Radio-News-1940-06-R

SEE rilE EXPER MENTER' AMPL I$$ PAGE E

NS'- JUNE 1940 25c Putting up a Cheap Antenna e Serviceman's

1 -Tube Signal Tracer A Receiver for Your Cycle

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A well -rounded photographic education in TEN POCKET -SIZE TEXT BOOKS Camera fans, let the Little Technical Library PHOTOGRAPHIC SERIES guide you through every phase of amateur photography; teach you the masterful photographic technique of such experts as Ivan Dmitri, Herbert C. McKay, Harold Lam- bert and many others. Here, in understandable form, is up -to- the -minute counsel on everything you've always wanted to know about photography. Each of the ten authoritative volumes is complete in itself; each deals simply, clearly, thoroughly with its chosen subject. This grand photographic library is beautifully printed, richly bound in blue leatherette, and brilliantly illustrated with a profusion of color plates, half- tones, line drawings, graphs, charts, etc. With this handy set of ten pocket -size text books at your fingertips, you need no longer grope for guidance. Now you can enjoy photography to the fullest! Now you can get more pleasure out of your hobby! Yes, cvz.oFZ the Little Technical Library PHOTOGRAPHIC SERIES is yours for better pictures! Little Technical Library PHOTOGRAPHIC SERIES COMPLETE ILLUSTRATED AUTHORITATIVE

NO. I -YOUR CAMERA AND HOW IT WORKS by W. E. Dobbs and Charles A. Savage. with a Foreword by C. B. Neblette, F.R.P.S. Selection, use, focusing. com- posing, lens, shutters, roll film translators, cut Ulm and fllmp:mks, accessories, etc. 132 pages. NO. 2- DEVELOPING, PRINTING, and ENLARGING by Al and DeVera Bernsohn. Elementary and advanced developing, chemicals, types of printing, enlarging equipment, elementary and advanced enlarging care of prints, etc. 96 pages. NO. 3- FILTERS AND THEIR USES by W. Bradford Shank. Types, selection, use, requirements, advantages. problems, suggestions, the care of. etc. Informative and up-to- the -minute. 96 vages. NO. 4- COMPOSITION FOR THE neth AMATEUR by Ken- Heilbron. This book is complete and norka Irle. It covers the joining of subject and picture, tones, lines, rhythm. problems, suggestions, etc. 96 pages. NO. 5 -MOVIE MAKING FOR THE BEGINNER by Herbert C. McKay. F.R.P.S. Modern movies and cameras. use. movies versus photography, producing, editing, processing. projection, etc. 100 pages. NO. 6 -COLOR IN PHOTOGRAPHY by Ivan Dmitri. Types of subjects, natural color film, mounting. projection, color separation, density scales, printing, etc, NO. 7 -CHILD PHOTOGRAPHY by Harold Lambert. Cameras and equipment, posing, types of pictures. finish- ing and processing, in nuturul color, problems. etc. 96 pages. NO. 8 -HOME PORTRAITURE AND MAKE -UP by Maurice Seymour and Syd Symons. l'art I: Lighting. camera, model, posing. background, arid suggestions. Part lI: Ile-styling contour, eyes, eyebrows, lips. Pow- dering, equipment, etc. 112 pages. N0. 9- TRICKS FOR CAMERA, OWNERS. An outstanding collection of the latest and most valuable kinky and hints, covering every phase of amateur photography. 160 pages, NO. 10 -A GLOSSARY FOR PHOTOGRAPHY. Com- piled b Frank Fenner. Jr. Over 3000 words having photogray significance are defined. They cover s ill and motion- picture photography in black- and-white and color. 152 pages.

AT ALL LEADING BOOK SELLERS, CAMERA AND DEPARTMENT STORES NOTE: If your dealer cannot supply you, order direct, enclosing your check or money order. Write to: ZIFF -DAVIS PUBLISHING COMPANY ATTENTION DEALERS! ORDER FROM Book Dept., 608 S. Dearborn St., Chicago, ill. YOUR PHOTO SUPPLY JOBBER TODAY! (60c Each outside of U. S. A.)

www.americanradiohistory.com 4 WIITHIN fa

Including Articles on POPULAR TELEVISION The Magazine for the radio amateur experimenter, serviceman & dealer VOL. 23, NO. 6 OF THE EDITOR Contents for June, 1940 YEARS ago we used to watch Walter Winchell prepare his daily stint. Some- times he would sit in front of his type- FEATURES writer with a blank piece of paper in the machine, and a similar look on his face. Build Your Own Marine Receiver .... Raymond P. Adams, W6RTL 6 "Say, Walter," we'd ask, "what do you Summer boating will be more enjoyable and safer with this receiver. ?" do when you can't think of anything Hayes, W6MNU 8 the same," he said "be- A Small Experimenter's Amplifier William D. "You write just uses. cause you have to eat, and you know that An amplifier for a multitude of small jobs and waiting umpteen thousands of people are A One -Tube Signal Tracer.... Charles R. Merchant 9 to start." Serviceman's for your typewriter A single tube is all that is needed for trouble shooting equipment. Well, \\-e feel just like Walter did on those occasions, with one exception . . Modernizing Old Receivers, Part 4 Charles Leutz 10 no matter what we write it won't have the Accessories improve the old set and bring the serviceman extra dividends. pith, nor the "punch" the old Master has in his pen. Sometimes we just wish we For Immediate Release 13 news hadn't met Walter . . . he's so hard to A new department for hot and spot emulate! * * * Let's Try 112 Megacycles Harold D.Millen, W1JOM 15 For portable gear, short distances, 21/2 meters is fine. and QST: SUGGESTION to RADIO Hagerty, W6JMI 16 please put out some information in fQMobile on 10" R J your respective handbooks on what should Describing a complete mobile ham station. mils in the grid happen to the rectified 1 Receiver Paul Popenoe, Jr. 25 amplifier when the final is A Rome -Built -10 Meter circuit of an receiver for the extreme ultra short wave reception. loaded down. We here at RN have been A special making experiments towards discovering "Cheap at Ralf the Price!" Horace E. Eddy, W8MTZ 26 just what percentage of the non- loaded Constructing an inexpensive yet efficient vertical antenna. rectified mils the final figure should be, but have made very little headway because of Save That Old Cabinet Clyde D. Kiebach 27 our limited facilities. Inquiry among the Converting old cabinets into a good source of revenue for the serviceman. other engineers in this city revealed that very little information. Why Music While You Cycle H G Cisin 28 they, too, had an automobile. not help all the hams with the dope since Motorcycles and bicycles can be equipped with a radio, similar to you each have the labs and the man -power H W Kline 31 know from listening on Doubling in Oscillators to do the job. We tubes in parallel double your output. the air and from our mail that the out- Two oscillator standing subject, next to antennae (Ah, Increasing Loop Sensitivity Charles A. Thoman 37 !) is "Rectified Mils." there, Mr. Webster Using a loop as a sensitive direction finder. * * * How About That Anteunav Ernest A. Vogt 38 ATCH the new department, "For A timely discussion on the most popular subject today. Immediate Release." In it we will Picture courtesy Agfa Ansco; photographed on Agfa Film. be able to feature all the "hot" and "spot" Cover news that comes our way. For the very latest and most interesting shorts in the radio industry, don't fail to read, "For DEPARTMENTS Immediate Release." Book Review 30 QRD? 30 Serviceman's Experi- * * * What's New in Radio 20 Bench Notes 19 ences 14 42 GOT a pet ? Interested in pets? Want Radio Physics Course 60 Manufacturer's Literature Serviceman's Cases 36 to know something about pets? Catch Hamchatter 32 "Remotes" ...... 24 new addition to the Ziff-Davis Publish- the Copyright, 1940 ing Company family, "Popular Pets." kiddies and grand for any- ZIFF -DAVIS PUBLISHING COMPANY Swell for the Member of the Audit Bureau of Circulations one who ever had a pet, or who has one now. Some very interesting information about all animals, too. RADIO NEWS is published monthly by the Ziff-Davis Publishing Company at 608 S. Dearborn St., Chicago, III., William B. Ziff, Publisher; B. G. Davis Editor; J. Fred Henry, Vice -president; Karl A. Kopetzky, W9QEA * * * Managing Editor; Oliver Read, W9ET(, Technical Editor; Raymond B. Frank, W9JU, Laboratory Technician; Eugene O. Gleeson, W9FXK, Engineering Draftsman; Herman R. Botin, Art Director; John H. Reardon, Cir- SCORE one for RN. Sometime ago we culation Director; S. L. Cahn, Advertising Manager. New York Office, 381 Fourth Ave. Subscription $1.50 said that the police would welcome the per year; single copies, 25 cents; foreign postage $1.00 per year additional except Canada. Entered as second class matter March 9, 1938, at the Post Office, Chicago, Illinois, under the Act of March 3, 1879. Contributors frequency modulation. We also suggested should retain a copy of contributions. All submitted material must contain return postage. Contributions will be that they would like a working model. We handled with reasonable care, but this magazine assumes no responsibility for their safety. Accepted material is subject to whatever adaptations, and revisions, including "by- line" changes, necessary to meet requirements. were right. Chicago's Finest are experi- Payment will be made at our current rates upon acceptance and, unless otherwise specified by contributor, all enting with FM and (Turn to page 55) photographs and drzwings will be considered as constituting a part of the manuscript in making payment.

www.americanradiohistory.com June, 1940 RADIO NEWS 5

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Compact in appearance, the receiver will not take up too much room aboard your boat. Build Your Own 1A1 by RAYMOND P. ADAMS, WÓRTL Hollywood, California

This fine receiver will take in everything from 132KC to 42.3MC. It will cover from marine beacons to u.h.f. police.

