated and the resulting pulses rience in radar and electronics you used to synchronize the 10 -kc multi- OSCILLOSCOPES! will receive additional training at vibrator. The 10 -kc output is also dif- Here, at last, is a practical full pay in the Laboratories ferentiated and used to synchronize the book to become following that makes it easy for you to thoroughly circuit. An output is taken learn to use the oscilloscope familiar with Hughes FULLY on all types of AM, FM from a cathode resistor of each multi- and radar and fire control equipment. TV service work-and dozens vibrator. This cathode -follower ar- of other applications besides! rangement provides a low impedance MODERN OSCILLOSCOPES AFTER TRAINING you will be AND THEIR USES, by Jacob H. When, where output and minimizes the loading effect Rutter, Jr. of Allen B. DuMont why and the Hughes representative Labs contains ex- at a com- of external circuits. The stability and 326 fact -jammed actly how to pany where pages of just the help you need- our equipment is in- accuracy of the output frequencies are written so you can easily under- use your stalled; or you extremely good, since stand it. The book shows exactly 'scope. will advise in the they are-in how the 'scope works; how to use operation of Hughes effect-crystal controlled. Circuits of it on all service jobs from trouble- How to equipment shooting to realigning; how to this type are useful for testing and make Interpret at a military base. (Overseas assign- connections; how to adjust patterns calibrating signal generators, oscillo- circuit components; how to set ments, single men only.) scope time bases, controls and how to analyze pat- frequency meters, terns. You get exact procedures on How to handle and similar devices. how and where to use your 'scope tough jobs in not just theory! 370 illus- less time trations including pattern photos HUGHES The asymmetrical multivibrator make things doubly clear. RESEARCH AND DEVELOPMENT If the R -C time constants of the two 10 -DAY FREE TRIAL LABORATORIES grid circuits of a multivibrator are Dept. made unequal, the duration of the cut- RE -54, RINEHART & CO., INC. SCIENTIFIC AND 232 Madison Ave., New York 16, N. Y. I off periods of the two tubes will be Send MODERN OSCILLOSCOPES ENGINEERING STAFF AND THEIR I unequal. This USES for 10 -dav FREE EXAMINATION. If I de- circuit, known as an cide to keen the book, I will then remit $6.00 plus a I Culver City, Loa Angeles County, Calif. asymmetrical multivibrator, few cents postage In full payment. If not, I will re- is shown turn book in Fig. 5. Since plate voltage is high postpaid and owe you nothing. I NA -.LE Assurance is required that relocation of when a tube is cut off and low when it the applicant will not cause is disruption saturated, a pulse waveform is pro- ADDRESS of an urgent military project. duced at the plates of the asymmetrical multivibrator. The tube which remains CITY, ZONE, STATE OUTSIDE U.S A. -Prico $6.50 cash with order. cutoff for a shorter time will produce a Money back if honk is returned In 10 days. RADIO -ELECT! QNICS

www.americanradiohistory.com best (black and white) picture quality

with the Amphenol

INLINE

The INLINE color advantages are Black & white or color, the also available INLINE assures to fringe areas Amphenol with 2 or 4 bay the finest audio /video Stacked Arrays. quality on any TV set.

Gain variation over the color modulation band for each VHF channel should not exceed ±.75 db; the following table gives figures for the INLINE on all channels. Gain Gain Set owners have their color television Channel Variation/db Channel Variation /db antenna right now if they have an 2 ±0.40 8 =0.08 Amphenol INLINE! Because the very 3 ±0.06 9 ±0.04 features that make the INLINE the out- 4 ±0.12 10 =0.03 11 ±0.20 for black & white tele- 5 ±0.27 standing buy 6 ±0.20 12 ±0.30 vision are the same that have been listed 7 ±0.20 13 ±0.30 as requirements for color television! Gain chart showing ±0.06 db variation over color For fidelity color reception the an- modulation band for INLINE, Channel 3 tenna must have these characteristics: U.S. Pat. No. 23,273 1. Antenna gain must be flat, no gain "Reissue or loss greater than 1.50 db within 1.5 mc below and 0.6 mc above the color sub -carrier. The INLINE gain (see charts at right) fully --I 5 mc--O6 meets this condition. .4 .4.nV 2. Antenna gain must be held down 272 t3s across the FM frequencies, 88 mc 3 to 108 mc. The INLINE gain has been engineered for a sharp cut- db +2 off at the end of Channel 6 -for rejection of FM signals.

Standard Tuned mc 65 75 mc folded dipole 61.25 me 64.83 66 mc reference 6 me 3.58 mc Channel Channel 2 1.25 mc 4.5 mc 6 mc

www.americanradiohistory.com BO -TY All UHF STACKED -V channels, 14 to 83 VHF /UHF channels, 2íe83

CONICAL High gain for all VHF channels

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LIGHTNING ARRESTOR ISONET Low -loss matching New VHF /UHF universal network for combined VHF/ Lightning Arrestor has lowest UHF installations. Incor- measurable loss of any porates lumped-circuit-con- arrestor! stants-filter-network.

DEPENDABLE ANTENNAS. There is a wide choice of fine Amphenol antennas for VHF or UHF frequencies. The Bo -Ty, Corner Re- flector, Yagi and Rhombic assure best picture quality at UHF. For VHF, besides the color- designed INLINE *, there is the new Amphenol Conical. And the Stacked -V will receive VHF, UHF or both. Each of these fine antennas has been designed and built to the quality standards of Amphenol -the highest in the industry. DEPENDABLE ACCESSORIES. There are many other tested antenna installation acces- TRANSMISSION LINE Popular Flat Twin -Lead sories in addition to those illustrated and unique AIR - on this CORE Tubular Twin-Lead' assure best- performance at either VHF page that are made by Amphenol. or UHF. 'U. S. Pat. No. 2,543,696 All re- YAGI Custom flect the engineering and production know - reception, how of Amphenol. 8 UHF models *Reissue U.S. Pat. No. 23.273

AMERICAN PHENOLIC CORPORATION Chicago 50, Illinois

TELE-COUPLER Two to four television sets operate from single antenna with new and STAND-OFF INSULATORS efficient sel couplers. Three types available: flat. coax and new universal type for Flat or Tubular line.

STACKING HARNESSES Complete harnesses available for two bay stacking of the VHF INLINE or Conical and the UHF Vagi, Bo-Ty or Cerner Reflector.

RHOMBIC Fine all -UHF -channel antenna

Amform 2350-34480 Printed in U.S.A.

www.americanradiohistory.com I 89 RADIO positive pulse waveform at its plate, -BtTSTA1fD111G for HIGH FIDELITY! and the tube which conducts for a shorter time will produce a negative 01RECS.. TUNERS pulse waveform. The asymmetrical L multivibrator, because of its simplicity and and the ease with which it can be REEIVEA controlled, is often used as a pulse generator. Cathode- coupled The cathode -coupled multivibrator, shown in Fig. 6, differs from the basic Each Collins Tuner Kit is complete with mutivibrator in that the second tube is punched chassis, tubes, power transformer, power supply components, hardware, dial assembly, tuning eye, knobs, wire, etc., as Bt well as the completed sub -assemblies: FM tuning units, AM tuning units, IF amplifiers, etc., where applicable. All subassemblies wired, tested and aligned at the factory make Collins Pre -Fab Kits easy to assemble even without technical knowl- r Y edge. The end result is a fine, high qual- 0 ity, high fidelity instrument at often less V2 PLATE WAVEFORM than half the cost - because you helped make it and bought it direct from the factory.

Fig. 6- Cathode- coupled nultivibrator. $55 coupled to the first by the common with AFC $58.50 the cathode resistor. To understand this The FM -11 tuner is available in kit form with chassis, wired and circuit, assume that the plate current IF Amplifier mounted in the RF Tuning of V1 is increasing and note the tested by us. You mount the completed power supply, then after some simple changes: r -.,._....,: Unit and 6J6 RF 1. The IR drop across the plate load wiring, its all set to operate. 11 tubes: $1525 68A6 1st IF, resistor of V1 increases, and the amp, 6AG5 converter, 6C4 oscillator, FMF -3 Tuning Unit 2nd and 3rd IF, (2) 6AÚ6 limiters, 6A15 plate voltage decreases. with AFC $18.75 (2) 6A116 discriminator, 6AL7 -GT double tuning eye, 5Y3 -GT begins to discharge. The best for FM. The most sensitive 2. Capacitor Cl 6 to 10 microvolts, less than and most selective type of "front end" rectifier. Sensitivity discharge current produces cycle response The on the market. 6 to 10 microvolts sen- V2 of 1% distortion, 20 to 20,000 to 1. 6J6 an IR drop across Rl. sitivity. Image ratio 500 with 2D8 variation. Chassis dimensions: 121/2" converter, 6C4 drop across Rl makes the tuned RF stage, 6AG5 7" high. Illustrated manual sup- 3. The IR oscillator. Permeability tuned, stable wide, 8" deep, grid of V2 negative with respect and drift -free. Chassis plate measures plied. Shipping weight 14 lbs. to ground, driving V2 to cutoff. 61/2 "x41/2'r. In combination with the of IF -6 amplifier, the highest order of 4. When the discharge current Cl sensitivity on FM can be attained. has become sufficiently small, the Tubes included as well as schematic R1 no longer and instructions. Draws 30 ma. Ship- IR drop across can ping weight FMF -3: 21/2 lbs. Dial avail- keep V2 cut off. able @ $3.85. 5. V2 begins to conduct and its plate current produces an additional voltage drop across Rk. IF6 Amplifier $19,s 6. The extra bias developed across ; Tubes. Shipping Wgt. 3 Ihs Rk drives V1 to cutoff.

7. The plate voltage of Vl increases, OF COLLINS TUNERS: The FOR USERS and Cl begins to charge. Receive $5.00 credit toward the new charging current produces an IR FMF -3A front endl Mail us your old front across Rl. end with $13.75 and we will send you the drop 5.000 8. The voltage drop across Rl makes new, improved FMF -3A with AFC., or, FM /AM Tuner Kit the grid of V2 positive. remit the full amount of $18.75 and when with AFC 581 old unit in return a check -fab kit 9. When Cl has finished charging, we receive your The original 15 tube *deluxe FM /AM pre the grid of V2 is no longer will be mailed you for $5.00. redesigned on cr. smaller chassis. The tuner now positive. measures 14" wide by 12" deep by 7T,2' high. current of V2 decreases, This attractive new front and dial assembly opens 10. The plate where space is at a premium. Rk becomes up new applications and the voltage across necessary to put it into keep V1 cutoff. Kit includes everything insufficient to operation- punched chassis, tubes, wired and l 1. Vl begins to conduct plate current, aligned components, power supply, hardware, etc. and the cycle repeats. Kit comprises FMF -3 tuning unit, IF -6 amplifier, A common technique for generating AM -4 AM tuning unit, magic a sawtooth waveform is to connect a eye assembly and complete capacitor across a tube which periodi- instructions. All tubes included. cally goes from cutoff to saturation. A Shipping weight 19 lbs. capacitor in this position will charge AM -4 Tuning Unit $24" Ce. Inc. RE -5 is Flo Coll n. Audio r,eduau the B plus line when the tube we.rnetd. N. J. from in AM superhet performance! A e O Be. 366, Tops Tcl Wt.rneld 3 -4390 discharge through the tube 3 tuned cut off, and 3 -gang tuning condenser gives Kit _ FM /AM TunerKit !] FMF -3 Tuning Unit and se- FM tuner when it conducts. The voltage across stages with high sensitivity E with AFC with AFC Assembly is completely wired, with AFC increases expo- lectivity. AM -4 Tuning Unit the capacitor therefore tested and aligned ready for imme- I IFU Amelif er nentially and then decreases rapidly - diate use. Frequency coverage 540 KC HAMS. The multivibra- to 1650 KC at a sensitivity of 5 micro- a sawtooth waveform. volts. Tubes 6BA6 RF amplifier; 6BE6 ADDRESS the necessary qualifi- IF amplifier and 6AT6 tor circuit meets converter; 6BA6 Ctty .. STATE its tubes are alternately detector.- Draws 30 ma @ 220 volts. cations since chassis plate measuring Mounts on a for S Ste ,.Fphis, add shipping cm! S...._ -- cut off and conductive. 4 "x73/e ". Shipping weight 21/2 lbs. IAmeunt at $3.85. S Check Q Monet O'de, ] A circuit suitable for this application Dial available I Two emounr enclosed in Fig. 7. If capacitor C2 were is shown YOU THINK OF TUNERS. THINK OF COLLINS AUDIO PRODUCTS not in the circuit, the waveform at the WHEN MAY, 1954

www.americanradiohistory.com 90 RADIO

plate of V2 would be a pulse waveform as indicated on the diagram. This negative pulse is produced each time the tube goes from cutoff to saturation. When C2 is connected in the circuit, it charges through R2 as long as V2 is ANNOUNCING cut off. When V2 begins to co :duct, its be an expert on plate current discharges C2. This type of sawtooth generator has become very popular in the scanning circuits of AUTO RADIO TI/E NEW television equipment. and most complete Electron- coupled SERVICING! In the electron -coupled multivibra- Get the only authoritative compila- standard tion of its tor, one (or both) of the kind -complete Auto Radio tubes are Service Data coverage of all impor- stock line... 6SN7-GT tant models since 1946 -in 3 great PHOTOFACT Manuals! All data corn - plete, accurate, uniform -based on lab analysis of the actual auto radios covered. Helps you service any model quicker, easier -for greater profits. Get the complete Library! TE ° . ; ATURE COMPE ING OUT WITHOUT C2 2 TUB CERI' CONS V VOL. 1. AUTO RADIO A/OUT WITH C2 SERVICE MANUAL NON- INSULATED Fig. Generation Covers over 100 models 7- of a sawtooth wave. made from 1946 to 1949 by 24 manufacturers. pentodes. The screen grid is INSULATED used as a Each receiver is com- MOLDED plate and is coupled to the control grid pletely covered in uni- of the other tube. This arrangement form format; includes leaves the actual plate free to provide schematics, chassis INSULATED photo views, replace- DIPPED PHENOLIC the output. The load is therefore con- ment parts data, serv- nected to the multivibrator ice hints, etc. All data based on actual lab only analysis. through the electron stream of the 396 pages, 8% x 11 ". Three Temperature Coeffi- pentode. A portable high -voltage power ORDER AR -1. Only ...... $4.95 cients: NPO, N330, N750: Close supply tolerance designed around a 3A8 -GT VOL. 2. AUTO RADIO on all temperature diode -triode -pentode electron -coupled coefficients. multivibrator SERVICE MANUAL Non -insulated, Molded insu- is shown in Fig. 8. Each Covers 60 different lated, Dipped Phenolic In- time V2 goes to cutoff, the magnetic chassis (40 models) sulated. used in 1948, 1949 and 3A8-GT 1950 auto radio receiv- Wide range of capacity values, ers. Authoritative, ISc + 1.35V ~? com- close tolerance on all capacity - plete service data that values. makes your work t55PPf ®Provide commercial equiva- I° 2 quicker, easier and more lents of many often used JAPE profitable. 288 pages. types. VI I5Uppf 8).¡ x 11". ORDER AR -2. Only $3.00 5 VOL. 3. AUTO RADIO .vnta. 1.55+ ,1N"' SERVICE MANUAL 2 + Covers 47 different chassis (80 Ì6tK IKV models) One purpose of the three temperature coeffi- H.V. used in 1950, 1951 and cients is to provide the means of combining 1952 auto radio receiv- in parallel, ers. Absolutely the most various combinations of NPO and complete, accurate and N330; and NPO and N750 to obtain inter- Fig. 8 -High- voltage power supply. easy -to -use data avail- mediate temperature able- uniform and coefficients. Formulae field for computing these around inductance L collapses. practically presented to values as well as a sim- The resulting make you an expert on the repair of any 'pie nomograph for quick counter e.m.f. is rectified auto computations will by V3 to provide the high -voltage radio. 288 pages. 8M x 11 ". be afforded in service out- AR -3. information. put. Geiger counters and other portable ORDER Only $3.00 The range of capacity values is the most high -voltage, low- current instruments complete offered as standard stock by any r- - can be operated from power supplies of SPECIAL ceramic capacitor manufacturer. Servicemen this type. The size and weight of the OFFER: I All 3 Volumes,Yours and engineers ... your distributor has these supply is considerably less than that for Only $9.95 I capacitors to meet Save on the Complete Library - your requirements for TV of the batteries that would be required see your PHOTOFACT Distributor replacements, laboratory work, and proto- to furnish an equivalent voltage. In .type development. addition, the circuit will be very stable. HOWARD W. SAMS & CO., INC. Write for complete list of capacity The electron coupling will prevent any values available JAN equivalent changes in the plate circuit from affect- Order from your Parts Jobber today, or table, and nomograph. ing the multivibrator. write direct to HOWARD W. SAMS & CO., Inc. 2205 E. 46th Street, Indianapolis 5, Ind. ERIE components are stocked at leading My (check) (money order) for $.... encl. Send: electronic distributors everywhere. One -shot multivibrators E AR -1 $4.95 0 AR -2 $3.000 AR -3 $3.00 A special kind of multivibrator is ELECTRONICS DISTRIBUTOR the Complete 3- DIVISION type in which one tube is so biased 0 Volume Library $9.95 ERIE RESISTOR CORPORATION that the circuit will not run free. There Name Main Offices: ERIE, PA. are many applications for this circuit, factories: ERIE, PA. LONDON, ENGLAND and a special article will shortly be Address TRENTON, ONTARIO devoted to these univibrators and flip- flops. END LCity State RADIO -ELECTRONICS

www.americanradiohistory.com NEW INVENTION OUTMODES ALL PRESENT ANTENNAS! 53 CLAIMS GRANTED IN 5 U.S. PATENTS ON NEW REVOLUTIONARY ANTENNA INVENTION!

#2,585,670 #2,609,503 #2,625,655 #2,644,091 #2,661,423 others pending * GUARANTEED TO POSITIVELY OUTPERFORM AU. OTHER ANTENNAS (with or without rotor motors) on ALL UHF, and ALL VHF stations 2 thru 83 from ALL directions. * GUARANTEED to positively give you the CLEAREST, SHARPEST, most PERFECT GHOST - FREE pictures possible in both COLOR and LIST PRICE black-white. $36.75

SEE YOUR JOBBER MONEY BACK GUARANTEED TO RECEIVE,41 CHANNELS 2 -83 FROM /4U DIRECTIONS i AND POSITIVELY OUTPERFORM t ,4e1 OTHER ANTENNAS WITH t ELECTRONIC OR WITHOUT A ROTORMOTOR ORIENTATION SWITCH The 9- position UP TO 10 TIMES MORE POWER- selector switch ! ALL PRESENT electronically THIS IS ALL YOU NEED FUL THAN The price includes the complete antenna ANTENNAS! rotates the and the 9- position electronic orientation CONVENTIONAL antenna in a switch. The Air Dielectric Polymicalene New, revolutionary antenna, while being up to 10 times Transmission Lin is purchased as required more powerful than conventional antennas, is still able to installation. stationary for the individual receive all television and FM stations from all directions position. without a rotor motor of any kind. The electronic orientation switch used with a new type transmission line developed specifically for this extra powerful antenna now POLYMICALENE heretofore 4 CONDUCTOR TRANSMISSION LINE makes it possible to clearly receive stations of range. It is now possible to put up just Low Loss External Air Dielectric considered out just Matched Impedance one antenna, use just one transmission line, pay for Eliminates End Sealing one installation and receive the finest possible reception Eliminates Condensation from the stations in and coming to your area regardless of Up to 50 °/ Less Loss their direction. Than Tubular When Wet r- Easily Spiraled or Shorting ALL No Breaking ,// NOW!! SOLVE YOUR ANTENNA PROBLEM ONCE AND FOR Patents Pending - T. M. Reg ALL CHANNEL ANTENNA CORP. SEE US IN BOOTH N3.3 IN CHICAGO 70 -07 Queens Blvd., Woodside 77, N. Y. Hickory 6 -2304

MAY, 1954

www.americanradiohistory.com 102

You have peter ordered by because youou di d not want too uy anythingng "sig h t unseen" or - HERE ' is your opportunity to You have ordered by mail but with ex what you want r n then pay the batonte in easy monthly disappointing results or - under our "Seller not Buyer, takes oll the payments with no interest or finance charges 1 risk" plan. We invite You have never purchased anything on time payments to order any item added. Otherwise, you may return the mer. because on this page and examine it in the privacy of ( of excessive fincnce charges, rhondise for prompt refund of your dawn. then - your own home. If r you deride to keep it, you payment.

Superior's new Model 670 -A SUPER METER A COMBINATION VOLT -OHM MILLIAMMETER PLUS CAPACITY REACTANCE INDUCTANCE AND DECIBEL MEASUREMENTS SPECIFICATIONS: ADDED FEATURE: D.C. VOLTS: 0 to 7.5/15/75/150/750 /1,500/7,500 Volts The Model 670 -A Includes a special A.C. VOLTS: 0 to 15/30/150/300/1,500 /3,000 Volts GOOD -BAD scale for checking the OUTPUT VOLTS: 0 to 15/30/750/300/1,500 /3,000 Volts D.C. CURRENT: quality of electrolytic condensers at 0 to 1.5/15/150 Mo. 0 to 1.5/15 Amperes RESISTANCE: a test potential of 150 Volts. 0 to 1,000 /100,000 Ohms 0 to IO Megohms CAPACITY: .001 fo I Mfd. I to 50 MM. (Quality trolytic:) test for elec- The Model 670 -A comes housed in a rugged, REACTANCE: 50 to 2,500 Ohms 2,500 Ohms to 2.5 Megohms crackle -finished steel 40 INDUCTANCE: .15 to 7 cabinet complete with Henries 7 to 7,000 Henries N DECIBELS: --6 to test leads and operat- ET +18 +14 to +38 +34 to +58 ing instructions.

Superior's new Model TV -11 TUBE TESTER SPECIFICATIONS: * Tests all tubes including 4, 5, 6, 7, Octal, Lock - to damage a tube by inserting in, Peanut, Bantam, Hearing Aid, Thyratron, it in the wrong Miniatures, socket. Sub -miniatures, Novais, Sub -minars, Free -moving Proximity fuse types, * built-in roll chart provides con,- etc. plete data for all tubes. * Uses the new self -cleaning Lever Action Switches * Newly designed Line Voltage Control for individual element testing. Because all ele- compen- ments are numbered sates for variation of any Line Voltage between according to pin- number 105 Volts in the RMA base and 130 Volts. numbering system, the user NOISE TEST: can instantly identify which * Phono -jack on front panel for element is under plugging in either phones or external amplifier test. Tubes having tapped filaments and tubes will with filaments terminating detect microphonic tubes or noise due to in more than one faulty elements and loose internal connections. pin are truly tested with the Model TV -II as any of the pins may be placed in the neutral position when necessary. The model TV -11 * The Model TV -II does not use any combination ates on 105 -130 Volt 60 type sockets. Cycles A.C. Comes housed Instead individual sockets are in an used for each type of tube. Thus it is impossible beWebeautiful cab,net com- pleteih ith portsb, cover EXTRA SERVICE - The Model TV-II may type oscillator incorporated in this mode NET be used as an extremely sensitive Con- will detect leakages denser Leakage even when the tre Checker. A relaxation quency is one per minute. $475° NIER111011811=11/

Superior's New Model 660 -A AN AC OPERATED SIGNAL GENERATOR PROVIDES COMPLETE COVERAGE for AM -FM b TV Alignment SPECIFICATIONS: Generates Radio Frequencies from 100 Kilocycles tilde is used as an R.F. oscillator. miner and to 60 Megacycles on fundamentals and from 60 Mega- amplifier. Modulation is effected by electron cycles to 220 Megacycles on powerful harmonics. coupling in the mixer section thus isolating the Accuracy and Stability are assured by the use of oscillator from permeability trimmed Hi -Q coils. R.F. avail- load changes and affording hi ph stability. A. F. able separately or modulated by the Internal audio Oscillator Circuit: A high trans - conductance oscillator. - Built in 400 cycle sine ware audio heptode coon clad as a high -mu triode oscillator used is to modulate the R.F. signal also used as an audio oscill tor in a High-0 Colpilis available separately for audio testing of receivers. Circuit. The output (ove I Volt) is nearly pure amplifiers. hard of hearing aids. etc. R.F. sine wave. Attenuator A 5 step ladder type Oscillator of Circuit: A high transconductance hep- attenuoter is used. TUBES USED: The Model 660 -A 1 -68E6 as R.F. Oscillator, mixer and comes complete with amplifier. coaxial cable test 95 lead and instruc- 1 -6BE6 as Audio Oscillator. tions. I -6H6 as Power Rectifier. NET I MOSS ELECTRONIC DISTRIBUTING CO., INC. MODEL 670 -A Total Price $20.40 Dept. 8-94, 3849 $7.411 down payment. Balance Tenth Ave., New York 34, N. Y. monthly for 6 months. 03.5e MODEL TV -11 I Please .. Total Price $47.50 send me the units checked. 7 am $11.5o down with enclosing the down Name payment. Balance Sh.Oir payment order and agree to pay the monthly balance as monthly for f1 months. shown. It Is mrderstuM there wilt be no tarrying. interest any other charges. provided or r' MODEL 660 -A Total Price $42.95 1 semi my monthly payments Address $12.95 down payment. when due_ It le further understood that should monthly Balance 05.00 when I fall to make for 6 months. due. the full unpaid balance shall become Im- 'paymentmediately due 71 1 and parable. enclose $ as down payment. R city Zone State o Ship C.O.D. for the down payment. RADIO -ELECTRONICS

www.americanradiohistory.com 91

HEY! INVENTION OUTMODES ALL PRESENT ANTENNAS! 53 CLAIMS GRANTED IN 5 U.S. PATENTS ON NEW REVOLUTIONARY ANTENNA INVENTION! CEO #2,585,670 #2,609,503 #2,625,655 #2,644,091 #2,661,423 others pending * GUARANTEED TO POSITIVELY OUTPERFORM ALL OTHER ANTENNAS (with or without rotor motors) on ALL UHF, and ALL VHF stations 2 thru 83 from AU. directions. * GUARANTEED to positively give you the CLEAREST, SHARPEST, most PERFECT GHOST - FREE pictures possible in both COLOR and black -white.

R' MONEY BACK GUARANTEED TO RECEIVE,4U CHANNELS 2 -83 FROM ,¢Ue DIRECTIONS AND POSITIVELY OUTPERFORM A 1 ,4ee OTHER ANTENNAS wail- ELECTRONIC OR WITHOUT A ROTORMOTOR

. S.01110 fot ORIENTATION t!r.%%lry*ii-...40-401 4%0- fttie SWITCH The 9- position UP TO 10 TIMES MORE POWER- selector switch ! THAN ALL PRESENT electronically THIS IS ALL YOU NEED FUL The price includes the complete antenna CONVENTIONAL ANTENNAS! rotates the and the 9- position electronic orientation in a switch. The Air Dielectric Polymicalene New, revolutionary antenna, while being up to 10 times antenna Tronsmission Line ,s purchased as required more powerful than conventional antennas, is still able to stationary for the individual installation. receive all television and FM stations from all directions position. without a rotor motor of any kind. The electronic orientation switch used with a new type transmission line devel- POLYMICALENE oped specifically for this extra powerful antenna now to clearly receive stations heretofore 4 CONDUCTOR TRANSMISSION LINE makes it possible out of range. It is now possible to put up just Loss External Air Dielectric considered low transmission line, pay for just Matched Impedance one antenna, use just one Eliminates End Sealing one installation and receive the finest possible reception Eliminates Condensation from the stations in and coming to your area regardless of Up to 50% Less Loss their direction. Than Tubular When Wet Easily Spiraled AND FOR ALL No Breaking or Shorting NOW!! SOLVE YOUR ANTENNA PROBLEM ONCE Patents Pending - T. M. Reg

No.3 ALL CHANNEL ANTENNA CORP. SEE US IN BOOTH IN CHICAGO 70 -07 Queens Blvd., Woodside 77, N. Y. Hickory 6 -2304

MAY, 1954

www.americanradiohistory.com 92 RADIO

I.f. -r.f. crystals are mounted on top.

WHEN WILD WINDS HIT.1. I.F. -R.F. CRYSTAL OSCILLATOR lä' USES JUNCTION TRANSISTOR PERNA-TUBE ST /WS U P By I. QUEEN and so does your reputation! MANY experimenters assume that junction transistors are effective only at audio frequencies, so they don't try to use them in high -frequency circuits. Actually most junction trsansis- tors I have tried perform well as oscillators through the i.f. range, often beyond 1 mc. This crystal oscillator uses a CK722 junction transistor, and oscillates in the intermediate- frequency and radio- frequency range. It is equipped Here's why PERMA-1UBE with an output control and is suitable for measuring, aligning, and calibrat- backs up quality service: ing. Fig. 1 shows the hookup. The transistor is powered 1. PERMA -TUEE IS STURDY by a pair of penlight ... it's made of special, cells that will last high- stre.!ti J a long time. Provi- &L Steel. sion is made for two different frequencies. 2. PERMA -TUBE IS CORROSION I used a 1 -mc crystal (looks like -PROOF . . . it's a metal treated with tube in the photo) and a 375 -kc vinsynite -then coated inside and outside crystal (surplus type). Both crystals with a metallic N.inyl resin base. are left in the circuit at all times. Only the coils are switched. The circuit oscil- 3. PERMA -TUE E IS EASILY INSTALLED ... it's the only lates when the collector coil is tuned mast with bets: aids of the joint machine fitted. close to either one of the crystal frequencies. Here's pro 3f of Perma- Tube's superior strength. The i.f. coil (L1) is a Grayburne Ordinary masts and Perma -Tube were subjected to Vari -Choke whose inductance may be varied from regular defection and permanent set tests with the 0.65 to 6.0 mh. It may be following res.iLs: replaced by a coil with an inductance of about 3.5 mh. For example, I found TV Mast Bending Force To that a standard 2.5 -mh coil in series Tested Siz3 and B W Gauge Produce 21/5 lbs Set with a 1 -mh coil works fine. The r.f. coil Mast A 114" OD x 20 Ga. 1870 inch pounds (L2) is a slug -tuned broadcast oscilla- Mast B 11A ODx18Ga. 2740 inch pounds tor unit (for 465 kc i.f.). It tunes to Mast C 1.155" OD x 17 Ga. 2780 inch pounds 1 mc with the slug almost all the way Perma -Tube 1t/" ODx18Ga. 2930 inch pounds in. If a Q meter or test oscillator is Mast D 1tá" ODx15Ga. 4370 inch pounds available, the coils may be pretuned to Mast E 1t/" ODx16Ga. 4560 inch pounds the desired frequencies. Final tuning Perma -Tube 11/4 " OD 16 Ga. 5950 inch pounds i,:_ CIlECK THE 500 HOUR MINIMUM SALI SF RAY TEST RATING OF YOUR TELE- VISION MASTS (Am. Soc. of Testing Materials -Spec. 511' -49T). Remember Perma -Tube passes thi; test ... remains JaL corrosion-proof. STEEL Joaea it Laugklic STEEL CORPORATION- Pittsbur2Jo Fig. 1 -The i.f. -r.f. crystal oscillator. RADIO -ELECTRONICS

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may then be done in the crystal / oscillator. NOonnr,nU i\l/ n LI V The i.f. coil tunes broadly; the same ASSEMBLE YOUR OWN setting can be used for crystals ranging from below 375 kc to over 400 kc. Thus, ELECTRONIC if you have a number of surplus i.f. ORGAN LEADS crystals, you can easily change frequency without retuning. Simply plug in the crystal you want.

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Tone Generators Keyboards Power Supplies Tremolos L'Wei-chassis View shows chassis layout. Amplifiers MOSLEY Tone Cabinets The oscillator is adjusted first with Consoles the switch in the R.F. position. Set the slug in L2 for output on 1 me or whatever frequency you select. Next, throw For Details Write Today To the switch to I.F. and adjust the tuning of L1 for output on the desired ELECTRONIC ORGAN ARTS frequency in the i.f. range. Box 16454, Dept. RE -2 Vine Station, Los Angeles 38, Calif. Materials for i.f. -r.f. oscillator

LIST PRICE $ .80 I -47,000 -ohms, 1/4-watt, resistor; I- 10,000 -ohm po- PATENT APPLIED tentiometer; I- .0015-µf capacitor; I FOR citor; -. 005 -µf ca- 2- crystals; I -CK722 transistor; 3-sockets for crystals and Low Loss, Permanent Connections transistor; I- 3.5-mh coil; I- slug -tuned broadcast oscillator coil; I- 3- position switch; 2- Of Transmission Line and Phasing penlight cells. Strips To TV Antenna Elements! Se4144eí410-al For UHF and VHF Antennas!

A single penlight cell is ' For All Types Transmission sufficient for SELF POWERED Line! the i.f. band. However, I found it ad- Eliminates Roof -top Soldering Jobs! visable to use at least two cells for the 2 WAY Quick - Easy to Install! 1 -mc range; otherwise the oscillator does not start each time and the output PHONE SYSTEM Available In Two Sizes system Operate To Fit All is weak. 2 way phone Since transistors are not uni- Sensitive clarity over distances Antennas! form, you may with telephone like find that still greater of aself- contained CATALOG 263 voltage is proof DoorStyrl ono with -S For all UHF Antennas needed for the r.f. oscillator. hock battery. Has full size and most VHF 11 Volt flashlight Co!n- Yagis, Conicals, Inline, You may have to use 9 volts or more. 24 carat gold plated. and other carbon mike type antennas where dis- However, of several tried with wall t,one here, I found plete Without a doubt, tances between terminals is 4" and brackets. or or less. all functioned satisfactorily. One even service, officeleads of the most sensational CATALOG 263 -L For TRIO Zig -Zag, offered. Complete $with and oscillated at 1 me with less than 1.5 home items ever other antennas where distance be- volts! END batteries. wire tween terminals is 6" = pair weatherproof or less. Two conductor twisted :1.50 2c. per ft 100 ft. Your reputation hangs on sine threads of cop- for above ..... per. Use the MOSLEY `Y -TY" on Every Instal- lation Job To Stop Antenna Call- HAM'S HEADACHE backs! FREE! NEW 1954 CATALOG! The NEW MOSLEY "Y -TY' now available at A complete, comprehensive Radio and Television by Jeanne DeGood listing of oll your electronic Parts Distributors requirements. eursti n g wit h - My SPECIAL VALUES Coast -to- Coast! neighbor says that I'm the guy 1 CONCORD RADIO,54 Vesey St., N. Y. 7,Dept, C5 WRITE FOR FREE COPY Who's causing all his TVI, I Please send .. sets of phones at ;4.50 ea. OF THIS CATALOG But often he's the guy 1 Enclosed find $ in complete payment. e Minimum 20% deposit with C.O.D. 1 iNi.}+'-r-;:r_ who wrecks O Send new 1954 CONCORD CATALOG! My QSO with rare dx. NAME

CPA I cannot hear a thing upon ADDRESS etecizo;u41 The bands when his TV is on . . CITY ZONE . /u STATE 8622 ST. CHARLES ROCK ROAD If he's as friendly as I am, CONCORD RADIO 54 VESEY ST. LOUIS 14, ,MISSOURI He'll turn it off so I can ham. ST. NEW YORK 7, N. Y. Dlgby 9-1132

www.americanradiohistory.com 95

TELEPHONE SCIENCE

GUIDES A PUNCH NO ENEMY CAN DODGE

under ¢uiilance of complex electronic controls. (Upper left) - Nike's missile climbs to destroy an eoeur-. Ny'kee) is named after the Greek goddess of Victory. A radar is shown at right. Nike (pronounced

from Army Ordnance, West- Is it possible to guide an anti- aircraft engineers Company and Douglas Air- missile so that it will track down and ern Electric destroy a rapidly maneuvering target? craft Company. No one knew the answer for sure when The first Nike installation has been Amer- the U. S. Army put this question to made, and more will follow. Thus, a Bell Telephone Laboratories in 1945. ica's defenses grow stronger through frontiers in the com- The special skills and techniques de- new extension of is a proud achieve- BELL TELEPHONE veloped to create the nation's communi- munications art. It and skills first LABORATORIES cations network uniquely fitted Bell ment of the knowledge Telephone Labora- scientists to answer this question. They developed at Bell nation's telephone recommended a new system, Nike, and tories to make the then worked to bring it into being with service ever better.

in scientific and technical fields Improving telephone service for America provides careers for creative men MAY, 1954

www.americanradiohistory.com 96.1 RADIO

IDENTIFYING TUBE TYPES

fimerican FROM Beauty DAMAGED ETCHINGS

By HECTOR E. FRENCH ELECTRIC E of the greatest irritations suf- fered by a radio service technician SOLDERING or experimenter is to find that the etched type indication has rubbed off a tube so it cannot be identified. Without IRONS this etch, for example, a 6SJ7 -GT looks just like a 6SK7, and a 6SN7 -GT looks just like a 6SL7 -GT (except for the for shape of the plates, and nobody can remember which plate shape belongs with which tube anyhow). Luckily, there are at least five different ways to bring out an etch that has become completely invisible from repeated handling. When placing the etch on a tube, the manufacturer has a choice of a number of different processes. He may obtain a permanent etch by sand -blasting the type number into the glass through a stencil. This method is seldom used because of problems in safeguarding the health of personnel. Or, as another method, the manufacturer could etch the tube identification into the glass with a strong hydrofluoric acid. This DEPENDABLE ... DURABLE ... EFFI- would undeniably eat a very permanent etch into the glass the CIENT. Since 1894 American Beauty -but trouble is that the acid would eat holes in every- Electric Soldering Irons have been the thing else, including the people operating the machines. standard for performance for all In addition, hydro- BANTAM -31 18 fluoric acid poses an expensive storage '/8' TIP soldering irons. problem. 30 -WATT Since the manufacturer's intention NOW ... American Beauty gives you is to etch the tubes and not his personnel, precision production a less dangerous procedure is re- soldering with quired. As a result, each manufacturer the new BANTAM -a light, sturdy, has his own concoction of chemicals which is rubber -stamped on BANTAM -3120 quick- heating soldering iron with small the glass - during manufacture of the tube. When 3Ae" TIP diameter tip. first 30 -WATT stamped on, the etch may be almost invisible, but after the tube has passed through the HEAVY -DUTY ELEMENT-IN- TIP -3438 various processes of manu-

A different, more efficient electric soldering HEAVY -DUTY iron than any on the market. ELEMENT -IN -TIP An iron designed especially -3438 for heavy -duty or production -line use. It embodies a new type of heat application with the element permanently- ` embedded in the tip. TEMPERATURE REGULATING STAND -475 TEMPERATURE REGULATING STAND 475

Set the thermostat at the desired temperature -your iron will be ready to use without waiting.