-N THE August and September with relative ease -retaining its all - here; and the selection will largely de- (1938) issues of RADIO NEWS, the wave tuning features but eliminating pend upon the builder's own tuning is in- - - writer described the construction loop input and all tubes and circuits requirements. If he primarily and application of a special all -wave not definitely necessary to the recep- terested in the amateur bands, then receiver suitable to both ham and fan tion of ordinary long and short wave very probably the latter tuning con- use aboard ship. This particular job signals of entertainment and informa- denser -coil assembly layout would be was really quite complete, providing tional value. In other words, they most suitable, as it places these bands for general reception on all frequen- sought something reduced to LCD lay- in the most favorable LC relationships cies from 132 kc. to 42.3 mc. and fea- out- compact, easy to operate, yet pri- and provides for preselection at 10 turing loop- antenna input on the marily developed for long -time use meters. On the other hand, if long longer waves so that the instrument under adverse atmospheric conditions. wave coverage is desired, then the might be useful in direction -finding. Perhaps the writer's 1940 marine re- first -mentioned tuning layout would Many correspondents wrote in ex- ceiver will meet these requirements. be requisite as it alone of the two in- plaining that while they remained in- The tuning range of this simpler cludes coils for 132 -405 kc. Actual cov- i terested in a good all-band set for version of the initial all -band job will erage for all coils in both assemblies marine application, they were not par- depend upon whether a 410 mmf. per is given in the parts list and need not ticularly concerned about taking bear- section gang condenser and matching be repeated here. ings at sea and wondered if the writer coil set or a 280 mmf. per section con- Electrically, the receiver is reduced would not get out a much simpler de- denser and similarly matching coil as- to the simplest possible circuit terms : sign- something which less experi- sembly are used by the individual r.f. stage; mixer stage; single i.f. stage; enced radio builders might duplicate builder. There is definitely a choice second detector -AVC -first audio; beam ihkaL. www.americanradiohistory.com i 7

Underchassis view and a topside view of the marine receiver. Note the compactness of assembly and the lack of stray wiring in set.

power output; p.m. speaker; power various incorporated components supply. are tacle on the front of the tuner panel The circuit is straightforward well protected from humid and salt at- permits and in every way familiar and features plug -in connection to power mospheres. As for controls, they are supply and battery, while twin binding but five tubes, three of which are of few in number: the main tuning knob; the low filament post assemblies provide for antenna drain type (the two a knob for sensitivity adjustment; one input and speaker 6S7G's and the 6T7G) and one of which output ties. for volume control and receiver on- The total "B" current is well within (the 6J8G) provides for excellent all - off (the switch on the control band conversion closes the 100 ma. limit of the Vibrapack when self- excited. both the filament circuit and the relay and the total filament Physically, the set is divided into three current is down circuit for the Vibrapack power sup- to 1.20 amperes. Overall drain on the separate assemblies : tuner and audio ply); and a rocker knob for antenna required 6 amplifier; speaker; and power volt storage battery does supply. load compensation and precision r.f. not exceed 6 All three units are compact and amperes. the stage alignment. One shielded recep- (Continued on page 50)

L1-Meissner 13 -7610 coil assembly "7.15 to R 100,000 ohms 1 2270 meters" w. IRC R,5- I00,000 ohms 1/ w or Meissner 13 -7603 coil as- Ri ohms 1 w. IRC sembly -300 IRC 30,000 ohms 1 w. "9.25 to 565 meters" R; ohms w. R1n- IRC Meissner 3 gang -300 I IRC Co ---.I mfd. 400 v. Sprague C,- condenser 21 -5230 "Used 20,000 ohms 3 w. IRC with 13 -7610 coil assembly" or Meissner R- C -.I mfd. 400 v. Sprague 3 R- 20,000 ohms 1/2 w. IRC gang condenser 21 -5227 "used with 13 -7603 C4 -.05 mfd. 200 v. Sprague R,,- 250,000 ohms 1/2 w. IRC Cs mfd. 400 coil assembly" 500,00 ohms -I v. Sprague NOTE -Assemblies, wired R,- Yaxley type N C,- .00025 fd. mica Sprague and aligned with all R,0-250,000 ohms 1 w. IRC trimmers, etc. 500,000 C,-.05 mfd. v. Sprague L2-456 kc. input trans. Meissner R,,- ohms 1/2 w. IRC Ca -.05 mfd. 400 v. Sprague 16-5740 R -400 ohms 3 w. IRC L;,-456 kc. output trans. Meissner 16 -5742 40.000 C -10 mfd. 50 v. electro. Sprague T,- Output trans. Kenyon T R0- ohms I w. IRC C,, mfd. 600 v. Sprague -104 R -400 ohms I w. IRC -.5 T2- Filter choke. Kenyon T -152 R1,- 50,000 Cu -.1 mfd. 200 v. Sprague R,-25,000 ohms pot. Yaxley ohms I w. IRC C,2-8 mfd. 600 v. electro. Sprague R,,- 500,000 ohms w. IRC R2- 25,000 ohms I w. IRC 100,000 1/2 RY -6 v. DC relay-Ward Leonard 1061114 R,- ohms 1/2 w. IRC V- Mallory 552 Vibrapack

www.americanradiohistory.com 8 4 sell eztse4iweate4f4 MPLIFICI[ by WILLIAM D. HAYES, W6MNU Oakland, California

Just the thing for the experimenter to build. The unit is simple to build and trouble -free in its operation. Reproduction is rather good. Makes a fine basic eleetro -phono unit.

LMOST everyone who has ever tion when the key is not plugged in. And now a word of explanation I- worked, experimented, or even Some experimenting with C2 may be about the filter choke. The one shown A - twiddled with radio has felt the necessary in order to obtain a note to in the photographs is a small Stancor need of a small audio amplifier when suit your particular ear, but it 15 mil. job (C- 1515). It happened to none was available. The usual solu- shouldn't be hard to find one that's be on hand and was installed with- tion for this predicament is to throw "just right," as Goldilocks would say. out reference to its characteristics, on together a makeshift amplifier in the When a low impedance source such the assumption that it was a 50 mil. hope that it will fill the bill, and be- as a single or double button mike is choke. After the amplifier had been cause it is makeshift and thrown to- used, the regular input terminals can in operation for several weeks, I hap- gether, it generally turns out to be be employed for connection. No high pened to be looking through a catalog both an eyesore and an earsore. The impedance terminals are provided, but and was much surprised to learn that logical solution is to build up a small when using a high impedance phono- the poor little choke was only sup- amplifier to keep as a permanent piece graph pickup for instance, it is quite posed to carry 15 mils. I have never of equipment, and to resolve not to simple to clip onto the secondary ter- bothered to change it because there is dismantle it no matter how you pine minals of the input transformer, leav- no undue heating in spite of the 250% for one of the component parts. Then ing the primary open. The gain of the overload, and the filtering action is when the need for an amplifier next amplifier is ample for ordinary pur- adequate. However I would advise arises, your pride and joy will be safe poses; about .05 volts across the 200 anyone building the unit to use a 50 and sound, ready to plug in. ohm input will drive the 25L6 to full mil. choke such as Stancor C -1003 be- The amplifier described here has output. No output transformer is in- cause the 15 mil. choke is undoubtedly proven its usefulness on numerous cluded on the chassis inasmuch as the operating in a super- saturated condi- occasions. It has served as a phono- usual procedure is to mount the trans- tion, and is probably so busy passing amplifier, a modulator for five mighty former on the speaker itself. This the d.c. that it can't pay much atten- watts of 160 meter r.f., the audio end arrangement also provides greater tion to stopping the ripple. For this of several experimental receivers, and flexibility. In conjunction with a small (Continued on page 57) last but not least as a code- practice modulation transformer, the unit oscillator. A glance at the circuit will makes a nice modulator for a five watt show nothing unusual, with the pos- peanut whistle. R,- 250,000 ohms pot. Centralab of feed -back To be P,2-7500 ohms 1/2 w. IRC sible exception the convenient the amplifier R:;- 100,000 ohms 1/2 w. IRC arrangement that permits its use as should have a self- contained power R4- 500,000 ohms 1/2 w. IRC 25Z5 R5-150 ohms 1/2 w. IRC an audio oscillator. A little audio supply. A is used as a half wave R,i-180 ohms line cord Ohmite from the plate circuit of the 25L6 is rectifier in the conventional AC -DC CI-1 mfd. 200 v. paper Aerovox of C2 -.0005 mfd. mica Aerovox fed back to the grid terminal the circuit. The heaters of the three tubes C3 -.006 mfd. 400 v. paper Aerovox input transformer through a .0005 mf. should be connected as shown with the C4 -25 mfd. 50 v. electro Aerovox C5-.02 mid. 400 v. paper Aerovox condenser (CO, and an open- circuit 76 at the negative end, because a high C,;-16 mid. 150 v. electro Aerovox jack. Although a condenser of .0005 potential difference between the heater C,.-24 mfd. 150 v. electro Aerovox T, -D.B. microphone to grid transformer. mf. may seem rather small for the and cathode of the 76 would be unde- Stancor A -4708 passing audio frequencies, it provides sirable, and might introduce serious CH,-30 H. at 50 mils. Stancor C-1003 SW,- S.P.S.T. toggle switch just about the right amount of feed- hum. The input filter J, -Open circuit jack. Yaxley back for a nice 800 or 1000 cycle note condenser of 24 m.f. may seem unnecessa- with the gain control almost all the 25L6 way down. All that is necessary is to rily large, but it keeps Ji plug in the key and fire away. If the the output voltage up leads to the key are more than a few where it should be; inches long, it is best to use two sep- and with the introduc- of the new com- arated wires rather than twisted pair, tion 5 pact electrolytics, a because the distributed capacity in the high capacity condens- twisted pair has a tendency to main- er can be fitted in al- 1 tain oscillations with the key up. most anywhere. The The shielding on the lead from the actual condenser used grid circuit of the 76 to the jack is not measures 11/16 "x necessary if the lead is reasonably 2 9/16 ". Speaking of 115V.AC.OR DC. short, but it is put on just as a pre - dimensions, the chassis caution against any possible regenera- itself is 4 x 8 x2 inches.