WRITE FOR DESCRIPTIVE LITERATURE

SINCE 1894 -ALWAYS DEPENDABLE American Electrical Heater Company"mecv =t "" NO 14O -H DETROIT 2, MICHIGAN S ,5888ted by ,lamer Ward. Milwaukee, Wise. RADIO -ELECTRONICS

www.americanradiohistory.com The fastet selling TV antennas! jJ ' ;, icaf

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facture, and has been heated to almost THE the softening point of the glass, the BIG 3 etching material has roughened the glass and swollen up into an opaque of SALES SUCCESS coating which will adhere to the glass during all subsequent normal handling. WITH BUXTON The normal method of reading the Super- Marker Injector etch is by reflected light, in the same POWER -VUE manner that this printed page is read. cuts bench time up to But when the etch is almost gone, there ANTENNAS are two other ways to identify the 75% on alignment jobs! tube. glut ticc >t z44'e The first is to read by transmitted light, as though the tube were a pho- 1. WHAT THEY WANT tographic negative, held up against the light. This method will 2. WHAT THEY CAN SELL frequently permit the etch to be read easily, es- - PROFITABLY pecially with an older tube. If the 3. WHAT PERFORMS BEST etch cannot be read by transmitted light, it can sometimes IN be read THEIR AREAS by diffused, or scattered, light. Allow the light FOR EXAMPLE: to shine on the etch location from a very small angle with the sur- COBRA* CONE (Conicals) face of the glass. If the light is coming directly from the left, for example, the PROVED UNIVERSALLY HIGH GAIN beams which strike the unetched areas for practically oll areas. WINNING simply reflect off toward the right and UNQUESTIONED are not seen. Beams which strike the MODEL SMI 53 APPROVAL slightly wherever used.... roughened etched area are $67.50 An EXCLUSIVE scattered in all directions, KEY FEATURE: and the small MAKES Quick -Lock "2 BOLT" percentage of this light which A SIMPLE MECHANICAL COBRA HEAD (Greater is scat- elerrlent tered is often enough to make the etch PROCEDURE OF WHAT IS NOW separation achieves longer, cleaner, readable. A TOUGH TECHNICAL TASK! clearer signal.) Other important When these methods fail, there is No longer do you have features, too. to connect and reconnect still another procedure which will al- a maze of cables, look at erroneous response most always work. curves, worry about overloads, traps, and weak This procedure, or invisible markers. The Scala Super- Marker In- strangely enough, depends on the nat- lector ends this completely) For example, a com- ural oils plete video IF alignment job can be accomplished of the scalp, which have just with only two cables and no reconnections) the right consistency to bring out the (Marker bypasses receiver circuits entirely.) Used with CONICALS etch on a tube. If the tube is any standard marker generator, rubbed sweep generator and over the hair at the back of the neck oscilloscope. the etched area collects more oil than does the smoother glass areas, and the OLD METHOD NO. 3cc POWER -VUE COBRA CONE etch can be read with surprising ease. (An outstanding sales number) OF ALIGNMENT About the only time this procedure The PLAIN FACTS about fails is in cases where the scalp has a Marker size is normal at top; almost invisible on BUXTON POWER -VUE YAGIS deficiency of this oil, or when the person slope of curve; disap- reading the etch is completely bald. pears completely in base MAINTAINED HIGH GAIN line. via correct design. Even then, there is no need to despair, because there are still two more 2 APPROVED PHYSICAL STRENGTH ways Aluminum alloys, Steel Support brackets, to make the etch visible. non -breok insulators. You will notice 3 "E -Z UP" ASSEMBLY. Either pre -assembled that each of these ' Snap -Out, or One -Piece, Elements. previous methods depend on the slight roughness in the glass left after the etch has disappeared. The next method is therefore almost obvious. An ordinary lead pencil, hard or soft, sharp or dull, depending on Marker size is now always the particular etch, will the same regardless of posi- bring out the pattern by careful rub- tion on response curve or bing. One particular tube may require base line. The traps and the an extremely hard, sharp pencil, while characteristics of receiver have absolutely no on A FULL LINE OF TYPES effect YAGI the next tube works best with a softer marker size. Broad Band, Delta Match, etc. lead. In either case, the roughened area BUXTON ALSO BUILDS: Power -Vue Straight collects more of the graphite from the Dipoles, Arrows, V Stacks, Diamondbacks, pencil than does the smoother ,glass Folded Dipoles and Fringe Area Antennas. around it. And Accessories. 'A Buxton Name The last procedure in case the pre- SOLD NATIONALLY THROUGH JOBBERS vious methods fail is to try refrigera- AN ABSOLUTE MUST IN THE ALIGN- tion. That's right, refrigeration -I MENT OF COLOR TV RECEIVERS! BUXTON INDUSTRIES, INC. RE -1 believe it myself. 88 North Fair Oaks Ave., Pasadena, California didn't When the tube is sufficiently chilled, breathing on PLEASE SEND INFORMATION the Avo: able at leading 'Donets AS CHECKED: tube will make etch FULL INFORMATION & PRICES. the completely Name & Address of NEAREST JOBBER clear when all other methods have failed. Once again, the reason lies in Name the slightly roughened surface left be- Street hind when the etch has been rubbed off. City Zone State The moisture in the breath condenses 2814 -19th STREET more readily on this roughened surface SAN FRANCISCO 10, CALIFORNIA RADIO -ELECTRONICS

www.americanradiohistory.com 99 Positive connections Transistors every time for the practical worker in electronics! TRANSISTORS -

THEORY AND PRACTICE boils down the findings of advanced physicists on transistors into the transistors the serv- theory and practice language and experience of ice technician and other practical

workers in electronics. Most complete low -cost book on transistors yet published. Theory and Practice Transistors - with Gernsback Library Book No. 51. By Fully Rufus P. Turner. 144 pages. SOME OF THE CONTENTS OF new illustrated. $2.00 TRANSISTORS -THEORY AND PRACTICE Centralab For you who depend on electronics Semiconductor Theory for a living or who work with it as a hobby, here is a book which gives Transistor Characteristics the you the lowdown on transistors, Equivalent Circuits dramatic new development which Attachable Terminal promises to revolutionize the entire Transistor Amplifiers industry. Transistor Oscillators D1ost of what has been written on HI-VO-KAPS' transistors so far has been limited to Duality in Transistor Circuit Design of the advanced the rarified strata Triggers and Switches physicist -so obscure that even Circuits some engineers have trouble under- Practical Transistor to high -voltage ca- it. When it comes standing Tests and Measurements pacitors, you just can't beat CRL Hi- Commercial Precision Attachable Terminal NEW PRACTICAL APPROACH Characteristics of for dependability. Here's Transistors Vo -Kaps But now, Rufus P. Turner, who knows more why: any technical about transistors than popular They are 100% factory - tested at twice writer in the business, lifts the fog on this J rated working voltage - withstand con- fascinating subject. In a simple, straight - tinuous overload up to 40,000 v.d.c. the transistor time in any book -o complete discus- forward manner, he traces First Terminals and taps have heavy 8 -32 from the basic semiconductor theory to the sion on the surface- barrier transistor! thread- cannot strip or break off, when of transistors in practical circuits. application FEATURE terminals are tightened. With the actual commercial use of transis- EXCLUSIVE at bottom of tap. in hearing aids. and Commercial Terminals seat flat tors already a reality Chapter 10 - Characteristics of No gaps between terminals and capaci- their use in radio and TV just around the Transistors is a complete guide to the physical of corona. transistor body - no possibility corner. the service technician and experimen- and electronic characteristics of commercial between stub learn all they can Actually the first published manual on tran- Positive mechanical bond ter owe it to themselves to tors. and internal electrodes pre- these new electronic devices. TRAN- sistors, it can save many hours of experimenting terminals about This unique feature vents loosening, when terminals are SISTORS- TIIEORY AND PRACTICE is a and trial and error methods. alone makes TRANSISTORS--THEORY AND PRAC- attached. giant step along the way to understanding today in practical cir- TICE a book you should own. Get your copy a stock of CRL Precision how to work with transistors distributor's. Keel) cuits. at your parts Attachable Terminal Hi- Vo -Kaps on hand. Separate packaging of ter- Books? minals and capacitor body lets you Have you read these Gernsback Library buy only the terminals you need. See your Centralab distributor. Design, Construc- TV Repair Techniques. No. 50.$1.50 High -Fidelity- Send coupon for bulletin 28 -2 No. 48. $1.50 Radio & TV Test Instruments. tion, Measurements. on CRL Precision Attachable No. 49 $1.50 No. 47 $1.00 Terminal Hi- Vo -Kaps. Radio & TV Hints. SEE US AT Boors 790.

mail this coupon Technotes. No. 46 $1.50 : MAY,I.]G CHICAGO See your distributor -or Television 4 Radio Tube Fundamentals. Inc., Dept. 54 i Gernsback Publications, No. 45 $1.00 EKMAiligsVKIIMItgaKKig 25 Broadway, New York 7, N. Y. I West CENTRALAB, Basic Radio Course. No. 44 $2.25 Inc. Enclosed is my remittance of f A Division of Globe -Union following books postpaid. 932E E. Keefe Avenue, Milwaukee 1, Wisconsin Please send me the By Radio. Transistors -Theory and Practice. $1.75 Model Control Send bulletin 28 -2 on CRL Precision 51 Terminal Hi -Vo -Kaps. 50 49 48 47 46 No. 43 $1.00 Attachable 4 042 04 0 04 04 3D High -Fidelity Techniques. Nome... Nome $1.00 (Please print clearly) No. 42 Address Guide. No. 41..75¢ Address.__.._._._....._... Street Public- C¢ty__.___...... ____--zone...... cace...... _.._...... __ 7one_State Practical Disc Recording. No. 39.75¢ D.1954 11 I City -I E11Aaawaaaalaaallailtaa11R1 MAY, 1954

www.americanradiohistory.com 100

THE #630 TV RECEIVER remains unmatched wise The for quality and performance RCA designed and original 10 "" set retailed at $375.00 Subsequent developedp this set quality-wisewise nor what BUYSbetter proof can there be TV sets serve to of its superiority than the fact that it is the choice of TV engineers IN TV! All you pay is the price shown and TVrtechnicians!rtHerewith we offer youce YOUR - Excise taxes have already been paid by us. BEST r.#630 SUPER DELUXE TV CHASSIS your owfi with U.H.F.- Licensed under RCA patents j3,í1 COMPLETE READY TO PLUG IN AND PLAY -Similar in characteristics and features to the TV KIT at left Manufactured Regal Electronics especially for us by Corporation No efforts or expense have been spared in workmanship or materials, to make CHASSIS this #630 SUPER DELUXE TV the Best obtainable for fringe areas, clarity and all- around- #630 performance, regardless of price. Customers report 200 miles reception better than Each Set is factory aligned and air- tested All parts carry the RMA three month guarantee Our CHASSIS (numbering mass volume of business on this thousands of pleased customers) now makes it Super Deluxe possible for us to reduce the price to Only $15 TV CHASSIS #630 TV SPEÏALS TECH -MASTER TECH -MASTER Model C -30 TV CHASSIS. This Model has retained the with - outstanding characteristics of the RCA -630 .. U. H. F. circuitry, namely the four - stage, full bandwidth picture IF strip and the three -stale tion In addition, the latest FM sound sec- innovations in synchronization and sweep With a circuits have been incorporated to #630 SUPER DELUXE 31 -TUBE TV KIT assuring produce a custom -quality receiver outstanding performance 30 tubes, 12" speaker. including your assigned U.H.F. Station OPERATES 16" TO TURE 24" PIC- TUBES Engineered in strict adherence to the genuine RCA Complete Ready to Plug in and #630 plus added features Play FULL 4MC BANDWIDTH CAS - Special at $149.5°I,. CRT) CODE TUNER COSINE DEFLECTION YOKE LARGER POWER TRANSFORMER TECH -MASTER KEYED AGC 12" SPEAKER Gold Medal Model 2430 -9 TV UNIVERSAL MOUNTING BRACKETS CONDENSERS and RE- CHASSIS, SISTORS at rated ca Including your assigned U.H.F. p aci ties and tolerances You receive a COMPLETE 90° deflection, operates Station SET of PARTS and TUBES, everything all 24" or 27" rectangular and needed is included (less wire picture tubes. The last word in 30" round & solder) All I.F. I TV achievement C of s a nd Transformers are factory pre-aligned and custom -cabinet mounting Ideal for wall or tuned. You will enjoy building it with "LIFE Detailed technical data mailed on step-by-step -SIZE easy to follow however with the knowledge that this request, ASSEMBLING INSTRUCTIONS" included with each CHASSIS is a 30 -tube #630 with KIT. both TECH -MASTER'S and OUR guarantee, you NOTHING BETTER AT ANY PRICE! sending your order in now. need not hesitate only ... 1191,ess41 Complete Ready to Plug in and Play Special at $26 2$0Icss DUMONT or SHELDON FINEST GUARANTEED MOST desirable 5 PICTURE TUBES sizes -ALL RECTANGULAR BRAND NEW in Factory Sealed Cartons -With a Full Year Guarantee rr ,r #I7BP4A ¢ // / rr Q p $2 63 $39.74 #mIEP4B 29 20 alu0CP=6d VV 21 A $44.68 24" #27EP4A 82.57 é 66.24 27rr Aiuminized CUSTOM -BUILT ALL CABINETS R #630 OTHER TV SETS from FACTORY S LEADING STYLES in ggenuine ne mahogany or walnut to YOU or 21" picture (blond 10% extra) Ready drilled for any #630 TV chassis tube at no extras in price Also supplied with undrilled knob and cutout for any easy perfect assembly is included panel for any other TV set EVERYTHING Each cabinet is delivered complete as pictured with mask, safety glass, NECESSARY for an hardware and assembling instructions Each cabinet is mounting brackets, backboard, shipped in an air cushioned carton from FACTORY to YOU! backcup, The VOGUE The MANHATTAN The MAYFAIR The PLYMOUTH Most Popular Style, Quality, Price Exquisitely modern, The TOWN & COUNTRY Table Model with an ele- Choice of interior Decorators, Patterned gonce of simplicity in styling. truly superb in after the popular every detail. Avauavie credenza. for ail size pintare tlit,o. 14" to 27"

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$62.54 MANHATTAN n,r_.r-r 27" Ill' la..pu.,... W-275/.t", u-2a^ 586.22 $98.56 F,t ,a 6°. 17:, $105.46 C,t ( , $109s2

PARTS FOR #630 TV SETS Modernize a #630 or any TV Set PULSE TV WIRE with a KEYED AGC KIT & SOLDER KIT, for any Set $.1.49 most ...... best. a,''ui-t- and the e. i._t : -..t 630 -KIT, scre:rs n,,ts in a to Install [vets, washers, etc. 1.69 =6:tu or in any other make TV receiver. PUNCHED STANDARD CASCODE TUNER Improves performance, and insures CHASSIS PAN, cadmium plated. 4.87 on all channels. a steady picture UNIVERSAL CRT MOUNTING BRACKETS... 6.97 For better all around performance POWER TRANSFORMER, 295ma. 201T6 9.97 COMPLETE SET OF PARTS VIDEO AND I.F. KIT, 19 inn, n,lInn ,'ß.3i C. iu, l.,. F: Instruct,,,,,, items 7.84 Complete with tubes, and Brooks CAS- T $4.59 VARIABLE CONTROL CODE MANUAL 49 KIT, 9 controls with st,'l,-I "' -stet, , 5.83 i, uctious and all extra part, needed. CARBON RESISTOR KIT, 107 resistors 6.98 WIREWOUND Brooks LIFE -SIZE TV RESISTOR KIT, 4 resistors 2.31 INSTRUCTIONS Qf for i ,ildiu;; n - ri, :s 'rs' 49 BRACKET AND SHIELD KIT, 18 items 8.63 Receiver. P''.tP:dd(- ELECTROLYTIC CONDENSER KIT, 6 cond 7.37 TUBULAR CONDENSER KIT, 38 Brooks CASCODE MANUAL,hmvtoinstall condensers 4.28 rascode 11 I HINTS FOR BETTER Tuner in v make TV Set, Postpaid5 PERFORMANCE Si on .A nr ::Rai, TV [ecniver. 00 BROOKS RADIO & TV CORP., 84 Vesey St., Dept. A, New York 7, N. Y. RADIO -ELECTRONICS

www.americanradiohistory.com RADIO than on the smoother glass, and makes the etch readable as long as the condensation lasts. When all these methods have failed, carrq there is probably no hope of ever read- Why do I ing the etch. The only sure way to then find the tube type is by using a tube tester to narrow down the possibilities to two or three types, and then to set up a breadboard layout to measure the tube element currents at various poten- ARON Capacitors tials and match these against the various published characteristics. END CORRECTIONS A. D. Burnett, of Richmond, Va., calls? attention to the fact that the on serve calls our heater shunt resistor in the picture - tube checker (page 145 of the October 1953 issue) should be approximately 14 instead of 33 ohms as specified. Well my business is SERVICE, and unless In the article "A Broad -band V.H.F. I use the best replacement parts available of the December, Antenna," page 53 I can't give the BEST service. 1953, issue, the last sentence in the first as follows: Adding all column reads I currents together we see that dipoles That's where ASTRON comes in. read The A and B cancel each other out ... about their new BLUE -POINT be dipoles correct statement should. ... CAPACITORS and Safety Margin A and D cancel . . . We thank Mr. Wilfredo Rafiores of ELECTROLYTICS and decided Loctugan, Roxas City, Philippines, for to try them. calling this error to our attention. I the advantages quickly ... for one A shunting resistor was inadvertently saw omitted from the heater circuit of the thing I could rest the soldering iron 12AU7 oscillator in the transmitter on on that bluepoint ... it wouldn't melt 1954, issue. page 134 of the February, and the leads didn't pull out. The seal This resistor is for bypassing the excess 150 ma drawn by the 25L6's around the was the BEST I've ever seen. heater of the 12AU7. Its exact value should be 84 ohms. You can use a 100 - The ASTRON Safety Margin ohm, 5 -watt resistor with an adjustable well made and correct resistance or ELECTROLYTICS are slider set for the is two 160 -ohm, 2 -watt carbon resistors their twist prongs line is compact. It in parallel across pins 4 and 5 of the easy to substitute ... no waiting for 12AU7 odd values. We thank Cpl. R. W. Bonta of Top - weeks for pahannock, Va., for this correction. Yes, ASTRON is an easy line to work with, knowing ilaDío Xhírtp-iíbe eat ago and there's great satisfaction in iln ce3erngbacb flublicationll that I'm working with the BEST. Try them and you'll agree ! HUGO GERNSBACK Founder Modern Electric' 1908 Wireless Association of America 1908 Electrical Experimenter Radio News 1919 Science & Invention 1920 Television 1927 Radio -Craft 1929 Short -Wave Craft 1930 Television News 1931

Some of the larger libraries still have copies of ELEC- TRICAL EXPERIMENTER on file for interested readers. In Electrical Experimenter for May. 1920 The New Radio Corporation, by C. D. Wagoner, General Electric Co. A War -Time Radio Detective, Part I, by Pierre H. Boucheron New York Girl's Radio Set, by Abby P. Morrison C O R P O R A T I O N Plan for World- Wireless A One -Tube Radio -Telegraph and 255 GRANT AVENUE, EAST NEWARK, NEW JERSEY Radio -Phone Transmitter Long Waves and "Strays" on Rogers Lieut. Corn. A. Hoyt Antennae, by W. POINTON, 6 ALCINA AVE., TORONTO 10, ONTARIO Taylor, U.S.N.R.F. END In Canada. CHARLES MAY 1954

www.americanradiohistory.com 102

You have - never ordered by mail because you did not want to buy anything "sight ueseen" or - HERE is your opportunity to examine You have ordered by mail but with disappointing what you want con then pay the balance in easy monthly results or - under our "Seller not Buyer, takes the all payments with no interest or finance charges You have risk" plan. We invite you to order never purchased anything on time payments any item added. Otherwise, you may return the mer- because on this page and examine it in the privacy of excessive finance charges, then of chandise for prompt refund of your down. - your own home. If you decide to keep it, you pcyment.

- I Superior's new Model 670 -A SUPER METER A COMBINATION VOLT-OHM MILLIAMMETER PLUS CAPACITY REACTANCE INDUCTANCE AND DECIBEL MEASUREMENTS SPECIFICATIONS: ADDED FEATURE: D.C. VOLTS: 0 to 7.5/15/75/150/750 /1,500/7,500 Volts A.C. VOLTS: 0 to 15/30/150/300/1,500 The Model 670 -A Includes a special /3,000 Volts GOOD OUTPUT VOLTS: 0 to 15/30/150/300/1,500 -BAD scale for checking the /3,000 Volts quality of D.C. CURRENT: 0 to 1.5/15/150 Ma. electrolytic condensers at 0 to 1.5/15 Amperes a RESISTANCE: 0 1,000 test potential of 150 Volts. to /100,000 Ohms 0 to 10 Megohms CAPACITY: .001 to I Mfd. 1 to 50 Mfd. (Qualify trolyfics) fast for elec- The Model 670 -A comes REACTANCE: housed in a rugged, 50 to 2,500 Ohms 2,500 Ohms to 2.5 Megohms crackle -finished steel 40 INDUCTANCE: .15 to 7 Henries 7 to 7,000 Henries cabinet complete with DECIBELS: -6 to +18 to test leads and operat- NET +14 +38 +34 to +58 ing instructions.

Superior's new Model TV -11 TUBE TESTER SPECIFICATIONS: * Tests all tubes including 4, 5, 6, 7, Octal, Lock - to damage a tube in, Peanut, Bantam, Hearing Aid, Thyratron, by inserting it in the wrong Miniatures Sub- miniatures, socket. Novais, Sub -minors, Free- moving Proximity fuse types, etc. * built -in roll chart provides complete data for all tubes. * Uses the new self -cleaning Lever Action Switches for individual element testing. * Newly designed Line Voltage Control compen- Because all ele- sates for variation of ments are numbered according to pin -number any Line Voltage between in 105 Volts and 130 Volts. the RMA base numbering system, the user can instantly * NOISE TEST: Phono -jack on front panel for identify which element is under plugging test. Tubes having tapped filaments in either phones or external amplifier and tubes will detect microphonic tubes with filaments terminating in more than or noise due to pin one faulty elements and loose internal are truly tested with the Model TV -II as connections. any of the pins may be placed in the neutral position when necessary. The modelodel TV 11 oper- * The Model TV -II does not use any combination ateE 105 -130 Volt 60 type sockets. Cycles A.C. Comes housed Instead individual sockets are in a used beautiful hand- for each type of tube. Thus it is impossible rubbed Oak cab,net com- elete with portable cover EXTRA SERVICE The Model - TV -1I may type oscillator incorporated in this mode NET be used as an extremely sensitive Con- will detect leakages denser Leakage Checker. even when the fre- A relaxation quency is one per minute. :4750

Superior's New Model 660 -A AN AC OPERATED SIGNAL GENERATOR PROVIDES COMPLETE COVERAGE for AM -FM & TV Alignment SPECIFICATIONS:

Generates Radio Frequencies from 100 Kilocycles Iode is used as an R.F. oseillator, mixer and to 60 Megacycles on fundamentals and from 60 Mega- amplifier. Modulation Is effected by electron cycles to 220 Megacycles on powerful harmonics. coupling in the mixer section thus Accuracy and Stability are assured by the use of isolating the permeability trimmed Hi -Q coils. R.F. avail- oscillator from load changes and affording high stability. able separately or modulated by the internal audio A.F. Oscillator Circuit: A high trans - oscillator. - Built in 400 cycle sine wave audio conductance heptode connected as a high mu triode oscillator used to modulate the R.F. signal also is used as an audio oscillator in a High -C Colpitis available separately for audio Circuit. The testing of receivers, output (over 1 Volt) is nearly pure amplifiers, hard of hearing aids. etc. R.F. sine wave. Attenuator A 5 step ladder type of Oscillator Circuit: A high transconductance hep- ettenuotor is used.

TUBES USED: The Model 660 -A

1 -68E6 as R.F. Oscillator, mixer and comes complete with amplifier. coaxial cable test 95 lead and instruc- 1 -6BE6 as Audio Oscillator. tions. I -6H6 as Power Rectifier. NET

MOSS ELECTRONIC DISTRIBUTING CO., INC. O MODEL 670 -A Total Price $28.40 $7.411 down payment. Balance $3.50 Dept B -99, 3849 Tenth Ave., New York 34, N. Y. monthly for 6 months. MODEL TV -11 Total Price 547.50 Please send me the units checked. I am enclosing 811.01/ down payment. Balance $6.00 the down Name monthly for 6 month Payment with order and agree to pay the monthly balance as shown. a Is understood there will be no carrying, MODEL other interest or 660-A Total Price $42.95 any charges provided I send my monthly payments Address $12.95 down payment. Balance $5.00 when flee. It Is farther understood that should I fall to make monthly for 6 month.. payment when due. the full unpaid balance shall become Im- I enclose mediately due and payable. $ so down payment. City Zone State O Ship C.O.D. for the down payment. RADIO -ELECTRONICS

www.americanradiohistory.com 103

Buy on our radically new NO NO CARRYING INTEREST!! Time Paymen Plan CHARGES!! Superior's New Model 770 -A The FIRST Pocket -Sized VOLT-OHM MILLIAMMETER USING THE NEW "FULL -VIEW" METER 71% MORE SCALE Features Specifications 0- 15/30/- * Compact- measures 3l/e" x 6 A.C. VOLTAGE RANGES: AREA!! 57 /e" x 21/4" 150/300/1500/3000 Volts. 6 D.C. 0- 7.5/15/75/150/- Yes, although our new FULL -VIEW * Uses "Full View" 2% accu- VOLTAGE RANGES: D'Arsonval type meter occupies ex- rate, 850 Microampere D'Ar- 750/ 1500 Volts. 2 RESISTANCE actly the same space used by the older type meter RANGES: 0. 10,000 Ohms, 0 -1 Megohm. sonval 0-15/150 standard 21/2" Meters, it provides 71% * Housed in round -cornered, 3 D.C. CURRENT RANGES: more scale area. As a result, all cali- molded case Ma., 0 -1.5 Amps. 3 DECIBEL RANGES: brations are printed in large easy -to- * Beautiful black etched -6 db fo +18 db, +14 db to +38 db. read type and for the first time it is panel. Depressed letters +34 db to +58 db. now possible to obtain measurements filled with permanent white. instead of approximations on a popu- insures long -life even with lar priced pocket-sized V.O.M. constant use.

THE MODEL 770 -A COMES COMPLETE WITH SELF- CONTAINED ONLY $1585 BATTERIES, TEST LEADS AND ALL OPERATING INSTRUCTIONS.

Superior's New TELEVISION BAR GENERATOR THROWS AN ACTUAL BAR PATTERN ON ANY TV RECEIVER SCREEN Two Simple Steps FEATURES: I. Connect Bar Generator to Antenna Provides linear pattern to adjust VERTICAL linearity, height, Post of any TV Receiver. centering Provides linear pattern to adjust HORIZONTAL vertical Cord into AC Outlet and drive, width, peaking, linearity, centering Provides 2. Plug Line and synchronizing vertical oscil- Throw Switch. sweep signal for adjusting lator discharge and output tubes Provides vertical signal to Result: A stable never- shifting ver- replace vertical oscillator to check vertical amplifier opera- or horizontal pattern projected tion Provides horizontal sweep signal for adjusting and syn- tical Pro- the TV receiver chronizing horizontal oscillator A.F.C. and output tubes on the screen of vides horizontal sweep signal to check H.V. section of fly -back Bar Genarater Teleuís on î r>> under test. and pulse operating power supplies Provides signal for testing video amplifiers Can be used when no stations are on _--- i , SPECIFICATIONS: the air. Power Supply: 105-125 Volt 60 Cycles i 4 Power Consumption: 20 Watts TV 8AR GENERATOR COMES : by harmonics ,, Channels: 2 -5 on panel. 7 -13 COMPLETE WITH SHIELDED 95 Horizontal lines: 4 to 12 (Variable) Vertical lines: -12 (Fixed) LEADS AND DETAILED OPER- NET Vertical sweep output: 60 Cycles ATING INSTRUCTIONS. ONLY Horizontal sweep output: 15,750 Cycles

SUPERIOR'S NEW MODEL TV -40 .T. TUBE TESTER A complete picture tube tester Tests all magnetically deflected * for little more than the price It tubes . . . in the set . . . out of a "makeshift" adapter!! of the set ... in the carton!!

The Model TV -40 is bv,,luteiY - SPECIFICATIONS: letel Self -contained, including ',Wit- h, power supply, it teste picture tubes Tests magnetically deflected picture tubes from 7 inch to in the only practical way to efficiently all test such tubes: that Is by the use of 30 inch types. separate Instrument which is designed by the well established emission method. All exclusively to test the ever Increasing Tests for quality number of picture tubes! readings on "Good -Bad" scale. Tests for inter -element shorts and leakages up to 5 megohms. EASY TO USE: Test for open elements. Simply insert line cord into any 110 volt A.C. outlet, then attach tester Model 0 C.R.T. Tube socket to tube base (ion trap need Tester comes absolutely not be on tubel. Throw switch up for complete- nothing else to quality test ... read direct on Good - buy. Housed in round cor- Bad scale. Throw switch down for all nered, molded bakelite NET leakage tests. case. Only

Model 770 -A Total Price 515.85 -, INC. $3.85 down payment. Balance $4.00 MOSS ELECTRONIC DBSTRIBUTING CO no. otnly to, 3 monina. Y. E -99, 3849 Tenth Ave., New York 34, N. Bar Generator Total Price $39.95 Dept. $9.95 down payment. Balance $5.00 Name monthly for 6 months. Please send me the units checked. I am enclosing the down payment with order and agree to pay the monthly balance al Model TV -40 Total Price $15.85 be no interest or $3.85 down payment. Balance $4.00 shown. It Is understood there will carrying, monthly for 3 months any other charges. provided I send my monthly payments Address when due. It is further understood that should I fall to make 1 enclose $ as down payment. shall become im- payment when due. the full unpaid balance Ship C.O.D. for the down payment. mediately due and payable. city Zone. State ...... I- MAY, 1954

www.americanradiohistory.com NEW DESIGN

LE ATl ( from iecolro5AnD

TOP VALUE at gold -plated in Antenna Switches contacts L -O -W really L -O -W and TRANSISTORS pan out! IN KEEPING with the color TV trend, Price i RCA has announced a group of tubes designed for use in color TV receivers. I '/'/--- Of particular interest /! i is the 15GP22, a {PII 4==e21D glass -envelope picture tube capable of $2.00 \ producing either List r a color or black -and- I white picture 11% x 8% inches, with Yes! You get im- rounded sides. UA-3-14 Wall ! ¡ Mounting mense satisfaction The 15GP22 uses i I three electrostatic- Receptacle I from gold in any / form ... and partic- ¡ I ularly from the performance of the gold - plated contacts in AS -46 Cannon's modern Model UA -3 -32 Wall "UA" audio Series I Matched two -position Mounting I I connectors. Receptacle ohm) Switch Contacts are ó (300 heavily gold -plated I Tops in performance over silver plate Most ... Its TELEMATIC for the not just "flashed" Switches Complete Line in Antenna UA -3 -42 Microphone with a light coating or Panel Mounting of gold. You get max- Receptacle imum protection Three -gun tricolor picture tube 15GP22. Model AS -18 from oxidation and focus guns spaced 120° apart with axes Three -Position deterioration. . max- ohm) imum protection parallel to the tube axis; magnetic de- (300 to flection; Impedance matched. vital audio electrostatic convergence; and Antenna circuits an assembly Low -Loss UA -3 -13 Wall ...absolute reliability. consisting of a shadow Switch Mounting x mask and a plane, Cannon's thumb - tricolor, filterglass Receptacle phosphor-dot (screen) plate located pressure LATCH - AS -49 LOCK prevents between the shadow mask and a clear - Model ac- glass faceplate. cidental disconnect. Four -Position The tricolor phosphor -dot plate (300 ohm) Available through serves Cannon distributors. as the directly viewed screen, Impedance matched. UA -3 -31 Wall and carries Antenna Mounting \.) an orderly array of small, Rotary Receptacle closely spaced phosphor dots arranged Switch in triangular groups. Each group con- Model AS -41 fit WRITE FOR sists of a green, red, and blue- emitting RJC BULLETIN! dot. The phosphor -dot plate has approx- Three -Position imately 195,000 dot groups or 585,000 (72 ohm) Antenna, Refer to Dept. 144 dots and is metalized after the phosphor Phono, Audio and UA-3-12 Plus: CANNON ELECTRIC dots are applied, to give increased light Microphone Switch COMPANY, 3209 output and contrast, and to prevent ion - Humboldt St., Los spot blemish. - -41)., Angeles 31, Calif. The metal shadow mask, placed be- Model AS -48 Factories in Los An- tween the electron gun structure and geles; New Haven; Co -Ax Toronto, Canada; the phosphor -dot plate, contains round Two- Position London, holes equal in Switch for Antenna, England. number to and centered Micro- Representatives and with respect to the dot groups. Phono, or distributors in all phone, etc. principal cities. The 3A3 is a rugged glass -octal half - wave rectifier tube, designed for use as See Us of Booth 885 a high -voltage Prices slightly rectifier in the scanning higher west systems of color television receivers. of the Rockies A3:11=13 Rated to withstand a maximum peak inverse plate voltage of 30,000, the 3A3 Write for catalog. Since 1915 can supply a maximum peak plate current of 80 ma and a maximum average 1, N. Y. plate current of 1.5 ma. 9 Joralemon St., Brooklyn RADIO -ELECTRONICS

www.americanradiohistory.com 105

DAD THOUGHT TH/S ANTENNA !WOULD HELP, BUT ALL WE NEEDED WARE SPRAGUE CAPAC / TOS .1

1 I Don't Be Vague..Insist on SPRAGUE P

Insist on Sprague Insist on Sprague Insist on Sprague CERAMICS TWIST-LOK- 'LYTICS BLACK BEAUTY TELECAPS'' Accept no substitutes. There is a Sprague Tiny, tough, dependable . . . Sprague TVL's fill the top The most imitated capacitor Distributor in every in every application . . . performance bill in the tough- Sprague ever introduced. But get Sprague performance soles area in the whether discs, plates, buttons, est TV circuits. High tem- you or door knobs. And there's a only when you insist on United States. Write Sprague ceramic capacitor to peratures, surge voltages, rip- Sprague Telecaps. Hundreds for the name of your meet every service need. You ple currents won't faze them. of millions are in use today nearest source of sup- give your customers depend- Like all Sprague capacitors, as first choice of quality con- ply today. able service, guard yourself are scious manufacturers and against costly callbacks, Twist -Lok 'Lytics your servicemen. It's the premium when you use only Sprague first line of defense against molded tubular at no extra Ceramic capacitors. expensive call -backs. cost. rr Trademark

Get your copy of Sprague's latest radio and TV service catalog C -609. Write Sprague Products Company *, 81 Marshall St., North Adams, Mass. 'Distributors' Division of Sprague Electric Company WORLD'S LARGEST SPRAGUE CAPACITOR MANUFACTURER

MAY. 1954

www.americanradiohistory.com 106 NEW DESIGN

The 6AN8 is a 9 -pin miniature general purpose tube containing a medium - mu triode and a sharp -cutoff pentode. It is intended for diversified uses in color television receivers. The triode unit with its relatively 1200 FT. REEL high zero-bias plate current is useful in Base low-frequency oscillator, sync separa- Genuine Plastic tor, sync clipper, and phase splitter cir- TAPE RECORDING cuits. The high -transconductance pen- made a ter- LAFAYETTE one the tode unit may be used as an i.f. ampli- rifle deal manuf of manufacturersof fier, video amplifier, a.g.c. amplifier, ?, leading to t0T us tape .?.r,e, r, pugs recording tape and reactance tube. The basing arrange- with their regularleg WE twice our 9 rite. ment and internal construction of the sells for almost which ABSOLUTE SATISFACTIONfinest, 6AN8 are designed so that coupling be- GUARANTEE BACK. The YOUR MONEYONEY tape obtainable. tween the triode and pentode unit is OR recordingthou la ings- Highest for thousands virtually eliminated. performancederBase uniformpcoaating; in maximum Red Oxide Base with fidelity: A very interesting tube type is the signal tfi from 40- 15,000 f response from 6BD4, a sharp -cutoff low- current beam uniform frequencyf1 and freedom at } /i perrysecond; Each reel is triode designed as a voltage regulator fps and distortion. 10 oz. background noise Shipping weight high boxed. for -voltage, low-current d.c. power individually supplies used with the tricolor 15GP22. MASCODE MODEL ABV AUTO. ALL (See diagram for base connections and I1 CHANNEL VHF 3 TUBE TV BOOSTER Features a new low -noise cascade circuit. circuit application.) Fully automatic - no tuning. Best for alt SALE/ TV receivers, old or new. Boosts all channels t EQUIV. RES.OF DC SUPPLY + 111 t . 2 to 13 automatically! Brings - up station UNREGULATED strength 8M REGULATED oc DUTPUT I I 1 i i I through Lowlnoisefactor III 13 (approx= DC SUPPLY 6BD4 imately 6). Automatically turned on and o$ VOLTAGE 129,8000) PLATE CAP 20,000V) MA SC ODE II l t by the TV set. Concealed behind TV receiver.! Mount it and forget it. Employs new 6BET -A tube for snow-free reception with new high BOOSTER' gain -low noise TV receivers. 3-tube circuit includes two 8.T8 tubes in push -pull. cross - neutralized RIP amplifier circuit. All -metal cabinet, brown hammertone finish. UIL anin lots of 3, proved. Undistorted sound and picture on all i95ea, 12 channels. Engineered for maximum performance. Size II" x 5" It 3 ". Shoe. wt. 4 lbs. singly, ea.6.2b MODEL ABV VHF -TV BOOSTER. List $39.50 TELEPHONE INTERCOM Talk about Self Contained Battery Buzzer Signal THE STANDARD CASCADE REF.VOLTAGE SUPPLY (500V) Ideal For TV installers tunerst TUNER TOPS 'EM ALL! Operates Typical shunt voltage- regulator circuit. Up To 2 Mlles BRAND NMI GUARANTEED! You can now have a complete 2- station telephone type intercom The No. I Tuner in the trade. $14.95 ea. The 6BD4 has a maximum d.c. plate - system at an amazingly low cost. Lafayette is out front with this Simply lift the receiver from Its red -hot voltage rating of 20,000, a maximum hanger and the button to STANDARD COIL $14.25 ea. press CASCADE TUNER deal. signal the other party. It oper- Lafay- in lots 3 d.c. plate -current rating of 1.5 ma, and ates on self- contained #1 flash- ette made a buy -we paid cash of light cell for as much as a mile. -and you get the saving) Reg- a maximum plate- dissipation rating of You may use Mallory 4 volt Mer- ular cury cell for longer distances. dealer price $24.50. Service- 20 watts. Heater rating is 6.3 volts at Batteries are easily replaceable. men, now is the time to stock up 'The Alnico 5 mUnet gives loud and save! Size: 41/4" x 31/4" x 600 ma. and clear reproduction. Molded 61/4" supplied with 616 high impact ease resista break- and Development of four new receiving ing. Installation is extremely 6BQ7. Stook No. TL -11. Shpg. simple and consists of merely at- wt. 4 lbs. tube types for color TV receivers has taching the clips provided to the ends of the wire. Ideal not only been announced by G -E. The new types for ordinary intercom use as a DIAMOND NEEDLES AT "telephone set, 2V2 -voltage rectifier, the but perfect for TV RHINESTONE are the high E installers antenna the PRICES t Consists of 2 phones, Diamonds maintain optimum per- 5AU4 high- output, full -wave rectifier, A for mounting on wall, batteries and 50 feet of 2- conductor formance and wire. give longer life to the 6AR8 sheet -beam synchronous de- 9 both records and stylus. This is a a Stook #ML39, Complete Set NET 5.96 genuine whole diamond precision tector, and the 6BU5 high -voltage polished to .002 PHILCO point. Plays all 3 pentode for shunt regulation. NOW BOOSTER speeds. Fits all single needle car- The Philco Television Booster tridges having thumbscrew or set- The 2V2 is designed for use in fly- Model TB -3 is high quality, screw. For the life of your records supplies. Its high push -pull. wide -band radio - -Buy Diamonds! back types of power frequency amplifier designed to PK26 Not 2.89 inverse voltage and average current amplify r -f signals in the television bands. This unit employs capabilities make it suitable for supply- TIMER -SWITCH two 636 tubes as r -f amplifiers, SALE color pic- het uses selenium This "almost human" timer will switch ing power to the anode of a rectifier in your radio, television, or any other appliance $12.50 ea. self contained power supply. on or off, fully automatically, W Ill turn ture tube or to a monochrome picture Channels 2 through 13. them on at any desired preset time. Can tube which operates at a high anode $11.50 ea. MODEL TB.3 In original factory be pre-set up to 12 hours. Full -vue crystal dial, 3 knob front, 3I/a" diameter. With in Pota of 3 sealed cartons. Money back mtg. ring and voltage. guarantee! bracket. Shp. Writ. S !be. ea. MS-62, for' 110V /60 Cy AC The 5AU4 is a twin diode designed In sots of 6, ea. 3.45 ;WESTERN ELECTRIC HEARING AID singly. ea. 3.69 for use in the power supply of TV re- Our price ceivers and other equipment requiring 1 Reg. price PRECISION DRAFTING SET 11 In full -wave oper- $14.95 Pieces -Fitted Felt-Lined Case high output current. Made In Germany, of heavy brass, nickel with a supply voltage of 300 per ¡Brand new, in original Western plated and polished. Instruments in ation Electric's jeweler's case. Sup- elude I We" Compass with pencil and pen plate, the 5AU4 can deliver a d.c. out- plied with receiver. receiver points and lengthening bar. 51/4" Di- I cord, battery cord and plug j Older, three 33/4" sidewheel bow dividers put of 350 ma. (less batteries). with needle point, pen point and pencil d Money back guarantee. ct now w hile t h point. 5" Ruling pen, extra handle for The 6AR8 is a miniature double -plate or capsule d last! Uses Burgess xx3OE aneyd pen pencil, with extra leads. Interchangeability of these many parts sheet -beam tube. A pair of balanced 1 SR batteries at $1.55 set. per makes this an exceptionally versatile set. Your money back-if this set is not deflectors direct the electron beam to IIOTO AUTOMATIC HACKSAW worth twice our price! either of the two a I Flu any Y," Electric Drill. Cuts F-I3 Not 2.75 plates and control t any wood, metal or plastic up to grid varies the intensity of the beam. %'e. There are ne gears or bear - !Write for free rill:d og. ]ngs to wear out! Saw blade fs NEW YORK,N.Y. 100 Sh th Are. These characteristics of the tube make only exposed moving part. Folds 11! to 1 "x1;4 "x4 any tool boa. (1 " -fife ae BRONI,N Y. 542 E Fordham Rd it especially suited as a synchronous Lies suoverd heckeaw blades. r e Bundle covers and protect. saw NEWARK,N I. 24 Cenlnl Are. detector in color TV receivers. blade when In t not use. Shpg. PLAINFIELD,N.I. 1 139 West 2nd St. ei. 1 lb. In this application, relatively large, -60 DEPT. J E HD NET 3.12 80ST01191ASS. 110 Federal St. balanced output signals of both positive and negative polarities are developed which eliminate the need for phase- RADIO -ELECTRONICS

www.americanradiohistory.com NEW DESIGN 107 inversion in the matrix circuits. Other features of the 6AR8 detector SUPERIOR'S NEW MODEL TV -40 circuit (see diagram) include low oscillator injection power requirements, freedom from space- charge coupling ef- C.R.T. TUBE fects, and linear output voltages. TESTER A complete picture tube tester for little more than the price of a "makeshift" adapter!! Tests all magnetically deflected tubes . . . in the set . . . ou of the set - . . in the carton!!

SPECIFICATIONS. Tests all magnetically deflected picture tubes from 7 inch to 30 inch types Tests for quality by *INTERNAL emission CONNECTION the well established The circuit diagram shows two 6AR8 method. All readings on "Good - tubes used as synchronous detectors. Bad" scale. Tests for inter - element shorts and leakages up to The 6BÚ5 is a low- current, high - S megohms. Test for open voltage beam pentode designed for use elements. as a shunt voltage regulator in the high -voltage power supply of color TV EASY TO USE Model TV -40 C.R.T. Tube receivers. Simply insert line cord into any 110 attach tester Tester comes ab- volt A.C. outlet, then complete G -E is producing hermetically -sealed socket to rube base (ion trap need solutely tube). Throw switch up nothing else to NET ceramic germanium diodes. Although not be on buy. Housed in for quality test . read direct on cornered, Good -Bad scale. Throw switch down round for all leakage tests. molded bakelite t case.

Write Dept. RC -5 for catalog of complete line. SUPERIOR INSTRUMENTS CO. 2435 White Plains Road New York 67, N. Y.