www.americanradiohistory.com 9

A Serviceman's 1 -Tube Signal Tracer

N servicing radios, it is almost a truism that a totally inoperative by CHARLES R. MERCHANT set is easier to fix than one that Coluuihus, Ohio "sort of works, " -i. e., is noisy, dis- torting, or weak. It was to make it easier to diagnose these headaches Try this extremely simple signal- tracer which that the following device was constructed, and judging by tests on a only uses one tube. While it will not be considerable number of actual cases it does all that it was intended to do. It is essentially a signal- tracer which as good as a multi -tube rig, it works. makes it possible to follow a signal, either from a broadcast station or from a modulated test oscillator, from tack. Two of these thumb -tacks, sep- the cable is then brought up about an stage to stage and from component to arated by one -sixteenth inch, make up inch over the other end of the probe component through a set and find out a minute air -gap condenser in the body and a couple of turns of friction tape just where it goes wrong. When that of the probe, which very effectually wrapped around to hold it in place. A is settled, it is seldom much trouble shields the probe tip from the ground regular phone jack is fastened to the to figure out what's the matter. capacity of the shielded cable used free end of the cable, the inside wire The hook-up used is a pentagrid to transfer the signal to the input of going to the tip and the shielding being converter circuit whose oscillator the converter. connected to the ground side. It is section generates frequencies which To the point of one thumb -tack a then complete. This is the r.f. -i.f. probe. lie in the regular broadcast band. This one -inch length of stiff piano wire - Another cable is made up exactly is coupled to the antenna and ground gauge 20 or 21 is right -is soldered like the first except for the probe, of a good set, either a T.R.F. or super- and the other end sharpened. A piece which in this case has a .00025 mf. mica heterodyne, but one preferably with- of wooden dowelling, of a diameter condenser set into a slot in the end of out A.V.C. A signal fed into the input just large enough to fit snugly in the another similar bakelite tube and of the set to be repaired may then be tubing, is cut one -half inch long, and taped fast. The inside wire of the examined anywhere in its career, a one -thirty- second inch hole is drilled cable is soldered to one terminal of the either as r.f., i.f., or audio, by being from end to end down the center. The condenser, and a one -inch length of fed into the input of the converter cir- piano wire is pushed through this un- piano wire is soldered to the other. cuit through special test cables. If the til the thumb -tack is all the way in, This is the audio probe. signal is to be examined in the r.f. and a turn or two of bare copper wire As to the converter itself, its con- stage, the oscillator of the converter is wrapped around the free end of the struction is not difficult. The 6A7 is rendered inoperative and the signal piano wire, flush with the dowel, and should be well shielded, and the cur- is simply amplified and passed on to soldered to hold the piano wire in rent well filtered; any hum which is the test set. If the signal is in the place. introduced into this tube will be very i.f. stages, it is changed back to broad- The center wire of a piece of shielded confusing when you're using it to lo- cast frequency in the converter, and cable about three feet long is pushed cate hum somewhere else. L and C in if the signal is in the audio stages it through another similar piece of the diagram are any ordinary broad- is used to modulate the oscillator fre- dowelling, and soldered to the pin of cast band r.f. transformer with its pri- quencies in the converter in the same another thumb -tack. The wire is then mary cut down to about a dozen turns, manner as a phonograph oscillator. pulled back through until the head of if it has more than that, and the tun- Thus any defective stage may be the thumb tack is flush with the end ing condenser that goes with it. located quickly. of the dowel, and the wire is secured (Continued on page 55) One prerequisite in such trouble in the same manner as the other. shooting is that the device used shall A speaker ce- C,, c3, C5, c5, C8 -.1 mfd. 400 v. Sprague very thin coating of Co, C,- .00025 mfd. mica Sprague not load the circuit. That was one of ment is then applied to the second C,, C8-16-16 mfd. 450 v. electro. Sprague the great difficulties of the analyzer piece of it is R1- 20,000 ohms I w. Aerovox dowel and pu shed through R,- 10,000 ohms I w. Aerovox method of set -checking; the extra the bakelite tubing until the head of R;,- 50,000 ohms 1 w. Aerovox capacitances introduced by the is Li -85 mhy. r.f. choke Meissner ana- the thumb-tack just L8-30 hy. filter choke 50 ma. lyzer cables were generally sufficient five -eighths of an inch TO ANT. OF to throw the set into an entirely dif- from the other end. A TEST SET) ferent frame of mind, and with a sheet very small hole is drilled II- - -z -__-r- of analyzer readings on hand it was through both the tube often more difficult to figure out what and the dowel and a they indicated than it would have been small p()) brad nailed TO GND.OF to diagnose the trouble "by ear." through to hold the TEST SET That difficulty is avoided in this in- dowel in place. The stance by using a probe which puts other piece of dowel is such an infinitesimal load on the cir- then pushed into the cuit that the effect is practically zero. open end of the tube, In fact, if the set under observation is thumb -tack first, until operating strongly at all, it is not the two thumb -tacks are necessary to touch the probe to the separated by one -six- 6.3V. components; by simply holding the teenth inch. By pushing L2 probe near them, enough energy can it in until the two 80 be picked up from the stray fields to thumb -tacks touch and '000-^ enable one to judge the quality of the then withdrawing it, C7 signal at that point. this distance can be The probe is constructed of a five - judged quite accurately. inch length of bakelite or fiber tubing A few drops of cement C9= of an inside diameter just large enough and a brad hold it in 5V. to admit a flat -headed metal thumb- place. The shielding on

www.americanradiohistory.com 10

A signal booster (left) and a frequency marker, described by the author.

M odernizing Old Receivers r HE possible addition of useful ac- by CHARLES R. LEUTZ cessories to existing radio receiv- Glendale, L. I., N. Y. - - ers covers considerable territory. Customers and dealers alike should be well informed on the various accessories available and able to weigh the PART 4 technical limitations as well as the advantages. No one book gives complete By adding various accessories to the old receiver, data on all radio attachments, but the different manufacturers go to consid- the serviceman can not only make a fine profit, but erable trouble and expense to prepare comprehensive literature c o v e r i n g the finished model will equal the latest 1940 set. their products. Most of this valuable literature is available simply for the asking; in a few cases a nominal sum is asked to off -set part of the cost. Every serious radio receiver owner, same, or possibly an automatic Previously, several obstacles im- radio dealer or service technician changer. In any event there is an op- peded the sale of record players. Orig- should invest a dollar or two and make portunity to demonstrate the advan- inally it was necessary to place the a complete collection of these booklets tages of a simple phonograph oscil- player close to the receiver and either which are invariably right up to the lator. alter circuit connections or use make- minute in new developments. For customers in the upper income shift adapters. The advent of phono- Dealers and service men can secure brackets, the Expansion-Compressor- graph oscillators has changed all this substantial accessory business by sim- Phonograph Oscillator shown sche- and dealers can sell easily manual and ply going out after it; volume sales matically in Fig. 21 is suggested. This automatic record changers by applying cannot be made by remote control device is not on the market yet and modern merchandising methods. Tele- from behind a desk or bench. Personal there is an opportunity for qualified phone, letter or even postcard invita- calls must be made on old customers dealers to make same up to order. tions addressed to local customers or and prospective new customers, to de- During the past year the sale of rec- prospects can suggest dropping in for termine just what items they can use ord players and discs has continually a demonstration or offering to install to advantage and also can afford. For increased at an impressive rate. Fur- a unit on trial. As previously men- example, the customer may be inter- ther sales increases along this line tioned, during a demonstration, the ested in trying a record player. In can be expected. Music lovers can ac- use of a good quality amplifier and that case it is most essential to deter- cumulate a record collection suiting the right selections will greatly sim- mine the prospect's musical tastes and individual tastes, play them any time plify closing the sale. send appropriate recordings. A set of desired, secure musical reproduction The value of the home recording fea- "swing" or "classical" discs may either comparable to the best broadcast re- ture, originally regarded as a novelty, make or break the sale, depending ception and most important, complete- is now being appreciated as a valuable wholly upon the customer's likes and ly eliminate the annoying, obnoxious adjunct in connection with voice cul- dislikes. Where the customer already "commercials ". Furthermore, it is ture, diction, word pronounciation and has a record player, there is an op- possible to secure some good records public speaking lessons. portunity to sell a modern pickup for which are never heard over the radio. Record players and recorders are