RECOGNIZE TELEVISION TROUBLES At A Glance!

e e e FIX 'EM TWICE AS FAST! Hermetically- sealed germanium diode. the announcement listed only three HANDLE 90% OF TV REPAIRS BY EASY PICTURE ANALYSIS looks the on a The of picture to minutes. Repairs are mode receiver . or bad television fast, easy and right! the lack of any picture at all can usually tell you in a WORK BETTER AND FASTER! jiffy what is wrong. PIX -O -FIX Troubleshooting Guides not only The two PIX -O -FIX Guides make this easy, but also show cover 47 different kinds of IV

just where and how to make trouble . . lust about anything repairs. you're likely to be called on to Just turn the PIX -O -FIX dial fix. Operation is simple and until the picture appearing in easy. its "window" shows the some Remember! PIX -O -FIX Guides trouble symptoms as the picture are NOT "gadgets." They're TV TROUBLE in the set you're repairing. practical, professional servicing PIX -O -FIX then tells what is devices by two of America's FINDING GUIDES likely to cause this trouble and best -known servicing authorities. gives step by step repair Our money -back guarantee pro- by Ghirardi and Middleton structions. Testing time is cut tects you fully! on Don't guess . don't waste time /0-DAY MONEY-RACK GUARANTEE Experimental high -power transistor. television receiver repairs! Cut service time in half on 2 jobs out of three! Dept. RE -54, Rinehart & Company, Inc. 1N69, 1N70, 1N81, 232 Madison Ave., New York 16, N. Y. JAN types, the and 24 of the PIX -0 -FIX No. 1- Identifies Enclosed find $ for which please rush the following: it stated that within a short time, most more common television receiver troubles PIX -O -FIX No. 1 ($1.251 PIX -O -FIX No. 2 ($1.251 G -E diodes will be hermetically sealed. by actual TV screen photos. Gives 194 causes and 253 remedies for these troubles. Both PIX -O -FIX No. 1 and No. 2 at the special Transistor Products, Inc., Boston, has Price separately 51.25. price of only $2.00 for two plus postage announced the availability of an experi- If not satisfactory, I will return PIX -O -FIX postpaid -power transistor. Desig- PIX -0 -FIX No. 2 (Just out! ) -Covers 23 in 10 days and you guarantee to refund the purchase price mental high additional troubles not included in No. 1 nated as type X78, it is a p -n -p diffused with accurate repair instructions. To Name gefher, the 2 volumes are a practical junction transistor. The X78 can be guide to "picture analysis" servicing of Street I used in matched pairs in class -B audio any TV set. Price 51.25 separately. and will provide a power City, Zone, State I amplifiers, Get both at only $2.00 OUTBID E U.S.A. s I.50 each. $2.50 for both. Same return privi lege. I gain of 10 db at room temperature. END SPECIAL'! for the two. Use coupon. MAY, 1954

www.americanradiohistory.com 108 WITH THE TECHNICIAN

RECEIVES AWARD Recipient of the first annual award of the President's Cup of the National "SAVE ON AUTO RADIOS' Alliance of Television- Electronics Serv- Also Kifs & Wired Units at LOWEST PRICES ice Associations is Fred Colton (left), chairman of the board of the Associ- ated Radio and Television Service Deal- ers of Columbus, Ohio. Making the SPECIAL! presentation is Frank J. Moch of Chi- CUSTOM AUTO RADIOS; cago, president of NATESA. FOR ALL CARS 1949 thru 1954 Models 5 Tube AC /DC Superhet Kit Kit -1.5 tube , uperhet kit, Am VD(' Custom Built dudes all quality components required to construct this latest design, highly Complete with 6 tubes sensitive Superhet broadcast receiver. 3 -Gang complete with black, glistening Bake- Condensers lite cabinet (excludes wire & solder). 4- Minute installation Kit of 5 tubes. 12AT6, 2 /1211A6. - 12BE6, 35W4, 50B5. no holes to drill Price. Less Tubes $9.95 Great Value Extra for Tubes 53,95

Ford: '49, '50, '51, '52 Terrific Value! Dodge -Plymouth: '49, '50 Dodge: '51, ,52 ,e. Chevrolet: '51, '52 iY. Hudson: '4$, '49, '50, '51, '52, '53 Studebaker: '50, '51, '52 Henry J: '51, '52 Willys: '52, '53

cavinrest Chevrolet: '49, '50, '53. Plymouth: '51, '52, g S g6s! -TUBE RADIO KIT '54 '54 J Kit #2: Low priced 6 -tube kit de- The President's Cup was presented Ford: '53, '54 Dodge: '53, '54 signed for extra high sensitivity. ex- to Colton "because of his zealous work Studebaker: '53, '54 Mercury: '52. '53, '54 cellent selectivity and good. rich tune Quality. Uses 25L6, 25 %6, 65(17. on behalf of NATESA during the year Indicate make and year of autontohile when ordering 6SA7, 2/6SK7 in an easily constructed circuit. Includes all parts: 1953, especially for his efforts in the punched chassis, resistors, condensers. coils, sockets, I'M speaker, hard- interest of the NATESA annual con- $2495 ware, etc. vention in UNIVERSAL Special closeout price. Chicago." AUTO RADIO (Less tubes & cabinet) $6.95v Earle FITS ANY CAR UNDER DASH Vlatched set of G tubes MOUNT Special! kit $3 25 RRuuu SERVICE AT ITS BEST RRuu A splendid example of an attractive SPECIAL Tube Offerings and businesslike shopfront is this display window of Rhodes Television STANDARD MAKES GUARANTEED FIRST GRADE Service, OA2 6F6 .. Paterson, N. J. The proprietor, .$ .75 .45 14E6 . .45 2021 1633 .. .45 . .95 6J5 .. .45 2807 .95 1644 .. .65 3A4 . . .55 6J6 .. .55 30 . .65 2050 .. .95 5Z3 . . .75 6K7 .. .45 39/44 . .25 5686 . 1.95 524 .75 CK5702 .75 6L7 .. .45 RK34 . .25 6-48 . .15 5814 .. 6N7 .. .65 VR90 . .95 1.95 SAGS . .65 6095 65C7 .. .45 VR1OS . .75 6AJS . .75 (6AQ5W) .45 SIGNAL GENERATOR 65G7 .. .45 89 . . .35 6AK5 . .65 6097 BROADCAST . 6V6GT . .55 211 BAND 6AQ5 .45 . .45 (6AL5W) .45

.35 12AU7 . .65 . 688 . 958A .55 6101 Completely Wired-New, simplified 68A6 12K8 . . . .35 1626 .25 circuit provides the following switch 6C4 . .45 12SG7 . .65 1632 . .45 6CÚ6) . .2.69 tuned, tone modulated frequencies: 1. 455 KC- Intermediate IF frequency 2. 1500 KC-Ill freq. of b'cast band Save More Than Half 3. 60(1 KC -Lo freq. of beast band 4. Audio tone for audio amplifier trouble shooting 5. Attenuator control is included for COMPONENT KITS adjustment of the output signal Paper Tubular By -Pass strength. INSULATED Housed in small, black Bakelite cabi- CONDENSER KIT net, 6"x6 "x3 h ". Excellent for align- RESISTOR KIT ment of all Broadcast Band R,,lin $10. Value-Now $1.65 Worth 51 5-Yours receivers. $7.95 for 52.95 Completely Wired-only.. Includes 100 resistors /, 1/e. Includes 30 by -pass c xfen- 1 & 2 watts from 5% to 20% sees ranging lu capacity from .00o mfd. to mfd and t 3 -TUBE tolerance. Comes in transpar- voltages from 200 to 1000. ent plastic box. New low Complete with transparent Harold "Dusty" Rhodes, is president of plastic cabinet 7 s :112" PHONO price. No. D 1273 $ 1 EDLIE Spe- the Radio -Television ial No. D 1278 $2.95 Service Associa- Complete 1.65 Complete AMPLIFIER Ck!A tion of New Jersey and Eastern NOT A KIT secretary of NATESA. DISC PRECISION An assembled unit ready for installa- RESISTOR KIT tion using tone and volume control CONDENSER KIT and G ft. rubber cord $2,95 Consists of 50-17 Wilknr (less tubes) Save over 57 earbofilm resistors of 50 dif- Lowest Price! PROMOTES SAFETY ferent ohmages, housed in a With comptele yet of mhos ....$4.45 Includes a. s,rtuu ont of 50 disc transparent plastic box. May Service technicians working for the eeramicons including the fol - be combined in serles or paral- lowing capacities: 001, 2 x lel to produce almost any de- Central Television Service of Chicago sired ohmage. .001, .0015, 2 x .0015, 2 x Each resistor PHONO OSCILLATOR retails for about 85e. may be called upon to take the hinges .004, .0047, .005, 2 .01, x .005, Terrific Cash Saver! NEW SAVINGS! NOT A KIT! off a 2 x .01 PLUS 10 assorted Kit of 50 Wireless phono oscillator transmits refrigerator, in addition to a printed .circuited .capacitors only $2.45 recording for crystal pickups or voice number of other duties. complete in a plastic trans- from carbon mike through radio All without wires. Can also be used as The company is parent box. Sells for $10. TERMS: mdse. shipped making available - Esili New York prices intercom by EDLIE saves you over $7. City. an using PM $A subject lu change without no- speaker as mike. 95 as a public service -its 150 service tech- No. D 1279 tice. Include 20r7e deposit for LL COD's. WRITE TODAY FOR (less tubes) nicians to make safe any abandoned Complete kit:... $2.95 NEW FREE CATALOG! With complete set of tubes . $3.95 ice boxes called to its attention. Chil- 154 Greenwich St. dren who play in the neighborhoods will then be unable to lock themselves EDLIE Electronics DI 9-3143 accidentally in these boxes, as has hap- New York 6, N. Y. pened in a tragic number of cases. Central Television Service asks any in- RADIO- ELECTRONICS

www.americanradiohistory.com 109 01650 p COMPATIBLE

Another HICKOK First ... The Model 650C is another example of HICKOK pioneer engineering and originality in test equipment design to meet the practical necessities of TV maintenance.

NOTE FOR VALUE .. . MODEL To the thousands of you who already have a Model 650, you will appreciate knowing that its For Color TV .. . 650C design is so complete that only a simple conver- The new 650C is an absolute sion is necessary for color use. This conversion must for accurate registration adjust- is from assembly, completely wired, available ment of the three color guns in the tube the factory for $5. You can add this assembly to the new color TV receivers. your present 650 in a matter of minutes and thus of all features of the latest convert to provide Simple to Use . . . Dot Generator for Color TV, Model 650C White Just connect to the antenna of the color TV receiver as well as retain the black dots for block and 650C to produce WHITE DOTS on the white receivers. and adjust the screen. Adjust color guns until colored fringes dis- You can always count on HICKOK engineers to appear from around the white dots. With the 650C, make special efforts to keep your present equip- color register adjustments are a fast and easy job. ment up to date and operating to full specifica- Without the 650C ... a near impossible task. tions. It is interesting to note that due to HICKOK The 650C provides the means for accurate adjustment engineering cooperation many HICKOK testers, of Focus Convergence Centering of Individual well over 25 years old, are still delivering top Beams Purity Yoke Dynamic Convergence Lin- performance in everyday use. It is policy such as this that has contributed a great deal to the earity and Aspect Ratio. HICKOK position "First in Preference ". present of In Addition . See the complete HICKOK line at your nearest The 650C is an excellent instrument for fast Radio Parts Jobber ... and write today for the troubleshooting in black and white re- new HICKOK Equipment Catalog No. 29. ceivers ... and includes all features of the present 650 model. MODEL THE HICKOK ELECTRICAL INSTRUMENT CO. 650 C 10531 Dupont Avenue Cleveland 8, Ohio MAY, 1954

www.americanradiohistory.com 110 WITH THE TECHNICIAN

dividual who sees an abandoned box to PRECISE - THE FASTEST- GROWING phone its dispatcher, and a service KIT MANUFACTURER IN THE WORLD technician in the same neighborhood will be made available on an emergency basis. The versatile service technicians of Central TV will not be at a loss on KIT AND WIRED their new job, as many of them have been trained in the company's other INSTRUMENTS services, which include air conditioning, piano tuning, and master antenna installation and maintenance as well as the more familiar TV and radio repairing.

CITY REGULATES ANTENNAS MODEL #308 A windstorm last January, which blew down several hundred TV antennas, is 8'/2" credited with the recently passed San Bernadino (California) ordinance requiring a permit for erecting TV an- SCOPE tennas and setting specifications for their construction and installation. Sev- KIT 512950 eral of the antennas fell across power ,j J . ft308W $229.50 fire lines in the storm, creating hazards No other oscilloscope, and danger to life. at any price, can to be of stand- meet all the specifi- TV masts are required cations of this elec- ard gauge galvanized steel or double- tronic masterpiece. strength aluminum tubing. Four guys VERTICAL FREQ. RESPONSE -Flat ± 11/2 db are to be used, and anchorage points DC thru 5 MC. must be more than half the antenna SENSITIVITY - Greater than 10 millivolts height away from the base of the mast. push -pull (3.9 Millivolts/CM) BLANKING -60 cycle or 120 cycle Blanking Ground installations must have a con- through Blanking amplifier circuit. crete base not less than 12 inches square SWEEP RATE -Linear sweeps from 1 cycle and buried not less than a foot in the to 80 KC in 5 ranges. (1.10 uses Ext. C.) DRIVEN and RECURRENT sweeps. ground. All free- standing masts must MAGNIFIER -Expands and magnifies signal Gives you facts that save be installed according to plans signed up to 10 times. you time and money while by a registered engineer and approved PUSH -PULL- Output in both amplifiers. by the city building inspector. CRT - The latest type 81/2" NEW tube a PRECISE troubleshooting - help To erect an antenna, a permit must EXCLUSIVE. eliminate VOLTAGE REGULATED. call -backs be obtained from the chief building in- ANODE INTENSIFIER -a PRECISE FIRST. A $2.00 is Here's a handy working tool. It puts spector. fee of charged for INTERNAL CALIBRATOR practical service dope right at your each installation. NEW 7" OSCILLOSCOPE fingertips where you can always find it. MODEL #300K. $94.95 It gives you information you can't ARTSNY SEES COLOR MODEL .#300W..... $199.50 afford to be without today. Over 36,000,000 Centralab Printed Electronic One of its biggest meetings in several Circuits ( PEC's) are now in use in years was the first lecture on color held today's radio and television sets. by the Associated Radio -TV Service- LOWEST PRICED IN ITS FIELD Just look at the "meat and potatoes" men of New York (City) March 18. between the covers of Guide No. 3: The large ARTSNY headquarters hall #EIY MODEL #909 Lists 127 radio and TV manufacturers was crowded before the meeting was and their PEC applications -showing VACUUM TUBE VOLTMETER Nearly 400 were present, part identification number, manu- due to start. ORt facturer's part number, and Centralab and over 300 had to be turned away at $3750 catalog number, the door. A number of technicians and / Shows circuit schematics that guide engineers of TV and radio concerns Model 909 Vacuum Tube Volt- you in using PEC's to replace the meeting, as meter. 1% Ceramic precision standard components. were also present at Resistors; Coax DC connector; well as representatives of several radio FM zero alignment scale; burn- Tells how you can easily check The out proof circuit; DC input 25 Centralab PEC's with a VOM and and TV magazines. meeting was Meg. Rugged oversize 41/2" simple 60-cycle capacitor bridge. presided over by Max Liebowitz, and meter. MODEL #909 KIT ... $25.98 It's easy to get your free copy of the Lewis Winner acted as moderator for Centralab Printed Electronic Circuit the lecture during the question-and-an- Guide No. 3. Just fill in and mail the swer period. coupon below today. *Trademark A new Westinghouse color receiver OTHER PRECISE TEST INSTRUMENTS AVAILABLE SEE us AT aOOTN 790. was present on the platform, and field 10¡ 9071 -71/4" VTVM with VR -Kit $35.95 Wired $49.95 -[ `v 1 4 no, 17.2e CHICAGO engineer Gordon Jolly demonstrated 610-RF SIG. GEN.-Kit $23.95 Wired $39.95 630 -RF -AF TV MARKER-Kit $33.95 Wired $53.95 color problems and color adjustment 303-3" PORTABLE SCOPE -Kit and Wired 760 -- VOLTAGE REGULATED POWER SUPPLY -Kit with the aid of a Hickok white -dot gen- $39.95 Wired $59.95 The large crowd made demon- I I I -EM -GM TUBE TESTER- Kit$69.95 Wired$139.95 erator. 912 -RE PROBE -Wired and Calib. $4.25 CENTRALAB, A Division of Globe -Union Inc. stration of adjustments on the purity 960- 10.1 CA. PROBE -Wired $5.95 999 -HIGH VOLTAGE PROBE -Wired $6.95 922E E. Keefe Avenue, Milwaukee T, Wisconsin coil and similar manipulations impossi- Send me a free copy of the new 1954 ble, as few could have seen what was See our exhibit BOOTH 130 at the show edition of the Centralab Printed Elec- Mr. made up for that, tronic Circuit Guide No. 3. going on. Jolly SEND FOR YOUR FREE 1954 DESCRIPTIVE CATALOG however, by going through a large num- Prices slightly higher in West Name ber of adjustments which produced an Company effect on the tube face. Most of these could be seen at a considerable distance. p7M7"- Address Some other points were explained with DEVELOPMENT CORP. City._. Zone State the help of a blackboard during the ! Y -5354 question period. END OCEANSIDE, NEW YORK RADIO -ELECTRONICS

www.americanradiohistory.com service To build a healthy, rowing bus ¡ne

YOU NEED THESE 6 NEW

SERVICE ITEMS NEW WALSCO CLEAN-O- MATIC... Covers contacts on "Standard Coil" tuners and kreps them clean, silent, oxidation -free. Very e2sy to install. Tube of "Tunerlub" and crocus cloth included. CFt. No. 1200 $1.50 net

NEW WALSCO REEL -EASY Portable wire reel holder. Light, durable, compact- weighs only 11/2 lbs. Handy to carry, easy to dispense lead -in wires. Eliminates tangled cables. Cat. No. 503 $3.60 net

NEW WALSCO FEED -THRU BUSHING Bring antenna cables into the house the professional way. This bushing fits all lead -in and rotator cables. Terminate "open line" outside... NEW WALSCO VIEW BINS bring flat line through bushing to set. Fits walls handy, visible and Keeps small parts sorted, up to 16 ". Requires 3/4" hole. . dust -free. Sturdy, tilt -type, spill -proof drawers Cat. No. 1551 $1.17 net reveal contents. No hidden corners. Silver ham - mertone finish. Welded steel. Cat. No. 1010-6 bin $4.95 net Cat. No. 1010-12 bin 9.50 net Cat. No. 1010.24 bin 16.95 net

NEW WALSCO TOOLS New I.F. alignment tool for all UHF RCA, Zenith NEW WALSCO GUY -TITE and other sets. Tighten guy wires faster and better with this net Cat. No. 2527 $0.42 Does /of a turnbuckle at new Walsco tool. the job "Slug Saver" front end alignment tool for all a fraction of its cost. "Standard Coil" tuners. Impossible to lose slugs Cat. No. 1568 Box of 100 $3.60 net Tool and 18 titer 4.95 net with this patented tool. Cat. No. 1566 Cat. No. 2528 $0.63 net Solder -ease tool. Bristles of brush and prongs of stainless steel. Solder will not stick. Cat. No. 2529 $0.99 net IaIIúaOMtt 3602 Crenshaw Blvd. Los Angeles 16, Calif

Canadian Factory Distributor: Atlas Radio Corp., Ltd., 560 King St. WE ;t, Torontc 2 -B. Overseas Distributor: Ad Auriema, Inc., 89 Broad St., New Yort 4, N.Y.

www.americanradiohistory.com NEW PATENTS

TAPE RECORDER EQUALIZER Patent No. 2,658,958 STAN-BURN Lawrence V. Wells, Charlotte, Mich. (Assigned to Wilcox -Gay Corp.) Tape requires a special type of equalization. It has a maximum response near 2 kc and the rolloff differs on either side of this frequency. The inven- * CATHODE RAY TUBE SPECIALS tor has designed a simple ONE YEAR GUARANTEE network that provides G, E. STAN -BURN flat response from below 70 cycles to above 7 kc. * 7JP4 $17.10 10BP4 $10.50 l OBP4A 19.25 12LP4 12.50 1OFP4A 24,00 12LP4A 14.50 12 KP4A FREQ DISCRIM. NETWORK * 27,10 12QP4 12.50 * 12LP4A - 21.70 12JP4 12.50 12QPAA 61013 12UP4A 15.00 * Dumont .. '21 -:00 14CP4 17,00 12ÚP46 28.75 150P4 18,50 * 1C4 24,50 16KP4 ay-tp ,* 145DPP4 8 '1014 16DP4 or A , 18.50 Dumont 23.75 I6AP4A -,., 16JP4 or A 18.50 * 30.95 16CP4 or A . -. 18.50 * 16DP4A (N.0 i 25,25 16FP4 18.50 16GP4 or B 31.25 16WP4 18.50 * 16KP4 16RP4 . 24.20 16AP4 19,00 36KP4A 16AP4A 23.00 * (Aluminum) . 28.75 16EP4 19.00 * 16JP4A (N.U.) , 25.25 16EP4A 23.50 16LP4A 28.50 16GP4 or A .. 21.00 * 16WP4A 26.50 17BP4 19.50 * 16GP4B 31,25 17CP4A 21.60 17BP4A 24.00 1;41,44/3 * 17CP4 23.90 22,60 * l7(Aluminum) 23,00 29.00 19FP4A 24,00 * 19ÁP io 43.50 19ÁP4 23.90 * 20CP4 ;4.50 19AP4A 24.90 * Fig. 1 shows the basic idea. A network couples 20LP4 37.50 20CP4 26.00 the speaker and a previous stage. By tuning this * 21 AP4 42.00 23 EP4 26.50 * 2IEP4A 36.35 21ÁP4 26,50 network we have various degrees of degeneration 24ÁP4Á 78,50 24ÁP4 49.00 over the audio spectrum. A typical network is * QUANTITY CRT USERS * shown in Fig. 2. Here L -Cl is series -tuned to the We will give you DUD al o ces if you ship then, * to us Prepaid. 10 CRT's minims shipment. WRITE frequency that needs minimum gain, near 2 kc. At FOR DETAILS. * this frequency the network has minimum impedance, therefore maximum degeneration. This * ANTENNAE SPECIALS means low gain. Above and 2 RED DOUBLE 6 or m e * below kc, the im- 'V" Antenna 2.1 1-59 1.98 r WORK BETTER, FASTER WITH pedance rises and the phase angle grows, 10 ELEMENT thus DOWeed lnrghtt° 2.98 2.79 the gain is higher. * Folded Hi Straight Low Quick Rig " elements 4,25 3.25 FEWER INSTRUMENTS! * WINDOW CONICT LS .. 4.95 3.75 5 FOOT * MASTS 10 FOOT E Test instruments are plenty ex- l!1.1011"1 PLAIN ..., 1.39 1.29 CI L * NEPCO MASTS 1.69 1.49 pensive these days . . . and that's rr= 42 Mil $9.95 M Mt. not all! TV WIRE 55 Mil. 300 OHM 11,95 M Ft. 72 OHM COAXIAL 35.00 M Ft. * No sooner do you buy one new CHASSIS 630 TECHMASTER instrument than Tun ther type comes Model C -30 with Cascode Tuner ~f OPEN FACE CABINET S149.50 ,k along 542.00 that is said to be even bet- w- _ -R ter and more useful. -YY- * TAPE RECORDERS IN STOCK You soon realize you've got to Fi .2 PENTRON -Model 9T3C- * corder J- speed '''ape lie- draw the line somewhere! * RADIO CRAFTSMAN Write for Price. * L -C2 is tuned to a 6 The answer is to really learn high frequency near or 7 model C400 -ni Fi Amplifier vet 542.90 Model ,- -t's1 kc. The high * C10- tsi 'rttn er , , , , . , Net 131.50 about instruments to KNO \V exactly what each impedance makes for lose feedback Model MAS * iamsoli Ampilfler. , Net 99.50 type CAN and CANNOT do. Actually, you can do and high gain at these frequencies. This raises e also c Cry MASCO- BOGEN -PILOT, ,tc, Am (ices- Pre -Amps, FM Tuners and WEBSTER first class work with only a comparatively few basic the high- frequency gain more than the low -fre- *wRecorders. Tape instruments , and you can save hundreds of dol- quency, and we have an amplifier characteristic * 6 "x9" PM SPEAKER $3.98 lars by learning to use old instruments more fully. as shown by the 7" PM SPEAKER * dotted line in Fig. 3. This corn- 70' Yoke 3.98 Remember! It isn't so much the instruments 1 9B you * 630 Vert. Output Upright 1,98 use . its the inntrun7ent "KNOW 'HOW' that IS 630 Vert. Output Potted 1.29 * counts! And that's where this famous book can he 630 Vert. Blocking 05f. Xform. * E TUNERS 17.95 worth its weight in gold to experienced radio -TV 10 111MMOa DUMONT 21.25 14,95 men and beginners alike' Famous INPUTVNER 30.00 * TV Permanent Magnet Focus Assembly 1.98 ó 5 011.,.'i * I THREE SPEED RECORD PLAYER * GET MORE WORK in portable OUT OF NE/1M carrying case. Special.. $39.95 I * 20CP4 Progressive Special $23.95 * YOUR OLD INSTRUMENTS KVnrad,RT -S 10 E11111i111I\ * ng ISTNago BOi RUnion, Den Wa IdE l Regal' Automatic and General Motors. * BASIC ELECTRONIC TEST INSTRUMENTS by Rufus Turner covers instruments and test equipment 15 * AUTOMATIC CUSTOM -BUILT RADIOS for Plymouth, * 50 70 100 200 400 700 ih 2K 4K 7K Ford, Chevrolet and many others, always in Stock. from a practical, on- the -job standpoint. No useless We carry stock of FREQ-CPS * HI-FIDELITY anda . theory! In 255 pages and with more than 170 SOUND EQUIPMENT. Send uss yarr akescofs. FII.3 also carry a complete line f popular makes of Radio illustrations it shows you how to select the right in- * tubes 50 10(,o discount. Also other special struments and how to use them on all kinds of earls a and transmitting west, and all end ( ra and equipment u jobs. pensates for the typical tape is earls lowest prices, Send curve which * of your r for prompt quotations. It shows how to modernize old types and use them shown by the solid line. R controls damping of Terms: with order. t once COD. All prices in new ways. It helps you avoid buying unnecessary FOB. NEW YORK price. Minimum iFi the network. It determines the degree of equaliza- * for e fur our latest price list antl HiFi CatalogCata loo instruments: teaches you work- saving testing short tion is, the rate of change of to Dept. RE .S. cuts; shows how to evaluate instrument readings fast -that the curve and accurately. slope. RADIO Over 50 types . . from the latest TV sweep, The degenerative network also acts to lessen and marker and linearity pattern generators to grid -dip distortion and flatten out any undesirable peaks STAN -BURN ELECTRONICS CO. oscillators. special- purpose bridges and all the old that may exist. (C.R.S. THEATRE BLDG.) standbys from V-0-M's signal generators to oscillo- 1697 BROADWAY NEW YORK 19, N.Y. scopes and dozens more . , are fully covered in a was you can easily understand. FLAT DRY CELL Written especially for servicemen, students, ama- Patent No. 2,666,802 teurs and experimenters. BASIC ELECTRONIC TEST INSTRUMENTS is the only book of its kind. William B. Woodring, Hamden, Conn., and It saves you money , helps you earn more money RADIO -ELECTRONICS is paying he helping you work better. faster and more William W. Eaton, Milford, Conn. accurately! Price only Si.lut (.5L50 outside U.S.A.). (Assigned to Olin Industries, Inc., New Haven, good rates on acceptance for origi- Conn.) nal and unusual articles on audio, This invention is a new dry cell made of flat television, FM and AM servicing, as elements to take up very little space. Elements are heat -sealed to each other. well as articles on industrial elec- In spite of the small size of this cell, it has Dept. RE -54, Rinehart & Co., Inc. tronic equipment and applications. 232 Madison Ave., New York 16, N. Y. remarkable energy content, due to the large active area and to low s,'d Turner's ?- -pege BASIC ELECTRONIC the resistance between ele- Send for a copy of our Authors' TEST INSTRUMENTS book for 10 -day FREE E1- ments. A typical cell, G inches in diameter, and A ITINATION. If I decide to keep hook, I will then .012 inches thick, showed the following charac- Guide. Address: remit $4.00 ohm a few cents postage. Otherwise. I will teristics: : return book postpaid promptly and owe you nothing, Open- circuit volts, 1.81. THE EDITOR Same With 0.75- ampere load, the terminal voltage was 1.52. Address After 30 minutes of continuous discharge, the RADIO -ELECTRONICS output voltage was 1.18 at 0.58 amp. City. Zone. State This cell is protected against drying out be- 25 West Broadway, New York 7, N. Y. OL-TSIC)E I..S.A. -Pr ire 51.50 rash only. Money back if honk i' rolnrn,"I in to ,lay,. cause there is practically no path through which moisture may be lost. RADIO -ELECTRONICS

www.americanradiohistory.com 113

offers

1. SUPERIOR QUALITY All Aluminum, All -Weath Construction - Quality first is the Telrex pledge. Extra rugged all- aluminum FOR ULTRA -HI construction includes GAIN ON UHF design with precision parts MODEL 84 fabrication for lasting installations. "CONICAL -V- Wherever feasible, Telrex pre - BEAM" assemblies at the factory to save Four bay you time and money directions at the site. All in -ph édition at all fie- quencies wi splitting uminum light weight and rugged

2. SUPERIOR RECEPTIO

"Better By Design "... Rain or Shine -For UHF or VHF you can depend on Telrex For clearer, sharper pictures... finer sound reception. Near or far - city, suburb or rural area there's a Telrex model FOR UNIF - CHANNELS 2 to 83 engineered for your par- DUO -BAND "CONICAL -V- BEAM" ticular locality. Over Uniformly Hi -Gain 60 antenna type Excellent Directivity are included in th Automatic Transition From UHF to VHF new Telrex catalog. Write High Signal -To- Noise Ratio for your copy, today! VISIT BOOTH 675 PARTS SHOW FOR THE UL 1954 ELECTRONIC CONRAD HILTON HOTEL, IN LONG DIST CHICAGO, ILL. May 17Th to 20th RECEPTION T V- Beoms" TELREX "Conical- are Produced 4 BAY under Re -issue "CONICA Potent Number 23.346 and BEAM" SE told only thru authorized The ultimate distributors distance al Guaranteed t perform any or combin cut- to -frequ h. tennno. Wh `sed with DuoBand AMERICA'S splines, it comprises STANDARD OF the ultimate from COMPARISON Ch. 2 to 83. Un- 9 equalled for recep- ASBURY "PARK tion to 200 miles. NEW JERSEY COMMUNICATION the MAKERS "'BEAMED POWER"

MAY, 1954

www.americanradiohistory.com NEW PATENTS

TRANSISTOR SIGNALING Patent No. 2,666,812 If you want Reymond J. Kircher, Summit, N. J. (Assigned to Bell Telephone Laboratories, Inc.) Transistors have found many applications in professional land -line telephony. sound quality Here is still another-it is used to replace the bell or buzzer in signaling. Although power consumption is very acoustic low, an level of about 25 microwatts is available. Sound engineers This is sufficient know that the selection of a fine for a clear, audible tone. The diagram shows the arrangement amplifier, typical for a pickup and speaker system is only part two -party line. A central-office battery.

STATION I of the STATION 2 story; that unless the turntable is of equal _tar,- IKa quality, music reproduction 200- COIL must suffer. That is 5 -I 5K why .5 "1-\i\ they insist on such high standards for turn-

\ . I table performance. 1.500 do as the professionals do... 20K LINE Rek -O -Kut precision turntables are made to conform to the highest standards in the professional field, and they certainly represent the finest you can use in the home. A Rek -O -Kut turntable will make all the difference in the world. The finer your CENTRAL OFFICE BATT. ©20C.PS. GEN. present system, the more in .ecies with a apparent the improve- 20-cycle ringing s tpply, feeds power through the telephone line ment will be. Whether you Pulsating to subscribers. select the deluxe T -12H rl.c. flows through a two- fier section recti- at each of the two stations. With the switch or the standard LP -743, the entire s in either performance of position, the rectifiers at one station Will be biased for conduction. your sound system will become At this station, the a new and thrill- ringing current will be shorted out and excite its cannot ing experience. transistor. The rectifiers at the other station are oppositely poled and cannot rectify. The ringing current will be fed use contact to the point - a transistor circuit, which oscillates about 500 at cycles. The position of S which determines station will be called when ringing current is applied to the line. The circuit shown is suitable for point- contact REK transistors. A junction type -O -KUT may he used in a modified oscillator circuit. precision turntable TRANSISTOR "FOLLOWER" Patent No. 2,663,796 Gordon Raisbeck, Morristown, N. J., and Rek -O -Kut Precision Turntables are Robert Lee priced from Wallace, Jr., Plainfield, N. J. (Assigned $59.50. Write for specifications and descriptive to Bell Telephone Laboratories, Inc.) The literature transistor is the dual of a tube. This means to Dept. 1 -13 that semiconductors behave with respect to current just as tubes do with respect to voltage. The new circuit was designed to be the dual of a tube cathode follower. It provides considerable power gain and handling capacity. Its input resistance is very low. its output resistance high. very It has less than unity current gain but The REK -O -KUT COMPANY considerable voltage gain. Manufacturers of Professional Disc A phase reversing transformer couples the Recorders and Specialized Sound Systems. put to in- the emitter. The signal may be a.f. 38 -01 Queens Boulevard, r.f. The or Long Island City 1, New York diagram shows polarity at a particular Export instant. Due to phase Division 458 Broadway, New York, U.S.A. Cables: Morhanex reversal, the emitter re- In Canada: Atlas Radio Corp., Ltd., ceives a positive signal. Conduction increases 560 King Street, W., Toronto 28 and the impedance between collector and base becomes smaller. Now the input voltage is the sum of the load voltage and the collector -to-base FIRST voltage. The first of these increases, while ... CHOICE second the with decreases. Thus the net input voltage (for anv given signal current) is small. The input current It is the sum of two rents. cur- servicemen because One is the load current 12. The other current flows through the transformer primary. Obviously Fenwire is BEST by TEST t 12 is smaller than I,. In spite of this. IN OUT

RFC *FENTUBE- AIRSPACED and TWISTUBE outstanding are for high performance -low loss stable characteristics under - t conditions- all atmospheric reduced interference pick up -reasonable price. I2

Write Dept. RE -5 for literature power gain does exist because the output resis- FENWIRE on complete tance line including "TUF -GUY" finest is so much higher than the input resistance. guywire made. ... The input resistance can be controlled by adding a resistor in series with the base. (Sold through jobbers In a typical only.) case, a transistor connected as in the diagram *U.S. & British Pot. had Pending an input of 71 ohms. Adding 800 ohms in series with the base FENTON COMPANY 15 Moore lowered the input value to Street, N. Y. 4, N. Y. Tel. BOwling only 3 ohms. Green 9.3445 END RADIO -ELECTRONICS

www.americanradiohistory.com 115

YOUR BEST BET for BLACK & WHITE and COLOR TV

RCA WR -89A Crystal -Calibrated RCA WV -97A RCA WR -59C Marker Generator Senior VoltOhmystR Television Sweep Generator

vide the flatness of color receivers, all COLOR In SIGNALS and crys- sweep output I.5Mc of the color information r COLOR tal accuracy that are is contained in the re- SUBCARRIER 0.5 I.5 for aligning r essential 2.4Mc gion from about 2 Mc Mc Mc-.1 PICTURE/ CARRIER color circuits. to 4.1 Mc on the over- -ilk00t) ND CARRIER In color receivers, all rf-if response curve, of there are a number I Response shown in Fig. 1. Any Fig. 3. Channel as Fig. I. RF -IF Response -frequency sec- in this re- video loss of gain including the video amplifier, the bandpass weaken the color signals. If the loss is tions, gion will I and Q channels (See Figures 2, 3, 4), it may result in such effects as poor amplifier, appreciable, and the green, red, and blue matrix networks - sync, poor color "fit" (incorrect registration color including the adders and output stages. A flat video color and brightness information on the kine- of sweep extending down to 50 Kc is a necessity in or cross -talk or color contamination between scope), checking or aligning the tunable bandpass filter and I and Q channels. the I and Q filters. Late The rf-if amplifier models of the RCA WR- be aligned cor- must 59C Sweep Generator rectly to provide flat 3.5BMc now provide a flat video I 4IMc response for modulat- sweep extending down to frequencies up to ing 50 Kc. It also covers all 4.1 Mc. The RCA A 9cM rf and if ranges required WR -59C Sweep Gener- for both color and black - ator and WR -89A Fig. 4. Q Channel Response and -white receivers. Fig. 2. Bandpass Filter Response Marker Generator pro-

REMEMBER that the high voltage (up to Y 30,000 volts and more) must be set to the specified value before adjusting purity or convergence. The RCA VoitOhmysts can be used with the RCA High Voltage Probe (WG -289 and WG -206 Multiplier Resistor) to measure dc voltages up to 50,000 volts. RCA WG -289 High Voltage Probe L ri,ope W Paa1- .stfleo RADIO CORPORATION of AMER/CA vcts- HARR/SOM. N. J. TEST EQU IPMENT MAY, 1954

www.americanradiohistory.com A REVOLUTION IN ew V

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NEW Aluminized Metalescent Finish (inside and out)

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THE FOSBOND PROCESS* The Fosbond process produces a new corrosion -resistant phosphate

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www.americanradiohistory.com STEEL ANTENNA PIPE.

willow STEEL PIPE FOR MASTIN. CHECK THE RECORD FOR YOURSELF

BEST COMPETITIVE MASTING OF THE MANY TESTED EXPOSURE TEST NEPCO TENNATUBE

500 Hours d; , ,;

¡4aeo,.rt,x, Hours I 500 ',1,rfeïy1 VERY POOR :t¡L1stin;Y,Tee ilaAssi) NO BREAKDOWN APPEARANCE HUMIDITY TEST 100% Humidity 120' F.

215 Hours 215 Hours VERY PRONOUNCED NO CHANGE RUSTING SALT SPRAY TEST -20% at 95 F.

300 Hours 300 Hours BEGINNING NO CHANGE TO DETERIORATE

WEATHEROMETER Nepco TennaTube with WRITE FOR THE WHOLE STORY Detailed Test Data Comparing process. other leading TV masting and Descriptive Information of the Fosbond OTHER PRODUCTS IN THE NEPCO LINE - depends When your reputation All Fosbond Coated VHF Antennas UHF Antennas installation - and Banding on a quality Wall Brackets . Chimney Banding Mast is quality your best insurance Clamps . Guy Rings .Telescoping Masts material. proved Only TENNATUBE TESTS BEST on ALL RADIO & TELEVISION DEPARTMENT, PITTSB " GEXO »

www.americanradiohistory.com 118 QUESTION BOX

PUSH -PULL 1619 AMPLIFIER ? I want to use push -pull 1619's in the output stage of an audio amplifier, but I'm not sure how to go about it because the tubes are pentodes with directly heated filaments. I want to use the tubes in class ABI. Please print a STANDARD BRAND WARRANTY suitable circuit.-A. J. S., Philadelphia, BRANDED Penna. BULK PACKED OR INDIVIDUALLY BOXED A. The push -pull 1619 stage is shown. CLOSE OUT The suppressor leads should connect di- OA4G $ .50 6465 rectly to the 6L6GA . .99 12507 center -tap on the sec- OZ4 .49 6ÁL5 .. .61 6547 .59 125H7 .49 1B3GT .. .65 ondary of 6ÁQ5 65A7GT .61 125 K7GT .49 the 2.5 -volt, 4- ampere fila- 1824 4.95 6406 6SC7 . .81 1CSOT .39 125N7GT .46 ment 6A55 65F5 .58 12SQ7GT transformer. Cathode bias is de- 1F5G .39 6AT6 .49 .36 6567 . .59 125R7 , 1L4 .47 ... .49 veloped across the 6ÁU6 ,36 65H7 .65 1223 .39 350 -ohm resistor be- 1Q5GT .39 6AVSGT .. .79 6517 . 19806E 1.15 1R5 .46 6AV6 .54 tween the center -tap and ground. It is ... .36 6567 1978 , ONE OF AMERICA'S 154 68116 .39 .81 .40 ... .33 65L7GT .49 25AV5GT 1.05 155 6BA7 ... .57 best to feed the screens from a .38 65N7GT .46 25BQ6GT .75 separate LARGEST 174 .46 68C5 .. .46 68E6 65Q7GT .37 25L6GT .40 IU4 .46 ... .37 WHOLESALERS IU5 68F5 6567 , .49 25Z6GT . .37 1%2A .38 66060 ... 1.16 6T8 .57 321.7 ... .39 .65 6BH6 ... .45 6U7 .49 33 .29 265 .39 2E22 6816 ... .46 6U8 .59 34 .29 1.45 6BL7 .. .65 6V6GT 3585 ... .38 2X24 .33 6BN6 ,72 6W4GT .38 3A8 .33 .41 35C5 , .38 6BQ6 .. .70 6W6GT .41 35L6GT 2.95 6BQ7 . .42 3064W 6X4 .35 35W4 .32 .25 .31 6X5GT 3B26 1.95 6C5 .35 35ZSGT .49 3Q4 7R7 .59 5085 .41 " .48 6C5GT .. .41 1266 . .39 SOCS 3Q5GT , .48 6C6 .49 .41 354 .46 12476 .. .31 5OL6GT .59 6C86 12AT7 .57 117Z3 3V4 .., 1.08 12AU6 .. .39 4C35 24.95 6C06G .34 801A ., .19 5FP14 .76 12AU7 .. .52 803 2.95 9.95 6F6GT .45 12AV7 5U4G .60 814 , 2.95 .49 6316 .49 124,17 SV3G .36 .72 832A 7.95 6.14 12846 .52 836 2.95 646 .35 6J5GT .34 128E6 61187 .69 616 .40 866A 1.49 6A .50 128117 .41 5670 .., 1.45 C7 . .68 617G .49 12116 . .. .49 5718 4.95 bAGS 6K6GT .36 6AH6 .éB .29 61O1CT 4.95 6K7G .49 125A7GT .58 9003 ..,, 1.10

MINIMUM ORDER: $10.00. Terms: 25% with order, ba once C. O. D. Please include postage. A- All prices subject to change without notice. F. O. B New York City. Mail Order Division: power supply, but you can supply them from the 400 -volt plate supply if you use a suitable dropping resistor and V -R tubes to stabilize the voltage. TRANSAMERICA ELECTRONICS CORP. The grid resistors and coupling ca- 120 LIBERTY ST., NEW YORK 6, N. Y., COrtlandt 7 -4307 pacitors are determined by the gain and frequency response you desire from the circuit. Values shown are typical ...... _`_` for PA circuits. About 40 volts peak -to- peak is required on the grids for full Mr. Ed. Lombard, of Dealer's Wholesale Supply, output. This can be supplied by many Ventura, Calif. states: ` conventional push -pull drivers and phase inverters. have "We tested almost every AUTO VIBRATOR FREQUENCIES ? Recently, while servicing an auto all- channel antenna, to find the adio, I did not have a 115 -cycle re- i placement so I tried a 90 -cycle unit. All voltages were normal and the set oper- best antenna for ated perfectly. Is there a possibility of damaging the set by making this sub - stitution?-G. our Dealers!"_'- E. H., Elwood City, Pa. A. It is surprising that you had a 90- ...... cycle vibrator. Engineers for various "We are in a fringe area;' says Mr. Lombard, "and vibrator manufacturers informed us since our dealers cannot and will not stock many dif- that these units are made in compara- ferent brands, we have tried to supply the antenna tively small quantities and that the that will give the best all-around performance. major output of the industry is in "With many manufacturers claiming top supe- 115 -cycle units. riority in their antennas, we were not sure which A 90 -cycle vibrator Every dealer has heard antenna one to choose. We therefore tested antenna after an- will operate in a manufacturers claim top per- tenna right on our own roof, and had our dealers try circuit designed for 115 -cycle operation, formance. Davis alone backs its and test antennas to see which brought in clearer, but it is highly possible that its life claim with a money -back offer. The Davis Super- Vision an- sharper pictures and the least interference on all will be shortened because the buffer tenna is factory- guaranteed to channels. capacitor will not match it. Too, there give the maximum reception "Dealers in our area have chosen Davis Super - is a possibility of the power trans- obtainable. Try one ... judge it Vision antennas, because our test and their test have former being damaged ... and you too will standardize proven outstanding results in every area. or burning out on the Davis. "There are many similar antennas, but our Dealers because it is not likely to have enough demand Davis from the results it gives:' iron in it to enable it to operate as efficiently on 115 cycles. Play safe and You Can't install a 115 -cycle replacement as soon as possible. Buy a COPYRIGHT 1954 Better MICROPHONE PREAMPLIFIER I I Antenna aV ArghgUJBV ? I built the amplifier on page 134 P.O. BOX 1247 BURBANK CALIFORNIA of the February, 1954, issue. It works Factories 'In; BURBANK, CALIF., CHICAGO, ILL., SILVER SPRINGS, MD. nicely. Now, I want to provide for high - RADIO- ELECTRONICS

www.americanradiohistory.com VIN service job r"---- CUS TONERS a YOUR¡ O on MMallory YOU AND Vibr'Vibrator the a'Mallory an ism °f use mechanism performance.e Mallo every time y paten°u ted, tuntuned because completely °r assures G Vibrat WI N r 1N com- OF he fir st PROOF t for set HERE' S YOUR nIlory produced et .N1 vibrators sur- roduces more And su ed PERFORMANCEs p combined. an us vibrator other preferred mercial all Vibrators are manufacturersanufactu hthan Mallory Another veys , d 6 servicemen. Mallory Winner! bs them for WINNER Us Vibra- THE name. The new Mallory STICK W Vibrators by tor Guide is a complete Mallory ask for jobs cross -reference and serv- radi service ice guide. It has always all your car been the accepted reference book for vibrator selection. Get one from P. R. MALLORY & CO.. Inc your Mallory distributor. MALLOR RESISTORS CAPACITORS CONTROLS VIBRATORS SWITCHES MERCURY BATTERIES RECTIFIERS POWER SUPPLIES CONVERTERS APPROVED PRECISION PRODUCTS Inc., INDIANAPOLIS 6, INDIANA

www.americanradiohistory.com 8 Vertical ÿ yoke de{lectto Chokel1nearity áilter controls 5 width and hacks ál Y replacement 17 exact transformers 13 PV power

5NV TV REPLACEMEN1 C A duplicates) X27 exact 28 {lybacks power transformers TV Yokes 8 deflection controls

9 width on outputs !TN4'ØR 15 vertical 8 blocking-oscillators YOUR MOST COMPLETE SOURCE 3locus o ils trans{ormers 5 {flame OF TV REPLACEMENT chokesc 22 {filter audio TRANSFORMERS 19

KARE NOW/I? RSI NN15

Ask for Stancor's new TV Replacement Guide listing 1HEStANCORINE replacement applications for these transformers in 6800 TV models and chassis. FREE from your local +e- Stancor distributor, or from Chicago Standard Trans- former Corporation.