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Various types of additions which can be easily put in an old receiver to improve it. subject to some limitations which can- sion ", during reproduction. This is with increased signal level the potenti- not be completely overcome without also a future possibility and can be ometer voltage increases, and vice - considerable expense. It is not a accomplished by using a separate head versa. This voltage is applied in se- simple matter to construct a single and groove from that used for the ries with the control bias of the master pick -up which will produce uniform music or voice. mixer tube. In the "expand" position, gain over the entire audio frequency So far, all of the volume expanding the voltage becomes opposite in po- range, at a reasonable cost. A double circuits are limited to relatively small larity to the bias of the control tube, pick -up, one to cover the lower fre- signal input voltages on the order of accordingly increasing the tube ampli- quencies and the other to handle the that obtained from a phonograph pick- fication factor. In the "compress" po- higher frequencies, each working in a up. Accordingly if the expansion cir- sition, the potentiometer and bias separate groove is a future possibility. cuit is built in as an integral part of voltages add, providing increased neg- It is generally known that at the the broadcast receiver, it may be a se- ative bias with corresponding de- present stage of the art, neither wax rious source of distortion in the hands creased amplification factor. or film recordings can be made to of a non -technical operator. For that The above circuit can be used with- cover the full maximum sound levels reason, it is suggested that provision out the modulated phono- oscillator, if involved, except by applying "compres- for volume expansion be confined to desired, by taking the audio output at sion". In compressing music of a very the phonograph pick -up mixer circuit, the plate of the master mixer tube and large volume during recording, it is as shown in Fig. 21. connecting it to the input of any re- anticipated that these records will be This same circuit can be used for a ceiver or P. A. audio amplifier. reproduced through a system employ- microphone pick-up, in which case the Push Button Tuners, both the built - ing corresponding volume expansion, switch is placed in the "compression" in and remote controlled types, are such an amplifier being shown in Fig. position to prevent blasting or over- subject to certain limitations as well 21. This amplifier, in the "expansion" loading and otherwise compensate for as advantages. The pros and cons position, does have a variable gain and differences in sound level produced by should be explained clearly to prospec- will amplify the higher amplitude sig- movements of microphone performers. tive purchasers. Push button tuners, nals more than the low amplitude sig- In this circuit, the 6H6 tube is used as operated at a location relatively close nals, but the exact rate of reproduc- a voltage doubler, the D C output to a group of broadcasting stations, tion or discrimination between low being applied across the 1 megohm po- provides a convenient and rapid means and high signal levels cannot be ex- tentiometer, which in turn is con- to change from one program to an- pected to exactly recreate the original nected to the D. P. D. T. (Expansion - other. The built -in type tuner is read- musical rendition. Some means is Compression) switch to permit revers- ily adapted to any superheterodyne needed to continuously record the ing the polarity of the voltage taken or TRF receiver having a two gang amount of "compression ", so this vari- from the potentiometer. condenser, and will give excellent re- able value can later be used to regu- Changes in signal level change the sults with such sets. Most of these late the proper amount of "expan- D C voltage across the potentiometer; tuners only act on two circuits and if

SIGNAL BOOSTER MC 28 -56 OUTPUT -ItALIGE 5 a 10 Meter Converter

U Mio 100 IG raI.Ew G tl h

Cho

L NA. _.J woce ope ehouo phi,. kin GainGb n Control 19 66 Tube eymboie indicole Whom wen of tube sockets _ _ - `... ALIGNENT s Double Receiver Range reea,eMy I 57 MC =l1. 2 10 MC äso-: 0 16 MC VR150

et u Doublet not Reed, mmtmee ccAnise,ee Io Noe" FIG.-26 FIG. -25 Am,ne to oeeK o e6 together. Circuit diagrams of addition to the old receiver.

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Three types of push- button renovating controls discussed by the author. used with receivers having a three mediate amplifier, and get through. One of the most useful adjuncts to gang condenser, some loss of perform- Simple interference of this nature can any all -wave superheterodyne re- ance must be expected. The loss is be corrected by the use of a single ceiver is a TRF pre -amplifier or sig- not serious if the desired stations are wave trap as shown in Fig. 22, or in nal booster. A typical modern unit locals or other strong signals. severe cases, by the use of a dual wave of this type is shown schematically in Practically all remote control push trap as shown in Fig. 23. Fig. 25. The circuit consists of two button tuners consist simply of a Receivers capable of wide band pass stages of tuned radio frequency ampli- duplicate superheterodyne converter and used for DX reception will pick fication covering a frequency range of tube, operable at the end of a re- up interference caused by inter - from 1.6 to 31 megacycles, divided mote control cable, to replace the re- carrier 10 KC "whistles ". This diffi- among four bands. For the broadcast ceiver's built -in converter tube. This culty can be corrected as shown in listener interested in picking up for- application is strictly a "local station" Fig. 24, wherein two filters are used eign news flashes direct from the Eu- tuning convenience and ordinarily un- for a push -pull output circuit. For ropean cities, the addition of this unit suitable for DX operation. this application, care must be taken facilitates more consistent reception. In spite of the limitations outlined to select well designed and constructed The image ratio and over -all signal-to- above, the applications are often ex- filters that will not detract from the noise ratio are both substantially im- tremely useful for sets to be tuned by receiver's audio frequency response proved. Both of the above factors are children, elderly people or invalids. range, other than in the immediate maintained at the most favorable con- Personal chats with customers often vicinity of 10 KC. dition by adjusting the signal booster bring out details of reception diffi- Several accessories, designed pri- for maximum sensitivity and using a culties that can invariably be read- marily for amateur traffic, can be read- corresponding lower gain in the re- ily eliminated. For example, a re- ily sold to some broadcast listeners. ceiver IRF amplifier. (Next page) ceiver may be subjected to interference from one station, either from the main carrier or a harmonic. The interfering signal may be within the broadcast band or it may be on a frequency in the vicinity of the inter-

A RCVR G

R,- 50,000 ohms, 1 w., Centralab R_.5- 150,000 ohms, 1 w., Centralab R. -1,200 ohms, 1 w., Centralab Ra0-500 ohms, 1 w., Centralab R5- 75,000 ohms, I w., Centralab R,5- 30,000 ohms, 1 w., Centralab R,- 250,000 ohms, pot. Clarostat R5e- 100,000 ohms, 1 w., Centralab R -1,000 ohms, 1 w., Centralab R33-40, 000 ohms, 1 w., Centralab Ra. R- 30,000 ohms, 1 w., Centralab Rs- 150,000 ohms, I w., Centralab Cs, C2, Ca, Cs, C5, C5, C7, Cs, C9, C50, Cu, R0- 300,000 ohms, 1 w., Centralab C,2 -.05 mf. 400 N. paper, Mallory R,0- 50,000 ohms, 1 w., Centralab C1a -.0015 mf. mica, Mallory R,1 -1,200 ohms, 1 w., Centralab C1 C5-8 mf. 450 v. electro., Mallory R,2-- 75,000 ohms, I w., Centralab C55 -.25 mf. 600 V. paper, Mallory PRI.OF R,a- 100,000 ohms, I w., Centralab C1 -.05 mf. 600 v. paper, Mallory Rl, -1,000 ohms, 1 w., Centralab Css -1 mf. 400 N. paper, Mallory OUTPUT R,- 250,000 ohms, pot. Centralab Csa -1 mf. 400 v. paper, Mallory XFMR Ruv R- 30,000 ohms, 1 w., Centralab C50- .00025 mf. mica, Mallory R,8- 150,000 ohms, 1 w., Centralab C21 -.5 mf. 200 N. paper, Mallory R,5- 300,000 ohms, 1 w., Centralab C2,-4 mf. 450 v. electro., Mallory PP FIG. -24 R20- 50,000 ohms, 1 w., Centralab C2a, C2x -16 mf. 450 v. electro., Mallory PLATES R2,- 500,000 ohms, 1/2 w., Centralab C2 -.1 mf. 600 v. paper, Mallory R_2- 40,000 ohms, 1 w., Centralab Rea- 400,000 ohms, 1 w., Centralab T1 -Input Transformer, UTC -0 -1 R2, -2,500 ohms, 1 w., Centralab T2 -Plate and fil. trans., UTC -1 -R -6 R5,-75,000 ohms, 1 w., Centralab CH- Filter choke, UTC -R -14 R55- 25,000 ohms, 50 w., Ohmite Rte-100,000 ohms, 1 w., Centralab SW1 -SPST Toggle. Cutler- Hammer Re8-1 meg. pot. Clarostat SW>-DPDT Toggle. Cutler- Hammer