Stancor transformers are listed in Sams Photofact Folders and in Counter. 3 592 ELSTON AVE. CHICAGO 118, ILL. facts. EXPORT SALES: R.buen Ayones's, Inc, 39 Warren Strout, Now York 7. N.Y.

www.americanradiohistory.com 121 QUESTION BOX and low -impedance microphones with independent volume controls. Please show me how. H. E. O., Lansing, Ill. A. You will probably need a preamplifier to get good results from a microphone. The diagram shows a suitable preamplifier circuit. A 6J7 is speci- newer EC M ASTE R fled instead of a 6SJ7 or similar type because its hum level is lower. MANUFACTURERS OF THE WORLD'S CUSTOM -BUILT TV CHASSIS HI IMP MIKE JACK FINEST

SOOK TO Al IN OF MAIN AMPk MIKE TRANS NOW OFFERS New Horizons

+135V of TV Enjoyment in the UHF Field A IOOK with a Ú IVERSAL PRI. Full 70- Channel PRONO IN (OPTIONAL) UHF Selector available in all transformer should The microphone TECH- MASTER be a high -quality unit with a primary impedance to match the output imped- 630 -type chassis! ance of the low- impedance microphone that you use. If you have several with different impedances, use a transformer with a universal primary. If you construct the preamplifier as a separate I f unit, you can plug its output cable into the input jack on the main amplifier. UHF or VHF - The diagram also shows how you can THE 630 BY TECH -MASTER connect an auxiliary phono input jack IS STILL THE FINEST with separate volume control. TV CHASSIS EVER PRODUCED MODEL 2430: For picture tubes up to 24'. Audio connection for optional use of ex. SIMPLE SHORT -WAVE ternal amplifier. CONVERSION UHF /VHF $249.50 VHF._ - $169.56 3,:BR -71TA receiver MODEL 2431: Same as 2430, but with ? My Airline True Fidelity Push -Pull audio amplifier. ke and 6 to 18 tunes from 550 to 1780 UHF/VHF _ . 259.59 VHF. ... 199.56 to receive a fire department mc. I want UHF SELECTOR, MODEL 2430.9: For new 90° kinescopes. and 30 station on 2.366 me with this receiver. MODEL TV 101U: (24" rectangular, 27" "). 299.50 VHF _.. 262.5e Please print a circuit of a converter or Fits into recess of UHF /VHF... show how this set may be adapted to any 630 -type chassis. MODEL 1930: Similar to 2430 with slight S., Brings in all available modifications including area control cover the desired frequency. -H. UHF stations. Factory switch at rear of chassis and cadmium Belmar, N. J. assembled, wired and plated finish Instead of nickel. aligned...... $36.95 net UHF /VHF _. 224.95 VHF .. 179.51

A. A converter won't be necessary. MODEL C -30: Designed for the utmost is You can receive the desired signal by Quality at an Economical price. cir- UHF /VHF. 209.95 VHF 149.50 modifying the receiver's antenna AT ALL LEADING RADIO PARTS DISTRIBUTORS a simplified (All prices NET. Picture Tube not includec.) cuit. The diagram shows Write For Detailed Literature circuit of the input section of your re- Tube M't'g Brackets with 2400 Models ceiver as modified for 2 -mc reception. Note that the shortwave 6 -18 -mc coils MAKERS OF CUSTOM -BUILT and the built -in bandswitch have been TV CHASSIS, TV KITS - R°oP &TeeAvs °N FIDELITY omitted. TECH MASTER AND HIGH 445 BROADWAY, NEW YORK 13, N. Y. AUDIO EQUIPMENT I400KC WAVE TRAP IF RED

CONY --L1313-- I EMPLOYMENT OPPORTUNITY radio The Force has on urgent need for electronics engineers; radar, 1.7-S.SMC Air -. ANLC.OIL technicians and wire communications engineers; and radio and electronic BC SW The and repair men, with salaries ranging from $3410 to $8360 a year. L - MMN TIlNÌt1G majority of these openings are at Air Force installations in New York, Ohio and Georgia. BROADCAST ANL COIL Qualified interested persons may submit applications to Carl T. Sieg, Division, Chief, Placement Branch, Placement cnd Employee Relations Directorate of Civilian Personnel, Department of the Air Force, Wash- AVC the ington 25, D.C., for referral to an appropriate opening at one of 1.7- 5.5 -mc shortwave antenna Add a above locations. coil and._ d.p.d.t. switch as shown. Con- nect a 350 -µµf mica or ceramic trimmer across the shortwave coil. With this MAY, I954

www.americanradiohistory.com 122 I QUESTION BOX

setup, the antenna circuit is tuned to the normal image frequency of a broadcast signal for shortwave reception. THE TEST OF TIME The set's tuning dial is set to a frequency equal to the desired shortwave frequency minus twice the i.f. (465 kc in your receiver). So, to receive signals on 2366 kc, you must tune the receiver to 1436 kc. This method will enable you to receive signals between 1945 and 3095 kc. If you use this system for short -wave reception on a set tuning from 550 to 1600 kc with a 456-kc i.f., the tuning range is approximately 1915 to 2965 kc. The circuit is easy to adjust. Set the receiver's original IN CONSTRUCTION bandswitch to the Rohn Towers are built of heavy duty broadcast band. Feed a strong modu- tubular steel electrically welded lated signal from a signal generator throughout by skilled workmen exact. Iv to specifications. Proof of Rohn con- tuned to 2366 kc into the receiver's an- struction lies in the fact that thousands tenna post. With the auxiliary band - of towers have been sold in the past several years and have successfully switch set for broadcast, tune the re- withstood the rigors of time in all ceiver toward the high- frequency end climates and under the severest of conditions! of the band until you pick up the sig- IN PERFORMANCE nal. Peak the signal with the tuning Rohn Towers assure you of trouble control. Throw the auxiliary switch to free performance and once installed short -wave and then adjust give unquestioned satisfaction year in the short- and year out! You are free of com- wave trimmer and slug for maximum plaints because over the years Rohn signal. Towers have proved themselves from the serviceman, dealer and customer In some areas, strong broadcast sta- point of view! tions on the high end of the band may IN SALES ride through and interfere with 2 -mc Sales acceptance has been phenomenal shortwave reception. This - thousands have been sold coast.to- can be pre- coast - and the design has been one 3 Self Supporting Rohn Towers vented by connecting a tuned wave trap which has withstood every test To Fit Your known! Why "experiment" with an Every Need in series with the antenna lead to the unproved tower design when you can The No. 5 -The self -supporting tower for primary of the shortwave coil as shown. sell Ro hn! use up to 40', or guyed to 80'. An economical, yet sturdy, permanent tower! Tune the trap for minimum interfer- So we ask you, "Why take chances The No. 10 with an untried tower? He sure sell -The standard 12' design that ence. - is self- supporting to 50' and can be installed Rohn - the only tower of its kind to The new antenna coil may be a - withstand every test! to 120' when guyed! Stan The No. 20 -The heavy duty Rohn Tower, wyck type 411 or J. W. Miller type ideal for communication and where great B- 5495A. The wave height is required trap may be a J. W. Rohn Fold -Over - self-supporting to 60', Tower or guyed to 150'! Miller type 811 -BC1. only one of its kind exclusive with All Rohn Towers are in IO' sections easily erected, - Rohn - transported and stored! patent INTERMITTENT VERTICAL pending. Rohn Telescoping CENTERING Mast - complete BE SURE TO SEE US AT THE line in a proven Admiral 20T1 structural ? In an receiver the design in 20' picture changes position vertically, leav- -30, -40'- PARTS SHOW ing a dark 50' models. area at the bottom. This occurs only once every several hours Booth 14 and returns to normal almost immedi- DISPLAY ROOM -616A ately. I have tried tube changes but this Conrad Hilton Hotel -May 17 -20 did not help. When the antenna is disconnected, the same thing happens to the raster. What checks should I make MANUFACTURING CO. to find the trouble? T. C., Philadelphia, DEPT. RE 116 LIMESTONE BELLEVUE Pa. A. If PEORIA, ILL. centering disturbance in a vertical plane is the only symptom, it could be caused by a variation in the voltage TRAIN AT HOME FOR COLOR -TV and applied to the vertical deflection coils. Initially, check the low- voltage power supply feed to the vertical deflection coils. Then check for defective components in the vertical output circuit, particularly the voltage feed to the oscillator and output tube. Also check the vertical size -control potentiometer for an intermittent -contact condition Learn prartirol, professional type TV Servicing without Leac- inv your present job. Included are money- making extras, such or change in value. as set conversion, master antenna installation, UHF -TV, NTSC ('olor System. field servicing short ruts. You can start earning The B plus for the vertical oscillator Television money after first few lessons. You learn to test, trouble shoot and repair all types and output tube is derived from the of TV lets, MILTON S. KIVER, President voltage boost HERE'S HOW YOU GET EXPERIENCE! TELEVISION COMMUNICATIONS INST. system in the 6W4-GT 605 W. Washington Blvd, Dept. RE -29, Chicago 6, III. You train on a large screen, modern TV receiver. damper circuit. Any voltage change in furnished Rush with the course and yours to keep! As an optional feature you FREE Catalog and Sample Lesson. I the damper (or a can get two weeks actual experience with Chicago's largest in- am not obligated. Salesman will not call. change in the horizon- dependent servicing organization. You learn by doing! Age is tal circuit flyback no barrier. Many students are veterans: characteristics) will over .50 I Beginner's Course avail- Name 0 able. Send for FREE Catalog and SAMPLE LESSON today! [_[ l'.heck here influence the vertical circuit. Try a new TV COMMUNICATIONS INST. VETERANS! Address damper; if this doesn't help, check the T.C.1, is approved for G.1 605 W. Washington Blvd., Dept RE -29 [raining. Under Pun!t, City Zone State components in the voltage boost system. Chicago 6, Ill. BEGINNERS cheek here for Basic TV Course END RADIO -ELECTRONICS

www.americanradiohistory.com 123

DELCO RADIO CANS ITS POWER TRANSFORMERS TO PROTECT THEIR QUALITY AND PERFORMANCE

If you want a part made right, you've got to he able to control all phases of its production. That's why Delco Radio exercises strict quality control over all its parts -for service use as well as for original equipment.

Let's look at some new power transformers for auto radios: The laminated core inserts are stamped out of low -loss silicon steel, then heat treated to insure retention of desired magnetic properties. Skilled operators use special machines to wind the primary and secondary coils. On the production line, laminations and coils are assembled and, with other parts, placed in a metal can. Finally, a hot asphalt compound is poured into the shield can. On cooling, it becomes a solid mass that holds all components in position, transfers heat and protects the transformer's quality and performance.

Satisfied customers are the basis of a good service business, and Delco Radio service parts assure customer satisfaction. Delco Radio service parts are available through your UMS DELCO Delco Electronic Parts Distributor. RADIO Potting power transformers. The transformer can is filled with an asphalt compound which helps to piSTt16U"' 'a ''yriF'O`t'CS WHOIESALFeJ EVfeYWHERE protect the transformer and transfer heat from the transformer to the can for better heat dissipation. DELCO RADIO DIVISION OF GENERAL MOTORS CORPORA "GN, KOKOMO,INDIANA

LINE A GENERAL MOTORS PRODUCT ., ."" A UNITED MOTORS NAY, 1954

www.americanradiohistory.com 124 TRY THIS ONE

QUICKLY CONNECTED REMOTE VOLUME CONTROL A volume control to change the sound level of a radio or television loudspeaker from a remote point is often desirable. The arrangement shown is somewhat unconventional in that it reduces the loudness by bypassing part of the signal around the speaker. It is practical for connections which must be made on the spur of the moment. For example, the control can be quickly made 1 on a public address setup where the operator wants to be located away from the amplifier so he can better judge the sound from the speakers and can reduce the volume at once in case of feedback.

FROM OUT TRANS SPUR

RHFASTAT-APPROX 25.,

Two wires are connected between the loudspeaker voice coil and the remote point. A rheostat is hooked across the ends of the wires, allowing the amount of bypassing to be adjusted. The resistance element should be wire-wound, and for most speakers its value should Designed, be about 25 ohms. engineered When the control is set at the high- and hilt to Triad's rigid Popularly priced est resistance the speaker operates at quality and performance standards, full strength, as determined by the reg- this fine group cf flybacks will ular volume control. As the rheostat is Low attenuation meet practically all TV service moved toward smaller values the vol- needs. The one transmission ume decreases. Unless the resistance They are among tf a more than element happens to be tapered, most of line for UHF - VHF the volume change occurs within a range of about a quarter of total knob rotation. For small sound systems the wattage 50 rating of the rheostat is not critical because it would ordinarily be set for YOUR CHOICE- only a slight reduction of volume. Tone quality is not noticeably affected, and in low- powered amplifiers there would . Stranded be no damage resulting from the extra copper loading. When several speakers are used in conductors parallel, all would be affected alike. Where individual control is required, L See your pads may be purchased so that each or speaker can be adjusted separately. distributor for copies of AMPLIFIER SAFETY KINK Solid Catalog TR -54 Output transformers of phono and copper PA amplifiers may be damaged by high - it completely voltages if the speaker or load is acci- describes the weld dentally disconnected while the power finest line of conductors is on. When constructing my latest amplifier, I decided to guard against transformers such damage by inserting made. Send for Samples TODAY! a circuit - transfer jack in the output circuit to

Sold through recognized jobbers only! OUT TRANS SPKR JACK

IT4c34,4,07i?",:j7 50/10 WIRE & SUPPLY CO. automatically connect a resistive load if the speaker should open or be disconnected. 4055 Redwood Ave. Venice, Calif.

RADIO -ELECTRONICS

www.americanradiohistory.com 123 Electroniry RADIO SCHOOL DIRECTORY fran JOBS xreltent EnhIneers MORE sefo than graduates ai groWthtZr.t' ror pm You Can Become an Ystin an edtan< Demand for our engineering graduates exceeds supply. Effective place- Mr lit. Study in this world -famed college estab- ELECTRICAL ENGINEER lished 1884. Quarters start June, Sept., Jan., Be "key" man. Learn bow to send and Vets. eceive messages in code by telegraph Degree March. Approved for Korean and radio. Commerce needs thousands of with a Bachelor of Science months men for Jobs. Good nay. adventure. in- Bach. Sc. degree in 27 teresting work. Learn at home quickly MONTHS TV, UHF and famous IN 36 Complete Radio Eng. courses .. Mutor mateura orieCommerccialLi- FM. Also Mech., Civil, Elec., Chem., Aero. and ceaN. Write for FREE RODE. classes. Well - CANDLER SYSTEM CO. Adm. Eng.: Bus. Adm., Acct. Small Denver equipped labs. Modest costs. Prep. courses. Write Dept. 3 -E, Box [128. Jean. McCarthy, Director of Admissions, for Catalog and Campus View Book. Quickly: Get Your F.C.C. LICENSE Correspondence or residence preparation for guaranteed. 2454 College Avenue, Angola, Indiana F.C.C. examinations. Results An FCC commercial operator license means greater opportunities and higher pay. We ore GET INTO specialists in preparing you, in a MINIMUM OF TIME, to pass FCC examinations for all classes Beginners get 2nd class license in S of licenses. Write ELECTRONICS weeks and 1st class in 3 additional weeks. 1 on r:m enter Ititi uncrowded. Inter- for free booklet.

, new ding field. Defense expansion. GRANTHAM SCHOOL OF ELECTRONICS developments demand trained special- Calif. or Power at ists. Study all phases 'radio ä elec- Dept. 101, 6064 Hollywood Blvd.. Hollywood 28. Major in Electronics ironics theory and practice: TV; 6M: "rnadcastl ng: servicing; aviation. ma- Milwaukee School of Engineering ,ine, police radio, 18-month course. l:rndnates in demand by maim. com- Everyone knows the tre- panies. R.S. or equivalent required. *mom EÓáEEERINGInONTt1S Ìteein Jan.. March. June, Sept. Campus mendous opportunities hails in site Write for cooky. lot ensh-e. specialized course including strong ahead in electrical engineering. The VALPARAISO TECH N ICAL INSTITUTE mathematics and electrical engineering, advanced radio nest. C Valearano, Ina. theory and design, television. Modern lab. Low tuition. expanding field of color television Self -help opportunities. Also B.S. degree in 27 months alone is one example. In addition to in Aeronautical, Chemical, Civil,_ Electrical, and Mechanical Engineering. G.I. Gov't approved. Enter the demand for engineers, thousands June, September, December. March, Catalog_ of engineering technicians are need- TV REPAIRMEN INDIANA TECHNICAL COLLEGE Milwaukee School of Engi- Indiana ed. The MAKE TOP MONEY! 156 E. Washington Blvd., Fort Wayne 2. neering can prepare you to become an engineer in 36 months or an en- In just 39 weeks, you can get in 12 to 18 complete TV service training! RCA INSTITUTES, INC. gineering technician l l: '?MTV, Streamlined course gives you all pay you to look into it A service of Radio Corporation of America months. It'll cssentials for a good job as service technician. Iÿ1`I 350 West 4th St.. New York 14. N. Y. today. No obligation. Graduates in reat demand; jobs ore plentiful in \/® this growing field. Other courses in electronics, OFFERS COURSES IN Technician and Service Courses rodio operation and maintenance. Day or evening PHASES OF for em- ALL TECHNICAL 18 classes; modern equipment. Opportunity RADIO, TELEVISION, ELECTRONICS - 12 to months ployment in local industry. be a radio Approved for Veterans In 12 months you can Write for Catalog 111 Tedse Write Dept. RC -54 for Catalog technician. An additional 6 -month INDIANAPOLIS ELECTRONIC SCHOOL course qualifies you as a radio -tele- 312 E. Washington. Indianapolis 4, Ind. vision technician with an Associate in Applied Science degree. Or you Only Book With can earn an industrial electronic First And technician certificate in 12 months. These technician courses form the first third of the program leading to a B. S. Degree in Electrical Engi- COLOR TV neering. Twenty-one subjects studied include electronics, electronic engineering, and electronic design. Also offered are: radio -television service course (12 mos.); electrical service course CIRCUITS & STEP INTO THE TOP PAY (6 mos.); general preparatory and refresher S5.000- S10,000 A YEAR course (3 mos.). CLASS. 7 MONTHS' SHOP TRAINING QUALIFIES YOU.

SERVICING If you want to reach your goal as SEND FOR a Successful Service Technician you will need plenty of "KNOW HOW" to FREE servicing jobs See Actual . qualify for the better Terms open ownership. BOOK TODAY! Circuits Used or profitable shop July, September, In Color Sets WESTERN TV offers real experience on live equipment In our BIG SHOPS AND LABORATORIES in the shortest January and April Color TV practical time under expert instructors. Graduates are Faculty of specialists - 50,000 former Jn big demand because they have the "field expe- Annual enrollment from 48 Principles or super- students - rience" necessary for immediate "bench" states and 23 foreign countries -Non- visory positions. You learn every phase of Radio and profit institution - 51st year of service Simplified win fast TV servicing (AM, FM, VHF, UHF). WTI men Course approved for veterans - 0 O promotion ...can demand better pay ... develop Residence- courses only. Servicing highly profitable businesses of their own with the latest and most PRACTICAL PERSONALIZED TRAINING BEHIND THEM. You concentrate all your time on being non- MILWAUKEE a PROFESSIONAL TV SERVICE 'TECHNICIAN - JUST OFF THE PRESS! essential math and engineering theory omitted. YOU SCHOOL OF ENGINEERING CAN EARN WHILE YOU LEARN. Special Finance Plan. To Know AND MAIL TODAY Everything You Want FOR VETERANS. Find out how you can get TEAR OUT APPROVED ENGINEERING into the TOP PAY GROUP - Send for this fact -packed MILWAUKEE SCHOOL OF TV! RE N. Milwaukee Street About Color NOW! Dept. -554 1025 book Milwaukee I. Wisconsin of color TV cir- America's Leading Down -to -earth explanations WESTERN Send me rl Free illustrated booklet on oppor- cuits with actual diagrams of various Television tunities in Electrical Engineering or ['Free illus- TELEVISION trated booklet on careers in Radio -TV. manufacturers. Basic principles told in INSTITUTE Servicing School everyday language. NTSC system explained I am interested in - - - Trouble -shooting and servicing (name of coursei in detail. Dept. E5.4 -I of color I Wes tenTelevision Institute simplified. Detailed explanation W. 18th St., Los Angeles 15, Calif. I 341 Name Age TV theory. Over 100 pages packed with Without obligation, please send FREE fully Illustrated I all the answers on color TV. Profusely il- booklet. (No salesman will call.) I lustrated. $2.95 postpaid. ORDER BY MAIL Address NAME AGE I TODAY . . . NOW!

City ' _Zone__ State Dept, P-4 ADDRESS Mathieson Building If veteran, indicate date of discharge CITY 7011E STATE BEECO Baltimore 2, Md. J f,,AY, 1954

www.americanradiohistory.com 126 TRY THIS ONE

The diagram shows how a jack and a 10 -watt resistor are connected to the NaW I (E/COQ brings you transformer secondary. The resistor value is not critical as long as it is comparatively low. I used a 50 -ohm A LABORATORY SCOPE AT unit. A resistor equal to the output impedance would be ideal.-Paul S. 'A PRICE YOU CAN AFFORD! Lederer Now you can enjoy all the tremendous advantages of trouble- CAPACITOR shooting with the greater speed, precision and visual mean- SUBSTITUTION ing which only BOX an oscilloscope gives you. With the EICO 5" Scope you can: This simple capacitor substitution box uses 2 switches to obtain 30 Visually align differ- TV, FM and AM sets ent capacitance values with only 20 Visually signal trace and troubleshoot every stage fixed capacitors. The of any electronic circuit shows how device the capacitors can be connected Visually analyze complex waveforms in series, or parallel, or used singularly to All without disturbing circuits give values that are one -half, one, and 425K 5" Push -Pull Scope KIT $44.95. Wired $79.95. two times the basic value. A 12 -point rotary switch selects the basic value EICO Scope and a double -pole, 3- position lever of Your and AM sets. of TV, FM switch sets the Ew 3 1 NSTRUMENTS stage multiplier range. A make tracing every circuits. neon lamp 3 PROBES signal hi g h impedance was connected in the 11th $ 5.75 -For and analysis. $3.75. wired broad bandwidth position as a handy KIT $5.75 For voltage indicator PROBE Wired measuremeir 51eneral DEMODULATOR KIT $3.75. and current 4 95 and test gadget. PROBE For voltage CAPACITY $3.95 - KITS 59.95' LOW Wired PROBE KIT $2.75' of three -If-b1 Ot DIRECT PROBE price, set SOOVUf 500iipt introductory Ht--o2 Special ÁO3~ Compare these Direct connections to deflection specifications with scopes selling plates at many times V & H Freq. Resp: 5 .004 the EICO economy price! cps - 500 kc; .004- usable to 2.5 mc. --f-4 Push -pull V Sens: .05 lf--- Vert. & Hor. amplifiers to .1 volts rms-'inch .005 A05 Full- V & H screen V & H centering controls input imp: 1 megohm Intensity (Z -axis) Multivibrator -Ii-bS mod. Sweep Generator Range: .03 .03 6.3 volt AC, 60 cps test signal output 15 cps - 75 kc Tubes: --if--06 o-ioH 2 -5Y3, 2.615, 3.6SN7, 1.5" CRT. .04 ® See this amazing Scope value at your jobber today. Write NOW for FREE Catalog SC -5 describing o---1(--- the complete EICO .05 .05 line. Read EICO'S other ads in this issue -turn to Adver- tiser's Indes. o---il- .5 .5 ELECTRONIC INSTRUMENT CO., INC. +1(-49 8 84 Withers Street, Brooklyn + 11, N. Y. (-o10 o-+lí--- 40 40 ---oll f o- WATCH FOR OUR OFFI*O? JUNE ISSUE

AT YOUR DEALER'S NE2 MAY 26 Smaller ia s at-et Etilecieeiev. The FAMOUS Parts for substitution box Capacitors (Miniature mica, ceramic, or paper): 500 µµf, 2 2- -.003, 2 -.004, 2-.005, 2-.03, 2 -.04, SUB -MINIATURE 2 -.05, 2-0.5 µf, 600 volts. (Electrolytic) 2-8, 2-40 µf, 150 volts. Miscellaneous: I- miniature rotary switch, 2 cir- ,0{.I cuits, 12 positions: I- miniature lever, slide, or rotary switch, 2 3 455 KS, circuits, positions. Small utility box, NE -2 INPUT neon lamp, 2 -jacks for test leads, points. tie - I.F. TRANSFORMER All capacitors in the unit are 600 -volt types ONLY 1/2" SQUARE BY 11/2" HIGH except the 8- and 40-ruf pairs Over -all, Inc. which are rated at 150 volts. Use the 2/ ACTUAL Terminals, 1- 15/16" smallest (physically) SIZE available capacitors and you will be able to fit the whole THE FAMOUS "K -IRAN" I.F. TRANSFORMER works HAS NOW BEEN MINIATURIZED. For the first into a 4 x 4 x 2 -inch metal box. time we are intermediate desirable ofeatures -R. Weingarten of thelconventional nsize I.F. than aominiatulre the use of a tube. Ferrite shell core material these Sub -Miniature I.F. Transformers offer the gain and bandwidth characteristics QUALITY assemblies. previously obtained only In larger I.F. RESISTOR STORAGE It is now possible to construct personalized receivers smaller than When a service shop has lots of room transformers may be used ever before. These with sub -miniature tubes where sockets are not required. for spare parts, Catalog No. a separate bin or com- Net Price partment can. be allotted 10 - Cl 455 KC Input Transformer for each re- 10 - C2 455 KC Output Transformer $1.50 sistor value. Where storage $1.50 space is (Available through your local distributor) at a premium, store all the Manufactured under "K resistors in -TRAN" patents of Automatic Mfg. Co. 10 compartments, labeling each only with the number of coded zeros on the J . W . M I L L E R COMPANY resistors. 5917 South Main Street Los Angeles 3, California By using the last color as a marker, Canadian it is necessary to look through only 10 Representative.- Atlas Radio Corporation, Ltd. 560 King Street, W. Toronto 28, Canada compartments. -Harvey Muller END RADIO -ELECTRONICS

www.americanradiohistory.com 127

V. E. C. TUBES AT WHOLESALE Minimum Order $1.00 BRAND NEW BOXED BRANDED 1000,o GUARANTEED "Send For Free Tube Listing" Use This Ad As Your Order Form TYPES AT 290 QUANTITY TYPE QUANTITY TYPE 5Y3 35W4 5Z3 35Z5 6X4 11723 QUAM 6X5 TYPES AT 390 QUANTITY TYPE QUANTITY TYPE 155 6W4GT 1U5 12AL5 SU4 12AT6 6AB4 12AU6 of GALS 12AV8 manufacturers 6AT6 12BA6 6AÚ6 12E1E6 QUAM Adjust -a -ConeÑ) Speak- 125Q7 BAVE ers for television, radio, high 613E6 25L6GT 6C4 25W4GT fidelity, public address, out- 2526 6F6 door use, replacement and 6K6 3565 654 35C5 many other applications. 65137 TYPES AT 490 Focalizer Units for TV QUANTITY TYPE QUANTITY TYPE QUAM IA7 66A6 picture tube focusing ... use 6BC5 INS Alnico V permanent magnets 1L4 6BH6 INS 68J6 . eliminate troubles inher- 6CB6 IRS to wire -wound focusing 174 6SÁ7 ent 1U4 6507 devices. 3Q4 6567 354 6VG When you specify Quam Traps for any size 3L4 125A7 QUAM Ion 5V4 12567 products you are assured or type of TV picture tube. 5Y4 5065 6AG5 SOCS of components that are GAQS 50L6 QUAM Tru -Match Output TYPES AT 590 carefully checked and Transformers, designed to get QUANTITY TYPE QUANTITY TYPE 1B3GT 651.7 tested for top perform- the best performance from 1L6 6567 your speaker. 1X2 12AÚ7 ance and dependability 3Q5 12AX7 6BA7 12BA7 ... delivered when you 61305 12867 616 1251.7 need them . . . at the 658 12567 TYPES AT 690 right price. QUANTITY TYPE QUANTITY TYPE 6A65 678 6AJ5 6U8 6867 12ÁT7 6BL7 12AV7 6L6 1976 TYPES AT 790 CO. QUANTITY TYPE QUANTITY TYPE QUAM-NICHOLS 6BQ6 68Z7 Marquette Road and Prairie Avenue 68Q7 256(16 TYPES AT 990 Chicago 37, Illinois QUANTITY TYPE QUANTITY TYPE 6606 19606 6CD8 117L7GT -with every order of $20.00 FREE or more famous "Oxwall" mt driver kit includes all sizes -Philips head, long handles to get in those tight spots, etc. 7 screwdrivers in all. May be pur- ro e $4.85 chased outright List HI-CAIN TUNERBOOSTER ONLY NEW TV DYNATRACER $1.99 each 3 for $5.50 1 HALL, t v 31n1-SALS $4.75 $495Pod. AND VOLTAGES O. ox or C.O.D. LOCATES DEFECTIVE VIDEO ELECTRIC CO' 1Ml'I.ETf: Chgs. Ne k,á N. J. Ki t COMPONENTS SFree complete tube listing REQUIRES NO Free magnetic screw driver kit ($20.00 order) ws $6.00 ADDITIONAL EQUIPMENT $ enclosed This sensationally Amount equipment ls ideal for trouble-shoot- Booster. ingg television sets in the home o Nome Solve poor TV reception with a Hi -Gain the shop. The alit Banish weak fringe areas. reduce snow. This unit more YexpennsiveR test Address as a highly serviceable High -Gain and should pay for itself on the very comes to you -Q repair. City Zone... State Tuner. Uses 616 Tubes in very efficient Hi first using pure silver Every TV Technician PLEASE PRINT CAREFULLY Circuit. Has 8 tuned circuits A Must For inductances and individual compensation provid- SPECIFICATIONS:s Built in 5:1 TRACER Im ered uuality ing high gain on all channels. designed to Vernier Drive. test instrument Sracle included makes TV signals through any All necessary parts and Instr. Sync. AFC. Horizontal or Vertical highest pain booster on the market reg. of price. Sweepweep Circuit-will trouble to a i isolate taceE voltages U(50 /500e V. ' AC/DC) ...id instantly lo- 100 ASSORTED RESISTORS or leaky (up to 20 When answering cate open. shorted, intermittent etc. Carbon insulated. New in M EGOHMS) condensers. resistors. coils. XFormers, 5%, Instruction and Trouble-Shooting Sank Enclosed current RMA Values o0 MONEY -BACK GUARANTEE 10 DAY addreç+ 10% and 20/ in /2,i I and Cut out advertisement attach name anti ,.ith 05.51(1 hill. check or mOnev order and mail advertisements please mention 2 watt

Shipments sent aid when o en- ELECTRONICS CO. closed. % on ..D f Senda for ofurs new RADIO- ELECTRONICS bulletin. NO C.O.D.'S TO CANADA. FRANK W. DECRAY & ASSOC. 211 -04 99th Ave.. Dept. 113, 11842 W. Jefferson Blvd. Culver City, Calif. Queens Village, N. Y. MAY, 1954

www.americanradiohistory.com NEW DEVICES

TV ANTENNA ROTATOR os on accessory unit for use with their model 99 transcription JFD Manufacturing Co., Inc., ic- amplifier or 613. their model 214 remote -control Avenue, Brooklyn 4, N. Y., announces ampli- production fier. The unit virtually eliminates turn of the new Rotenna, a TV table rumble BUILD antenna rotator featuring and record scratch or 15 RADIOS 360° rota- hiss, but without losing tion, a music audible cartridge -type detachable to the ear as occurs drive unit, in -line with fixed filters. ONLY mast collars, a This is done by restricting the bond - finger -tip control switch with pointer. width type during soft passages when the direction indicator, and stop - human otch ear is relatively insensitive to turning accuracy. The latte extremes of treble feature describes the ability and boss, and then ATHOME$1 of the by opening the bandwidth to the 9 full unit to be stopped at exactly the same range, predetermined allowing complete passage of With the point when approached loud music New Improved 1954 from either direction: which itself drowns ouf any and close track- extraneous noise. ing between the antenna and the direction indicator. The frequency response is flot from Progressive 19 to Radio "EDO -KIT" The control 20,000 c.p.s, Two controls are pro- unit, finished in mahog- vided, the Dynaural any, has a finger -tip control for ad¡ost- bar -type control ing the degree of switch. Pressing the switch noise suppression, NOW INCLUDES once actor and the Dynaural Range ates the pointer to show the control which present offers o choice 12 antenna direction. Pressing it of 20 kc, kc, and 6 kc SIGNAL a second high- freuuency cutoffs (record TRACER ' e starts the rotator which distor- contin,es tion filters) each with both _' 'on until the switch is released. rumble and and scratch suppression, a position for dy- nn --'c rumble suppression only, and u CODE OSCILLATOR eon for suppression off. ATTRACTIVELY GIFT PACKED INDICATING FREE SOLDERING IRON FUSE POST Littelfuse, Inc., ABSOLUTELY NO KNOWL Des Plaines, Ill., has introduced a miniature indicating EDGE OF fuse RADIO NECESSARY post designed for 3AG and 3A6 fuses NO ADDITIONAL PARTS NEEDED in ratings up to 15 amperes and 250 volts maximum. EXCELLENT BACKGROUND FOR TV The device, No. 344010, measures 10 DAY MONEY -BACK GUARANTEE 2% inches over -all, 3/4 inch above SCHOOL INQUIRIES INVITED panel, 1% inches below panel, includ- ,ng the solder terminals. WHAT THE PROGRESSIVE RADIO "EDU -KIT" OFFERS YOU The Progressive Radio E,IuK,t" offers yob bottom price Our Kit a hone study course at a rock of Radio ,s designed to train Rad.o Technicians, with the Theory and Construct'on Prael'ee expressetl mply basic facts gain a knowledge of basic Radio Principles and clearly. You will Transmission and Audio Amplification. involved t in Radio Reception. Radio You will learn how to identify radios, using regular radio Radio Symbols and Diagrams: how to build how to C reuit Schematics: how to mount various radio wire and solder i a r professional parts: Receivers. m . You will learn how Transmitters. and Audio Amplifiers. You to operate trouble -shoot radios. You will learn will learn how to service and license, code. You will receiveeeeiv training for F.C.C. In brief. you will receive a basic education would expect to receive in in Radio exactly like the kind you Radio Course costing several hundreds of dollars. 4/10 THE KIT FOR The Progressive EVERYONE UHF ANTENNA who has a desire learn a for any person SELENIUM and Id n. The Kit has been Ilusedr successfully'fully ey young RECTIFIERS Acme Tool & Specialties all parts of the world. It is not neen Co., 224 N. slightest background i that you have even the Looms St., or radio. Radio Receptor Co., Inc., 2Sf W. 19 Chicago 7, LI, has intro- The Progressive RadionEduK is in this country and abroad. ;t' used by many Radio Schools and Clubs St., New York II, N. Y., has duced a u.h,f, all- channel corner re- rces It s used for training and rehabilitation added a Personnel and 'Veterans throughout the of Armed new range of cartridge flector featuring molded gloss fiber The Progressive Radio world. type selenium are included. EduKit" equires no instructor. All instructions rectifiers to their construction and a new reverse V All parts are individually hoxed, and identifiedfi Seletron line. In- di- and diagram. Every step involved in b ame. photograph cluded in the new group pole design, the Acto- tenna. You cannot make mistake. building these setsá is carefully explained. are hermetically sealed, glass- encased units The two reflector screens are pro- phenolic- encased half -wave axial lead duced by permanently molding a series PROGRESSIVE TEACHING METHOD units. the phenolic encased bridge of U- shaped aluminum reflectors into The Progressive Radio Edu -Kit comes complete with type and o glass fiber spine. This molded instructions are arranged in a clear. Mmple instructions. These unmounted cells for special con- of Radio and progressive manner.. The struction guarantees Transmission, Radio Reception. Audio Amplification theory assem bly. the critical spac- Signal Tracing is, clearly explained. Every and servicing by ing of the reflectors You willill learn part is identified by photograph and These rectifiers, the GA series, pro- in o weatherproof, the function and theory of every part used. vibrationproof The Progressive Radio EduK;t' uses the principle vide o true hermetic seal by using mounting. The antenna Therefore you will build radios. perform of Learn by Doing". has high her'zontal trate the principles jobs. and conduct experiments to metallized glass, solder -sealed and vertical direc- which you learn. These radios illus- to met- anner, according to the best principles are designed in modern tivity, be in by building of present-day educational practice. You a simple radio. TV next set that build advanced.. Gdually, in a progressive manner, you you is slightly more 11W7 till advanced multi-tube radio will find yourself constructing Radio Technician. sets. and doing work like a Altogether you will build fifteen radios, including ional Mr= Transmitters. Amplifiers, Code Oscillator and Receivers. nn 105.125 V. AC DC. Signal Tracer. These sets operate THE PROGRESSIVE RADIO "EDU -KIT" IS COMPLETE You receive necessary different !II kits containlltubes, tube sockets.ckets, radio sets. Our mica chafss. variable Bond on denser s. paper c ndensers. resistors. line cords, fiers. tie strips coils, hardware, tubing. etc. selenium recti Part that you d is included. These parts are individually so thatEvery you an as;ly identify every item. packaged. an Electrical and A soldering iron is included, as well as Radio Tester. pComplete, e y -to- follow instructions In addition, the Edu -Kit" now are provided. Progressivrade Si contains lessons for vicing with the Complete instructions. The og course. donal to r[d YKit is a the smallest detaiF.C.C. al caps. This class of enclosure is lesirable wherever long life is required TROUBLE -SHOOTING LESSONS under extremely adverse conditions of and humidity servicing are included. You will be taught or atmospheric contamina- and repairTrouble.shoot,n troubles. You will build rand to recognize Tracer. You receive learn to operate a professional Signal tion. Ratings can be exceeded where wanin. repair` isdp Tester. and learn use it leefor d;o you arere learninglearn ;ei in, this practical way, you only limited fife is expected. job for neighbors and friends. will es able to do quickmined cost the and charge fees which will Half -wave stacks may be used in the others'. Here is your opportunity to learn .1p ashy, and haveal others pay for it. Our Consultation radio combination for doublers, bridges. you withiith any technical problems which you Service will may have. and center -tap circuits. Typical appl - cotions are in power supplies for rada FREE indicators, photo -flash oscillators, Ge.- EXTRAS ger ELECTRICAL counters, precipitron cost collec- & RADIO TESTER ELECTRIC SOLDERING tors and relay coils. They are also IRON TV BOOK used in RADIO TROUBLESHOOTING GJIDE o wide variety of computer. CONSULTATION SERVICE control instrument, and commun'ca- MINIATURE QUIZZES F.C.C. TRAINING t:ons circuits. Prone . INSTRUMENTS

497 - Union A.. kE r3, 5.00.lyo I, N. T. NOISE SUPPRESSOR Weston Electrical Instrument Co., 614 Frel:nghuysen MAIL TODAY Hermon Hosmer Ave., Newark 5, N. J., ' Pped some day rece -vc Scott, Inc., 365 Put- has announced a new 10 Day nam line of min'ature Money-Bock Guanlee. Include ALL FREE Ave., Cambridge 39, Mass., has Send EXTRAS designed 'Edu -Kit" Postpaid. I enclose full payment of o dynamic noise suppressor Send Edu $19.95 (U.S.A. only). -Kit" Postpaid. I enclose full payment of $20.95 (Outside 210 -250 V. Adapter for "Edu- Kit " -52.50. U.S.A.). Send "Edu -Kit" C.O.D. I will pay $19.95 plus postage (U.S.A. only). I wish additional information describing 'Edu -Kit ". No Obligation. I Sand me FREE Radio -TV Servicing Literature. I Name Address PROGRESSIVE "EDU- KITS" 497 UNION AVE., Dept. RE -83, Brooklyn 11, N. Y.

.11 RADIO -ELECTRONICS

www.americanradiohistory.com NEW DEVICES 1129

7- 13. Its forward gain averages IO connected by a 10 -foot 13. d.c. instruments incorporating transducer db across channels 8- portable cable to a control unit which contains o self- shielded mechanism, moael 281. insures the power supply and other electronic The core- magnet mechanism TUNER CLEANER mov- components. It produces a d.c. voltage 1 The larger accuracy within %. when any metal- Wolsco Electronics Corp., 3602 Cren- improved per - of constant amplitude ing coil employed gives near the pickup. shaw Blvd. Los Angeles 16, Calif., has high torque -to- weight lic mass is brought ormance with a contact is made with announced a new tuner cleaner, the allows increased sensitivity No mechanical ratio, and the exciting metal. The d.c. voltage Clean -O- Matic. where needed. as the excit- conventional, brush -like clean- bakelite cases, remains constant as long Unlike Furnished in complete is close prommity to the ers that cover only one set of contacts instruments withstand a ing metal in model 281 and drops to zero when it is at a time, it fits all Standard Coil of 2,600 volts a.c. r.m.s. pickup dielectric test removed. The rise and delay time of tuners, and cleans and protects all between case and terminals, applied fast, one in use. specifica- the voltage produced is extremely contacts except the ,n accordance with A.S.A. a definite snap are hand -calibrated, with thereby producing tIons. Scales action. to their mirror and knife -edge pointers com- added three new antennas to eliminate parallax errors. line. bined is high -gain v.h.f.- are supplied in a wide variety of ANTENNA ROTATOR The model 98 a They volt- covering channels 2- 83. The ranges in single and multirange Cornell -Dubilier Electric Corp., South u.h.f. ammeters. u.h.f. section is rhombic and the v.h.f. meters, ammeters and volt- Plainfield, N. J., and its subsidiary, 41/2 x is conical in design. Measuring only approximately Corp., 3455 Vega Ave., Cleve- section are Radiart Model 713 -6 is a 6- element dual- 41/2 x 11/2 inches, these instruments Ohio, announce the model TR -4 in labora- land, especially adaptable for use Rotor. tories,'in inspection, in educational antenna rotator has a meter a precision This work, and wherever else using 4 -wire cable and can size is re- cabinet instrument of miniature handle a load of as much as 150 quired. pounds. PROXIMITY PICKUP Electro Products Laboratories, 4501 N. TV REPLACEMENTS Ravenswood Ave., Chicago 40, III., hos Corp., 4055 Redwood im- Triad Transformer .developed a new proximity pickup Ave., Venice, Calif., has added six fly- pulse generator, model 4900. The unit to their line, making to the back transformers works on o principle similar a total of nineteen. Of the new addi- tions, four are universal type and two are replacements. driven broad -band Yogi for channels 7 -13. It uses two folded dipoles and multiple parasitic elements, and has 71/2 to 8 db gain throughout all seven channels.

military mine detector and may be excited either by magnetic or non- THREE NEW ANTENNAS Model 713-10 is a IO-element dual - -band Yagi for channels magnetic metals. Mfg. Co., Griggsville, Ill., has driven broad This new pickup system consists of a Trio Just for Examining COYNE'S New 6-Volume Set Get T h i s Valuable BookB o FREE Yes, you get this big, new 1954 book, "150 and Di-ft Radio -Television Picture Patterns " 7 DAY agrams Explained ", absolutely FREE! Just off the press! Gives complete 11x22" Sche- matic Diagrams on leading models Radio and FREE Television Sets. Easy -to -read, large 81/x11" pages, with how to read and use the diagrams. full instructions on -man's A "must" in every Radio and Television service TRIAL! repair kit. You get this valuable book as a FREE Gift for asking to see Coyne's great new 6 -book set, "Applied "! Practical Radio -Television SEND NO MONEY! Just mail coupon for 6- volume set Last! Money- Making "Know -How" of 150 TV -Radio Patterns At on '7 days free trial. We'll include book $2 in 7 days and $2 per on Transistors, Color TV and Servicing & Diagrams. If you keep the set, pay you all the answers to (Cash price $20.95) . Or Coyne's great new 6- volume set gives is month until $22.50 plus postage is paid. servicing problems- quickly! For basic "know -how" that you can return the library at our expense in 7 days and owe noth- you'll find everything you want in vol- THE JUDGE. Either way, the book of TV -Radio easy to understand, facts and data. ing. YOU BE limited. Act NOW! umes 1 to 5 which contain over 5000 practical Patterns is yours FREE to keep! Offer is every step from principles to installing, servic- They cover all types of radio and TV ing, trouble -shooting and aligning adapt- sets. So up -to -date it includes COLOR TV and UHF, FREE BOOK -FREE TRIAL COUPON! Also covers latest data on TRANSISTORS. ers, converters. -RADIO SCHOOL, Dept. 54 -T1 Extra! 802 -Page Television Cyclopedia Included (COYNE ELECTRICAL & TELEVISION volume 6 500 S. Paulina St., Chicago 12, III. then, for speedy on- the -job use, you get -the days FRE And answers 6-volume "Applied Practical Radio-Television" famous Coyne TELEVISION CYCLOPEDIA. It YES! Send eásrDiagram 7 FREE television problems on servicing, alignment, installa- TRIAL per your offer. Inc ludeTV- RadioPatterns today's indexed. Age and others. In easy -to -find ABC order, cross Name tion 7 days; Use this 6 volume TV -RADIO LIBRARY free for get the valuablo Servicing Book ABSOLUTELY FREE! Address City Zone... .State

ELECTRICAL & TELEVISION -RADIO SCHOOL Where Employed COD. You pay postman ( ) Check here If you want library sent COD postage on delivery. 7-day money -back guarantee. 12, Ill. $20.95 plus CDYNE 500 S. Paulina St., Dept. 54 -T1 Chicago

MAY, 1 954

www.americanradiohistory.com 130 I NEW DEVICES

ALL -PURPOSE ANTENNA be manufactured with ratings of 15, 20, 25, and 30 amperes. Brach Manufacturing Corp., 200 Cen- tral Ave., Newark, N. J., a division of General Bronze Corp., has announced the development of an all- purpose tel- Jobbers,Technicians evision antenna, designed especially with color television in mind. The new No. 555 Delta -V -Beam antenna eliminates the need for mixers, couplers, networks, and switches to combine u.h.f. and v,h.f. signals on a common NOW a brand new transmission line. - The new antenna has been tested in the New York - New Jersey area, and has proved very effective in discriminating against Insuline plant! reflections. AMATEUR RECEIVER EXTENSION SPEAKER . The National Co., Inc., 61 Sherman St., Malden 48, Mass., hos added a new Sootins, Inc., 321 N.W. 3rd Ave., receiver, the NC -98, to its Miami 35 line of To Fla., has announced the amateur and short -wave listening ra- Floritone extension speaker for TV sets. dios. The NC -98 is equipped with a The model uses a 5 -inch Quam heavy- crystal filter. S- meter, and accessory magnet PM speaker encased in a socket, and serve you Fiberglas is calibrated with either cone and mounted on a ham or short -wave bands. swivel on on aluminum base. It has a The receiver hos 550 kc-40 mc cover- 4 -way switch enabling the user to play age, 8 miniature Pubes plus a rectifier, either the TV or the extension better speaker I r.f. stage, 2 i.f. stages, slide -rule or both, or to shut off the sound corn - dials, an antenna trimmer, a noise pletely. limiter, provision for narrow -band The Floritone is fre- available in white, quency modulation, and a separate gray, blue, green, coral, and buff, and high -frequency oscillator. can be used for "personalized listen - ing," late evening programs, and the like.

INSULINE'S NEW HOME

IN MANCHESTER, N. H.

This modern new building pro- siding and air transportation vides 281,000 sq. ft. of air con- facilities planned ditioned to provide manufacturing space our customers with better serv- with complete trucking, rail ice from design to delivery. SIGNAL GENERATOR Precision Apparatus Co., Inc., 92 -27 EXPANDED Horace Harding Blvd., Elmhurst 4 FAC ILITIES INCLUDE L. I., N. Y., is producing a new model Added Equipment Enlarged of their E -200C signal generator, with factory personnel a direct reading frequency coverage Latest streamlined Expanded engineering staff from 88 kc to 240 mc, fundamentals to production methods 60 mc. The circuit uses a 6AU6 in a stable electron- coupled oscillator circuit, modulated by a 6U8 sine -wave audio oscillator, and a 5Y3 -GT full - wave rectifier. For the convenience See us at of customers in the s11111111111 and ROOM 512 New York City BOOTH 403 area. MOTOROLA at the Insuline maintains a REPLACEMENTS Parts Show sales office at: 1954 Electronic Hotel Ram Electronics Conrad Hilton Soles Co., South Buck - May 17-20 36 -02 35th Avenue hout St., Irvington -on- Hudson, N. Y., Chicago. Long Island City I, N.Y. has announced the X103, X104, X105, and Telephone: AStoria X106. These units are exact re- 8 -3738 placements for all the flybacks Teletype: NY 4 -4386 used in Motorola chassis TS -14 to TS -505 with practically no exceptions. Spe- cifically, 40 chassis and 416 models are covered. The flybacks apply to 29 dif- insuline TOOLS -Engineered to the ferent Motorola flyback numbers. specifications of television set manufacturers ALL CHANNEL Line includes every necessary TV tool to U.H.F. ANTENNA service all receivers. Here are just a few: JFD Manufacturing Co., Inc., 6101 16th Ave., Brooklyn 4, N. Y., has announced N0. 6847 a u.h.f. antenna, the Bowtie-Flector, model 615. The antenna features a rigid wire grid reflector and aluminum No. 6162 bowtie dipole. The reflector is plated with cadmium to resist rust and corrosion. Extensive field testing in Penn- sylvania reveals an average gain of 6.5 db across the u.h-f. spectrum (over half -wove folded reference dipoles).

ONo. 6171

No. 6165 Be sure it's Insuline when you need the right tool for a TV service problem. Write Dept. RE -5 for complete tool list The X103, X104, X105, and X106 are and new TV autotransformers which are engineered tool brochure. to operate in the 66- to 70- degree hori- THOUSANDS zontal deflection angle system. They OF OTHER OUTSTANDING INSULINE PRODUCTS INCLUDE deliver 10, 14, 16, and 16.5 kilovolts, Racks, cabinets, cases Auto radio components respectively. Panels, brackets, grilles TV antennas and accessories Auto antennas Miscellaneous hardware NEW FUSE Sightmaster Corp., New Rochelle, TV COMPONENT TESTER N. Y., is producing an indicator -re- Tronsvision, Inc., New Rochelle, N. Y., peating fuse for insuline home and industrial is manufacturing a TV component use. The item features a neon indicator tester which tests flyback transformers CORPORATION OF AMERICA which lights up when a fuse ceases to and yokes, selenium rectifiers, we function. and picture tubes, and also reactivates worn. The light is a signal to switch to the out picture tubes. next position 186 Granite St. Manchester, New Hampshire on the fuse. Since there As a flyback transformer and yoke are six positions, it can be used re- tester, it peatedly checks for shorted turns. Posi- without replacements. It will tive reading shows if flyback output RADIO -ELECTRONICS

www.americanradiohistory.com NEW DEVICES 1 131

transformer or yoke need replacing. As Its amplitude is constant over the en- be used in over 40 chassis and more o selenium rectifier tester, it checks tire sweep range. The 697 features a than 100 models, and may be installed rectifiers in half -wave circuits and piston -type attenuator. It is designed without any chassis or circuit altera- tests all radio and TV power supply to provide bare minimum loading ef- tions. rectifiers. As a picture -tube tester, it fects on u.h.f. circuits under alignment. provides for checking the picture tube This Instrument was described in the SERVICING AID without removing it from the set, mea- new items, the Vari -Tenna and the March issue, but the illustration with sures cathode emission accurately, lo- Energized Ferri.Loopstick. The former it was that of the model 690 u.h,f.- Raytheon Manufacturing Co., Receiv- cates shorts between elements, locates is a coil with an extremely high -Q v,h,f. marker generator, described being Tube Division, Newton 58, Mass., high -resistance shorts o, leakage as winding and o ferrite core, designed low. Both photos are shown here. has announced the Brow -Lite, a flash- high as 3 megohms. As a picture tube to replace the antenna coil and long The u.h.f.- v -h.f- marker generator, light which frees both hands. reactivator, the unit provides for re- hank of wire in old radios. model 690, covers frequencies from The device fits easily above glasses activating a picture tube in or out of The loopstick is a miniaturized "bar 4.25 to over 225 me on fundamentals and has a movable socket which ad- a set, restores brightness and detail, loop" for use where space is o factor. with a 0.25 volt r.f. output, and pro- justs light to any angle, eliminating and prolongs life of pic'ure tube, Because of the exceptionally high Q vides dual markers with any TV sweep of the ferrite rod (Q up to 400), a generator. Marker setting of 0.05% ac- core length of only 23/4 inches is re- curacy is featured. quired to give superior results. A quick -lock vinyl collar is used to ROTARIES maintain the core in its adjusted position. Telrex Inc., Asbury Park, N. J., has The unit is not intended as a re- announced their Beamer Power rotaries placement for the Ferri -Loopstick or Vari- Loopstick. It is a supplement for use in coses where their excellent performance has to be surpassed, such as in small portable radios.

TEST INSTRUMENTS unnecessary head motions. Using stand- Hickok Electrical Instrument Co., 10531 ard parts, the light is pocket size, Dupont Ave., Cleveland 8. Ohio, has easy to carry, and constructed of dur- announced a u,h -f, sweep -alignment able plastic. generator and a u- h,f,- v -h -f, marker generator. INDOOR ANTENNA The sweep -alignment generator, model 697, is an all- electronic sweep that Brooklyn Television Co., Inc., 72 Steu- has no moving parts. It provides ben St., Brooklyn 5, N. Y., hos an- fundamental output on cha -nels 14 -83. nounced on indoor TV antenna, the F lash- for FM v -h -f., u.h.f., for 2 -, 6 -, 10 -, 15- and 20 -meter per- O- Matic, The is formance. These arrays feature a bol - and color reception. antenna en with a T transformer for optimum mounted on a nontip cut -glass base coaxial line coupling, brood -band re- and a revolving swivel. END RADIO AIDS sistive match, balanced pattern, no Superei Electronics Corp.,, 23 Atherton matching problems, and minimum St., Yonkers, N. Y., has announced two interference. REPLACEMENT FLYBACKS Chicago Standard Transformer Corp., Addison & Elston, Chicago 18, III., has announced three new replacement fly - backs for RCA sets. These are Nos. All specifications given on these A -8233, A -8234 and A -8235. They may pages are from manufacturers' data-

eleTision CotvYSe selvicint, PRACTICAL, NEW. LARGE COVERS EVERYTHING IN TV Let these lessons take you into TV serv- Here is your complete training in very first lesson new les- icing the easy way. The television servicing. These of this sensational course tells how to do sons cover every fact, adjustment and simple repairs. You start earning money I make TV repair of every type and of immediately. Second lesson tells you what receivers. Giant in size, mammoth in picture scope, just like other correspondence is wrong, by just looking at the - ,Nurses selling for over $150. Our no instruments used. Lesson 4 has 32 large, amazing offer permits you to obtain 8th x 11" pages and 28 large illustrations on the course complete for only $3, noth- practical antenna installations and improve- -t,?wvp ing else to pay. Easy -to- follow, well ments. Another 12 lessons deal with trouble- illustrated lessons on circuits, picture shooting, stagger-tuned alignment, inter - faults, adjustments, short cuts, about carrier sets, UHF converters, use of TV test B47TMp1' UHF, alignment, antenna problems, equipment, picture analysis, new circuits. N troubleshooting, service hints, how to TV facts that puzzled you will be quickly clearest up. Yes, you will find yourself doing 5 use test equipment, and many practical sections prepared by leading man- TV repairs in minutes - instantly finding ufacturers. Just published. Send trial faults or making all needed adjustments. Mt- coupon today and use the complete amine this course for 111 days in your own Compiled by TV course at our risk. Satisfaction home. Look over this collection of material, M. N. Beitman, guaranteed. Your price for all lessons read a few lessons, apply some of the hints. radio engineer, in large manual form, complete, post- Fliers decide to keep the lessons at the bargain teacher, author, cost of $3 (full price), or return the material. a serviceman. paid, only $3. Send trial- coupon now COUPON RADIO & TV Manuals NO -RISK TRIAL ORDER Your complete source of all needed RAIDIO and TV diagrams and spryly, SUPREME PUBLICATIONS,1760 Balsam Rd., Highland Park, ILL. data. Most amazing values. Still sold al pre -Korean prices. Only $2 to $l per vol- Radio Diagram Manuals Send TV manuals checked EX below and Radio ume. Every Radio manual contains large manuals at left. Satisfaction guaranteed or your schematics, all needed alignment facts, 1953 Radio Manual. $2.50 money hack. parts lists, voltage values. trimmers, dial p 1952 Radio New Television Servicing Course, complete ...$3. stringing, and service hints. Each TV 1951 Diagrams ( EACH 1954 Television Servicing Manual, only ..$3. manual is a practical treatise on servicing l Latest a run year's sets, with giant blueprints, 1950 Manual $2.50 1953 TV Manual, $3. 1953 UHF Units, $1.50 waveforms, hints, alignment and voltage 1949 Radio 1952 Television Manual, $3. 1951 TV, $3. changes. See coupon titans, production 1948 PRICED 1950 Television Manual, $3. 1949 TV, $3. a list of these low - at right for complete & FM, only $2. priced Supreme service manuals. 1947 ? AT ONLY 1948 TV, $3. 1947 TV 1 1942 I am enclosing $ Send postpaid, 1942 f j 1941 o Send C.O.D. I am enclosing $ deposit. 1940 a Supreme Publications 1939 c EACH Name: 1926-1938 Manual. $2.50 Sold by All Leading Parts Jobbers Master INDEX only 25, Address: MAY, 1954

www.americanradiohistory.com 132 RADIO- ELECTRONIC CIRCUITS I REFORMING ELECTROLYTICS An electrolytic capacitor that has OPENING - been in storage or idle for six months to a year may have an abnormally high Fror leakage current when voltage is first applied across it. This current will gradually taper off to normal as the PHYSICIST capacitor reforms. But in many in- or stances it does not taper off fast enough to prevent internal heating. This in- SPECIALIST creases the leakage current and leads to early breakdown. To prevent such In occurrences, clectrolyytics which have not had voltage applied to them for a ULTRASONICS is here! comparatively long time should be reformed before being placed in service. Must be fully experienced and well The process consists of applying nor- qualified for mal working voltage to the capacitor through a series resistor to limit the RESEARCH AND current to a safe value. DEVELOPMENT WORK

400ac7/soMA 807 Unusual opportunity in new department in progressive, fast growing metal working industry in mid -west. Write Letter, 1I7VAC stating experience and salary require - nr8nts to Box 541 Radio Electronics

*PAPER GET THIS NEW for Quick TV Set EXTERNAL VOLTMETER SPRAGUE T -C RULE The diagram shows the circuit of a Adjustment variable -voltage power supply designed and for reforming electrolytic capacitors. It was described originally in The Alignment! ;f Radio Constructor, an English publication. Voltage for reforming the capacitor is supplied by a triode -connected 807 used as a grid -controlled half Save time . avoid mistakes . in finding -wave the values of stock N750 and MPO type ceramic rectifier. Its output voltage may be capacitors to connect in parcllet to equal a varied between about 40 and 400 by capacitor of desired intermediate temperature varying coefficient of the required capacitance. Just slide a positive voltage applied to this handy, pocket-size rule to -he proper values the control grid. This bias voltage is and you'll come up with the right answer quick * For adjustment of vertical developed as a wink every time. On bock are complete by a metallic rectifier and is color codes on all types of ceramic capacitors. linearity and height controls tapped off the 100,000 -ohm, 5 -watt Ask your Sprague Distributor or one, or write control. to Sprague Products Co. dl Marshall Street, * Accurate positioning of focus North Adams, Mass. It's only 15c. coil or magnet The capacitor to be reformed is connected across terminals 1 and 2. RL is SPRAGUE PRODUCTS COMPANY * Precise setting off yoke placed in series with the capacitor to Distributors' Division of the Spragce Electric Co. * Complete with instructions limit the leakage current to a safe NORTH ADAMS, MASS. value. A value of about 10,000 ohms is sufficient for an 8 -Rf, 450 -volt capacitor. RADIO TELEVISION The maximum safe leakage current in microamperes is 0.15CV for dry SERVICEMEN! electrolytics, 0.35CV for wet electro- HERE IS YOUR 1954 OPPORTUNITY lytics, and 0.3CV for reversible elec- TO DEVELOP A PROFITABLE trolytics, where C is the capacitance of SMALL APPLIANCE REPAIR SERVICE the unit in microfarads and V is the WITH PRESENT SHOP EQJIPMENT working voltage. HORIZONTABAR We supply a complete program designed Dealer Net Connect the capacitor to be reformed to maintain you in the highly profitable GENERATOR -_v:° across terminals 1 and 2, set the voltage traffic appliance repair field. sí95 control to minimum, and connect a ELECTRIC SWEEPER SERVICE CO. 400 -volt d.c. meter across terminals 1 `ee YOLI Jobber Today! and 3. Increase the voltage until the "The House of ESSCD', 100,000 Parts" current rises to the maximum safe value. 2034 EUCLID AVE. CLEVELAND 15, OHIO manufactured Leave the voltage at this level by until the current drops, then gradually increase the voltage- without drawing CROSS -OVER excessive current -until the leakage I-FI NETWORK A tweeter- woofer circuit Ch sago 25, III. current does not exceed the maximum for two speakers using TWO with full working voltage applied. CHOKES, TWO CAPACITORS & ONE POT. Write Manola,luaers al rletlronit EyvipmrnP Sirs 1978 for nearest dealer's name, also free wiring diagram, Reforming current is read on a 1 -ma specs. etc. meter that is shunted to read 10 ma Audio IMprovemenfs full scale. When the current & Accessories Co. Export Scheel International drops "AIMAC" 252 Greenwich St. New York City 7 4237 N. Lincoln, Chicago 13, W. RADIO -ELECTRONICS

www.americanradiohistory.com RADIO -ELECTRONIC CIRCUITS 133 below i ma, pressing the switch removes the shunt and makes the meter easier to read. STABILIZING THE HEATHKIT SCOPE A simple modification may improve the stability of the direct -coupled ver- NSTR UME:11111, tical amplifier circuits of the Heathkit model 0 -8 oscilloscope and make the instrument easier to use in areas where all channel UHF converter line voltages fluctuate. In this instrument, the 6C4 phase inverter is direct- coupled to half the 12AT7 vertical voltage amplifier. Volt- tuning element ups age fluctuations on the power line cause [X proportionate changes in the B voltages delivered by the scope's power supply. reases gain to noise ratio In the direct -coupled amplifier circuit, these voltage changes affect the amplifier gain and cause the trace to jitter. Fig. 1 shows the original B plus cir- C on cuit in the 0 -8. Point the supply Now the introduction of a of the 6C4 phase feeds the plate circuits frequency oscillator in the inverter and 12AT7 amplifier. By add- fundamental ing two series- connected OB2 voltage - new, improved tuning element regulator tubes, the voltage at this increases the useable gain of the point is stabilized at 210. General Instrument all channel UHF converter to provide even greater performance. Simpler construction, easier maintenance H.V.RECT and better design are additional features of this new tuner, already operating successfully as a component part TV receivers. L.V. REGT in leading

15K FIRST... in side -by -side tests! Jobbers: Some choice territories still remain open. Write for details. T Pit.!

The modified diagram in Fig. 2 shows how the 15,000 -ohm, 2 -watt resistor between A and C is replaced by two 4,700 - ohm, 1 -watt resistors (Rl and R2) in series. The 10 -µf filter capacitor for point C is removed and reconnected to the junction of Rl and R2. The values General of Rl and R2 were selected to provide a current of approximately 20 ma Instrument through the voltage -regulator tubes to & Appliance assure stable operation. CORPORATION Srrbtdi..o

il tulr Mr

EXTENSION SPEAKER Fit.2 -FI Floritone "CONTROL AT YOUR FINGERTIPS" rkayHIAMPLIAUDIO FIER With this modification, the scope now kitit The extra "personal" speaker for your TV -a operates satisfactorily in any area 1D WATT HIGH- FIDELITT AMPLIFIER ifith Built -in Pre-Amplifier "must" for the "hard of where heavy electrical equipment causes for Magnetic Cartridge, Mike, hearing" and the utmost the line voltage to fluctuate. This sim- CrrrtolPhonoorRadioTuner. in luxurious listening Frequency response: 1 db., TV or ple modification is well worth the time 20 to 20 ,000 cps. t pleasure for every Wide response bass and treble Model AO Z1 . radio owner. 4 in 1 switch and expense to any user of the 0 -8 controls Write for new s eaker output inductance: catalog of the com- controls either speaker - K. Schaefer 4. 8. 18 ohms plete ARKAY line shuts oscilloscope. -R. e Negative feedback of radio. TV, pho- both speakers -or w Hum: 70 db below rated output nograph and test off sound. Easily installed SAMPLE TYING SCOPE TO RECEIVER Complete with tubes equipment kits. and lists for only $14.95. $10.00 Dealers and distributors, write Scopes are often connected across the RADIO KITS, INC. for liberal discount informa. (Dept. R.E.) output of the i.f. amplifier of communi- 120 CEDAR STREET INC. arkay NEW YORK 6, N. Y. "io ". SOOTIN'S, cations receivers to check frequency BE 3-6686 321 NW 3rd Ave., Miami 36, Fla. shift and modulation percentage of in MAY, 1954

www.americanradiohistory.com 134 1 RADIO- ELECTRONIC CIRCUITS

coming signals. The scope detunes the circuit to which it is connected. This COMPLETE makes it necessary to touch up the tun- The COMPLETE line ing of the circuit each time the scope is connected or disconnected. DR Double -Reentrant TRAINING Projedors I eliminated this problem by con- FOR BETTER RADIO -TV necting the scope across the b.f.o. coil SERVICE JOBS and adjusting the b.f.o. pitch control for maximum pattern height. Typical b.f.o. circuits and the method of connecting Paging the scope are shown in Figs. 1 E Talk -Back Speakers

fij.I ALNICOV -PLUS Dual Speakers 3 MONTHS PAY Driver Units and 2. The b.f.o. is turned off when the scope is used for checking phone sig- Let these two great new Ghirardi training books teach you to handle all types of AM. FM and TV service jobs nals so its performance is not affected Public Address need! by approved professional methods-and watch your efficiency and earnings marl in any way. Mount a phone jack on the Completely modern, profusely Illustrated you and written to front or back of the receiver so the can easily understand every word, these books pave the way to fast, accurate service on any scope can be radio type of home plugged in at will. Use -TV- electronic equipment ever made. Each book is brand new. Each contains the latest data on the latest low-capacitance coaxial cable such as methods and equipment -NOT a re -hash of old, out -of- RG -59/U date material. Each is co- authored by A. A. Ghirardi for the connection. whose famous RADIO PHYSICS COURSE and MODERN RADIO SERVICE were, for 20 years, more widely used for military, school and home study training than any other WRITE NOW books of their typal for FREE Catalog 553 FULL -GRIP, VELVET-ACTION Mike Stands THE NEW Ghirardi ATLAS RADIO -TV SERVICE LIBRARY (° A `. Almost 1500 pages and over 800 clear illustrations show SOUND CORP. step -by how -step to handle every phase of modern trouble- Fif.2 shooting and servicing, 1443 39th St., Brooklyn 18, N. Y. In Canada: Allo, Radio Coro ., Led., Toronto, Onl. 1 -Radio and Television Receiver The height of the pattern on the TROUBLESHOOTING & REPAIR screen depends on the strength of the TV GLO -TEST A complete guide to profitable professional methods. For incoming signal and on the sensitivity Replaces the novice, it la a comprehensive training course. For the of $279 in experienced serviceman, It is s quick way to "brush up" on the scope. A strong signal will pro- specific jobs, to develop improved techniques or to find fast duce a trace 3 or more answers to puzzling service problems. Includes invaluable inches high on a TESTING EQUIPMENT "step -by -step" service charts, 820 pages, 417 illus.. 5 -inch scope $6.75 separately. price with vertical deflection sensitivity of 10 mv. -G. P. Oberto This is the instrument 2 that appeared in feature -Radio and Television Receiver articles THREE in RADIO -ELEC- CIRCUITRY AND OPERATION -STATE FLIP -FLOP TRONICS and other Dub - This 669 -page volume is the ideal guide for servicemen The Eccles- Jordan circuit is widely lications. GLO -TEST is the who realize It paye to know what really makes modern sensational new tester radio -TV receivers "tick" and why. Gives a complete unused as a scale -of -two counter in radar, that almost talks! For TV derstanding of basic circuits and circuit variations; how to recognize them at a glance; how to eliminate guesswork loran, computers, and in timing and and Radio servicemen, and useless testing In servicing them, 417 plus, Price Sound Technicians, separately calibrating circuits. is Ama- $6.50. It similar to con- teurs, Experimenters, ventional multivibrators except that the Electricians, New low price ... You Save $1.25! cross -connected grids and plates are OVER 50 USES, INCLUDING If broken into lesson form and sent to you as a "course," PIXTUBE - you'd regard these two books direct- coupled. TESTER -AC -DC VOLTAGE MEASURE- great as a bargain at $50 or MENTS TO 50 morel Together, they form a KV-SIGNAL GENERATOR- SIGNAL complete modern servicing While developing register TRACER -TUBE TESTER library to help you work faster, more efficiently and more circuits for -RESISTOR AND CAPACI- profitably. an electronic TOR MEASUREMENTS-DISTORTION AND LINEAR- Under this computer, Andrew D. ITY CHECKER. ACCURACY COMPARABLE TO VTVM. new offer, you save $1.25 on the price of FULLY the two books -and have Booth GUARANTEED the privilege of paying in easy and H. Ringrose discovered that Replaces instruments Coating many installments while you use themi times its cost, does it is comparable job yet is only a small fraction of their total possible for the Eccles- Jordan flip - weight and size. GLO -TEST, complete with test leads and instruction booklet, postpaid, is priced flop circuit to have three at in 10 -DAY FREE stable states BEa TRIAL Send heck or money order. 1O -day money instead of only two as we have grown back guarantee. Free literature on request, aÍ BSO to expect. A report on the scale-of V. ENTERPRISES, Dept. RE -54, RINEHART -three A. Dept. AA & CO., Ine. 608 East Rosecrans Blvd., Compton, 232 Madison Ave., New York 16, N. Y. flip -flop counter appeared in Electronic Calif. Send books below for 10 -day FREE EXAMINA- I Engineering (London, TION. In 10 days, I will either remit price (plus post- England). The age) or return books postpaid and owe you nothing. I circuit is shown in Fig. 1. EASY TO LEARN CODE Radio & TV Receiver TROUBLESHOOTING L. RE -' PAIR (Price $6.75 separately) It is easy to learn or Increase speed 0 Radio & TV Receiver CIRCUITRY & OPERATION with an initructograph Code Teacher. (Price +15011 $6.50 separately) 1 22K 221( Affords the quickest and most prac- f tical method yet developed. For be- here MONEY for -SAVING COM- 6SN7oo6J6 ginners or advanced students. Avail- CheekBINATION OFFER Save $1.25. both of above ... send able tapes for beginner's alphabet big books at special price of only $12.00 1 to typical messages on subjects. for the two. (Regular price $13.25 you Dave OUT all of postage) Speed ranges 5 to 40 WPM. Always days ) if yout decide to a books and month3 a for 3 15Lgt 33k ready -no QRM. months until the total of $12 has been paid. ENDORSED BY THOUSANDS! Name The Instructngraph Code Teacher 33k literally takes the place Of an oper- Add»aa 1 ator- Instructor and enables anyone to learn and master code without fur- 1 the[ assistance. Thousands of successful operators have City, Zone, State PULSE IN "acquired the code" with the Inatructograph System- Write today for convenient rental and purchase plane. Outside U.S.A.-$7.25 for TROUBLESHOOTING REPAIR: $7.00 for CIRCUITRY & OPERATION;&' $13.00 for both books. Cash with order, but I refunded if you return books in 10 days. INSTRUCTOGRAPH COMPANY 4701 Sheridan Rd., Dept. RC, Chicago 40, III. RADIO -ELECTRONICS

www.americanradiohistory.com 135 RADIO- ELECTRONIC CIRCUITS 1 With this circuit, three stable conditions can be obtained with a 6J6 or with EMC 6SN7 -GT. The 6J6 operates in this manner when the common cathode re- YOU SAV MORE.. sistor has a value of from 3,800 to precision 4,200 ohms. The 6SN7 -GT requires a cathode resistance of 3,000 to 4,000 instruments INPUT PULSES ...SERVI E BETTER The top quality of EMC precision instruments has been proven by years of coast -to -coast tests per- 66v formed both in the field and on the bench covering servicing condition. 56v- every 36v- Exceptionally low prices on these quality instrurrents are nade possible by combining every new engineering with EMC large volume production. o advance Fì1.2 Convince yourself ...check ohms. Fig. 2 shows the output wave- the features and prices of with six successive forms available exanples trigger pulses. The authors report that the two outstanding the circuit will not have the third quoted below ... steady -state condition if the second plate -to -grid coupling resistor is bypassed. MODEL 700 UNUSUAL PENTODE DOUBLER 1 a con- The diagram in Fig. shows 5 unit ventional pentode frequency multiplier stage. Operating bias -three to five times cutoff -is developed by grid - signal generator current flow through Rg. Cathode bias to protect the tube against excessive plate dissipation when excitation is removed is provided by the drop across Saves money, time and space by an of functions. Accurate to within Rk. Rfis is the screen -dropping resistor. e :clusrve combination 1 on RF and 3% on A.F. ranges. A British amateur, G2JAM, has devel- /2% on oped a novel circuit which eliminates 1. R.F. Generator -300 kc to 110 megacycles the need for the screen and cathode re- fundamentals sistors and their bypass capacitors Ck 2. A-F. 3enerator -18 cycles to 300 kilocycles and C. His circuit is shown in Fig. 2. 3.Squae Wave Generator -600 cycles to 20 kc FRED. MULTIPLIER 4. Bar Generator variable number of bars available 5. Crystal Market Generator

Model 703 New combination price 55.90

f IN

Compare these high qua ity features with meters selling up to twice the puce of Model 106.

Fig. I completely electronic -meter cannot burn out In the revised circuit, the screen grid Dual triodes balanced bridge circuit operates with zero d.c. voltage. Its op- Zero center adjustmer>

F .2 The simplified circuit in Fig. 2 is one MIN of the doublers used in G3JAM's all - band exciter described in The Short BIM wave Magazine, a British amateur publication. This circuit is applicable to circuits E MEASUREMENTS CORPORATION ELECTRONIC using tubes where the screen -grid volt- 280 Lafayette St. New or 12, N.Y. Export Dept., 303 W. 42nd St., N.Y. age is only about five or six times cut- NTI off bias. END Write deeartnent RE.5 for complete catalog MAY, 1954

www.americanradiohistory.com 136 TECHNOTES

ELECTRON 1! eE WHOLESALERS, INC. RCA 2XF -91 DIAL DRIVE Dial -cord slippage is a frequent com- RECEIVING Li =' TRANSMITTING SPECIAL PURPOSE plaint on the RCA 2XF-91 a.c. d.c. 140 DUANE STREET AM NEW YORK 13, N. Y. Phone: BArclay 7 -7616 -FM receiver. The AM and FM pointers and drive pulleys are mounted SENSATIONAL DISCOUNTS! on fiber bushings to insulate them from We specialize exclusively in TUBES -of every the chassis. Seemingly, the speed fast- kind and description -serving the industry for eners used on this model years. More than 3000 different types in stock are not suf- for IMMEDIATE DELIVERY-including hard -to- ficient to hold the bearing get and discontinued against the numbers. All tubes extension of the dial cord, haustively tested in our fully equipped labora- because time tories, and re- tested at time of shipment. after time, they have Iposened up short- FULL ONE YEAR GUARANTEE ly after I've tightened them. This con- All tubes individually boxed and code -dated. sumes the technician's 082 ... .74 3A4 .44 6eG6 .1.18 time and can be 0Z4 . 6567 .60 12A6 . .54 3A5 . .93 6BH8 . .59 125N7GT 1A5GT. .39 .45 65H7GT .50 124117 .58 56 .. .49 dangerous to the set owner 3A8 ,60 6BJ6 . .89 12507 when 1ABS .42 65.17 . .50 12AT8 . .56 the .. .39 387 39 6BN6 .79 6587 .39 58 .58 1AX2 . .61 3118 .40 12477 4 12Z37. bearings loosen enough ,39 6BQ6 . .79 6SL7GT , .49 12AÚ6 .39 70L7ÓT .1.00 to let the pul- 163 . .67 3Q4 . .39 14A4 . .48 87Q7A . .88 .69 714 . .54 1D8GT .77 354 65N7ßT . .49 12AU7 .58 14AF7 leys drag on .48 8BZ7 . .89 6507Q .40 . .59 76 ... .43 the chassis brackets. This 1G6OT . .25 12AV7 .69 , 3V4 .Sl 8C4 . . 14F7 .67 7g . .37 65R7 . 1H50 . .45 12AX4ßT .45 .25 574 . .59 1467 places -1.28 6C3 .39 6577 . , .59 80 . .35 the metal dial pointers 1HSßT . .49 12AX7 at chas- .48 5730T . .38 8C8 . . .55 .59 14N7 .69 6770 .79 81 , .1.11 1.186 . .59 12477 . SZ3 . . .79 19 . .44 gCBß . .85 6T8 . .59 ,49 82 . . .69 sis potential 1L4 . .45 646 12846 .49 which may, be 117 volts .47 6CB6 .45 BU70 . 196G6Ó, .99 1L54 . .79 .45 12847 648 . gg 6CD8 .59 Z2T7 ' .1.10 6U8 .59 .79 84 . . above 1LA6 . .79 6AB7 12BE6 .54 ground under some .75 606 . . .69 6V6ßT . .39 .44 .59 conditions. 1LCS . .66 64C7 . I2BH7 .65 25BQ6ÓT .85 6D8G . .98 6W4 . . .75 89/Y . .49 1LC6 . .79 .45 128117 6AF4 ,gg 6F5 . . .39 84 25L86T .39 117Z3 1LDS . gW6 . 32eZ7 .38 .77 6AFB .75 6i7 , 83 25Z5- .84 .93 6X4 . . .36 807 .1.39 1LN5 . .59 12C8 6AG5 .46 6F8C . .34 2SZg6T. .44 FLOW SOLDER .99 6X8 . . 2051 .95 1114 . .74 12F5CT DIAL BRAGIET- I AT .89 6407 . .95 668 , .33 26 , AROUND EACH END OF CHASSIS 11.5 .49 6Y76 . .79 .. .44 9001 . 1.49 STRAP . .56 6415 .89 1266 . .44 27 6J5 .. . .40 8570 . 9002 .98 IRS . .48 6A65 . .73 75 12J5ß7 .39 6J6 .. .49 746 , .69 32L7GT .98 9003 .1.48 154 . .58 6ALS .36 6J7 12J7ßT .58 35C5 .37 .95 12K7 9004 . .97 .42 .37 . .SS . 6J70 . .39 7ÁG7 35W4 .37 9006 . . . 55 .68 1558 48 6A55 . 12K8 .50 6J80 . .95 .58 35Y4 .45 1T4 . .48 6AT6 784 .44 12L7GT1.40 PULL Y FIBER BUSHING .37 6K7 , . .39 35Z3 . .43 1U4 . . .59 12Q7GT .48 6AU8 . .40 6K80 7C4 .59 41 .. .41 CATHODE . .48 . .58 12580T lus 6AV5 . .79 6L50 . .79 7C5 .61 42 .41 1X24 . .83 6AV6 .59 125470T RAY PULLEY .37 6L7 , . .85 7E5 .84 43 . .55 243 . .95 6AX4GT. .55 . .59 12SC7 . .69 .42 61.70 . .59 767 . .59 45Z3 3EP1 . 5.50 SHAFT 2A4G . .99 668 . . 6piy 125F5 .85 .98 71.7 .49 46 . .49 !BPI . 3.95 2A5 . . .59 668G .59 125F7GT 49 GND . .69 . .44 58p4 . 9.95 STRAP 266 . . .49 6BA6 .85 12507 .40 657G .59 . .75 SOBS , .40 SCP1 . . 7W7 5.95 SOLDERED 287 . .64 . .85 12567 . .75 SPEED NUT 6647 .56 6547 . SOCS .44 7BP7 . .40 7Y4 . .44 125J7 7.45 OVER FIBER 6BC5 . .49 6507ßT .38 7Z4 .59 SOLBOT .62 12DP7 19.50 2X2 . .39 .49 12SK7GT 6gE6 . .37 65G7ßT .40 IOY ' .62 50X8 .64 1611P44 BEARING 69 125L707 49 5011807 .59 FREE! SEND FOR OUR LATEST LISTING- minimum 24.98 Prices subject o change wI hout nottc. Orde w10. leue inelude 2s depenit All prices F.OB. our varehoun. N.Y.C. wlth order. Writ. ter Types not listed. WASHER FIBERFIBE BEARING fooKar RADIO- TELEVISION ENJOY 3 COLOR TELEVISION FILTER CHASSIS CHASSIS Changes SCREEN NOW dull ye-straining black and ,ITEMCM Get More into E l white pietures Service Calls with solar tonea, seeandn to attach. No used. Helps eliminate gglare and snow in fringe teal. Order 174. Send $1 for er52 size areas. To correct this EICO DECALS 51.50 size 21 condition permanently. 24 ^. S3 size 27 ^. (Also available S2,5Ó sii color screens in are single solid solder a volume -control ground For Store Windows 86 Cars. blue. green. or amber.) Prices on strap L7 /CO17 Solid color screens are 10% Ins. We pay except on C.O.D. orders. Satisfaction postage over the lip of each fiber tlSt iNSirUMfMIS Write EICO Inquiries from guaranteed. bushing as dealers also welcomed. shown in the illustrations. The Brooklyn 11, N.Y. Dept. DC Zingo Products, Johnstown 13, straps -5 New York supplied with most replacement volume controls are just right for the job. They are large enough for soldering to the e mounting bracket ? ÿi a D é and thin enough to -o ú-. _w .°N.pa -T B fit in the available space. _4 m= :1,:w aNCÚI.a rl ?, w Before reinstalling the dial -drive pul- C?dúi"- leys ve