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From the diagram it will be noted that a special output transformer enables connecting the booster unit to any receiver having a standard or doublet input circuit. A two way FOR IIIIIEDIATE RELEASE... switch throws the booster in or out of the circuit, as required. The use of a two stage booster on the broadcast Dot & Spot News will be found in this band, even with a mediocre receiver, eliminates the need of any wave traps column every month. Don't fail to read it! previously mentioned. A signal calibrator is another valu- COMMENTING on Frequency Modula- violations of this nature in order that the E. President of Commission may refer to the appropriate able and interesting unit useful to tion, F. McDonald, Jr., Zenith Radio Corporation, stated : United States Attorney for prosecution the short wave DX fans and European The company commenced broad- cases in which it appears an indictment news report listeners. One well de- casting from its Frequency Modula- should be sought. . . . signed standard signal calibrator is tion Station, using the new Arm- strong System under which it is 31R. BERNAL C. PAYNE, 5022 Maple shown schematically in Fig. 27; al- licensed, on February Ist and is now Avenue, St. Louis, Mo. would like the though this circuit requires six tubes, transmitting daily programs of ap- Editors to identify the headphones worn by the necessary parts are contained proximately sixteen and one -half Paul Whiteman in his picture on the cover within hours duration, from its permanent of the March, 1940 issue of RADIO NEWS. the compact space of 8 "x8 "x12" location in the tower of the Chicago We are unable to do so. Can you readers deep. Towers Club on North Michigan Ave. help both Mr. Payne and us out? The calibrator can be operated un- With regard to the company's new line, Incidentally, the headphones worn by the modulated to check the frequency of Mr. McDonald advised: British sailor on the right in the cover of The company's new combination the May, 1940 issue of RADIO NEWS are any incoming signal, by the zero beat battery electric portable receiver in- those manufactured under the name of method. Modulated, the calibrator is corporating the removable Wave - "Brown" in England. They are the same useful to pre -set or tune a receiver to magnet, an exclusive Zenith feature, general type as those worn by the "boy" in any desired signal frequency. In was announced to its distributors the January, 1939 issue of RADIO NEWS. other early in March. Orders received from distributors for April and May Fr HE Federal Communications Commis- SIGNAL CALIBRATOR delivery greatly exceeded the expec- sion has been notified that the United .w tations of the management. Ship- States Admiralty Court, Norfolk, Va., has ments of substantial quantities of ordered the barkentine -rigged vessel _Marsala these receivers are now going for- sold to satisfy a $5,500 penalty incurred when ward to distributors and dealers. it cruised 11 days outside of port without Zenith Portables equipped with the radiotelegraph transmitting equipment as re- Wavemagnet will perform where quired by the Communications Act. other portables fail, such as on The violation occurred November 16 to 26, trains, in airplanes, boats and metal 1938. It was made known when the vessel structures. This performance is be- ran into a storm off the Virginia capes and ing guaranteed. The company is pro- lack of radio facilities imperiled students and tected against imitation of its remov- crew. On March 27, 1939, the Commission able Wavemagnet feature by a strong notified the owner, the American Nautical patent and no other manufacturer Academy, Nautical Training School for Mer- FIG. 27 has been licensed to use it. chant Marine Officers, Washington, D. C., of the forfeiture. The school, on April 8, filed BY providing for flexible reception now application for mitigation, but the Commis- words it eliminates "fishing" for a de- and in the future in his television recei- sion after full consideration denied the re- sired signal. For example, by setting vers presently cooing off the assembly line, quest and advised that the forfeiture was the receiver to the desired frequency Allen B. Du Mont, pioneer television manu- payable immediately. Payment was not forth- facturer of Passaic, N. J., believes he has coming, so the matter of collection was re- a minute or two before the station is struck the happy compromise between fear scheduled ferred to the Department of Justice. to start operating, the very of freezing the art on the one hand, and pre- On September 1 S proceedings were insti- opening announcement is available in mature obsolescence of receivers on the tuted by the United States District Attorney full In work, other, indicated in recent op:oions and deci- for the Eastern District of Virginia, and on intensity. amateur a sions of the Federal Communications Com- of this is required by February 19 the case was heard by the Ad- calibrator type mission. He states : miralty Court. law to maintain an accurate check on "I an the rare exception in up- holding the F. C. C. in its television the transmitted frequencies. RK. WHEELER, serviceman -author of citation of March 23, ordering a lead- Indianapolis, Ind., predicts for the Some broadcast listeners find de- ing company to explain its high - version in tuning in various non - pressure merchandising of inflexible serviceman the following for the balance of broadcasting signals, airway traffic, television receivers. Frankly, I'm 1940: in Daily business in 1940 will consist police signals, amateurs, etc. In this not accord with the widespread of $5.00 job, and several cheap criticism of the F. C. C's. action one connection a 5 and 10 meter converter by other television interests and by ones. Anything over $5.00 will be adds to the interest. The 5 meter an obviously misinformed or at least considered strictly as an Act of inadequately informed press. It is Providence. Customers will con- range is ordinarily limited, but the 10 tinue to lug in auto radios bought meter patent that all the facts in the case band provides plenty of oppor- are not being considered by those "wholesale" and expect to have them tunity for signal explorations. Fig. 26 hasten to accuse the F. C. C. of installed for $1.10. Tube checkers who bought this year may be obsolete be- gives the schematic wiring diagram of autocratic handling of television. fore they are paid for. The service a modern 5 & 10 meter converter which man will be called a "screwdriver includes the desirable features of a mechanic" at least once a month by IT has been brought to the attention of the high gain r. f. stage (6AC7/1852), a equipment manufacturers. Filter F e de r al Communications Commission condensers in Christmas midgets will high -C oscillator (6F6) and a stable through complaints from police departments fry out in August resulting in a oscillator (6AC7/1852). Freedom from and other parties that certain automobile re- minor boom. Tube prices will bob frequency drift and stable amplifier pair men, ambulance operators, and other up and down as usual, with profit to unauthorized persons are making a practice the printers. Business will be much operation are insured by the voltage of intercepting police shortwave radio mes- the same as 1939. regulated power supply which consists sages relating to automobile accidents, of a 6X5 rectifier and VR -150 regu- crimes, etc., and using them for their own benefit, or for the benefit of other parties IN March, 1940, the Editors wrote to the lator tube. Using the new "televi- not entitled thereto, with the result that Federal Communications Commission re- sion" type tubes provides a combina- police investigation of mishaps and crimes questing information regarding the so- called tion of low noise level is being hampered. station WHD reported in the then current and high signal issues of TIME magazine. This station was gain on these high frequencies in- It would appear . that any person who intercepts a local intrastate message and operating at Dartmouth College, with the volved. Even when used with an old divulges the existence of same or uses the knowledge of the College authorities. The existing receiver that tunes to 5 and same for his own benefit or for the benefit means used to broadcast was by what is gen- 10 meters, a decided improvement can of another not entitled thereto acts in viola- erally known as a "phono oscillator." We tion of this section. were struck by the fact that the station had be expected by using the converter The Commission's inspectors are being in- a regular listening audience, and that it had (Continued on page 59) structed to investigate complaints alleging (Continued on page 56)

www.americanradiohistory.com 14 .icarnac.. jALQnePL by LEE SHELDON Chicago, Illinois What to do with customers who always expect something extra in the way of a discount.

FVERY time I decide I've seen "About ten years ago," Ken solo'd, with him and use your head; no mat- everything in the radio business, "I bought a Colonial 31." ter what profit we make, it will be something new happens to "And I bought -" began Ben. double!" astonish me all over again. "Let me guess," Al said, covering his I was about to answer, but two horns One day last week I explained a eyes. Then "A Colonial 31 ?" honked. dandy sales stunt to my partner. "Right," Ken said, amused. "A "You fellows live together ?" Al "First," I said, "we hang pluggers friend of ours worked for a distribu- asked. on door -knobs. They read `Who knows tor, and gave us cards so we could get "Same building," Ken replied. the evil lurking in the heart of your them wholesale." "You -ah- married ?" I asked. radio? The shadow knows!' That "We did business with the janitor," "Sisters," they said quickly. starts them wondering. Then we fol- Ben added, "and he let us in on the I knew I was wasting time, but went low up with a personal call, handing ground floor." to Ben's apartment just to show him out a card saying 'This is the Shadow "Forty off," Ken continued. "Seeing he couldn't pull any fancy business on in person, come to take care of your that we're neighbors of yours and that me. set.' Like it ?" the publicity will do you good, we've "You can have a five -tube table "The set owner," Al replied, "will decided to let you supply our new sets model," I said, rapping the console probably tell you never to darken her -at the same discount." expertly, "for this job and thirty door again." My partner lives to Then I understood what "doubling bucks cash." discourage talent. in brass" meant. What nerve! He went up in the air so fast his "You mean," I asked incredulously, "Hmmm," Al said tolerantly, in- fountain pen leaked. "you like ?" don't the idea stead of throwing them out on their "Why, man!" he shouted, "know . "Wonderful idea -simply marvel- collective ears, "perhaps I could work what this set listed for when it was ous!" Al said, waving his arms. Then, out some sort of trade -in." new ?" in a lower voice : "Confidentially, do "Well," Ken said, "we -" "What's the difference ?" I asked. you mind if I breathe through my "Uh -uh!" Ben interrupted, "My turn. "You didn't pay list!" mouth ?" If you take our sets, we of course ex- "And the quality is wonderful!" he Believe me, Al would have been pect an extra discount." added. stung by some very pointed remarks That was too much. I groaned "Sure, sure," I agreed, "that's why if we hadn't been interrupted just then. loudly, but Al frowned me quiet. Al you're trying so hard to get a new one. Two customers came in - twins. always says never to discourage a fel- Don't bother turning it on for me!" They were dressed alike, kept in step low after cut rates, because there's On the way out I noticed Al's car from the door, and stopped before the always some way to get around him. was still in front of the house. I made counter with four heels that clicked But I know he's wrong. up my mind to bawl . him out if he as two. I sort of expected them to "Let's go look at those sets. Maybe stayed too long. cross their legs and raise bamboo we can work out some sort of a deal," Al finally came back to the store. canes. Al suggested, playing dumb. He knew For some reason, he wasn't mad when "We," they announced simultaneous - as well as I we couldn't take off forty I let him have it, and I felt a bit fool- like, "are Ken and Ben." plus, no matter what we sold them. ish for rubbing it in. They were as unsophisticated as a "Excellent - come along," they "Anyway," I comforted, "you had couple of butter -molds. My jaw was agreed, and walked out to the truck sense enough not to let Ken talk you still hanging when Al said: and Al's personal car. While we were into a silly sale. We haven't lost any- "Well, gentlemen- what's the dif- locking the store, Al turned to me and thing." ference ?" said: "Ken's a very good talker," Al re- This pleased the hay- shakers, and "You look bored. Been seeing too plied owlishly. "It was a tough they laughed in phase. much of yourself lately ?" struggle, but he finally landed me!" "No difference," the chanted, "ex- "You're wasting your time with "Don't tell me you bit on that cept for our fingerprints!" those chiselers," I shot back. "What 'publicity' line he was stringing us "Taking care of you," Al commented, do you expect to get from your half along with!" I shouted. "will be a double pleasure. What's on of the team ?" "Not exactly," Al explained. "You your minds ?" "Ben's in the truck," Al said. "Go see, I didn't know just what to do until I met his wife. She said she AIN'T IT THE TRUTH? after didn't want a new set." "From this we make a living ?" I asked. "The husband a cheapskate, the wife refusing to buy ? What sort of a sale does that make ?" "I found out," my partner continued, "the reason the missus didn't want a new set was because she liked the cabinet, and didn't want to give up such a beautiful piece of furniture." "It gets worse and worse," I said. "She won't let go of her furniture, and he won't let go of his money." (Continued on page 59)

www.americanradiohistory.com 15 r 1- 7 _a 112 MC

by HAROLD ID. MILLEN, %V LIOM Boston, Massachusetts

The "works" of the rig look like the For short hauls, for summer outdoor uses, there average 5M transceiver used to. is nothing that can compare with 21/2 meters. If WITH summer just around the corner, many a ham's thoughts are again turning to you will but try this band, you will be pleased. the idea of mobile operation. The ten meter band would seem to be the ideal band for such operation because it is given other hand is tricky to work the the signals traveled, I had never to get going and an everyday occurrence the band a moment's thought as far should be constructed exactly as West Coast and the Cubans, and also as mobile operation was concerned. shown in the photographs. can be depended on to give consistent After listening on the band for a few The detector socket, which must communication locally for a distance weeks we came to the conclusion that have ceramic or other low loss insula- of 25 or more miles while traveling there were enough stations on the tion is mounted directly behind the va- along the highway. band to warrant the construction of riable condenser for the shortest pos- From what the reader has just read, described. sible leads. It is we the transceiver to be raised off the chassis it might seem that had forgotten At I might mention that by two angle brackets to put it on a dif- this point the the title and decided to build 112 mc. much better same level as the condenser. com- the signals on are ferent job. But after building a than five meter signals were at the (Continued on page 56) plete station for our own buggy and In- results mentioned, we same period of its development. getting the stead of from scratch, the found that too many of our fellow starting boys have benefited from their ex- T h e circuits of hams turned thumbs down on mobile hearing the periments with the u.h.f. and have the various corn - operation on ten after gone ahead from the point they left ponents of t h e cost of the equipment. two & a half M. was out off in December, 1938. Five meter mobile operation The chassis, front panel, and cabinet transceiver s e t . of the question for the same reason, comes from the the new regulations require that for our transceiver C,-10 mmfd. ceramic padder Cardwell since well -known transceiver, which -.0001 mfd. mica Micamold five be equal in quality "Barr" G. the signals on was very popular a few years ago. C;-.01 mid. 400 v. Micamold to those on ten. R,-500,000 ohms 1/2 w. IRC In its original form, it used a 49 det.- R2-500,000 ohms pot. Centralab This left only 21/2 meters for our 30 first audio, and a 19 as Class R3-2500 ohms 1/2 w. IRC consideration. Frankly, until I had osc., T1-Transceiver trans. Thordarson T -72 A59 for the band and B audio. It had the disadvantage of T., -Class B input Thordarson T-67D50 built a receiver poor sensitivity, could not run a T3 -Class B output Thordarson T- 17459 heard the signals that the boys were L, -4 Turns No. 14 Wire, Space to 1 ", 5/g" dia. speaker, and could only be operated RFC-Ohmite 5 meter choke putting out and also the distance that with batteries. In the revised circuit, the tubes used TO SW. are; a 76 or if desired a 6C5 det. -ocs., 76 or 6C5 first audio, and a 79 or 6N7 Class B Audio. There is now plenty of audio to run a permanent magnetic speaker, and the unit runs equally well from an a.c. supply or from a motor generator when mobile, MIKE < or vibrator supply. WINDING While this unit has as its foundation the commercial transceiver previously _L IMFD.400V. mentioned, there is no reason why a similar job can not be duplicated by the reader from parts available at the .11 B+ linderchas:is view. regular sources of supply. The metal cabinet is approximately 100,000 OHM POT. FIG. -3 11" long, 61/2" wide, and 91" high. It is T large enough to hold 4 the a.c. power supply 0 0 can and when portable Rz R be used to hold spare parts and the microphone. R 06 ItA. '11-1- 1+2500 portion is =3 The audio TCH relatively simple and MPUT OUTPUT A+ MOTOR no special attention GENERATOR Y-Y 6V BATT need be given to the A Topside chassis view. wiring. The r.f., on the

www.americanradiohistory.com 16 "MOBILE ON 10" by R. J. HAGERTY, W6JMI San Diego. California

In spite of the skip, 28 megacycles still presents the best mobile band. The average car can be remodeled to house a complete low- powered transmitter and receiver.

TODAY portable -mobile gear is definitely attracting the amateur's attention. It offers diver- sified thrills and experiences that are without number and at the same time offers the most practical solution for emergency communication equipment. The author has had a mobile unit of some kind or other in his car for over five years and the described "layout" is the result of dozens of ideas, combinations, tubes, etc. Its performance can be best attested to by the following facts: It has been installed in the car over ten months and has traveled 11,500 miles -6,000 of which were on a transcontinental trip. The log book shows that to date there has been 103 QSO's. Briefly, this rig consists of a 6J5G with a ten meter crystal driving an RK -34 push -pull final amplifier to 15 watts input. The audio uses a single button carbon mike with a 79 Class A speech amplifier and a 79 class B modulator. The receiver is a ten meter converter, using a single 6J8G, the out- The author in his radio equipped car ready for the road. Notice the put of which is feet, into the automo- antenna sticking out from the after deck, where it is easily carried. bile radio for the necessary I.F. and audio amplification. The antenna is a quarter -wave Marconi with a concentric line feeder. Power for the transmitter is furnished by a motor -generator and the necessary voltages for the converter is obtained by tapping into the auto radio power supply. Sim- ple, isn't it, but all who have seen and heard it agree that it works wonders. Sad experiences of other hams as well as myself say that for portable - mobile operation just any old thing won't do. It is the last place in the world that hay -wire and poor connections can be tolerated. Tricky circuits, super -critical adjustments and the like are definitely out of the question. Sim- plicity is the watchword with ruggedness a close second. And a little previous thought and preparation will avoid remodeling the car to put the rig in. If yoot think the photographs are unusual just remember that the transmitter was built on a masonite chassis that fits perfectly in a shelf behind the driver's seat. Its power socket lines up with a hole in the rear of this shelf through which a plug -in cable con- nects with the associated power supply in the rear. The 10 meter receiver fits into the glove compartment and is so well The converter is mounted in the built in, that it does not destroy the beauty of the car's dashboard. glove compartment on the left side of

www.americanradiohistory.com 17 the dash and its output feeds directly to the radio installed on the car's bulk- head. The antenna is mounted on the turtle deck of the car and the concentric line feeds to an antenna changeover relay. Back contact of this relay feeds through a low capacity shielded cable to the antenna connection on converter. A single 0 -150 milliammeter is mounted in the car's instrument panel in the space provided for the electric clock. The microphone and its cable comes out between the seats. If you plan on going portable -mobile plan the layout so that it is ac- cessible- -just in case- -and so that you don't have to go through a bunch of contortions when you switch from send to receive. In our case the switch on the microphone does the whole thing with the aid of two relays. The antenna relay should have good insulation and the power relay should have heavy points. Incidentally, good adap- tions can be made from old battery charger relays if the coils are rewound trunk keep This is how the author's auto with Number 30 wire so as to is filled with 10 meter radio gear. the current drain down. The circuit diagram of the trans- note ameter and 1" long. It is soldered di- mitter, (and please the absolute of 6J5G is shown. The rectly onto the plate prong the minimum of parts), condenser, Cl, res- 6J5G is a standard triode crystal oscil- socket. The tuning lator with the series resistor R2 to onates at about 70% of full capacity. to 200 volts. All parts are mounted underneath the lower the voltage about so as high C tank chassis and near the tube socket Note particularly that a The crys- circuit is used -both for maximum to make short connections. output and stability. This tank con- tal choke, RFC1, while not critical, is is best to experiment sists of 5 turns Number 12 -3/4" di- important. It with different types and makes in this position as it has quite an effect on TO VIBRATOR the crystal stage current. The one in SPKR. XFMR use at present showed a 12 ma. de- 411I crease in plate current over some that OD were tried. A word here about ten meter crys- IWO tals would not be amiss. They are not critical and handle very much like SEND RECEIVE lower frequency crystals. But out of RELAY, S.P.D.T a half dozen that were tried the output in all cases was improved as much as Closeup view of the antenna installation (above). Below, the topside and "PHOT ,L.,_".. E 200% just by cleaning and grinding FIG. -6 TEXT the plates perfectly flat. You can be front view of the 28 mc. receiver. sure the plates are true when they stick on a wet piece of glass held ver- DET. PLATE tically. FIG.7 The amplifier stage is the result of many, many experiments. Pentodes PRIMARY and tetrodes all have their places but for care free and non -critical operation there isn't anything like a good .11 TO AUTO The RADIO' triode, in the final RF stage. RK34 fills this bill admirably -being a fine high frequency tube, easy to ex- FIG. -4 cite and neutralize, and very efficient. We spent a month trying to neutralize a 6L6 and never did get it neutralized DET PLATE I.F. PENTODE to our satisfaction. But once the RK34 was wired in, it took less than TO AUTO 3 minutes to neutralize it right "on the nose" and the adjustments have never needed to be changed. The grid of the RK -34 is inductively coupled to crystal tank. The grid tank, FIG. -5 B+ L2, consists of 19 turns Number 12, 3/4 " diameter and 3" long, and mounts on the grid prongs of the RK -34 socket. C3 is a 3 -30 mmf. compression type ISOL A NT IT E 5534 BEADS trimmer condenser also soldered onto TANN the same grid prongs. The grid leak, R3, connected at the center of the coil,