Employed by RE RADIO -ELECTRONICS

www.americanradiohistory.com TECHNOTES

minimized callbacks by removing the jumper between terminals 3 and 8 on the 117Z6 -GT socket and inserting a 47 -ohm, 1 -watt resistor between these points. The diagram shows the power - supply circuit of this set. -George R. A'nglado MOPAR 606 The complaint was intermittent re- reption with occasional traces of smoke f coming from the receiver chassis. This trouble is caused by an intermittent short in the spark -plate on the i.f. chassis at there is the point where the B plus lead connects to the second i.f. transformer. This overheats and damages the 1,000 - ohm filter resistor on the power and a correct audio chassis. Replace the spark plate or disconnect it and install a suitable B plus bypass capacitor. Replace the 1,000 -ohm resistor in the filter circuit. -Harry C. CO RNELL-DU BILlE R Keller WESTINGHOUSE TV SETS Faint light and dark vertical lines on REPLACEMENT* the left of the raster may be caused by ringing in the horizontal linearity coil. It can usually be suppressed by shunting a 5,000 -ohm resistor across the coil. VIBRATOR -Marty Brill PACKARD -BELL TV SETS The set came in with no high voltage. for every The entire horizontal sweep string seemed to be dead. I could not drive original equipment the output stage with an external oscillator. All voltages were near normal vibrator made except the horizontal oscillator and the grid and cathode of the 6BG6 -G. Plate voltage was low at pin 5 of the 6SN7- GT oscillator and a.f.c. tube. After removing and checking most of the horizontal components without success, I tried replacing the horizontal all you need is C -D oscillator transformer. The set's performance returned to normal. I had previously checked and rechecked this `ask your distributor for your" C-D VIBRATOR GUIDE" transformer with an ohmmeter without finding anything wrong. Apparently the defective unit had a few shorted turns CONSISTENTLY DEPENDABLE deep within its winding. The external sweep oscillator would not drive the output stage because I CORNELL-DUBILIER had overlooked the fact that the circuit SOUTH PLAINFIELD, NEW JERSEY returns to 100 volts negative and I had not used the correct ground return. - E. V. Snider, Jr. END ROTORS CAPACITORS VIBRATORS ANTENNAS CONVERTERS

ltÌ$Cl- .- .111E'Ci7 CpO(111 OUTPUT TRANSFORMERS Exclusive patented design for optimum use in Acro Ultra- Linear circuits SOUND BEST TEST BEST SMOOTH NATURAL SOUND V/ RESPONSE =1 db 10 cps to 100 kc V/ UNDISTORTED POWER 20 cps to 20 kc CRISP WELL -DEFINED TRANSIENTS V UNSURPASSED SQUARE WAVE CLEAN SEPARATION OF INSTRUMENTS PERFORMANCE SOLID BASS -SILKY TREBLE \/ PERMIT UP TO 30 db FEEDBACK TO. 300 -20 watts for KT-56. TO- 310 -10 watts for 6V6 TO. 330 -50 watts for pa par 807, 5881 tubes ..$24.75* tubes $18.75* KT66, etc. $39.75*

e Slightly higher in West

$ngpested by Joseph J. dntonitis, Orono, Maine Descriptive Literature and High Fidelity Amplifier Schematics and Data Available on Request. "You wear the antenna in ACRO PRODUCTS CO., 369 SHURS LANE, PHILADELPHIA 28, PA. place of your usual tie" MAY, 1954

www.americanradiohistory.com 138 CORRESPONDENCE

HIGH -FIDELITY SPEAKERS Dear Editor: STOP TV TUNER NOISE... H. A. Hartley's Part I of his article on High-Fidelity Loudspeakers shows, QUICKLY- SAFELY! with by far and away, the best approach to this subject I have ever seen. By this I mean very definitely to indict the many mathematical approaches to this subject which are all but worthless; SPRAI(iEi# even, I strongly suspect, to those whe made them. My hat is off to Mr. Hart- Pressure - Applied CLEANER -LUBRICANT ley for a down -to -earth appraisal based on physical concepts and good ears. His reference to Hans Vogt's Oscillo- plan capacity speaker is much to the point. I spent several days with Mr. A NEW MUST FOR Vogt at Berlin in 1930 and brought EVERY SERVICEMAN back one of these speakers with its high -voltage rectifier, and polarizing - No Harmful Ingredients voltage supply apparatus. All of this Exclusive X -79 Formula I still have in my laboratory. Reaches Everywhere-No Need To Mr. Hartley- through no fault of his own Pull a TV Chassis! -credits Rice and Kellogg with the introduction of the first real dynamic speaker in 1926-27. I would G -C's new SPRA -KLEEN Electrical like to make claim to Contact Cleaner and Lubricant is just an earlier date; for. in 1921, while developing the first elec- WRITE TODAY for your what you need for fast, easy, safe tro- phonographic recording and repro- free copy of the big servicing of TV tuners and other parts like relays, switches ducing apparatus for the Brunswick - new G -C Catalog 156. and controls. No need to pull that chassis; just ''poop" Balke, Collender Co., in Chicago, I pro- and SPRA -KLEEN's directional nozzle duced such speakers. One of these used reaches any remote corner. See your the earliest Magnavox electrodynamic favorite jobber today! horn- loaded speaker to which Mr. Hart- ley refers, but fitted with a very thin GENERAL CEMENT MANUFACTURING CO. and radially- ribbed (and therefore, very stiff and light) diaphragm provided 910 Taylor Avenue Rockford, Illinois tonka'riECTR, "'":' with a tensioned, thin, annular rubber , DEALER'S NET $1.00 AND tU{I.N ring at its edge for support. This re- LIST $1.67 (6 full ounces) placed the circularly -ribbed diaphragm normally provided with these speakers. with Its high frequency response was not thereby impaired, but the bass was set i phenomenal and smooth. The other of v these used a massive electromagnetic pot 12 inches in diameter and 4 inches high, with a 2 -inch diameter voice coil and a 12 -inch diameter, flat, thin, radially- ribbed, aluminum diaphragm as a direct, hornless radiator. Its outer edge was also supported by thin, stretched Identified with rubber. QUALITYsince the swaddling But these speakers had what I then termed "transient dissonance," days of Radio. The era of when re- producing music, due to too low a Television finds them, more damping rate of the moving system. TRAIN QUICKLY! OLDEST, BEST thon ever, the Serviceman's This caused the residual vibration EQUIPPED SCHOOL of ITS KIND in U.S. Friend. (mostly of the diaphragm and voice Come to the Great Shope of Coyne in Chicago. Get coil practical training in opportunity fields- TELEVI- from one tone) to heat with other SION -RADIO - ELECTRICITY- LLECTRON- tones after the tone in question had ICS -vital in Defense Program. Prepare nowfora bet- TV LEAD -IN CABLES 11/ ter job in Industry or better service rating. quit the stage. This speaker defect Approved for Veterans ANTENNA CONTROL CABLES is now finally being recognized, and Finance Plan -Enroll now, pay most of tuition later. It you need part -time work to help out with living ex- efforts are being made to suppress it penses while at Coyne, we'll help you get it. Special INTERCOMMUNICATION CABLES tuition plan for men of Draft Age. by electrodynamic damping of the Clip coupon for Big Free Illus- COAXIAL CABLES voice coil itself, or by inverse feed- FREE BOOK trated Book. No salesman will call. back, high flux density in the air gap, Act NON. MICROPHONE CABLES B. W. Cooke, President and the like. A TECHNICAL TRADE The ideal condition here, INSTITUTE RED NOT FOR PROFITPROFI SHIELDED CABLES of course, is an aperiodic moving sys- ISCHOOL Established 199 500 S. tem, which is what, in effect, Mr. Hart- CC II Paulina, Chicago TEST LEAD WIRES ELECTRICITY -)r TELEVISION ley says, when he speaks of a speaker RADIO * REFRIGERATION * ELECTRONICS HOOK -UP WIRES without "personality," or with absolutely no resonance. I B. W. COOKE, Pres. PORTABLE COYNE School CORDS Mr. Hartley mentions briefly a nodal 1 500 S. Paulina St, Chicago 12,111. Dept. 54.811-1 vibration pattern (Fig. 5) due to axial Send FREE BOOK and full details on: REPLACEMENT CORD SETS I TELEVISION -RADIO O ELECTRICITY compliance of the cone. There appears to have been no general notice of NAME this defect among speaker engineers.

CORNISH WIRE INC. ADDRESS COMPANY, It is due to a standing -wave pattern (for a fixed frequency) caused 50 Church Street, New York 1, N. Y. by in- CITY STATE terference between the direct wave RADIO -ELECTRONICS

www.americanradiohistory.com 139

EXPERIMENTERS! Now! get the NEW (EC l FLYBACK TRANSFORMER 81. YOKE TESTER Model 944 QUICK, KIT $2395 POSITIVE WIRED $34.95

TESTING OF

FLYBACK

1111ta1IE1 HERE IS YOUR OPPORTUNITY Now one of tarn AND 1111 117111 TO BUY A COMPLETE PRO - the most TELGRAM PHILIPS TV SYSTEM YOKES difficult TV AT A REMARKABLE ?RICE . , . 8995 service jobs PLUS ONLY or out THIS OFFER INCLUDES .. , in becomes 510 00 extra 1 with 23 © Chassis complete quick and for cabinet of set tubes plus 1 diode wired and ready for use. easy as 2 Protelgram projection unit including picture v 1 A -B -C! tube 3 25,000 volt power supply ready for use. 4 dynamic speaker on large baffle. out of 8" Positive check of all types flyback & yokes, in or 5 23" flat viewing screen and full size reflect. ing mirror. set -in just seconds! sun NOTE: !'trial+ include. . . Automatic beam - sensitive grid -dip principle . . on the extremely pres.ur . 11Igh Fidelity sound .5-1mo ...... Operates etc. matie control . "Stan.lar,l il" Tuner, gala -shows up even 1 shorted turn! iron core GOLDSTAR CO. Exclusive separate calibration for air core and THE flybacks for accurate testing of all types. 58 Walker Street. New York 13. N. Y. BE SURE! low. Checks any inductance whose impedance is not too SAVE TIME! New 2nd Edition Covers Transistors. Large easy -to -read 41/2" meter. Data on AM -FM Receivers, and BEFORE you Latest 3 separate colored scales. on the install or Up -to -date Material etc. Tests continuity of yokes, coils, speakers, switches, remove a New Radio Tubes! flyback or New compact size for extra -easy portability (7 "x5 "x4 "). yoke- CHECK RADIO SERVICING Smart professional styling - New satin finish etched it with panel with contrasting knobs and meter and grey by ABRAHAM MARCUS EICO's coauthor of famous "EU,ntent. of Radio' wrinkle steel case. Model which has sold over 800.000 copies! Here 944 I is every up- Predate detail yon Head In know Kit comes complete with easy -to- follow INSTRUCTIONS. radio repair. ella mentent aml re- ad7uslntrol. Easy- to -ttnr lrrstanel. step -hy- step stir.Irnlning handtm.k al volt how instrument at your parts jobber today. to Ierrnlr and r ntedv defects qulrkly Compare this new EICO Covers: Titi'' , Itecelve snPerhelenaivnt ® Write for FREE Catalog CF -5 Receivers: cl 1-Wave r lteeeiVery and Con - Yertrrs Molt lbn,.,.I It,mriser. PI tacle Re- Read EICO's other ads in this issue ceivers: Automobile Receivers: ('ommlullca Index. lion Receiver:: 141 Receivers: Power SUM -see Advertiser's Plies "petaled from A('. Ill'. Flatteries. Motor- f.enernIseo. mie. Tells yoli the 111)w and WILY of: El Tubes !Male. Triode, Inc., - ELECTRONIC INSTRUMENT CO., Pentode. Ream Puw r, Thyratron. Photo laboratory Precision at lowest Cost tube. ('nthol, Hay, rte.): Rectifier Circuits Y. Voltage- 84 Withers Street, Brooklyn 11, N. Ill:tlf- wave. Full -wave, Bridge, Priers ,4 butt, N 1 ! ttttt tiler. etc. t. Detector Circuits 11110.1,', Tri- ode. Ilegetterativ,', SuperregenrrUtive. ' -Inlited a etc.,: Amplifier Cir- AII in one big nib ,Atoliu. Radio. t -P. Video. It-C. CUSTOM CABINETRY volume - easy etc ): Oscillator Circuits IIlurllev, Col - to read. 16 Big pills, Crystal ait.in tttt. Mull7vu,ratnr. Chapters. 121 Sweep-env-toil. ele.t. Control Circuits Sections. 400 ,Volume. AVC. IIAVC, Tone, Noise- TV and Hi -Fi -Show- HOW- .npprteshrn. A alle Tu Auto- for Diagrams. 775 marte Franueury Control at.1. F:V- pages. You get more for plains how tu use testing instruments LOW COST! fir tel, as: meter, vacuum -tulle volt at your cabinet dollar I,s ,,.tien trudges. mull lmelcrs, signal gener- ttuln.slutr checkers, cathode-ray ose illustolts, etc. Over when you buy sec ' alone! 1110 pages and n I Illustrations In Otis .Standard. Beautiful Oct this authoritative radio repair handbook today! Coupon fidelity st ling, choice below brings you -Radio Servicing" on FRIC trial for 10 days. Mail it NOW. select -gra_n woods, r careful construction, PRENTICE -HALL. Inc.. Dept. MRE -554 functional design, 70 Fifth Ave., New York 11, N. Y. acoustical correctness semi me for 1(1 RASIS' F'ItF.E. TRIAI.. "Itadlo Servleine to sue acknowl- 11t1 Edit ion." Icy Abraham Marcus. 1 will return il -all keel, it miel send In ten days and pay nulhinlr »,r fil-97. ` I, edged finest standards down ¡plus postage) and 82 monthly fur 2 np,nits. /`- \_.,/ FRENCH PROVINCIAL 11 of the industry. Closed View ' °-- tri Name L /- Compara - Write now for ' 'FRENCI- PROVINCIAL our encra Im 3 Way Combination Address FREE Catalog RE S showing 1 4Ne7 West 63d Street, City State pay postage Corp./ ( t SAVE! Send $5.95 WITH COUPON -we Standard Wood Products w York 23, N. Y. MAY, 1954

www.americanradiohistory.com 140 CORRESPONDENCE

motion from the voice coil vibration source and the reflected wave from the LEADING TELEVISION AT LAST cone edge support. Aurally, it shows up as a wholly foreign frequency tone, usually an octave lower than the test DEALER TELLS YOU a good frequency, and is generally in about the 1,000 -1,500 c.p.s. frequency range. THE VALUE OF KRYLON Speakers rated at say 50 watts can only be used at 8 or 10 watts input due to this "cone break -up." Radial ribbing near the cone rim can cope with the tendency for the cone to de- UHF velop the "flower" nodal pattern, but these circular corrugations have no BOOSTER appreciable effect on the other type. (Fig. 5). Shallow cones are especially subject to this (Fig. 5) effect. "I use Krylon on the high voltage I have found an effective solution sections of TV receivers, for this, by using cemented -on, radial and on the antennas as well. stiffening tubes (experimentally I've It does a good job, cuts down used 32 common, paper, soda straws for contract calls, and I know it gets the this). A frequency -sound level output word around about my servicing curve shows only a 1 to 3 db drop in reliability." -Edwin G. Schaffer, sound level at some parts of the audio President, Edwin G. Schaffer range when directly compared with an Company, 7920 Frankford Avenue, otherwise identical (Jensen) 12 -inch Phila., one of the Quaker City's electrodynamic speaker, but the power most progressive television handling ability is much higher. organizations. As to directional effects: in 1926, I KRYLON 1 00% Acrylic Spray is published measurements on cone, horn a crystal clear, high dielectric and flat diaphragm transducers (both strength coating in a push- button microphones and speakers). While dispenser. For all high voltage with the Brunswick Co. (1921), I used sections and component parts of flat horns with vertical slot openings television receivers. Because of its to give a more nearly uniform disper- weather -proofing qualities, it is sion from low to high frequencies. I ideal for coating antennas, even had a very narrow, axial slit lead -ins, etc. along one side of the horn BEST NOISE FIGURE - Nothing ap- to prevent proaches the noise figure of 6AN4 horn resonances, and these horns were special UHF triode tubes. lined with sheet lead to reduce side wall resonance "The HIGHEST GAIN -18DB gain uses two of the (wood) enclos- 6AN4 tubes in push -pull, grounded ure. most grid, neutralized non circuit. It really The -uniform directional effects important removes that snow. of speakers produce a serious and not CUSTOM BUILT - Covers approxi- yet fully recognized type of distortion. handyman mately one third of UHF band. Comparing the acoustic situation with in the TV Checked on the channels in your a visual analogue, the loudspeaker is area only. See chart below. like a lamp which generates white light industry." Guaranteed to double your UHF sales of all visible frequencies from near area. infra -red to near ultra- violet. It should A must in dealer demonstration rooms equally illuminate all parts of a room where customers buy only one thing - the picture on the end of the tube. Con- with the mixture of separate frequen- version strips and booster make a won- cies contained in its white light. The KRYLON, INC. derful low cost combination in fringe lamp, we areas. will assume, is the ideal, 2038 Washington Ave., Phila. 46, Pa. Simple capacity tuning - no sliding con- aperiodic- moving-system loudspeaker, tacts to wear out. with every link in the chain leading No need to disconnect -when turned off, up Krylon also available in Bright antenna is connected straight through. to it from the original sound source, Aluminum, Flat Black, Glossy Black, Touch -Up White Complete with simple operating instruc- perfect in every respect. This includes tions. the loudspeaker cone, as to flat fre- and Bright Gold 73/4" x 5" x 41/2" -net weight -31/2 lbs. quency response, linear power response, At TV Jobbers Everywhere and no harmonic, intermodulation, or MODEL CHART other defects, such as extraneous Available now noise Model 14 -31 or tones. Model 20 -35 However, this lamp light Model 25 -50 must pass Model 40 -60 from its source through a sort of pris- TELEVISION Special models matic device which strongly refracts Big demand for graduates Available to cover any B.S. DEGREE IN third of the the light rays, so that the highest fre- 27 MONTHS in radio including band on TV -VHF, two weeks delivery. quency, violet- end -of- the -spectrum engineering UHF, AM and FM. Students rays use over 5100,000 worth of equipment including 2 large commercial Cut out and mail to: are concentrated, beam -like, along the type transmitters to new TV lab. lamp's axis, instead of spreading uni- Intense specialized course includes strong basis in SERVICE INSTRUMENTS CO. mathematics. science and advanced design in 422 S. Dearborn Chicago 5, III. formly all around. The medium -fre- radio and TV. blue and green Hundreds of young man each year are earning engi- I quency waves are less am interested in the new Senco UHF Booster. neering degrees in this recognized institution. Start Please rush further information to: concentrated in a broader beam; the any quarter. Many earn a major part of expense lowest, from yellow to in this industrial center. Low tuition. Competent in- Name orange and to struction. Thorough. intense, practical program. red frequencies spread more and more Also B.S. DEGREE IN 27 MO. in Aeronautical, Firm Name uniformly all around the room. Chemical, Civil Electrical and Mechanical Engi- neering. G.I. Gov't approved. Enter June, As a result of this, there is no Sept., Address place Dec., March. Free catalog. ENROLL NOW. in the room where one can see the de- INDIANA TECHNICAL COLLEGE C if Y Zone State sired, white light. Way off of the light 1754 E. Washington Blvd., Fort Wayne 2, Indiana RADIO- ELECTRONICS

www.americanradiohistory.com CORRESPONDENCE 141

red and orange, axis, one sees mostly RADIO & TY RECFiYCNG while between these points and the TESTED and axis, the light color is generally yellow to green. As we approach the axis, GUARANTEED the color changes again to blue and TUBES because the longer wave for finally violet, We've EARNED your Confidence . and we mean to KEEP it! PEA there are very weak, due to Thousands of Service Organizations and Dealers throughout America K lengths send us REPEAT orders month after month -they now KNOW you can their spreading out through such a wide DEPEND upon the WINDSOR promise of PEAK PERFORMANCE! PERFORMANCE course, assumes a room And here's why: Every tube we ship is first carefully tested in our angle. This of laboratories. for maximum functioning characteristics, right in a radio with completely absorptive walls, floor or TV set-under actual operating conditions! That's why we ncon- ditionally guarantee every Windsor Tube in ordance with the and ceiling, such as an anti- echoic room standard Warranty: Full replacement of any defective tube within 90 days of purchase. excepting only burnouts and breakages. Each tube or no room at all. A room- enclosed attractively packaged in individual carton. as the above BUY -AND SELL, WINDSOR TUBES -WITH CONFIDENCE! Type Each speaker is not as bad 7AG7 analogue would depict since the re- 7AH7 .65 Type Each Type Each Type Each Type Each 7A17 .70 flections tend to equalize, at least near IAIGT 5.67 3V4 .62 IiBDSGT .98 6Q7GT .55 784 .54 the various fre- IB3GT .69 5R4GY 1.011 613 D6 .54 6S4 .51 785 .51 Type Each room boundaries, . the IH5GT 5U4G .44 68E6 .51 6S8GT .75 .52 12BY7 .77 F5 .66 6SA7GT .57 .... spec- 116 .93 5V4G .83 68 .58 . quency sounds of the acoustic 6SC7 7B7 I215GT .48 closer IL4 .63 5Y3G .37 66 F6 .43 .63 7C4 1.05 12SA7GT .. .57 trum. But as one approaches 116 .66 5Y3GT .32 6BG6G 1.47 6SD7 .55 7C5 .56 12SH7GT . .67 .82 5Y4G .43 6B H6 .63 6SF5GT .66 7C6 .50 12SK7GT .. .55 closer to the speaker, the ana- I LA4 and ILA6 .80 6ARGT .68 6616 .53 6SH7GT .52 7C7 .58 12SL7GT .. .67 6S17GT . .52 and more nearly a true ILB4 .82 6A B4 51 681(5 .76 7E5 .85 12SN7GT .. .59 logue is more .82 .97 fiSK7GT .55 I LC5 .80 6AC5GT 6BK7 7E6 .65 12SQ7GT .. .46 since there the relative amplitude 6SL7GT .68 7E7 .85 14A7 one, I LC6 .80 6A G5 .59 6BL7GT 94 .58 are vastly .80 6AH4 .68 68N6 .98 6SN7GT .59 7F7 .69 14AF7 .... .68 of direct and reflected sounds 1L0 .89 .98 6SQ7GT .46 I LE3 .80 IiAH6 6BQfiGT 7F8 .97 1486 .50 6A1(5 1.05 68117 .92 6T8 .85 different. I LG5 .80 7G7 .85 I4C5 has ever been ILH4 .80 6AL5 .44 6BZ7 I.09 6U4GT .60 7H7 .61 14C7 .70 Practically nothing IL N5 .80 6AQ5 .51 6C4 .41 6118 .86 717 .85 14E6 .70 fiAQ6 .47 fiC5GT .60 6V3 1.09 7K7 .85 14E7 .85 solve prob- I N5GT .63 done commercially to this .51 I R4 .85 6AQ7 .75 6CB6 .58 6V6GT 7L7 .85 14F7 .69 R5 .42 6W4GT .50 of direct -radiator, single sneak- I R5 .62 fiA 6CD6G 2.04 7N7 .62 14F8 .99 lem 6W6GT .63 The ideal type of sound radiator IS4 .67 6AS5 .55 6D6 .63 7Q7 .62 1417 .85 ers. !SI .52 6AT6 .42 6E5 .72 6X4 .37 7R7 .70 I4N7 .75 would of course consist of a pulsating, 114 .62 6AU5GT .85 6F5GT .54 6X5GT 36 7S7 .90 1407 .62 1U4 .61 6A U6 .47 6HfiGT .55 6Y 6G .64 7V7 .92 14R7 .85 .57 spherical surface. A radiator of very 1115 .51 6AV5 .85 615GT .44 7A4 /XXL 7W7 .99 1437 .80 IX2A .74 fiAV6 .41 616 .68 7A5 70 7X6 .62 19BG6G 1.53 dimensions, at least as small or 7A6 .57 small 2X2 1.43 6A X4 .72 617 7Y4 .45 19T8 .87 preferably smaller than the wavelength 3L F4 .76 8B8G .93 KfiGT .45 7A7 .58 7Z4 .50 25BQ6GT .98 304 .66 fiBA6 .50 6K7 .70 7A8 .56 25L6GT .53 of the highest sound to be reproduced 3Q5GT .72 6BA7 .66 CLOG .88 7A D7 1.05 12AT7 .75 3S4 .61 6BC5 .58 6L6GA .88 7A F7 .63 12AU6 .47 25 6GT .46 would also answer the problem. 8 35A5 .55 The very early "speaking arc light" 2A V6 .41 3585 .53 12AV7 , .87 is an example of such a radiator but 12AX4 .72 35L6GT .52 of the ionized 12AX7 .67 35W4 .33 the thermal modulations 12AY7 2.15 35Z5GT .33 air in the arc would have to be very 1284 .66 50A5 .55 12BA6 .50 5085 .52 great to derive sufficient sound energy 12BA7 .66 5065 .52 from such a small -area source, and 12B06 .51 50L6GT .52 WINDSOR 12BE6 .52 11723 .43 the arc would have to be energized by 12B117 .69 1I726GT .75 frequency, a current of ultra -sonic TUBE CADDY Deposit with Order. All mer- A 25% modulated by audio frequencies. horn The most practical Service- chandise F.O.B. NYC. For orders slot Aid ever YS less than $10. add SI handling speaker with a horizontal, annular d T V nee pai rm an. Carries appruximatcll e d i o and including me and is helpful, except for the vari- This ideal television carry- tubes cost. Deduct 2% if full remittance opening with tools. a t/ç all now offere 3/ inches long 11./4 accompanies order. All merchan- lis- of $160.00 or 133/y inches able -phase relations at any given every purchase ches wide dise subject to prior sale and price accumulated prches high. waves from dia- 90 tdays. nine pounds. tening point of sound $160.0 within weighs only th changes without notice. ling credit memo with Ruggedly constructed metrically opposite sides of the annular (You get covering. Note to Our each pdy heavy plastic handle, stong hardware. slot. Windsor Tube Caddy may nickel pl ated metal Latin- American Friends: outright né reinforced with As previously mentioned, a horn with also be purchased clamps. SE HABLA ESPANOL! a narrow, vertical slot opening will for $14.95. OFFER! MISS THIS SE NSATIONAL spread the frequencies laterally around DON'T WRITE FOR ADDITIONAL the room, and at the same time con- 1 I TUBE TYPES AND PRICES. We I TUBE CO. also stock Special Purpose and fine the radiation in a horizontal, fan- tnîbSDr ELECTRONIC Transmitting Tubes at similar like beam, but this is still subject to 2612 -C NOSTRAND AVENUE, BROOKLYN 10. N. Y. savings! Dept. C -5 1 some of the same objections, due to the variable dispersion through the vertical planes of its radiation. TUBES -TV, RADIO. TRANS\II'l"l' LN.:. AND sPEl'L\L I have wrestled with this problem PURPOSE TYPES BOUGHT, SOLD AN!, E XI'I1-A NGIr.D. OPPORTUNITY ADLETS Send details to B. N. Gensler \Vf1,N I. 136 Liberty. over many years and perhaps others N. Y. 6, N. Y. also; it is an elusive one but, if Rates -45e per word (including atm.. address ati,i have Minimum ad 10 words. lash must arcosiI ALL MAKES OF ELECT1tICAI. INSTRUAIENTS ANT) initials). TESTING equips rut repaired. write for free catalogue will do toward long - ads except those by accredited agencies. Di solved, much that all placed on new and used instruments at a savings. Hazelton Instru- sought solution for perfect reproduc- count. 111'; for 12 consecutive issues. Misleading or ment Co., 128 Liberty Street. New York. N. Y. uhjeitionable ads not accepted. ropy for .TUIy tion of sound. ni usl reach us before May .11. 11I57. SALESMEN WANTED -SELL AT MANUFACTURERS :.OW PRICES-Television Wire Retail Outlets. 25 New York 7. N. Y. to 10% We have come closer to this goal Radio Electronics. W. Broadway. commission on Original and Repeat orders. All Territories is still the imper- Open. King Mfg. l'o., 45 Huron Road. Slohegan Heights. but the loudspeaker Yonkers, New fect link in the chain. York. PASS AMATEUR THEORY EX.\y1S. (1110 K YOUR- YOUR \'N ELECTRONIC 011 BENJAMIN MIESSNER novice BUILD ll \ ORGAN, MINIA- J. SELF with sample FI'(' -type questions and and TI'ItE electronic brain. slim Kirk. Wad KX. 1553 ('hutch general class examinations. All for only 5or. American Street, Han Francisco 14, California. Morristown, N. J. END Electronics, 13035 Bryant Ave., New York 59. New lark. WANTED: AN/APR-4, other "APR -", "TS -". CORRECTION SPEAKER REPAIRS ON ALL MAKES. Jabbers wanted. ARC-1. AR(' -3. AltT -13, BC -348, etc. Microwave Equip- Anlprite Speaker Service, 70 Vesey St.. New York 7. N. Y. ment, Everything Surplus. Special tubes, Tec Manuals. Lab Our printer inadvertently inverted Quality Equipment, Meters. Fast Action. Fair Treatment. the formula on page 137 of the Novem- Top Dollar! Littell. Fairhills Box 28, Dayton 9. Ohio. RADIO REPAIR SHOP AND FOUR RENTAL UNITS ber, 1953, issue. The formula, used for ON ACRE. Stock. Furniture. Station Wagon- genuine. COMMUNITY TV OPERATORS: FOR SALE 80' Twin Any trial. Retiring $12.000 -half rush. C. E. Buckingham. Steel Tower, 20' catwalks, 25' top extensions. Paid $1050: finding one wavelength (in inches) at 1728 G Street, Sacramento. California. sell for half. Pocono TV Relay, Inc., Stroudsburg, Pa. of a u.h.f. TV channel, the center ALUMINUM TUBING. ANGLE AND CHANNEL. Plain read: DIAGRAMS FOR REPAIRING RADIO $1.00 TELEVI- and perforated sheet. Willard Radcliff, Fostoria, Ohio. should SION $2.00. Give make and model. Diagram Service, Box 11,800 072 -11E, Hartford, Conn. TELEVISION SETS $30 UP. W4API, 1420 SOUTH 1 (inches)= (6 x u.h.f. channel No.) + 389 Randolph. Arlington 4, Virginia. TEST E(]UIPJIENT REPAIRED AND l'ALIIOIt:1TED We thank C. A. Tracy, of Sewickley, by factory staff. .fill makes. Solar. Simpson, Triplett, TV FM ANTENNAS. ALL TYPES INCLUDING UHF. Heath. etc. Immediate service. hongras Instrument Labora- Mounts, accessories. Lowest prices. Wholesale Supply Co., Pa., for this correction. tory. 176í Norfolk Avenue. Roston 19. Mass. Lunenhurg 3, Mass. MAY. 1954

www.americanradiohistory.com 142 I PEOPLE

Charles A. Hansen joined Gramer NEW Transformer Corp., "RACON" RADIAL HORN Chicago, as man- Famous Double Re- Entrant Type. RIDER ager of the Dis- (Mod. SR-35R). Weather- proof alumintin, deflec- tor,. :166 hi -Ii sound tributor Division. projection. Takes ,v BOOKS He BACON driver unit. U" was formerly ;. hracket. 16" I.. 148" Ist. Isiah): 17" O.D. sales manager of (BRAND NE\V (List 817.56)$' 8.95 FOR MAY Jensen Manufac- ..POUR PR ICE 25 WATT RACON DRI- turing Co. He is VER UNIT for ahuve.. Powerful Ahi no magnet, past chairman of ' a therproof alum. shell. 15 hm Im -$' 4.95 the Association of pod., 4" O.D. Electronic Parts BRAND NEW. C. A. Hansen RM -38A CONTROL UNITS (LN) . . a "gold - and Equipment mine" 'II .ia,ks, Plugs, Cables, Switches, etc. 2.95 BLOWER WHEEL 6 HOUSING . use with any ha,all motor. I: It Type =3 (51 /2+ O.D.). Moulded Manufacturers and former president of kelite 1.9° 1 30 HP A.C. MOTOR . 115V .94A. APProx the Electronic Parts Show. '3(110 111'M. Uhle, shaft (1/4 "- '1'161. 3" x nl _" 3.95 1 17 HP G -E MOTOR (Type SD) . 1725 T1P\I, amp. tilde. 4n" shaft. 1111V. DC. ("!" x 511" 3.95 RUBBER TAPE x 15 ft... roll 100 (( /1.00 CRYSTAL MICROPHONE Hi- fldclit >: h i -1m- F. Birney Farrington, founder of Xcel- ped. Rubber shark u1. 13/4" x tit ". Less housing 1.29 ALUMINUM HOUSINGI for :thrive mike ...... ite, Inc., Orchard Park, N. Y., hand tool HAND MIKE CASE moulded black bakelite. manufacturing 1.1). Rubber mouthpiece ea 490 1 2,5.00 firm, was elected KITS ! ! KITS ! ! KITS ! ! president at the an- A BARGAIN FOR EVERYONE!! ALNICO MAGNETS . . Powerful liar, Block, nual stockholders' "11", Rod. etc. Kit of 111 asstd ...... 1.98 MIDGET WOOD CABINET 6 CHASSIS (walnut) meeting. Other of- 7" a 51/2" x 4" beside. Punched 4 tube chassis ...... 1.49 ficers include John CARBON RESISTORS . 1 ,:1 -2 watt- 100 : ssld 1.95 MOULDED BAKELITE CONDENSERS . 5ónunf O. Olsen, vice -pres- to 2mfd, 2(16- RIIIWV.. :i6 sstd /1.!IS 11111/2.98 ROTARY SELECTOR SWITCHES ' . . inel. multi- contact. multi-leek. Kit 6 asstd...... 1.49 ident, and Clarence EXPERIMENTAL TUBES ... Test. lteseal'ch, write for the etc. Fit. tested. Kit 46 asstd. rova, types 1.98 Schwabel, secre- SPEAKER REPLACEMENT CONES . Popular sizes 4" to 12", incl. oval. Less voice coils. 12 tary. Arch Warden, 4d 1.98 SPEAKER REPAIR KIT . . . SAVE 888 with this complete sales manager, was professional 'stmt. of: Spiders, Icings. V. C. 32 page Forms, Felt, Chamois Lthr, Shim Kit, Cement & newly elected to the F. B. Farrington I listruct inns 2.49 ! 1 SPECIAL . . ROTH CONE 6 REPAIR KITS 3,95 office of treasurer. ! ! XMAS IN MAY ! ! NEW when you get the ".JUMBO IRAIDIO E1.ECTIIONTCS PARTS KIT" . . chock -full of inventory odds A end, worth several times the price. 17 lbs. f: swiircrigs, Warren M. Stuart, former Central Dis- SOCKETS. WIRE, RESISTORS. CONTIF..NSF.Its. TV PARTS Æ DIAGRAMS. PHOTO- FACTS, CONTROLS. RIDER trict manager for Belden Manufactur- ETC. ETC, Shp,. wl. 20 lbs. _ $3.95 ing Co., Chicago, DIRECT FACTORY SPEAKER REPAIRS SINCE 1927- Min. Order 8:1.06. 26.} depnsit exe all t'.O.D.'s. CATALOG was promoted to Please add sufficient postage -excess refunded sales development RADIO CORP. manager. He will 67 Dey Street New York 7. N. Y. continue as mana- L áN .1 ger of the East Central District. OSCIL-O-PEN HOW TO LOCATE AND ELIMINATE Robert N. Alvis Extremely convenient test usci flat or for all radio servicing: alignment Small as a pen Self RADIO & TV INTERFERENCE was promoted to powered Range from 7 IiO cycles audio to over by Fred D. Rowe, W. M. Stuart (1011 megacycles u.h.f. Output from zero to 25 West Central Dis- v. Lote in VOA lsed by Signal Corps Northern California Electricity Bureau trict Manager, and Edwin D. Stull, Jr., Writ e fur infurmat inn. An expert from the Northern California Electricity formerly in Belden's Mid -Western Sales GENERAL TEST EQUIPMENT Bureau tells how he located sources of radio and 38 Argyle Ave. Buffalo 9, N. Y. TV interference -and the things he did to eliminate Service Division, was transferred to the them. This is not a theory or a "perhaps" book. The Philadelphia territory. content is direct to the point and tells what to do. 128 (51/2 x 81/2 ") pages, illus $1.80 George TECHNICIAN'S GUIDE Kollar joined Finney Co., Cleve- land, as special assistant to M. L. Fin- TO TV PICTURE TUBES ney, Jr., sales man- by Ira Remer ager. He will initi- A picture tube servicing guide for the television installation and repair man. Covers the care, ate and co- ordinate methods of handling, replacement maintenance the company's field and repair of the picture tube. It is written for the promotion pro- technician who desires basic and specific information on the picture tube and its accessories (in- gram. Kollar was cluding conversion) without wading through reams formerly with Stre- of technical data, complicated circuit explanations. x ator Brick Co. At i.!1!Jøisics 140 (51/2 81/2") pages, illus $2.40 TE the same time, Vic- Only from famous COYNE do you get this modern up- FUNDAMENTALS OF TRANSISTORS tor Trebules, for- to-the minute TV Home Training. Easy to follow, Step - by Step instructions -fully illustrated with 2130 photos by Leonard Krugman merly of the me- and diagrams. Not an old Radio Course with Television G. Kollar tacked on. Personal guidance by Coyne Staff. So practi- The transistor is now evolved to a point where it chanical engineer- cal you can quickly EARN MONEY IN A TV -RADIO is suitable for many applications, both as a direct ing department, was promoted SALES AND SERVICE BUSINESS-part time or full replacement and as a supplement to electron tubes. to the time. Not only Fl NEST TRAINING hut COSTS MUCH An expert has consolidated in practical form for the position of plant superintendent. LESS - pay only for training -no costly extras. repair man, the engineer, the hobbyist and the en- SEND COUPON FOR DETAILS FREE SEND COUPON BELOW for Picture Folder gineering student the explanation and application and full details including EASY PAYMENT of the transistor. Basic transistor operation, Ralph C. Powell was l'I.AN. NO COST OR OBLIGATION - NO characteristics, performance and applications are named product SALESMAN WILL CALL. explained. manager of Ameri- 160 (51/2 x 81/2 ") pages, illus $2.70 can Screen Prod- B. W. COOKE, Pres. C OYN E FOUNDE0 1889 Buy these books now from your jobber, bookstore 1 ucts Co., Miami, A TECHNICAL TRADE INSTITUTECHARTERED NOT FOR PROFIT -if not available from these sources, write to: Fla. He will be in 500 S. Paulina Dept. 54 -HT4 Chicago 12, Illinois CB. W. COOKE, President charge of sales of COYNE ELECTRICAL SCHOOL /DER PUBLIS,HER IN C. television antennas 500 S. Paulina St., Chicago 12, Ili., Dept. 54 -HT4 doff F 480 C1a11 Sbeet Ke YuY l3, X. Y. and accessories Send FREE Picture Folder and details of your Tele- "a. vision- Radio -Electronics Home Training offer. 1014 ^G 51r1.1[ 11 Mane" 51, :;' which he formerly designed for the Name 211,20 c, company as a con- Address :I`::. rI,l.r"; r. sultant. City State...... RADIO -ELECTRONICS

www.americanradiohistory.com 143 PEOPLE

Joseph M. Coleman joined Sylvania Electric Products as a merchandising assistant in the Ra- dio Tube and Tele- vision Picture Tube Divisions. He was formerly with J. Walter Thompson, ONLY1MAN New York City advertising agency. J. M. Coleman ö Obituaries Walter R. Jones, Professor of Electrical Engineering at Cornell University, and TO INSTALL THE FAMOUS an authority on the design and construction of vacuum tubes, died of a heart attack in Ithaca, N. Y. Before going to Cornell in 1948, Jones spent 19 years with Sylvania. Fred Aylesworth, of the Chicago Stand- ard Transformer Corp. sales staff in the RAD [IC O Southern California area, died at his home in Hollywood, Calif. He was a pioneer in the radio industry. 57.R.., BALL'' Personnel Notes AUTO ANTENNA . . . Roger H. Bolin was appointed manager of general advertising for Westinghouse Electric Corp., succeed- ing Harry J. Deines, who joined the J. Walter Thompson Co., New York ad- IT'S THE EASIEST AND QUICKEST vertising agency. Bolin was previously assistant to J. M. McKibbin, vice -pres- OF ALL ANTENNAS TO INSTALL! ident and general manager in charge of the Westinghouse Consumer Prod- ucts Division. W&k:e raff, 4/ ... A. C. "Chuck" Elles joined I. D. E. A., Inc., Indianapolis, Ind., manu- Insert one edge of facturers of Regency boosters and con- 1 split -washer into sales IT'S hole ... twist ... and verters, as assistant industrial mount- E. M. entire bottom of manager. He will work under ing base slips into posi- Sheridan, industrial sales manager, pri- tion beneath cowl or marily with Radell Corp., an affiliate fender. company. BETTER

Clark C. Rodimon rejoined Ray- Slide ball -top into theon Manufacturing Co., Waltham, 2 place over mount- staff to the mana- IT'S ing hole ... adjust an- Mass., as assistant tenna to proper angle ger of Government contracts. For the .. tighten ... and the past four years, Rodimon was with Na- mounting job is done. tional Co., and Melpar, Inc. DIFFERENT Quickly! Easily!