www.americanradiohistory.com 18

ened more than two inches. As 79 class B. Incidentally, the entire is consistent with good practice modulator has a resting plate current in each stage the ground re- of 16 mills and kicks up to 35 -40 mills turn was made to some conven- for 100% modulation. If one wishes ient point near the associated to use the newer type tubes the 6Y8G apparatus. Then these grounds is the octal base version of the 79 and were wired to a common differs only in that all connections are ground bus. brought out the base. The class B The modulator is simple and transformers should be heavy enough straight forward. Low gain to carry the load as the smaller variety microphones have no place in have the annoying habit of saturating portable gear as the necessary and burning out. equipment required to bring The question of a receiver for their level up to a usable value portable -mobile operation is undoubt- results in too many parts as edly the cause of many headaches. The well as increasing the filament super- regenerator for ten meters is drain. Suffice to say that in a definitely out of the running these single button carbon mike a days. T.R.F.'s proved too critical and good one can be very good and a poor lacking in selectivity. Simple super - one can be awfully bad. The necessary hets did not provide sufficient "umph" mike voltage can be obtained in a num- and large ones were too cumbersome. ber of ways such as dropping and fil- Some had a terriffic amount of hash tering the car battery but difficulties and others had too high noise level. might be encountered from hash and Finally, most receivers would not take feed -back. Flash light cells are not the jolting and jarring around and dependable enough for consistent op- Three everything happened from tube shields views of the 28MC transmitter. eration. Standard dry cells are cheap coming off to getting out of alignment. and can be mounted in the rear with One converter we made up was al- also serves to steady the coil mounting. the power supply using a relay con- most the answer but wasn't so hot on The plate tank circuit, C5 and L3, is tact to break the current while re- ten meters, and wouldn't work at all mounted above the chassis so as to ceiving. These dry cells after ten on five meters. We had been consider- make short RF leads and provide the months of operation show little signs ing the automobile radio for some necessary isolation. In the top view of wear. time. It had a power supply with effi- of the transmitter may be seen a thin As to why 79's were chosen for mod- cient hash filters already built in. Also sheet of copper fastened to the top of ulators instead of 6Á6's or 6N7's the most auto radios are perfect examples the masonite chassis and this provided reasons are : First -79's at this voltage of how a portable receiver should be all the shielding that was necessary. have 8 watts of audio output which is built. They are rugged, stable, and The neutralizing condensers, C4, are more than ample for 15 watts RF in- had the ability to take a lot of bumps. 3 -30 mmf. compression type trimmers put. Second-their static plate cur- Right here let it be said to the pro- with their screws removed, and the rent is lower giving a few more spective builder of this type of appa- movable plates turned out to an angle mills for RF. Third -their filament ratus that if he will take the cover of approximately 45 degrees. By cross - drain is lower. The first 79 is off of an automobile receiver and connecting the plate leads instead of connected with its elements in par- notice how everything is tied down it the more usual cross connected neu- allel making it a high mu triode with will probably save him many troubles. tralizing leads the latter were short- plenty of "sock" to drive the second (Continued on page 43) 6J5G RK34

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L , turns No. 18 long Cs mmfd. -5 -3/4" -50 mica Solar R- 50,000 ohms 1 w. Centralab L0 -13/4 turns No. 26 -1/4" long Co-.01 mfd. 200 v. Solar R,-200 ohms. 10 w. Ohmite L3 -21/2 turns No. 18 -1/2" long C,o -.1 mid. 200 v. Solar R,-3000 ohms 10 w. Ohmite L , -23/4 turns No. 26 -1/4" long C -.005 mfd. mica Solar R5 -2000 ohms 2 w. Centralab All coils wound on 11/2" dia. plug -in forms. C -.005 mid. mica Solar R,,-1000 ohms I w. Centralab L in opposite direction to L,. C1-, -Z00 mmfd. var. Hammarlund T,-Mike Trans. "No spacing between windings." C,,-3-30-mmfd. trimmer Hammarlund T, -Class B input C,-20 mmfd. variable Hammarlund C, -3 -30 mmfd. neutralizing cond. Hammarlund T -Class B output "Modulation" Co-15 mmfd. variable Hammarlund C,,; -25 -25 mmfd. split -stator, Hammarlund C3 -30 mmfd. variable Hammarlund C, -10 mid. 50 v. electro. Solar Transmitter Coil Data C4-100 mmfd. variable Hammarlund R,-300 ohms Z w. Centralab L -5 turns No. 12, 3/4" dia., %" long mfd. 400 v. Solar R2- 50,000 ohms 1/2 w. Centralab L6 -19 turns No. 12, 3/4" dia., 3" long C6 -.002 mfd. mica Solar R3- 50,000 ohms pot. Yaxley L -19 turns No. 12, 3/4" dia., 3" long C, -.005 nxfd. mica Solar Ri-25,000 ohms 1 w. Centralab "All self- supporting."

www.americanradiohistory.com ENCH N27' 19

by LEE WARD Service Manager, San Francisco, California The answer to the No. 5 Repairmatfs Middle; and the start of No. 6 Riddle are this nrontles features.

AS soon as a serviceman sets himself up in Simply tell us how to make it tough for Model 426 0 -I d -c milliameter, 4" square, or business, he is surprised to find technical the gunman. Without unduly extending the a Simpson Model 29 0 -I d -c milliameter training plays only a small part in the con- narrative, state what you think would be the 45/g "x41 /8 ". Or any other meter you choose duct of his store routine. Accounting, sales- best action to be taken at the point where having the same retail value. manship, and protection of cash the story leaves off. Address entries to Re- advertising, SECOND PRIZE: Ghirardi's headache pre - important. pairman's Riddle No. 6, Radio News, 608 S. and investment are equally venter for servicemen, the Radio Trouble usually located in a low - Dearborn Street, Chicago. Answers must be Repair stores are Shooter's Handbook. rent section -which means few passers -by. Re- received not later than June 25, 1940, and the ceipts often accumulate for a week or more. winners will be announced in the September THIRD, FOURTH, and FIFTH PRIZES: Each Both these conditions make the shop appeal- issue. a year's subscription to RADIO NEWS. If you ing to a robber. In the story below, how Entries will be judged for logic and ex- are already a subscriber, a twelve months' would YOU prevent a robbery if the store was pediency. Duplicate prizes to tie winners. extension. is of YOURS? Everyone eligible except employees Well, let's not stand around -a guy's comin' is an unusual hold -up; you have a Ziff -Davis Publishing Company or their fami- This in with a gun! chance of GETTING something instead of hav- lies. ing it taken from you. FIRST PRIZE: Choice of either a Triplett Lights! Action!! Camera!!!

E had an unfortunate acci- past the show window for several showed he didn't want any, but only dent in a customer's house hours. Neither of us recognized him, wanted to stall. I coughed, and was last week. Cliff, walking so we knew he didn't live in the neigh- afraid to turn my back. At last, down- stairs with a Fada 50, didn't borhood; he carried no sign, so we though, he asked to see a reel of wire notice one of the 10's worked out of a knew he wasn't a picket. I noticed on the top shelf, and -" socket. When he saw the tube roll one of his overcoat pockets sagged- "Wait a minute," Pete interrupted. off the chassis, he let go with one and it wasn't because it was full of "I got a better idea. Let's act this hand; the 10 was smashed, and the set half- dollars either. thing out. Lee, you stand right where came in with a bad dent. "I told Pete. He said not to worry, you were that night. I'll go back to "You're as awkward as a stump - but to stick behind the cash register the workbench. Cliff, you be the thug. legged ballerina," Pete, the Signal and cough if the bloke walked in. Sure Here's a pair of diagonals; that's the Chaser, announced. Pete's a swell enough, he did; looked up and down gun. Careful, they're loaded!" mechanic, but he doesn't get along the street, came in, and stood so the "Oh, boy!" Cliff said sarcastically, with Cliff very well. till was between us. Asked a few "now we're playing cops and robbers!" "Naturally," Cliff admitted, "I was dumb questions about tubes that "Walk in to the register," Pete in- excited when it happened. But structed, "and then I'll come I'd like to see you in a situation in and do my stuff." head "Not fisticuffs!" Cliff said. where you had to use your REARk DOOR WINDOW-4 on the spur of the moment. WORKBENCH "No -no rough stuff," Pete You'd show less presence of replied. "I'm simply going mind than an expectant father! to show you a handy trick The tightest squeeze I've ever PETE WORKING HERE that can be done without seen you in came when that calling for outside help, with- customer wanted to wait while out weapons or violence, that you installed a Majestic drive has prevented many a well - cable!" PHONE planned one -man stick -up. DESK GATE) would be darned "Yeah ?" Pete snarled, turn- PART IT ION You'll find it ing to me. "Tell him, Lee. Tell N inconvenient to do anything him what happened right here TUBE B PARTS SHELVES you shouldn't and you'll wish he started iylllllll you were out of the place. in this store before OH idea, my - working with us!" LEE STANDS HERE Now--got any quick "Well," I said, remembering RADIO witted friend, what's going to night, but wishing ROBBER WALKS IN, occur when you try to `hist the an exciting el STOPS HERE the boys would think of such jint ?' " things on their own time, "we -.. "Sure, Belasco," Cliff one winter ti laughed, "the till will be were open late eve- REGISTER ning. I was behind the front tapped." counter, tidying up stock and R "Go try it!" Pete challenged. waiting for Pete to clear away Cliff walked in and stopped a sudden surge of chassis. I1Iu11'iüdI11611iiIInIi1111ii1111ml1úü11i: u at the register. I coughed. "We had noticed a seedy SIDEWALK i DOOR Pete went into action. fellow walking back and forth (Continued on page 57)