. Seymour Mintz was appointed president of CBS -Columbia, Long Island Entire mounting job is done from the top. City, N. Y., and a vice -president and and easily installed by one Sys- It's speedily director of Columbia Broadcasting use of special tools tem. He was formerly vice -president of man ... and without the Admiral Corp. He succeeds David Co- or gadgets. resigned as president of CBS - gan who is absolutely nothing like it on the Columbia and vice -president of CBS. There market! The "screw" portion of the as- and economical ... Robert L. Parrish was named man- sembly assures quick ager of the new Sprague Electric Co. installation. The "ball" provides angular plant in West Jefferson, N. C. He had adjustment for every type of cowl or been associated with the main plants fender contour. in North Adams, Mass., for some time. ATTRACTIVELY LOW PRICED MODEL LIST SEC. -LEN. E. "Kay" Kayser joined Elmore $3.55 2 -49" Krylon, Inc., Philadelphia, Pa., as ad- EZ -2 vertising and sales promotion mana- EZ -3 5.10 3 -57" ger. He was formerly with Sun Oil Co. ... Gene Royster was named adminis- 7580 GARFIELD BLVD. trative assistant in the Sales Depart- CLEVELAND 25, OHIO ment of Merit Coil & Transformer Corp., Chicago, Ill. MAY, 1954

www.americanradiohistory.com 144 I PEOPLE . Jno. J. Cahill, well -known West Coast advertising man and sales executive, joined Ralph W. Harker & Assoc., Your customers ... Los Angeles, advertising representative for RADIO -ELECTRONICS. Cahill will head and your cash register... the San Francisco office. Robert A. Har- will you ker, son of the founder of the firm, will tell be Cahill's associate in the San Fran- cisco office.

... C. Russell Feldmann, New York hallicrafters industrialist and chairman of the Board of National Union Radio Corp., Hat- SHORT boro, Pa., was elected president of the WAVE RECEIVERS company. He succeeds Kenneth C. Mein - are the finest -fastest ken who resigned. selling on the market! ... Anthony L. Conrad, former manager of the Technical Operations Sec- tion of RCA Service Co., Camden, N. J., FoR twenty years hams all over was promoted to manager of the RCA the world have agreed Missile Test that Project, Government Serv- Hallicrafters receivers -dollar for ice Division. In 1953, Conrad received the RCA Victor dollar -are the finest on the market. Award of Merit, the They company's highest award for salaried are in a class by themselves. employees, for his work on guided mis- Your own customers know this. siles. They talk about it-on the air and off. They will tell you -so will . Edmond I. Eger joined Admiral your cash register- Hallicrafters is Corp., Chicago, as vice -president, ad- the fastest moving, most profitable vertising. For the past year he had been line you can handle! vice -president of Russel M. Seeds Co., Chicago advertising agency. Eger has Stock - Feature - been handling Admiral advertising. Display Hallicrafters -IT PAYS!

. Oscar Kraut joined the sales staff They're small in size! of G & H Wood Products, Brooklyn, They provide N. Y. He will handle the sale of the flexibility! Cabinart They offer positive protection! line of cabinets in Metropoli- tan New York, upper New York State, Dependability that gives you confi- and New England. He had been with dence. Flexibility that helps you do a both Arrow Electronics better job! These are things you can and Hudson count on getting in Centralab's new Radio. PA -1000 Series. See for yourself: You get high- strength, high- resin, ... Charles T. Carroll, former chief laminated phenolic insulation that ex- of Government Engineering for Halli- Finest buy in SW -the S -38C ceeds Phenolic Standards Grade XXX. crafters, Chicago, was promoted to di- The 38 -C is the finest buy in all short- You get one -piece rector of engineering. wave. 540 kc to 32 mc in four bands. shaft construction Broadcast reception for accurate indexing. Adjustable stop that far exceeds permits selection of positions or contin- ordinary sets. Maximum sensitivity per ... Eugene C. White was named prod- tube. uous rotation (11 active positions. 1 Built -in speaker. Has band -spread off- position) . uct manager for General Electric in- control. 4 tubes plus rectifier. Operates dustrial and on 115 V AC . . You get steatite spacers transmitting tubes. His or DC . . $49.95 with nickel - office is plated brass shafts, bushings, tierods, in the Tube Department head- and nuts. All other metal parts are quarters in Schenectady, N. Y. He was treated to pass 50 -hour salt -spray test formerly industrial specialist for the a must for applications in a humid Tube or- salt atmosphere. Department. You can get complete switches or sep- . Ralph Mendel, manager of the En- arate miniature phenolic sections, index gineering assemblies, hardware, and accessories. Products Division of Radio Receptor Co., Brooklyn, N. Y., That's only part of the PA -1000 story. was Get it all - send coupon for Centralab upped to the post of vice -president in catalog sheet 28 -1. charge of the division. Then order Centralab Miniature Phe- nolic Rotary Switches from your . Raymond L. Johnson joined the Amateur's favorite -the 5 -40B Centralab distributor. Instrument Division Electrical SEE US AT SOOTH 790. of Allen B. Du band -spread tuning to sepa- Mont Laboratories, Clifton, N. J., as rate crowded stations. Switches for auto- °-[nr 4 M.117.10 (M1(.GO technical sales engineer. He was for- matic noise limiter, code reception, three ELECTRONIC position tone control. r -f, i PARTS SNOW merly with the Public Service Electric One two -f & Gas Co. stages. Broadcast plus three short -wave bands, 1680 kc to 44 mc. Built -in CENTRALAB, A Division of Globe -Union Inc. speaker $119.95 922E E. Keefe Ave., Milwaukee, Wisconsin H. J. Tutwiler and Lt. Commander Send me Centralab catalog sheet 28 -1 Thomas A. Marshall, U.S.N. (ret.) Name joined Miller Television, Burbank, Calif., as national sales manager and develop- Company ment engineer respectively. Tutwiler hallicrafters Address has spent a lifetime in selling and The Name is Famous Marshall has held many naval assign- City Zone State 4401 West Fifth Avenue -2454 ments in radar, and radio work. Chicago 24, Illinois END Radio Television High Fidelity RADIO -ELECTRONICS

www.americanradiohistory.com ELECTRONIC LITERATURE

Any or all of these catalogs, bulletins, are available to you on re- WORLD! or periodicals FEDERATED SCOOPS THE ELECTRONIC quest direct to the manufacturers, whose addresses are listed at the end of each item. Use your letterhead -do not use postcards. To facilitate identification, mention the issue and page of RADIO - ELECTRONICS On which the item appears. GROWN All literature offers void after six months. JUNCTION TRANSISTORS

SUBMINIATURE CAPACITORS to offer production changes now make it possible --- - & Marine Instru- 'Manufacturer's Dumont-Airplane at this sensational price. Use these transistors ments has issued Catalog 53 on their you NPN Transistors NO 195 keyers, R.F. & I.F. amplifiers. Milcaps (glass -to -metal hermetically in low -level amplifiers, oscillators, specs! EACH sealed subminiature capacitors) which First quality units! Guaranteed to meet are designed to meet the operating requirements of military specifications MIL- C -25A. The 17 pages are devoted to the elec- 7 trical and physical characteristics of their various capacitors of the stabilized Halowax, mineral oil, and Duroil types. GROUNDED EMITTER No. 53 from Da9notlt LIFE -SIZE GROUNDED BASE Request Catalog OSCI LLATOR OSCILLATOR -Airplane & Marine Instruments, Inc., Clearfield, Pa. SUPPLIES LIMITED! MAIL COUPON TODAY! ELECTRONIC COMPONENTS Stackpole's 56 -page Catalog RC -9 gives PURCHASER,INc electrical and mechanical specifications complete tederated data on their and application DEPT. 401, NEW YORK 7, N. Y. of fixed and variable composition 66 DEY STREET, line Transistors at $3.95 each. (We pay slide switches, fixed Rush me NPN Grown Junction resistors, line and Instruction sheet included. powdered -iron postage in U. S. Sorry, no C.O.D.'s.) composition capacitors, N.1. coil forms, and ferro- Newark, cores, molded NAME - -- magnetic cores. Easton, Pa. -- -- Copies available free on letterhead Allentown, Pa. ADDRESS - -- ZONE STATE - request to Stackpole Carbon Co., St. Los Angeles, Cal. CITY_ Mary's, Pa. L CO, LICENSE. CORP. UNDER WESTERN ELECTRIC 'MANUFACTURED BY GERMANIUM PRODUCTS s4++ MASTER TV SYSTEMS 4+++ i Blonder -Tongue has released a new manual, How to Install Master TV i GUARANTEED Systems, which includes complete instructions and diagrams covering all and installation. TELTRON TUBES phases of planning EVER Antenna installation, choice of trans- LOWEST PRICES unconditionally guaranteed for one year. mission lines, signal amplification and FREE GIFT OFFER W e now have a complete line of spe- distribution to TV sets are all clearly FREE One 6BG6G Tube will be shipped clal purpose and transmittingransmittin tubes explained and illustrated with charts this ad. with any accompanying in stock. and tables. y your ordersd to beb shippedh' d the We guarantee Write for quotations on your require- Available at no charge from the some day they are received! 526 North boxed and mints -Dept T. Sales Dept., All our tubes are individually TYPEY PRICE Blonder -Tongue ¡ PRICEP TYPE PRICERICE .40 STYPE PRICE TYPE PRICE TYPE .78 6U 8 12K] Ave., Westfield, N. J. OZ4 .45 .40 6BK7 .78 6V3 .80 125K7GT GT 53 6AB4 .43 6BL7GT .90 6V6GT .48 125 .45 183GT .62 6AG7 .65 6BN6 .76 6W4GT .43 125L7GT -60 GAGS .52 66Q60T .53 125N7GT 56 S 195GT .51 6855 .85 6W6GT .38 1L4 .53 6A/14G7 .65 .60 6X4 .37 125Q7GT HYBRID JUNCTIONS 6ÁJ5 .96 68YSG .38 196G6G 1.4P I 1L6 .51 6647 .959 6X5GT .71 1LC6 .49 6ÁK5 .96 .41 6X8 .80 19T8 Development Laboratories .51 641.5 .43 7F8 49 25BQ6GT .82 Microwave 1N5GT 6C86 .51 .49 25L6GT .41 o 1R5 .51 TARS 1.63 7N7 .43 released a bulletin on short -slot 1T4 b3 6AR5 .48 6CD6G .95 12ÁL5 43 25W4GT d has .51 6A76 .37 6CV6 .42 12ÁT6 3] 2525 .55 spe- S 174 73 .36 junctions, which describes 1U4 .51 6AUSGT .60 .40 12ÁT7 25Z6GT hybrid 1U5 .43 6AV6 43 6FSGT 70 12ÁU8 43 ?.BS .60 6N6 .58 . 5C5 S.48 and gives electrical and 1X2 .65 6AVSGT 1 02 12A U7 .48 cial features .35 6AV6 .37 6AFb 49 12A V6 42 35L6GT .41 2A3 .60 613GT 73 .33 of these units .35 6AX4GT 61 1 2ÁV7 35W4 physical characteristics .53 6AX5GT .60 616 ,38 12AX4GT .60 35Y4 .42 3Q4 .56 6K6GT 61 .31 wide application in 35SGT .61 68A6 6L6 .78 12q X7 3525GT which have found SSS354 .48 6BÁ7 .58 .41 12AZ7 .65 50A5 49 3V4 .48 6805 .65 1264 5085 .4P communica- .4 F8 65867 high -frequency radar arid 5U4G .43 65E6 .4$ I2BA 6 46 SOCS .4P 5V4G .4 68F6 .48 65A7GT .45 12B A7 SB .48 6SN]GT .46 SOL6GT tions. Some applications are illustrated .30 6BF6 .600 128E6 TYpe 80 :áó t .40 1.18 6SL7GT 2 Y7 .65 5Y4GT 66666 65N7GT .60 121377 117Z3 .33 5Z3 .42 6BJ6 .Sl 38 2ß9] 1:20 and described. .40 6816 6T8 126Z ] 63 117L7GT 6A8 .75 6T8 .71 Obtainable gratis on request to Micro- 6K7 40 6BK5 - Inc., wave Development Luboratories, SS.aD sist raite Bonus Bort of S P E C I A L TV components includ- S Waltham 54, - Radio & while they last 220 Grove St., dills ing condenses -eon- randand any other items with 39c Each or more. 10 for $3.50 FREE eaels,h order of 525.00 RESISTORS TYPE TYPE TYPE TYPE TYPE WIRE -WOUND 37 I A4P IRC's 4 -page Bulletin D -1 gives com- Minimum order $10.00. 25% deposit on C.O.D IC6 1E7GT I9 34 39/44 o orders -Save parcel post charges. Orders companie IC7G 1F 1629 35 46 ap- with full prepaid 22 35'51 49 prehensive data on characteristics, Allbordershippedsubict to prior sale IO5GP IH46 $ in Continental tU.S.A- 107G 2A7 33 36 I F5G plications, construction, ranges, ratings, These specials are n Sylvania's indi id. We have types Th ly boxed. tolerances, terminals, insulation, tem- may orderp any type at similarlar nsavings. Order now. i perature coefficients, and Berating of Send for Free complete tube listing i MIL type wire -wound resistors. The bulletin is illustrated with photographs, TELTRON ELECTRIC COMPANY's charts, and graphs. Waverly 6 -1333 $ 428 Harrison Ave., Harrison, New Jersey Phone: $ MAY, 1954 %%,444%4%%%44%%44%444%%%4%4%%%4%%4% t

www.americanradiohistory.com 1461 ELECTRONIC LITERATURE A Free from International Resistance SIG ATOR Co., 401 N. Broad St., Philadelphia 8, Pa. OFQU RSATI LITY ELECTRONIC PARTS THA Clum's 7 -page 1954 catalog describes TENTION and illustrates antennas for radios and crystal sets, TV coils, video clears (interference eliminators), r.f. chokes, terminal strips, and oscillator coils. Available without charge from Glum illfg Co., 601 W. National Ave., Mil- "WIDE RANGE" RATOR waukee 4, Wis. BRACKET -MOUNTED ONLY S67.?0 SOCKETS 6 et 706A) Dialight's 24-page, 2 -color catalog, L- 154, describes bracket-mounted sockets used in electrical Equivalent in performance to signal appliances, equipment, and instruments. They are divided into generators priced as high as $125.00 groups, of those with soldering terminals or those with wire leads. Schematic COMPARE THE VALUE -compare the price! You diagrams with dimensions will lind that the RCP 706A Signal Generator feature occupy the for feature Is the finest performer In Its class. left -hand pages. On the right -hand VERSATILITY: Continuous coverage from ISO Kt' pages are descriptions to 220 Mc. In 8 ranges. Six FUNDAMENTAL ranger of the sockets, cover up through 55 Megacycles. with suggested lamp types. ACCURACY: within 1% of calibration adjustment. Units described fall into STABILITY: five groups, and constancy of calibration is asaureti and for each group by special electron- coupled circuit design. permeability a choice of 12, 14, adjusted coils and air trimmer capacltators. or 15 basic types of mounting brackets MODULATION: 400 cycle sine wave audio oscillator are illustrated. Units with modulation continuously variable from 0% are UL approved. 80'Só.. Above to 80% has no practical application. At Available without charge from - this point tremendous distortion occurs in all signal Dial generators. l'nmodulated signal is available if desired ight Corp., 58 Stewart Ave., Brooklyn ATTENUATION: Ladder sisting type step attenuator con - 37, N. Y. ut a multiplier and One attenuator control Witt fu latest catalog to IqL I(.5 AUDIO OSCILLATOR: 400 Impedance cycles at 50 ohms output is available for external use-terminals HIGH -TEMPERATURE on panel. RADIO CITY PRODUCTS CO., INC. UNITS Astron has published a Eight scales are clearly calibrated- continuous read- technical data ing from 150 kilocycles to 220 megacycles. Planetary bulletin on the high -temperature drive gives vernier tuning with no backlash Tube capac- complement-6 B A 6. 63.17. 6X4. itors in their metallized paper line. A high quality instrument in performance. These capacitors are designed struction and con- for oper- appearance. Size 16 "z8 "z7 ". 11't. 152 W. 25th Street 14 lbs. Complete with leads. ready for operation ation over a range of -55° to +125° C. on 106 -130 rolls. 60 cycles. New York 1, N.Y. The bulletin, AB -19, describes the standard sizes, ratings, mounting styles, LAST MINUTE and engineering characteristics. SPECIALS Copies may be secured We just scooped by writing to the market on Astron Corp., 255 Grant Ave., East standard top brand tubes latest Newark, N. J. 1954 dating . The prices speak for themselves! ! ! ELECTRONIC PRODUCTS ALL AMERICAN KIT Development, Design and Production is a 6 1250\7, 12SK7, 12507, 35Z5, 50L6 -page brochure describing these as- List price $8.20 pects of electronic equipment manufacture Your Cost only $3.54 at the Rollins Corp. The brochure describes the operation TV TUBES and the type of products manufactured. TYPE LIST PRICE YOUR COST Included in the corporation's product line 163GT $2.65 98c are all types of transformers, fil- 5U4G 1.75 49c ters, control units, and subassemblies. 5V4G 2.80 $1.28 Copies are available free from De- 615 1.70 49c partment 101, Rollins Corp., Lewes, Del. 616 2.50 87c 6BÁ6 1.95 69c COIL DATA 6ÁL5 1.75 49c 6AG5 2.25 Meissner's Catalog 54 -A contains 83 82c schematics 6AU6 1.85 69c covering approximately 300 6BG6G 5.25 $1.99 coils, cross references to competitors' 6K6GT 1.80 59c numbers, 62 new TV coils, a new 6AC7 r.f. 3.35 $1.16 heater supply, and complete listings of 6AT6 1.65 64c its hi -fi components and kits. 6SN7GT ... 2.35 68e Gratis 6SH7 from Dept. C, Thordarson- .... 2.50 72c Meissner, Mount 6606 3.80 $1.22 Carmel, Ill. 128H7 2.75 94c 12AÚ7 2.40 78c AUTO SPEAKER 12AL5 1.80 59e Utah Radio's Catalog AR100 lists the 6AV6 1.65 56c correct replacement speaker 6C4 for more 1.65 56c than 95% of all auto radio speakers. TREMENDOUS STOCK - It is indexed by make of auto, receiver At these prices they will move last. manufacturer, receiver model Buy Quickly number, and buy plenty. and speaker part number. BROOKS -84 Vesey St., New York, N.Y. Available free from Utah Radio Prod- This ad is reprinted from page ucts Co., Inc., 1128 E. Franklin St., 101, April issue, where the Huntington, Ind. END deices appeared incorrectly. RADIO -ELECTRONICS

www.americanradiohistory.com 147 BOOK REVIEWS

PRACTICAL TRAINING MANUAL (Volume 1, Basic Radio). Published by Howard W. Sams & Co., Inc., 2205 E. 46th St., Indianapolis 5, Ind., 83/4 x 103/4 inches, spiral binding, 240 pages. original ROGERS TV DEFLECTION COMPONENTS Price $5.00. are used in the manufacture of This manual is a combined text and ROGERS Deflection Yokes and Flybacks to use these some quality components workbook prepared from lectures, lab- most better sets, that's why it's wise s oratory and classroom material used by for replacements. one of the country's largest trade Every ROGERS Full -Focus Deflec- schools. It can be used alone as a basic and is at its best tion Yoke -precision made text on radio theory but perfect focus -is de- by one or two tested for when supplemented signed for peak performance and standard radio texts. extra long life; and assures The first section of 196 pages contains double brilliance with knife -edge 36 lessons, each covering a basic phase sharpness. Each lesson begins with of radio study. the a statement of its objective. Next is the ROGERS Flybacks -pride of broken down AT industry- feature higher voltage lesson content material and sub -paragraphs, and LEADING insulation, greater efficiency into paragraphs, higher voltages. sections. Each lesson concludes with a DISTRIBUTORS summary and a group of questions related to the text. Ruled lines are provided for writing the answers to the questions and for listing pertinent packaged individually -attractively references. Schematic and pictorial dia- 43 .ckr SYt.. grams, graphs, tables, and photographs ELECTRONIC CORP New49YorkBleel2,N. the lesson. ROGERS are used to illustrate new catalog "A," listing TV set models and section of the manual con- FREE: Send for The second or see your jobber. tains 13 suggested job projects or ex- ROGERS Yoke and Flyback replacements, periments designed to supplement the material in the first section. Each experiment or job lesson begins with a statement of the objective and refer- home study course ences to lessons in the first section. Fol- Non -mathematical lowing the list of materials required is a step -by -step procedure for perform- OPERATIONS" ing the experiment. A number of true - "ATV STUDIO or -false questions are included at the end of each job lesson. helps you grow with television Although the manual is written as an a year, course aid to instructors, we feel that it will networks cooperated Field-tested for more than to the The four major 27 years of tech- prove to be exceptionally useful in the preparation of this is backed by CREI's technician, experimenter, with CREI teaching experience, by 15 years self- taught course (so up -to -date it contains two nical and home constructor.-RFS experience with our own tv studio facili- lessons on the approved color system). in the in- non -technical, ties, by engineering leaders Non -mathematical but not own speed in FIELDS and WAVES IN MODERN engineers and tech- dustry. You proceed at by Simon it is for broadcast interfere with your RADIO, Second Edition, must convert to tv, as well spare time; does not Ramo and John R. Whinnery. Published nicians who work. For complete details for inexperienced personnel who want present - by John Wiley & Sons, Inc., 440 Fourth as course outlines and costs-use coupon 9 inches, 576 to increase their income in the rapidly Ave., N. Y., N. Y. 6 x today. pages. Price $8.75. expanding field of television operations. This text is a second edition, con- from the first (see siderably expanded I- RADIO- CRAFT, November 1944) to in- CAPITOL RADIO ENGINEERING INSTITUTE clude postwar developments in elec- Dept. RE, tromagnetic theory. Name expected, most of the 3224 16th St.. N.W. As might be Washington 10, D. C. new material in the text is related to Street guiding struc- n Send details of TV Studio microwaves. Slow -wave Zone State tures and other miscellaneous systems Operations course City have been added. The chapter on radiation includes new material on horns, slot antennas, paraboloids, and receiv- `SERVICING BY ing antennas. Outstanding among this OVER 50,000 new material, is the chapter on microwave networks. Definitions and network TECHNICIANS SIGNAL SUBSTITUTION' developed. The chapter is theorems are SELLER FOR OVER 12 YEARS! on waveguide junctions and A BEST very strong HAVE LEARNED_ -TO -DATE, 12th EDITION) cavity coupling, concluding with sim- (NEW, UP ple discontinuities and analytical approaches. The Modern, Simplified, Dynamic Approach to The helix as a guiding system was Receiver Adjustment & Alignment Problems. the be- HOW TO GET chosen because it illustrates to learn of waves with phase velocities * Nothing complicated havior equipment to purchase less than the velocities of light, the THE MOST OUT * No extra sectoral horn guide because it illustrates * Universal... non- obsolescent Test Instruments the phenomenon of a gradual cutoff, ONLY 400 * Employs only Basic OF BASIC TEST or and the wedge guide because it so 103 pages. Invaluable in- Ask for "S.S.S." of your local Radio Parts Jobber formation that wilt help remit 404 in small stamps or coin directly to factory. clearly illustrates the principle of you redouble the value or quality.-.11C EQUIPMENT your basic test equipment. APPARATUS COMPANY, INC. A.M. - F.M. - TV PRECISION 1 for MAY. 954 92 -27 BORACE HARDING BLVD. ELMHURST 4 N.

www.americanradiohistory.com 148 I BOOK REVIEWS

LOW -FREQUENCY AMPLIFICATION, Principles of by Dr. N. A. J. Voorhoeve- Published TELEVISION by the Philips Technical Library, Eind- hoven, Holland. Distributed in the U.S. SERVICING by Elsevier Press, Inc., 155 East 82 Step -by -step information St., on New York 28, N. Y. 6 x 9 inches, all types of commercial re- pages. 497 ceivers -how to install, serv- Price $9.50. ice, and repair them. Shows Occasionally a book is written with how to do most testing with just three pieces of such meticulous care and equipment: vacuum -tube voltmeter, oscilloscope, thoroughness and alignment generator. Dozens of troubleshoot- of detail that it becomes difficult to ex- ing charts . . . suggestions about going into a press the reader's servicing business. By Carter satisfaction in words. and V. Rabinoff, Dean: Such Magdalena Wolbrecht, Vice -Pres., Amer. TV a book is Low -Frequency Amplifi- Lab. of Calif. 560 pp., 375 illus. $7.50. cation. While the author's aim is to furnish TELEVISION the audio engineer with a thorough in- FUNDAMENTALS sight into the many subjects he may en- counter in his Now you can own an intercom that has a Written by General Electric Co. practical work, the text thous- book gives experts, this and uses at a price you wound normally pay for a simple presentation of basic TV is not excessively technical. When a kit. principles that a radio technician it This intercom comes housed in wooden advance must know to does go into abstruse cabinets completely wired and ready to TV service and installation work. The theoretical detail, to operate. treatment is sound such Outfit consists of one master, one sub station and theoretical, describing matter is printed in small type and each element of the receiver from fifty feet of two wire cable. Ideal for home antenna to pic- that may be skipped as baby ture tube. Includes practical installation pro- without destroying sitter. Perfect for office cedures, and troubleshooting charts the continuity of the or factory. Order now as quan- spotting for quick text. tities are s 665 of receiver faults. By Kenneth Fowler The sequence of limited. YOUR COST and Harold B. Lippert, both of the General Elec- subjects is conven- COMPLETE only.._...... _ ...... tric Co. 524 pp. 444 illus., $7.00 tional. The book begins with a chapter on the principles of audio, and follows RADIO OPERATING through with chapters on amplifier FAMOUS G. I. tubes; preamplification; output amplifi- QUESTIONS and ANSWERS cation; feedback; TUNER Thorough, easy -to -study book gives matching, control, you complete and YOUR CHOICE "Passing" answers to every single question in the limiting; and electrical components. latest FCC "Study Guide and Reference Material The author for Commercial Radio scrapes rock bottom, to a Material Operator Examinations." practical $499 is grouped by topics, such as Laws, extent, on each topic. His Power Supplies, and Theory. Covers discussion everything on feedback is particularly These tuners are in the exam, including the advanced material outstanding. brand new andlguaran- on aircraft radiotelegraph and ship teed. Your choice of two or three radar. By tube J. L. Hornung, Hopkins The latter half of the book discusses tuner. 2 -tube has 6CB6, 6J6. Engr., Co., and Alexander A. McKen- zie, Assoc. Ed., Electronics. Ilth more integrated units such as power 3 -tube has 3 - 6J6. Ed. 545 pp., 139 illus., over 1900 supplies, amplification 3 -tube has 6BCS, 6BC5, 6J6. answers, $6.00 systems, and radio FREE BARGAIN relay systems. A discussion on CATALOG WRITE DEPT. RE :5 the principles of acoustics and their STEVE Principles of applications in audio techniques is un- -EL Electronics Corp. 61 Reade St. usually comprehensive. The final text New York 7, N. Y. RADAR chapter, Deals with the fundamental con- "Measurements on Sound Sys- cepts and techniques tems," covers radar. of pulse the standard tests and Describes the general features of radar sys- measurements in TREMENDOUS tems and system components ; discusses pulse cir- great detail. BARGAIN! cuits and their application to radar modulators, If the book has a weakness, it will indicators, and receivers. Covers radio-frequency be IN CONICALS aspects of radar, including basic concepts pertain- apparant only to the American ing to transmission lines, wave-guides, cavity reader. Written as part of the Philips 2 -BAY resonators, and antennas, and the techniques of Technical their use in radar systems. By the Massachusetts Library, the author consis- 16- ELEMENT Inst. of Technology Radar School Staff. Revised tently uses European tube types, equip- by J. F. Reintjes, MIT, and G. T. Coate, formerly ment, CONICAL ARRAY of MIT. 3rd Ed. 887 pp., 165 inn,. $7.75 and expressions. Rich in bibliobraphy and copiously With Hi -Band Adapters illustrated and diagrammed, Low- Sturdy 3!a" Elements HANDBOOK of INDUSTRIAL Frequency Amplification is by far the EACH IN SINGLE LOTS ELECTRONIC CIRCUITS most comprehensive work on LOTS OF 3 $5.30 EACH Reference the sub- $4.99 manual on 433 industrial electronic ject yet published. Never before has National Electronics circuits -JK like We had a BARGAIN for immediate practical use. a special purchase i For each hi,. haleprices. order to gel circuit there is a clearly thing. And this array has every- drawn diagram along This conical 2 -hay 16- element array with a brief yet comprehensive description ultra -fine fringea reception. Includes sixteen provides how it works, performance - airplane type luiinumnt elements, including characteristics, appli- DIAL adaioers for grea,er gain on the hi.hat ,i cations, etc. Values CORD STRINGING GUIDE one high channels and is of all the important com- These pair of ponents are given to (DC -3 and DC -4). acte packed in cartons of threet facilitate conversion of the Published by Howard per canon, with tie rods. at 514.95 arraysrrays theoretical circuit to actual When per carton. practice. Contains W. Sams & Co., Indianapolis, purchased in single 16- element a all types of circuits, from Ind. 511/2 suparately boxed -your counting to welding x 81/2 3 i,'' I R:, .itrays t is. .$ 5.30 each control, both simple and inches. Pages not numbered. Rod. per cation without Tie advanced. Brings you 13.50 hundreds of 4 Bai l'Ii._.1- i -inge carton war -developed industrial circuits. Price $1.00 each. Aboi.- Stacking Assembly for By John Markus, Associate -4e1 4B $1.95 set Editor, and Vin Zeluff, These are Volumes 3 and 4 Managing Editor of Electronics. 272 pp., 433 of the diagrams. $7.50 Dial Cord Stringing Guide. They show UHF CORNER REFLECTOR the service technician the correct and r -10 -DAY FREE easiest way to restring the intricate ONLY $n 99 EACH IN SINGLE LOTS EXAMINATION -. L LOTS OF i an EACH McGraw -Hill Book Co., 330 W. 42nd St, NYC (36) dial -drive mechanisms on present -day This hi -gain UHF Corner Reflector Send me book(s) checked below automobile, AM, only be offered at for 10 days' FM, communications, price for short this low, low examination on approval. In 10 time. 8 to 11 ib gain days I will and TV receivers, The cross UHF band. Order Model P.O. remit for book(s) I keep, plus few cents de- third volume livery, and return unwanted book (s) postpaid. (DC -3) has 394 dial- stringing diagrams, re -- VHF Tubular Twin lead -100' 1 coil.. (We pay delivery if you .1- antenna Matching Transformer -permits$4.55 remit with this cou- o . ,o1 1 pon -same return privilege.) a short discussion on the properties of lead from VHF & UHF antennas $2,75 Itabinott a good dial cord, Ask for i V Spring & Wolbrecht-TV Servicing-$7.50 and a few general Profit-Sharing & Summer catalog -Contains New Fowler & Lippert -TV Fundamentals -$7.00 notes Point Plan. Hornung on restringing dial -drive mecha- & McKenzie -Radio Operating Questions ALL PRICES F.O.B. CLEVELAND, & Answers -$0.00 nisms. Volume DC -4 has Do not remit mure than complete OHIO 347 diagrams. shipping charges purchase price. Pay G Reinties & Coate- Principles of on receipt of uiis. -: deposit Radar -$7.75 Both volumes have all C.O.U. orders, please. Money -back on Markus & Zeluff-Hdbk. Ind. Elec. Circ. -$7.50 comprehensive guarantee. (Print) indexes listing all receivers covered in Name previous editions. Volume and diagram Address numbers are given. Thus, the technician City Zone. .State need look only in the latest volume to OF CLEVELAND Company find the number of the diagram for the Position THE HOUSE OF TV VALUES RE -5 set being serviced. All diagrams are t- This offer applies to U. S. only numbered consecutively.-RFS END 205 Delco Building Cleveland 3, Ohio RADIO -ELECTRONICS

www.americanradiohistory.com 149

SAVINGS! CHECK These Terrific RAD -TEL Tubes and Parts INDIVIDUALLY 90% OFF on TUBES BOXED FULL YEAR GUARANTEE! 70% to AT ALL TIMES! DAY SERVICE . . OVER 300 TYPES IN STOCK SAME Type Price Type Price Type Price Type Price Type Price Type Price Type Price Type Price Type Price .69 128E6 .39 144F7 .59 42 .42 .55 6807 .90 6SH7GT .49 7C5 .55 0A2 .74 1T4 .49 6ÁK5 7C6 .59 12BF6 .39 14H7 .59 43 .49 6AK6 .59 6BZ7 .90 6SJ7GT .41 45 .55 0A4 .68 l U4 65K7GT .41 7E5 .59 12BH7 .63 14J7 .30 .81 lU5 .43 6ÁL5 .38 6C4 .37 .65 14N7 .84 45Z3 .44 OB2 6C5 .39 65L7GT .48 7E6 .30 12BY7 1 V .53 6405 .39 14W7 .30 4525 .49 0C3 .72 .58 65N7GT .52 7E7 .59 12BZ7 .65 1 .37 6C6 50A5 .55 OD3 .70 X2A .63 6406 .37 7F7 .79 12C8M .34 19BG6 .95 .30 6ÁR5 .37 6CB6 .44 6SQ7GT 19C8 .70 50B5 .43 OZ4M .55 243 6SR7GT .45 7G7 .89 12H6 .56 2A4G .24 6A55 .50 6CD6 1.11 .63 19T8 .69 5005 .39 1A5 .30 606 .59 6SS7GT .42 7H7 .59 12SC7M 1A7GT .47 2W3 .38 6476 .37 7J7 .79 12.15 .42 19V8 .79 50L6GT .61 6AU4GT .68 6E5 .48 6T4 .99 .49 14X2 .62 2X2 .59 .56 7L7 .59 12.17 .49 24A .39 50Y6 3A4 .45 641-MGT .82 6F5GT .39 618 25AV5GT .83 50Y7 .50 1B3GT .68 .59 6U4 .60 7N7 .69 12K8 .59 .43 3E5 .46 6AÚ6 .38 6F6 .70 12Q7 .59 256Q6GT .79 55 .49 105 .83 6G6 .52 6U6 .59 7X7 .58 1E7 .29 3Q4 .48 6AV5GT 7Y4 .69 1258GT .62 25L6GT .39 57 .49 6AV6 .37 6H6GT .41 6Uß .61 .59 58 .60 1G6 .24 3Q5GT 6V6GT .39 7Z4 .59 12547G7 .65 25W4GT 354 .49 6AX4GT .53 6J5GT .43 .50 25Z5 .66 7017 .97 1H4 .30 6J6 .52 6W4GT .44 1246 .54 125F5 1H5GT .49 3V4 .51 684 .64 12A8GT .61 125G7 .51 25Z6 .49 75 .49 6.17 .43 6W6GT .44 .44 1L4 .46 5Ú4G .50 6646 .39 12AL5 .37 12SJ7M .67 26 .45 76 .57 6K5 .47 6X4 .37 77 .57 11.6 .59 5W4GT .50 6847 12405 .52 12SK7GT .63 27 .39 6ßC5 .49 6K6GT .37 6X5GT .37 .89 78 .47 1LA4 .59 5Y3GT .37 6X8 .75 12476 .37 12SK7M .63 32L7 5Z3 .45 6805 .59 6K7 .44 .47 35 .58 80 .35 1LC5 .59 6L6 .64 6Y6G .48 12477 .66 12SL7GT .79 5 Z4 .59 66D6 .45 12SN7GT .52 3585 .40 83V .68 1LC6 .39 6L7M .68 7A4 .47 12ÁU6 .38 1LD5 .59 6A6 .51 6ßE6 .59 12ÁU7 .54 12SQ7GT .56 35C5 .39 84/6Z4 .46 6BF5 .41 6Q7 .45 745 .41 85 .59 1LE3 .59 6AB4 .44 7A6 .69 12ÁV6 .39 12SR7M .49 35L6GT 6A7 .69 6ßF6 .37 6R7 .69 .46 35W4 .37 1171.7 .99 1 LH4 .69 7A7 .69 12ÁV7 .63 12V6GT 6BG6G 1.25 654 .38 .54 1 17P7 .99 1LN5 .59 6AC7M .86 7A8 .68 124X4 .56 12X4 .38 35Y4 .46 657M .79 1 1N5GT .67 6AF4 .90 6ßH6 124X7 .56 1445 .59 35Z3 .59 17Z3 .37 68J6 .43 658GT .53 7AF7 .53 .47 117Z6 .69 1P5GT .57 6ÁG5 .48 764 .44 12ÁY7 .99 14A7 .63 35Z4 .99 6BK7 .80 65A7GT .43 .63 35Z5GT .47 807 .99 1Q5GT .58 6AG7M .41 786 .69 12846 .38 1486 .49 6A144 .57 6BL7GT .83 6SD7GT .60 1488 .63 36 .39 i 866A 1.39 1R5 .59 65F5GT .46 787 .49 12847 154 .59 6A116 .73 6BN6 12806 .45 14C7 .79 41 .424 HiPo5671.39 AA .79 6SG7GT .41 7C4 .59 155 AS ls .65 6BQ6GT - LOW LOW in Price! RAD -TEL Parts - TOPS in Quality Granco "Star" SANDER -POLISHER PHILCO ""WEN STANDARD UHF CONVERTER Enables you to sand wood satin smooth in Brand new! Latest model! Unit is highly seconds, sand rust off metal, polish furni- receives all UHF channels. Co- shoes. TV BOOSTER BOOSTER engineered, complete with ture. famed for quality and axial tuned cavity elements your car-any- Made by PHILCO, Com- with self -con- 6AF4 oscillator, 6CB6 I -F a d crystal mix - Even precision tubes 12 channel RF Amplifier Shipped ready to install and operate. thing! -f " iegr,pment.including 2 Handsome gives a good p.ypletely rlontancirè and 1 Low tained AC power supply. List Price 529.95 22.45 1 for High Chauve is d, n n fo, and plastic cabinet. List price $23.00 m a s s a g e . Model selenium r De loon od- Weighs only fier plastic cab - el Five Star 21ía lbs. List net. In factory- UHF Con - price 13.95. sealed cartons, e ter. Pre- cmplete with 7.95 select., 1502 -6007 ca - instructions. each and 6AF oscil- Lots of S lator. List 10.95- price $39.95 10.46 In Lots of 3 7.45 29.97 of 3 9.30 ea. 9.95 Lots MA PRICE FLYBACK RAY UNIVERSAL CATHODE 65 59c FERRITE core horizontal SELENIUM WEN High efficiency 69c . 14.0110 For 75 transformer . supplies Volts. TUBE REJUVENATOR Type. In RECTIFIERS 100 79c SOLDERING all 65° to 70' kinescopes. Famous List price 1 1.50 Fits all makes of picture tubes. Completely 150 840 constant demand. automatic. Easy to install. no tools needed. Mid. by FEDERAL 200 1.25 GUN For A.C. parallel circuits. Your Old Picture Tubes Are Still 250.1010A 3 seconds on 120 Volt Useful. List price 1.75 AC readies it for any soldering re- 1.95 -55.95. 250 -1028A quirement. each Lots of IO 1.75 250 Watt 300 1.39 size. Also {V9.71 Lots of 3 350 -1238A cuts plastic Each 1.59 tile (with 512.95 special tip). List price- 1.c?!? 350.1023A Lots of 3 8.64 Each 1.59 Multi- useful! 1.85 UL Approved. Feraloy Long 400 1.59 Built in spot TIPS 350 ea . each 1.39ei 500 1.99 light. Standard Tip .110 ea. New! Famous Make Sensational! KNOB KIT VOLUME Control Famous Make Personal Portable Famous 3 -Way CLOCK RADIO BATTERY RADIO INDOOR ANTENNA (Choice Groups!) clock. For UHF, VHF and FM radio.pDelta- Assortment of Kit With Telechrome luminous beam. 500. increase Automatic shut -of and wake -up Has extraa longl life hundred hour di poles. For home, auto and erkg:'n Long distance rekep- power by extend Kit of 10 features. S tarts batteries. finge and UHF area,. TV knobs. All col- switches n applianfces. 5 at t,on. Large dynamic Spear. pictures. o Bu, It -in ten- Thumb wheel tuning. All sta- Foe movie-clear includes iincluding rectifier. colors - plastic, AC. L. plastic case with antenna - . 60 cycles U. tions. single and bake - wire Pure akelite or ivory runedp . lapsible handle. Rich gold finish 5 wood Red. brown nr aomgrey. 6, wound, ,.Old d pure plastic grille. Om). Lots of lite knobs. re with dual and Ebony - 3.69 522.9 5 batteries carbon d e Lots of 5- leath- RESISTORS saut 1.29 The price of 522 ea. (UAsst. of 200) for the Walnut laced. one (I) - each Va Watt. 1 quantity of ten 523.95 9.95 Watt,. Watt, Super Bag Lots of 5- COT- and 10 of 100 (10). Short and 523 ea. plete Watt. extra val. 1.9 5 long shaft. Lots List price- Lots of 3 kite Ivory- of 3 51 0.00 eSells from $24.95 519. 12c to 1ee Lots of 5_ 1.39 e.. 1.79 524 ea. 1.59 PER KIT

A 25% deposit most accompany all orders TERMS: -balance C.O.D. All shipments F.O.B. Send For Handling FREE U B E CO. Irvington warehouse. Orders under $10 -$1.00 RAD -TEL T Charge. Subject to prior sale. Illustrated "Integrity Is Our Chief Asset" send full remittance . allow for post- PARTS We re- N. J. PLEASE age and save C.O.D. charges! CATALOGUE Write to Dept. RE -5. 115 Coif St.. Irvington 11. fund oll unused money) Phone: Essex 5 -2947

MAY, 1954

www.americanradiohistory.com rIvt ADVERTISING INDEX IO? NAME BRANDS Make your Radio -Electronic does not assume Math for responsibility any errors appearing in the index Acro Products below. - All Channel Antenna Corp. 137 Alliance Mfg. Co. Allied Radio 79 American Corp. Electrical Heater Co. 15 American Phenolic Corp. 96 Amplifier Corporation of America 87. 88 Arkay Radio Kits, 66 Astatic Inc. 133 EASY! Corp. at Sensational Astron Corp 16 Atlas Sound Corp. 101 Audel Publishers 134 Savings! Improvements... s AccessoriesAudio Co. " 132 You'll find Barry Electronics Corp, those time- FULLY Beeco 150 GUARANTEE D Bell Telephone Labs 125 saving equations easy Brooks Radio 95 INDIVIDUALLY BOXE a TV Corp , D Buxton Industries, Inc. 100, 146 to use, easy to solve NO SECONDS ... NO REHASHED CBS Hytron (Div, NO REACTIVATED -BARGAINS" Cannon of Columbia Broadcasting System) 23 TUBES. YOU CAN PLACE YO Electric Co. with the aid CONFIDENCE IN OUR DEPENDABLE UR Capitol Radio ...... 104 of NEW TUB ES. Engineering Intitute ' ' ' ' Centralab- Division of Globe Union 27, 147 Century Electronics Co. 99, 130. 144 1 ube Orders Over S25.00, with Channel Master remittance, fulÌ Chicago Corp. 127 ce, PREPAID to you in U.S.A Standard Transformer Corp. 20 Cleveland Institute of Radio -Electronics 111 Collins Audio Products Co.. Inc. 11 Columbia Wire a Supply RECEIVING TUBES Concord Radio Co. 12469 Elements of CornellDobilier Electric Cornish Wire Corp, 13794 Net Type Net Type Co. OType 95 let Electrical Si TV 6AX5GT . Radio School .80 Coyne 082 "-. 706 75 Davis Electronics 138, 142 063/VR90 .82 7B7 76 003 61366 ... .70 768 Decray, Frank W. 118 Mathematics for VR105.80 78 Delco Radio (Division 6805 .74 7C4 . 29 of General OD3'VR150.89 66E6 Decry Teehneal Motors Corp.) 123 024 /0246 .55 .. .72 705 69 Dumont, Institute . 613060 ..1.89 Alien B. Labs . 1A7GT , 7E5 ''' .77 39 " " "f nside Front IB3GT 68H6 ... .85 7F7 Edlie Electronics Cover Radio, TV . .90 68.16 & Electronics 1B27 ,11.50 .85 7F80 .1 55 Electric Sweeper Service Co. 108 IH5GT 66K5 . . .95 7H7 Electro- Voice, 132 6BK7A ..1.15 Electron Inc. By Bernhard Fischer 1L4 . .. .60 767 .1 20 Tube Wholesalers, Inc. & Herbert Jacobs 1L6 6BL7GT .1.20 7Q7 98 Electronic Instrument 1366 1LA6 60N6 ..1.20 7X7 Co., Inc. (EICO) If you've ever hesitated to use a 1.30 6BQ6GT 30. 126, 136, time -saving equa- 1LB4 ..1.10 .1.27 12676 55 Electronic Measurements Corp. 139, 151 tion because you were not 6BQ7A . Electronic quite sure how to set h tLN5 ..1.10 126T7 ..1 05 Organ Arts 135 up; or had moments IN5GT . . .95 ..1.75 12AU7 .84 Erie Resistor Corp. 86 of doubt about decimals 164 6627 ..1.28 90 percentages; or .65 6C4 12AV6 .55 Federated Purchaser or wanted a quick check on your fig- IRS . .75 . 12AV7 .1.00 Federal Telephone 145 uring 155 .70 6C6 .50 12AW6 Radio Corp -THIS IS THE BOOK FOR YOU. 60E166 .88 Fenton Co. 77 It makes 1T4 .75 75 12AX4 . .90 crystal clear each 11)4 0006G General Cement 114 step in the reasoning and each 12AX7 . .80 procedure . 6CU6 "2.30 General Instrument 93, 138 in the arithmetic, geometry, 1U ,7Q 6126. 126Y7 .1.90 General ta Appliance Corp. and alge- 1v Test 133 bra i n- .75 1284 . .98 Equipment needed by radio and TV technicians. 1V2 6F4 , ..3,5e 12BAG .70 Goldstar Co.. The 142 find You'll 1X20 6F5 .. .68 139 it EASY to work out frequency resolutions. 6FSGT 12006 .75 Hallicrafters Co. voltage 122 ..3.7.5 .. .68 128E6 .72 Heath Co. drops, inductive reactances. decibels 2X2 6F6 .. .70 Hickok _ 69172 and 364 6F6G 120117 .1.00 Electrical Instrument Co. the many other radio and TV problems 6F8G 12877 .1.05 Hughes Research 4 Development 189 accurate in which 387 . . .39 Labs 80 use of math is essential. 3 4 606G .. .85 12627 .1.10 Indiana Technical Hundreds of 6H6 12567 .69 Insuline College sample problems, with 30507 . . .9089 S2 Corp. of America 140 answers, give you thorough 6J4(RCA) 5..7- 125F5 . .70 tnstructograph 130 practice. 354 . .. .75 12507 .80 International Co. 3L4 . 90 6J5 . .55 Correspondence 113 .. 125117 , .63 International Schools " " "' 3V4 616 .... .80 12SJ7 Rectifier Corp. 13 5AW4 ..1.55 6J7 .75 JFD 24 5R4GY 12567 .69 Manufacturing Co.. Inc. ,.1.50 6K4/6K4A 1251.70T, .65 Jensen Industries 20, 21 5U4G 2.25 Jones A Laughlin 146 5V4G .97 SPIGOT .65 125N7GT, .85 Steel Corp. 5W40 687 1250707. .63 Kay-Townes Antenna 92 _ .60 125117 .69 Krylon, Corp. Radio & TV Inc. 97 6L6G . . 1.10 125X707 1.10 5Y3GT . .48 6L6GA ..1.10 Lafayette 140 66807 ..1.10 6L6M 14F7 .. .75 Radio ...1.25 19006G .2.0! Leader Electronics 106 6AB4 .. .70 6L7 ,Bg Leotone Radio 9 6687 6N7M .70 19T8 .1.10 Littelfuse, Corp. 6AC7 .. 2511516GT Inc, 142 ..1.14 6Q7GT .. .80 1.3! McGraw 29 Mathematics 6AF4 .,1.39 654 .63 25L6GT . .7( Hill Book Co 6605 ... Macmillan Co., 148 .78 657M . .98 25W4GT. .7( The 6607 25Z5 Mallory, P. R., 150 by ..1.10 6567 ... .69 .75 Master a Co.. Inc. Bernhard Fischer 6AHSGT . .89 6507 . .88 25Z6GT . .6) Electronics 119 Miller, .1. A handbook of -by 6AH6 6SD7GT . .80 28D7 ...1.55 W., Co. 136 step -step solutions for 409 ..1.80 6507 ... .66 3565 .72 Mosley Electronics 126 problems in radio, TV, and 6665 65117 3565 .7C Most Electronic Distributing industrial electronics. ... .98 .. Co, 10393 Whatever YOUR problem- whether W. 65J7 . . .65 35C5 National -11G, is 6AK6 .72 Electric Products Corp. " rect it to cor- 1.98 6567 .69 351.6517 . .75 National Electronics f 116, 117 the power factor of a motor, find the 6AL5 ,60 65L7GT . 35W4 Cleveland impe- 6AN4 .65 , .45 National Radio Institute 148 dance and length of a matching .,1.50 65N7GT . .79 3523 . stub between .70 National Schools 3 tenna an- 65Q7 . 352507 .48 5 and transmission line, or any of 6AQ6 .. .73 678 50A5 .75 Opportunity Adlets of hundreds BASS .75 6U8 ... 141 other problems -here is the clear, 6A56 ., .1.OS 5005 ... .7n Perms-Power Co. tion. exact solu- ,2.65 6V3 SOCS . .72 Philco Corp. 132 1,41570 ,.3.75 6V6GT .67 5OL6GT 70 Precise 6ÁT6 .SR Development Corp, 28 6W4GT . .65 80 66 Precision Apparatus 110 6AU4GT .1.00 6W6GT .82 81 75 Prentice Co., Inc. 6AU6 .65 6XSGT -Hall, Inc. 147 6AV5GT .^2 83V ..1 15 Progressive "Edo -Kite" Inc. 139 .1.10 6X8 ,. .1.00 84 '6Z4 . 65 128 6AV6 .57 Quam-Nichols Co 7A7 .. . .75 11723 75 127 Have you got your copy 6AX4GT. .84 7A8 . .. .69 117Z6 . 1 00 RCA Institutes. Inc. of RCA Victor Div, (Radio Corp of America). Rad -tel Tube Co. 115, Back Co ear "The most helpful" service guide? SPECIAL PURPOSE RadelCo Manufacturing 149 TUBES Radiart Corp. Co. 143 Radio IN2113 .1.88 211 VT4C .88 City Products 85 1N23B .2.20 C81005 .65 Radio Craftsmen, Inc., The 146 304TH 1616 .. .85 73 16346 .55 (Surplus) 7.75 Mandl's TV 1N48 . . .55 310A(WE) Servicing 1N54 3.75 1622 ..1.95 . .75 407A(WE) 4.95 1625 .30 2051 . .4.85 40860111E) .. The book that is eagerly 2E26 3.00 1626 .20 RADIO SCHOOL bought by servicemen 3.40 803 ....3.25 1629 .. .25 DIRECTORY throughout the country 2E30(Iiyt) 2.20 805 ....2.95 2050 PAGE 125 helpful as the most practical and 2J39 . 12.50 807 ....1.55 guide to quick, accurate troubleshooting 809 ...3.50 5528'C6L5.00 Candler System Co. Milwaukee on today's 2J62 . Grantham School of Eng, receivers. 25.00 ' . School of 812A . 3,65 5654 1.75 Elec. RCA Institutes, Inc. -K28 . 25.00 816 3BP11 ...1.40 5656 .10.00 Indianapolis Elec. Tri-State College .7.00 8300 ,. 2.75 5670 ..3.25 SchoolSchoos so Tech.eh. 3B28 .4.95 851 .,39.95 5687 Western Telev. Institute Institute 3C23(GÉ) 6.75 866A ...1.25 5691 ,7.00 3C24/2401.00 5693 .,6.20 4824 .. 4.50 5814 ,1.75 Mandl's TV Service Course 5022 . .44.95 87211(0E)3.25 6096 ..1.85 5021 . Radio- Television 11.90 10 for 29.50 9003 ..1.45 Raytheon Training Assn. 7C25 .110.00 9004 Manufacturing Co. 17 Laboratory 7C30 ..85.00 955 Rek -O -KUt Co. 10 Manual .... .45 9006 .. .25 John 114 Rinehart 142 46 experiments, stock. rt a Co.. Inc. with exact what-to-do and what - 'l'.. l,t, 94, 107, 112, 134 to- look nut listed m pt be i ordered at t approx. the same -for directions, show how each RohrsManufacturing Con . 147 part of a saving. Many new special purpose types in stuck. 122 typical receiver operates and what Sams A Co., Inc., Howard W. causes trouble. DELUXE TUBE CADDY Sangamo Electric Co. 12. 90 This newly designed Tube Caddy is lightweight Scala Radio 82 163/4 and Ca. x 81/4 x 133/4". Ruggedly constructed, Service Instruments Co. 98 mpact. tl throughout. Holds approx. 150 tubes plus Sonotone Corp. 1 meters and tools. SPECIAL AT $12.95 otin's, Inc. 22 SEE THEM ON APPROVAL Sprague Products Co. 133 TWO- COLORED TUBE CARTONS. Sprayberry Academy of Radio 305. 132 with new Stan -Burn Radio A Electronics 67 The Macmillan Safety Partitions. Prevents Tune Breakage. Thit Standard Wood Products 112 Co., 60 Fifth Ave., New York 11 E2 Super -Gloss lied and Black Carton Is Steve-El Electronics 139 the alo.t Corp. 148 Please. send Distinctive Bus Avai lahme Today! Minimum: 100 Superior Instrument Co. me the books checked below. I will any one size. Quantity on remit full price prices request. Sylvania Electric Products 131 plus small delivery charge, or 19 return books SIZE EACH Tab in 10 days. (Save: Send check or Miniature....(6AU6, 6AL5, etc.) SOS Tech -Master Corp. 152 money order and we pay delivery GT (65N7, 6W4, etc.) 0125 121 charge) LARGE . (1B3, GT. 660607, etc.) 015 Television Communications Institute 122 LARGE G..(SU4G, 6606G. etc.) 02 Telrex Inc. 122 Elem. of Moth. $7.20 TV Servicing, Teltron Electric 113 $5.50 Co. Radio E Transamerica Electronics 145 TV Math. $6.75 TV Seer. Lab. Terms: 2504 with Order. balance C.O.D. Triad Transformer 118 Man. $3.90 Minimum Order Corp. All Merchandise $5.00 Tung -Sol Electric Co, 124 guaranteed. F.O.B. NYC. Turner Co, 8 14 Signed Phone: REctor 2 -2562 Utah Radio Products Co., Ino, University Loudspeakers 0 . . . . Inside Back Cove8r V. A. Enterprises Video 134 Address ELECTRONICS Electric Co 127 Walseo Electronics Corp. BAR RY CORP. Ward Products Corp. 111 Wen Products, Inc. 75 Westinghouse 18 136 -B LIBERTY Electric Corp 26 This offer ST. N. Y Windsor Electronic Tube Co good only within continental limits of U.S.A. Zingo Products 141 136 RADIO -ELECTRONICS

www.americanradiohistory.com 1.31

NEW! PEAK -to -PEAK VTVM complete with NEW DUAL- PURPOSE AC /DC New Pend.) unL P'zobe lPot. DELUXE PEAK -to -PEAK VTVM A EICO's revolutionary new engineering design! all with 7'/2" METER The professional peak -to-peak VTVM that beats 'em Model 249 low price! & exclusive 1/ni-Paobe (Pat. Pend.) -in laboratory precision features and features KIT $39.95 All the outstanding & exclusive of Model 232 -plus the extra convenience Model 232 KIT $29.95 WIRED $49.95 WIRED $59.95 and readability of its big 7''2" meter. An ideal bench instrument. TV -FM dis- p-p voltage O Zero- center foi Measures directly alignment. of complex & sine waves: 0-4, criminator 14, 42, 420, 1400, 4200 volts p-p. O One zero- adjustment for all ranges. DC,RMS sine voltage ranges: functions and 0-1.5, 5, 15, 50, 150, 500, 1500 Frequency Response: 30 cps - volts. Reads up to 30,000 V. 3 me (up to 250 me with PRF with HVP probe. probe). Resistance ranges: 0.2 ohms 1% precis }on ceramic multi- to 1000 megs in 7 ranges. plier resistors. tp 7 non -skip ranges on every Exceptional circuit stability

-,áaeKi ,,, mir function. and accuracy. 4 functions: + DC Volts, -DC p New compact size for extra - Volts, AC Volts, Ohms. easy portability (7 "x5 "x4 "1. Uniform 3 to 1 scale ratio for Smart professional styling - extreme wide -range accuracy. new satin finish etched panel knobs and 41/2" meter in can't - with contrasting Large wrinkle steel burn-out circuit. meter and grey case. Calibration without removing from cabinet. O Leather handle.

NEW! DUAL-PURPOSE AC /DC Un Pzobe (Pet. Pend.) VTVM VALUES! Terrific time- saverl Only 1. probe BEST performs all functions -a half -tunt of probe-tip selects DC or AC-01114S1 E/CO VTW4 Kips to choose from ! .s VACUUM TUBE VOLTMETER ever -popular DELUXE VTVM with 71/2" METER The reliable, performance- proved EICO VTVM - for all TV /radio /electronics servicing. Model 214 KIT $34.95 WIRED $54.95 universal instrument All the versatility and periormance-proven features Over 50,000 in use! legibility of its Model 221 Model 221 -plus the extra convenience and of instrument. big 7' t" meter. An excellent bench KIT $25.95 WIRED $39.95 ranges: 0.2 ohms to Large 41/2" meter in can't-burn-out 5 Resistance circuit. 1000 megs. to + 55. p Zero -center for TV /FM discriminator 5 DB ranges: -20 alignment. DC input resistance: 25 megs. p 4 functions: +DC Volts, -DC Volts, 1% precision ceramic multiplier AC Volts, Ohms. resistors. Electronic AC ADC ranges: 0 -5, 10, Double -triode bridge circuit for extra 100, 500, 1000 volts. stability and accuracy. Reads up to 30,000 volts with HVP O Rugged grey wrinkle steel case. probe. accessory ® 3 -color etched rubproof panel. -to -peak with PTP acces- Reads peak with AC DC and common probe. Complete sory leads. Reads up to 250 me with PRF aces - sory probe. O Leather handle.

See these sensational VTVM values at your local jobber today. in this issue Advertiser's Index Write for FREE Catalog CV -s Read EICO's other ads -See 11, N. Y. ELECTRONIC INSTRUMENT CO., Inc., 84 Withers Street, Brooklyn West Coast. fibroro,Yireattes et lowest cost Prices 5% higher on

MAY 1954

www.americanradiohistory.com 152

SELENIUM RECTIFIERS AUDIO AMPLIFIERS ,ETA READY FILAMENT TRANS. TO GO Ice peeiaD.d xeo- 2.SVCT 10A 12. : INS. .$5.50; linrs. Potter sIIPPlies MODEL TUSP 2.SVCT l0A 3 for $14 Ill (o Ultra HI- 5h1 IN, $359 specifications. Im- Fr 5 watts. with ~ tï 7.5VCT 12A 15 10 :'. 10.95; 1# mediate delivery. in Pre -Amp, built tJ 24V/1.25A 2 for $17.50 15Ú11 Bass CSD .$1.98; 2 far $3.49 Curr, 18/14 36/28 THAT'S A BUY boost & ut same for 42.5V 2A Sel Rect .Xflnr Cont. 54/40130/100 trbl. 4 --( 64V '1 .52.95 Volts Volts inputs, 4 con- - -/ Amp H\ISI.D $3.49; Volts Volts 2 for $5.00 LAMP 1.35 2.15 3.70 WATCH! THIS SECTION trots, 40./5000 cy, sat- r PRI 220/4407 Sec: 3X 2.5V/5A. 2AMP 2.20 8.50 in finish chassis -., 2.5V /15A 4AMP 3.60 6.00 10.50 EVERY MONTH movable & re- -- - $4.95; 2 for $8.00 4.25 7.95 12.95 25.25 FOR control face for 6AMP 4.75 9.00 TREMENDOUS BARGAIN PRICES custom mtg. "l'AB" TRANSFORMERS SOAMP 13.50 33.00 MEG,1 TECHMASTER special $27.49 6.75 12.75 20.00 44.95 HI-VOLT/hRESISTORS TM1315A Ultra Linear Williamson All 115 V 60 Cyc Input TV, & 12AMP 8.50 16.25 20.50 49.00 .75 H Deluxe amplifier, kit 548.95 CR pwr Xmfr up to 20" 20AMP 13.25 2 Meg "MVC" DD TMDISA completely assembled Ili VOLTS tubes. 25.50 38.00 87.50 4W Kt' ...8c9 to "n KV1 V 24AMP 16.25 2 Meg SPRG 5W 30 $ 7.50 TM15P 4 channel $83,00 iw luad- 32.50 45.00 95.00 10KV... .99 10 S Pre -Amp kit 519.95 'tpler kt.) AI.I, tubes. PL 2.5 Meg 2(15V 8.50 751150 t/nnpletely assembled FII. wtolgs. & Rectifier t, Transformer "MVA" 25KV 1.50 111 SI2.00 ... , 531.00 2.5 Meg "MVT" 5W 7.5KV 300 VDC 275 Ma í15V /fio a M eg .891(1( $ 7.00 AUDIO Full -Wave: up to 14VDC at 12 i.. 10W 11197 1.35 IO COMPONENTS 6.4V /10.3A. 5.4V /8A. 2.5V Amps $12.00 /3A up to 28VDC 5 19.98 10 Meg "MVP" í/1W 10KV 1.69 El ectrovu I IyPersil ('ore. Oil Fill $4.98; at 4 amps 14.98 12 Meg SPRG 10. 515.00 ioe triply cart. 2 up to 28VDC at 12 IOW 10KV..1.69 10/$15.00 GE 110X040, 78 $1.98 for $8.50; 6 for $22 or to 28VDC 20 Meg 'MVO" :35W 50EV 2.25 GE Culdtone $5.25 1600CT/SMA, 6.3VCT at 24 amps 63.99 50 Meg "MVE" 10- $20.00 RPXt14I M(: Gold lmle $5.25 2.5VCT /5A 3A, 6.3VCT /IOA, ur to 28VDC 't 50 127.00 100 23W 40KV 2.75 10/$25.00 (;E RPX050 /Dual trlplay SPECIAI.. $7.95; 2 for $14.00 Meg "MVP" 10W 10KV 2.25 10 CE IlPX052 $5.25 1000VCT /45MA, 795V('T /80MA, Rectifier & Transformer b Variac WRITE FOR /$20.00 /Dual (D &' 5551.t 3X5V 360VCT tip to QUANTITY PRICE GE 1[0X053 /,001 .003 :L\. 6.:3VCT /IA, 6.3VCT /,3A 14VDC at 12 amps S 30.98 & diamdiamonds $25.98 C'SI IllINS CAN BE up to 28VDC at 12 amps "TAB" GTD Phono Needle Replacements RAI- 'l'HEON USED 2X RATING up 45.50 VARIABLE VOLTAGE R151010 Dual .001 .$4.00; 2 for to 28VDC at 50 amps., 167.00 RP.1012 & .003 sapphire. $1.98 900V, 35518 2X2.5V/2A. $7.00 C "TAB" fast delivery TRANSFORMERS Dual ,1101 & 003 Iiamomis.$20.89 Dltli /H TlVO XCLENT 18001' SPECIALS RPJOOI or RPJ004,00)` X^ FIL WNDGS $2.25; SUPERIOR- GR /78 aPphlre$1.35 850VCT 148MA, 5V -STACO . 118 nordxmnuml /3A, 6.3V /5A, HIGH CURRENT 0.135V/3A 11.25 110.1013 IT diamond. $10.89 6.:3" 33. CSD sapphire $12.89 $4.98' 2 l'or 59.00 /135V/7,5Á 20.70 MG or 78 Simile 0s 54.98 PWR SUPPLIES U -CSD/ 135V/7.5A 16.20 MG 78 imitas 59c: 12 .'55.98 7707 /C2.5MA.. 2. SV/ 3AÁ HVINS CS0/270V/3Á or Single Sapphire Styli 87e: 12 cludes FILTER HM5I In- Variable 0- 28VDC. Corn 23.40 MG A 78 Vtol( Twin all mfrs /$9.75 l'ARTS 4 /scope $3.69 pletcly Built, Ir 5.- UCSD /270V/3.í 18.00 1,47 700VCT- 120MÁ. 2X6.3V ,3A. 6.3V '13 Ready Price . Co. Wave to CSD /0,135V /15A 41.98 ..53.98; Two for 57.25 Full Selenium CSD /0- 270V/9A 41.98 COAXIAL SPEAKERS 68OVCT 200MA, 5V /3.5,5. Rectifier, Transformer, e GRSOA /Ú135V 78V/1A 6.3V /4A Variac, Volt ® /45A /LN 100.00 $4.39; 3 for 512 & Amp GRSOB /0- 270V /31A /I.N Magnets, 600VCT, SOMA. 6V :SA, 6V Switch, Terminals 115.00 htInbuilt .Netwol.k, 2 /1.5A. 5V' 1:5 Heavy & Case 2 2 $2.49; for $4.50; 10 for 520.00 Duty, Seel Cabinet. 115Vu 3000BU ces needed fm HF & 1.1' 420VCT /90MA, 22V input. and /or /0.135V/30A/. ...49.00 Response. F. outs 6.3V /1.9A, W /INPUTS 6 3020BU, (1 -2707 /18A Uncased 11 Fl 12. 24. 115VDC & 115 & 2a0 Continuous With 3020B/0- / 49.00 500VCT /60MA 0.3V VAC Q) 51.49 Number 270V/18A/. Cased 55.00 15" Cola t PM /43 Hslrl 52.99 Rating STACO 12- iaÎ & 0" Tweet T28V4A O.28VDC 4 Amp salt, ( -17500 cy. 543.00 7 /Metered /135V/7.5A 40.50 "1 cl $23.75 FILTER CHOKES 728V24A 12 Write for Qty Price & Catalog w Coaxial 728V50A 0-28VDC at 4 Amp 129.50 Modeler. PM & 3í.y" ` I211)./BUma /H'sl1 /3KVins 2.25 0 -28VDC at 50 Amp 12 1535 1 OHy /125ma 239.50 Model 1'12 UU ...1' /UTC, Cod ODD'S & END'S $12.75; ' wee5 H'sid /lEvins 8" Coaxial ei 21/2" Tweeter, 1.98 RECTIFIER XFMRS RF PI CHOKE 20311I /500MÁ 12000 vus líäÌ attdel watt 5011y /123ma, CSD, H'sld 2.89 A 9C; 12 for87.49 12. HI-FI .$7,5 2U Hy /300ma or 15HY /4(10mä Primary 115V 60 Cyc RF PI CHOKE BOMB 200 Ilµ lt-l5- 4ke ....$9,95 12KVins Secondary O.9- 12.18.24.36V FI PM 7 watt 45 -14kc $9.95 8.95 4 Amp FILTER r 52.00 12 Amp S 8.75 GE I0(IAMP/050V 6 Hy/175nm.P250 ohm ..l 49oit for $16.75 2 fur DC 32.49 24 Amp 535.75 20 Resistors on fibre strip $2.00 POWER SUPPLY 18 Volt, 2 Amps Sir P 1/26' 1W lÚ0/ Variable TUBE SOCKETS $ 1.98 ' 7 for DC lower Sup- Antenna Sections .. each ply. Full Wave CINCH -NATCO- JOHNSON -AMPH section MS45) & ft. tio11. lifica- Octal (low -boos 2 for 25 for 4 6000Mfd riring 01g.10 for 1.00 RECTIFIER CHOKES $3.00 Condenser, fused. filter Octal (mica) ring) mtg 4 Amp .07 13y .6 Ohm SHOCK Rated Octal :steatite, 12 for 1.00 57.95 MOUNTSOUNTS 45 lbn...39c: 4 6.3V or 12.6V at 2 amp. hug mtg 12 for 2.00 12 Amp .01 Ily .1 Olm, 14.95 VEEDER ROOT Counter for $1.00 Octal (b8kel(te) ring mug 24 Amp .004 By .025 Ohm 5" DYNAMIC 'I Die'et...2 /51.00 7512.98 Octal (hakelitel 15 for 1.00 29.95 SPEAKER & Transf-Pent, Model[ 2DC'F. Octal saddle anta.. .15 for 1.00 31Hm oho, livid $1.19: for As above except 4 amp 12 ....6 $5.00 Model Octal I :steattite)il saddle 4IICF. .S20.98 Loktal (steatite) t mtg 2.00for *From ring mtg 111 This Special List We Ship $10.00 125C7 1.08 Loktal (mica) saddle mtg. for 2.00 Up Tube and 12SF7GT CKS34AX .99 7 pin min (mica) 12 for 1.00 Orders At Our Expense (Post- .84 C9536AX .99 base skid 204; 12 for 2.00 paid) Within 125127 .80 CK538DX n (mleal bottom mtg.. 10 for 1.00 Continental Limits of U.S.A. 125117 .63 CK539DX 7 pin min (hklt) rubber shock 90 Day God. 12SJ70T . 2.19 7 pin min mtg. l 2 for 2.00 TUBE When ordering mention .54 CK543DX . walfer. 9e; 15 0A2 88 6AQ6 5RE 12597 .99 9 pin min bottom far 1.00 043 1/1175 ,81 6H6 .66 CK544D% (nier, nt tg 12 for 2.00 .. 1.04 6AQ7GT .60 6X5 125L7ß7 - .62 9 pin c, n ibklll bottom ... 1.29 614 .S4 CK546DX , 1.99 mtg'... 7 for 1.00 082 . 1.37 6AR6 6.66 6V6G .88 125N7GT .68 9 pin min (Milt) base shld.286; 3.27 645 CK573AX . 5 for 1.00 OB3/1/R90 . .96 6ASS .54 7A8 125Q7ß7 .54 2.49 .79 646 .68 CK1005 . .68 0C3/VRIOS . .92 6A56 2.22 .58 7C7 .76 19BG6 1.98 2050 1.8 003/VR150 . .92 647 .72 SOLDERING GUNS 1/13/8016 6A570 3.48 696 7F7 .82 1978 1.98 CK5672 .. 1.20 & .. 80 6AT6 .54 697 .54 7F8 1.24 25806ßT .98 CK5678 1.28 TORCHES MAKE GTD 6AUSGT .58 797 .72 25L6GT . .67 5687 1L6 1.35 1.10 6944 3.68 7N7 2525 3.74 Lenk BAU6 .92 .78 CK5702 - 2.90 -77LP Blow torch. Instant *LDS .98 6K6OT , .54 no BAVSGT .566 7V7 1.06 25Z6GT .58 CK5703 - Icgli, printing, no soot 1LNS 6L6 1.48 2807 1.29 tor. adj 1P5 .78 64176 6LOG 1.08 .48 1.94 Xtal Diodes flame $3,75 6AX4/6U .. .74 1286 .48 3585 .52 1N2*A 1.55 Extra fuel tanks, only .79 194 1.29 6L6GA 1.08 12AH7GT 35L6 114218 Lenk 1501 soldering gun. 1R5 .59 6B4G 1.18 6L6GAY 1.98 1.45 .67 180 68A6 ,54 12AL5 ,54 3525GT , .54 1822 1.22 watt, hey ally XFMMR. 7.45 1U4 .52 68A7 6SA70T .66 12876 .54 35Y4 .68 1923 TAS -4 solder gun 135 watt 7.89 lus 1.09 65C7 .90 12AT7 4523 1.35 L TAS -5 solder 1X2A 6BC5 .63 65E5 ,gq .88 IN23A 1.89 gun 2: (1 watt 8.77 .998 68C7 1.23 .78 12AU6 .72 50A5 .76 1N23B 2.10 TAD -4 dual heat 100 -150 w 9.65 2A4G 1.18 6806 65 F7 .73 12AU7 .69 5085 .54 11425 TAD -5 dual heal 200 -275 w.10,53 2X2 .83 6567 12AV6 SOCS 4.98 TA32 soldering 594117 2 66E6 54 .64 .52 .54 1926 8.75 iron 115V /60watt 1.20 1.20 6SN7 .61 12ÁV7 .98 5OL6GT .62 1927 1.55 TA -250 snidt'' I ig il I.5 VACAC /250W , 68E5 ,98 SR4GYW - 1.75 6547 12AW6 ,. 1.18 RK61. %FR' 2.65 fucus light, built for 574 1.48 68G60 1.58 .S8 1934 .64 e"nll'ort 10.29 6BH6 65 K7GT .56 12AX7 .. .98 BO .58 1N34A .88 5U4ß .55 .63 65L7GT .64 12AY7 1.69 81 1.39 1935 6ÁC7 .80 6E146 .69 6514707 12BA6 83 1.65 OIL CONDENSERS 61397 .68 .. .59 1.12 1N38A 1.29 SAGS .71 1.58 65Q7ß7 .62 12BA7 .94 83V 1.22 1941 8.95 NEW WAREHOUSE LIST 6BL7GT . 6407 1.14 1.19 6597 .62 121106 .59 84/624 .62 1942 .000255IFD 2 5KV $6.00; 2 for SANS 1.21 6BN7 2.89 6557 128E6 117L M7GT 16.95 UUI6MFD 510 6AJ5 6BQ611T .88 .59 1.98 11145 1.45 / í5R $7.00; 2 for 512 1.40 1.20 678 129E6 11726GT , 2X.1MFD, 6AKS 6BQ7 .96 .85 .96 1846 .69 2000V $1,39; 2 for 52 .87 1.65 6U4 12897 1.29 CK502AX . 1.49 11447 .55IF1) 601)5' 256. 6AK6 .92 6C4 í2C8 CKS03AX 4.00 531FL, 6 for SI 6AL5 BC5 SUR .B974 .62 1.49 1848 .47 1500V 85e 6 for $2 .48 .68 6V6 1296 .64 CKSOSAX 1.79 1N51 1MFII 5110\ 336: 4 6AL7GT .98 6C86 1.39 1245 CK5I2AX .45 6011V for SI .59 SV6G7 .52 1.45 11454 .78 1MFD 396; 3 for Si SANS 3.27 604 2.70 1298 .68 CK531DX 1.89 1511,il i11011V 396; 3 6AQ5 614/467 .52 12Q7GT 1960 .60 2MF11 for Si .52 6F6GT .79 .55 CK532DX 1.89 1N63/K63 fil ,.V 596' S for $2 6)(4 .49 125A7GT .68 2.49 4MFD :ul:n:l" CK533AX . 1.29 1969 .98 $7.98; 2 for 514 4MFD $19.95; 2 for 515 BATTERY CHARGER RECTIFIER ',MFD I 51.50: 3 for 54 13-0-13V (CT) 100 Amp., fan 866A KIT and 16 5IF Ir nííí.: íC'1 S00VDV.55.95; 2 for (dace your cooled Re- 100 WATT SEC PHOTOFLASH KIT 510 ld netlicient sulfide reel iller XFORMER Includes \IL Flash Lamp Rated w /new' selenium [ type. SPECIAI....611.98 2 Tubes, Sekts, sm0', 150 Watt Second, Flash Gun OIL CONDENSER and Cable, CRYSTAL DiODES 11 c- sv60cyc Inpt, out- SPECIAL put 2.5vct /l0A/ Transns & ! nsers 100 121 Lots Hi vins $4.98 61171) .450V 1(10 Watt Sec. Re- 10 MFD of 50 300 ea s tore Capacitors. Rectifiers $1.75 ea Smaller gty....49c: 10 for $3.98 DIODE PROBE TUBE & Kemtron Unexcelled for No -Loss Sockets ..... 600 VDC lets of 3 -W. E.- Sylvania 100 Watt eond Condenser C:,.0 1N238 ....52.10: 5 VHF testing. Ultra- ,lunensiuu s. includi, 1N21A for S 9.50 sensitive subminia- Bank. 7251ED/1800V per )ít'85 units insulators x 3345V ....51.55; 5 for S 7.00 tuais 61.2MFI) /100 4,0i X 14.,!í1 19216 , , , ture-envelope. NEW. W.S. SPEC. ..$4.98 smaller Quantities. special . 52.10; 5 for S 9.50 ,i 16M FD 51.98 1N27 tt i... \ I:i_ 256: 5 for 61101-A(' 18011 \'DC 280(1V Inter- $1.55; 5 for 5 51 ns ttenl ( 1948 69c; 7.00 "debil ter 55.95 11447 5 for S 3.25 CK 5517 \ Ii::inttiro Rectifier $2.88 TRANSFORMER SPECIAL $4.00: 5 for $16.25 INFRARED SNOOPERSCOPE WRITE FOR DETAILS & SPECIAL PRICES SEE -IN -DARK TUBE "TAB" PHOTOFLASH 6.3 VOLT Im'ne- (',rave rter 'Tube Hi,. i .. t lty' LAMPS AMP AND plilled design 2" dia. Wille,i.( screen- "lab" W -Sen. troua:, ,I... I( 15VAC inn No. 2-5/ I0"O !'-I. I Oil Assorted data & tube, ea. 57.98: 2 for $13.98 Replaces Max. Each ^LV mug Eleetrolytics 51.25 SNOOPERSCOPE PWR SUPPLY TLW FA104, USW 150 55.98 cote 2.rs': channel mtg RSI. Assorted... 5 for 1800VDC 1'111 AMULO SMMF(;RS.- JOBBERS -DI.R Silver A Mica Cndsrs..... 15 for /35MA, Using Doubler Crkl. 5804X 100 10.98 REGULAR S. Controls, Popular Values. 1.25 Transformer. Rectifiers, Stockela, Resistors. 23S'í' GE FT 210 201 9.98 $1.98 VALUE- 5 for 1.25 Capacitors and Diagram 56.98 THVA SYLV. 4330 200 9.98 "TAB" SPECIAL....01.00 Vitreous{ .100 TL1O CE FT 118 150 6.98 12 for $10.00: W'W Resistors. 8 for 1.25 \'4X4 X400 50 for 536.00 Sockets, Asstd. 8, 7, 5, 4P 12 200 10.98 Iron Core Slug for 1.25 TV & COAX CABLE TLX FA100 /DX 150 9.00 A Screw. 50 for 1.25 :153GT51 FT 503 2000 Knobs. Asstd. w /Insert.. 10 for 300 Ohm Twines. Heavy. duty 65 53GT 49.98 YOU 1.25 nil copper FT 403 500 13.50 WHILE "TAB" TS' lead in. sí9 TRIGGER COI1. FOR GF: 86041 SI.47 PICK THEY PICK per ft. 2e; IOO feet .. el7 J SPECIAL EM $1.00 1000 Ft. $11.95; 5000 Ft. 550.00 NEW RHEOSTAT LIST THEM LAST Lots of 5 300 Ohm fwinex. 100 59¢ Mil Extra I'1 otan 25W 1.10: heavy duty lO() ft. 53.29 20 oMo 10 for 7.00 LOTS OF 10 Your selection of 10 at 596 each Ft. Ell 50W W knob o r TELEVISION ANTENNA RGBU 52 Ohm 100 (ft. $11;24(100 100 1.98; 10 for 14.00 smaller quanti[ at indicated prices. VEE RG11U ft. 598 ohm 50W w /knob 1.50: 10 for 9.00 CONICAL Broad re- 75 Ohm 1011 ft. $11; 10110 ft. $98 123 ohm 23W Model H 1.10; ELECTROLYTIC CONDENSERS sponse, all channel, RG59U 73 Ohm 100 5 50(1 10 for 7.00 2X 20MFD power- ft. 5: ft. $22 225 ohm 50W 1 98; 10 for 15.00 /45OVDC..691; 3 for $1.95 ful for fringe sax. .$8. HiVolts 15KV Wire Per Ft. 3e; 50 Ft. 1.25 250 ohm 25W 3X 15MFD /450VDC..9B6; 3 for 2.50 FOLDED DIPOLE 1.10; 10 for 6.00 3X HI low 3f)0 ohm 223W Model P 2.98; 5 for 10.00 2O5IFD /400VDC..79e; 2 for 1.29 all channel, sturdy 4? 500 25MFD /450VUC -69e; 3 for 1.95 constructiont [ruction \ 7.50 $4.93 METER SPECIALS 800 ohm 5lK MUtel .1 1.98: 10 2OMF /4507 &20MF /257 - -3 for 1.95 TV CONICAL ANTENNA for 50 mf /35Ovdc FP ri All Channel. 53.95 0.30 VDC AS 2.98:3for8.00 1200 ohm 225W Model P 2.98; 2 for 5.00 ....5 for 1.00 cross boor R ohm 30 -15 -10 , DOUBLE-VD .$ons. 0 -150 VAC /WSTGHS/ 2500 25W .1.10: 10 for 7.00 f/ 25Ovdc 5 for 1.00 V Ant, Channel.Channel, 5000 ohm 30- 2x2Omf . IND Sturdy' Cons. 2',a/RND 60 cyc 3 49 25W 51,äh( H 1.25; 10 for 9.00 /450 -25vdc -.3 for 1.00 Clamps Alt, annex 0.150 VAC WINDOW CONICAL All Channel ....53.95 /25- 125cy/ PRECISION IF 5 FOOT interlocking ,.$ ;,g$ Stay "S,I'RA3R .5.98 Mast Sections, 7 O -1 MADC WSTG11S "Sq CIRCUIT BREAKERS DU R. r,i- l ¡cronf... .2 for /:31/ /1íA35...5.98 LABORATORY 51.49; 10 for 57 0.120 MA I1F 31/" RND Weston 301 11.98 POTENTIOMETER Ileimnann Hag, Bkrs. Amps: 2"'0, 3. 7, il. 0 -800 MADC 31/" END .4.49; 2 12, 15, 20, 30. 3n, 40. 80, 180 0.1 MADC for 7,98 Wirtw nnml 211,000 ohm TEST CORDS MINI 11/s" DIA 3.98; 2 for 6.98 ., Eä.$1.98' 12 for $20.00 300 -0.300 Watt . C.," Diameter S. D & CH Toggle 8 FT 26 Strand Wire Micro Ammeter Movement Cen1 Radio Sw Brkrs. Amps; 5, 50 Div Scale 31/2" Type 433AC 15. 2U. 25 98e . Alligator Clips. as RND, Hickoek ..4.49 Rey. 812.00 Value...... 10 for $8.98 Shown 0 -240 ADC -AN" Ic /Shunt 5 98 Elison Therma Push Button Bkrs Amps; Pair . .51.00 SPECIAL $2.98; 5'$10. 5. 10. 15, 20. 25, CD277 8 Ft/6 Con- 30 89e .10 for $7.98 ductor, With AN Con- nector, P/O BC312 \, Money Back Guarantee (Cost of $1.25 -T- A Mdse. Only) $5 Min. Order F.O.B. 15 FT Extension SJ A Cord Heav Duty. BUYT,S N.Y.C. Add Shpg. Charges or 25% Rubber BUY Dep. 4 FT Flexible 0 B Tubes Gtd. via R -Exp. only. Instrument Test Leads Red & Black 2 Pair Dept. 5RE Prices subject to Change Without 10 FT .$1.25 111 LIBERTY STREET, NEW YORK 6, Line Cord. Rubber Instil & PM, 494 N. Y., U.S.A. Notice. Phone Rector 2 -6245. CABLE: "TABPARTS" RADIO -ELECTRONICS

PRINTED IN THE u. S. A. BY THE CUNEO PRESS. INC.

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www.americanradiohistory.com RCA PIONEERED AND DEVELOPED COMPATIBLE COLOR TELEVISION

RCA- 15GP22 Tricolor Kinescope Heart of Compatible Color TV You're ready for COLO ft Tv ...because R CA is ready for you RCA- pioneer in the development of new 15GP22 Tricolor Kinescope . . . voltage dc power supply; compatible color RCA -3A3 television -is ready heart of compatible color television. Hal f-Wave Vacuum Rectifier for pulsed now to supply you with the replace- To supplement its other receiving rectifier scanning service; and RCA - ment receiving tubes and kinescopes tubes applicable to color television, 6AN8 Medium -Mu Triode Sharp - you will need when color TV comes including the RCA 6BY6 Pentagrid CutotfPentode your for general -purpose use. to town. Amplifier and the RCA 6AU4 -GT To restore the original performance Engineered for color by RCA, these Damper Diode, RCA has developed of color TV sets, play safe . . . use tubes are designed to work together three new types specifically for color genuine RCA tubes for color 1 for superior performance. TV. circuits: RCA -6BDk Sharp -Cutoff Be posted on Color TV ... keep in RCA announces with pride the Beam Triode for regulation of high- touch with your RCA Distributor. RAD/0 CORPORATION of AMER /CA ® ELECTRON TUBES HARRISON, N.J.