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National Union Radio Corporation announced attractively finished in ripple from gray and has exter- separate bass and treble controls. The four mike their Newark, N. J. headquarters this week nal dimensions of 8" x 8" x 8" inputs use four input tubes and that they are prepared to supply Sound x /tra, a Coupling to the transmitter is accomplished by volume controls. individual special line of One master phone volume tubes for use in Sound Amplifiers. means of a concentric cable supplied with each control is used for the two phonograph in- In making the announcement, Mr. H. A. Hut- instrument. A 2 -prong plug is furnished such puts and chins, N. a second master control with pro- U.'s General Sales Manager, states: that the cable can be connected to the plug and visions for remote operation is used to adjust "Our chief requirement for these tubes is that the Vari -X plugged into the present crystal socket the overall volume of all channels. The indi- they must be demonstrably better to the ear. We in existing transmitters. The Fart -% has its own vidual are now prepared bass and treble controls are of the booster to supply thirteen types after power supply which works from 110 volts 60 type. permitting raising or lowering the amount several months of field experience in addition to cycle A.C. of bass or treble individually. engineering and laboratory work. The tubes are The 'heart" of the Vari -X is, of course, the This standardized Preamplifier when attached branded Sound x /tra on the base to plainly VF2 Wide -range Variable Crystal Unit. This to the chassis identify them and are specially packaged in the of the 60 or 100 watt Amplifiers largest becomes an integral part of the Amplifier. size National Union cartons with special When more than 100 watts is wanted. extra labels to make them stand out in stock. It 100 watt chassis are connected should be noted that Sound x /tra types can be amplifier. to the Pre- substituted in all Provisions are made for using up to case for the like type of tube five 100 watt chassis, giving a total power output in the regular line which means that they can of 50(1 be sold for watts. special audio work for any amplifiers, Where low cost is of major importance, the public address. inter -office systems, or other audio Preamplifier and 100 work where the identical type number is speci- watt chassis may be bought as individual units-or-if a Deluxe installa- fied." tion is desired, In order to accomplish the demonstrable dif- a combination of Preamplifier and ference in 100 watt units can be supplied, mounted in a performance of these tubes. modifica- steel racle cabinet,. The large illustration shows tions in construction and details of engineering a Deluxe installation, were incorporated. Emission are including a high fidelity limits very high radio tuner, an automatic record changer, and a to insure exceptional uniformity, long life and 300 watt Amplifier adequate power handling capacity. Gas and grid (three 100 watt units). current This equipment was developed by Montgomery are held to exceptionally low limits to Ward. Chicago. Illinois, and will be described in insure minimum distortion, uniformity and sta- their new Sound bility. Every tube is carefully tested for hum catalogue. ready about May 1. and microphonics and, where necessary, changes have been made in construction such as the use A new Cardioid Dynamic Microphone specially of special micas. extra rugged supports, double engineered for Broadcasting and Recording is helix heaters, special insulation for minimum now offered by Shure Brothers. ":Microphone hum, etc. Headquarters," Chicago. The types of tubes as announced, cover a This new Model 555 Unidyne utilizes the exclu- major percentage of replacement requirements, sive "Uniphase" principle developed by Shure and while it is possible that additions may be made to this list from time to time, every effort will be made to keep the number of tubes in the line to the lowest possible figure consistent with industry requirements. No tubes will be added that are not demonstrably better.-

The Model RC -2 -P Bell Record -o-f one is a com- 80 -meter crystal plete, self- contained, portable combination recor- unit, a direct development by der and phonograph. our engineers, has a total adjustable frequency Remarkably simple to range of approximately 121cc. The variation ap- operate, incorporating its own high fidelity ampli- proaches 24kc. when fier it assures professional results in the record- frequency doubling to 40 ing of any sound, meters and 48lcc. when quadrupling to the 20- lending itself to innumerable meter band. The VF2 unit can truly be termed uses for the home or business. No auxiliary a rubber crystal." equipment is required and it may be connected Descriptive to any AC circular D -2, a copy of which is outlet. Recordings can be made on attached, can be obtained from any Bliley distributor or directly from the factory where desired. Webster-Chicago announces the addition of this popularly priced 60 watt amplifier to their standard line. The unit, housed in a modern wrinkle finish case, incorporates such features as electronic mixing of two high gain microphone inputs, multi stage inverse feed back, voice coil and line impedance outputs. no -glare illuminated

Engineers. It provides true Cardioid uni- diree- tional pick -up- reduces the pick -up of trouble- some reflections, reverbration effects, or random background noise-and solves most of the sound pick -up problems encountered in studio and remote applications. The 555 Unidyne gives wide -angle front -side glass panel and locking type input plugs. The coverage, but is "dead" at the rear. It gives amplifier, conservatively rated at 60 watts, uti- prominence and definition to the direct sound, lizes four 6L6 beam power output tubes with stops the pick -up of unwanted sounds. As a a 6X5 rectifier tube for bias -flat from 50 to result, it assures truly fine reproduction of voice 10,000 cycles and with a gain of 125DB it is and music. an ideal high power amplifier for large audi- The Shure 555 is functionally designed in the toriums and outdoor installations. modern manner and finished in satin chrome. Construction is rugged throughout. It employs Montgomery Ward. announces a new addition a specially suspended double any disc to their popular Airline Equip. Great savings wind -screened standard and played back immediately. moving -coil system. Built - It will reproduce any commercial are accomplished by designing these Amplifiers -in flexible rubber made record around cushioning unit provides effective transverse or its own transcriptions with excellent faith- a standardized Preamplifier and mixer vibration isolation. Microphone tilts forward as fulness of tone and provides for a sufficiently unit. This unit has four individual mike chan- well as rearward through an angle of 150 de- wide range of amplification to be used as a public nels and two phonograph inputs. It also has grees. Easily mounted or demounted from stand. address system. The compact, leatherette covered Call Letter Plate is optional. Fits on the case carrying case has compartment for microphone, of the microphone easily and snugly. Makes cables and records. Truly a revolutionary de- call letters visible from all four sides. velopment of the highest quality construction and The "555" Unidyne is available in 35-50 ohm with wide utility and attractively priced. and 200 -250 ohm models for in high impedance model). List price is $60.00. For complete in- The Bliley Elect. Co. of Erie, Pa. announce a formation, write to Shure Brothers, 225 West new unit known as Vari -X. The purpose of the Huron Street, Chicago, Illinois. Vari -X is to provide a variable frequency exciter having the frequency stability of a crystal con- Of interest in the educational field and indus- trolled oscillator (so difficult to approach with a trial field is Victor's new Two Speaker Unit in self-excited oscillator). Since the Vari -X is basi- one case under one handle (as shown above). cally a crystal controlled oscillator, designed for This exclusive Victor arrangement permits the use with our VF2 Wide -range Variable Crystal use of two speakers when they are required. and Unit, it is immediately apparent that crystal avoids the inconvenience of carrying two cases stability with crystal control is an actual fact. in addition to the projector. In addition to the The Vari -X, like other variable frequency ex- superior sound from two speakers, it is unques- citers. is intended for installation at the station tionably the greatest advance in portability of operating position. For ease of operation, a slop- sound movie equipment ever designed. ing front panel is used. The metal cabinet is The Victor engineering department also takes

www.americanradiohistory.com 21 pleasure in announcing new engineering develop- 100 meters, inclusive, automatic noise limiting, door or for indoor radio enjoyment. The meas- ments in the Anim atophone units. The model single signal c.w. reception, a continuous range urements are 814" x 5" is 4" carrying weight 40 A Amplifier output has been doubled -turd the of 5:35 hr. to 42 me. in four bands, "S" meter is only 4t/, pounds. The ''Candid" is the fore- model 40 B Amplifier output has been increased calibrated in "S" units and decibels, a 6- position runner of a new trend in the already enormous in movement made G0 , . Both models have separate cun- switch which one selects the type portable radio field. It has been possible huit built in. of reception desired (phone or c.w.) the selec- by the introduction of the new miniature tubes lu addition to Victor's Famous Finn Trip, there tivity desired and autonuttically cuts the a.v.e. and by improvements in circuit design and battery is now even more film protection. In these new in or out depending on the type of reception capacity. It represents a remarkable advance in selected, provision for operation from the a.e. radio receiver design progress. line or for instant changeover to a battery- vibrator combination for mobile or emergency A new,- and very unique home workshop and work, etc., etc. industrial tool has just been developed by The The ciri nit employs 12 tubes in 2 r.f. stages. Barron Tool Company. 415 Brainard Street. mixer -oscil I at nr. 2 i.f. stages. detector- a.v.c. -1st Detroit, and is being marketed under the name, audio, noise limiter, ti.fu., phase inverter. push - Barron IIUlti- Purpose 5 -in -1 Rotary Wood Planer. pull output, and rectifier circuits. It is inclosed The extreme novelty and added usefulness of this in a craclilo- finished 11u01al cabinet with satin tool lies in the fact that it not only planes and steel trim. A separate loudspeaker in matching finishes to a satin smoothness all types of woods cabinet is included. and plastics. but it goes a long step farther in Seusi tivit.y ( equivalent - noise - sideband -input) paneling, rabbeting, routing and tenoning. averages (1.3 microvolt throughout the tuning- This tool is beautifully streamlined and engi- range, with a minimum of 0.6 at 15(1(1 lie. and neered. It is designed to fit any to h.p. or maximum of 0.17 at 30 me. Image ratio is 32 larger or model drill press. No db. ut :30 me.. 56 db. at 14 rue., 78 db. at 7 mc., table pedestal 10:3 db. at :3 me., etc.

Infidels no pi or tract area is ìn contact Claimed to be one of the most popular ampli- tc ll. Ii plates, shoes or rollers. 'l'he new l'iclur fier foundation chassis of the 1940 season is the Filter also completely eliminates "Wows' or Deluxe Sloping Front unit shown here. This new Miller. Complete information on all of these foundation. manufactured by Pnrnieta) Products details, as well as many other Unproven-rents iluit 49th St._, Long Lsl and City. N. Y., Peeing is const:uit ly making, is available by writ- follows the latest trend in Amplifier design and ing I" ;clot. a n inu (up,'ap L. )'unsure/ ion, Davenport, enables one to build lip a job similar to that Iowa. used in commercial amplifiers. All parts are finished in slate gray ripple You can't forget to tune in your favorite pro - gran. and you earl also use the radio for an alarm cluck in the morning, if you equip the ,set with a new timer switch, or control clock just placed on the market. The timer switch wilt Lire the radio on and off it any time you may designate for music or silence. This time switch resembles, :dso actually is an accurate time piece. It turns on and off the electric current actuating any appliance or thing connected to an ordinary wall outlet. The appliance, or thing to lie controlled, is then plugged into the time switch which then will adjustment or change is required to obtain any turn on the current at any lime for which it is one of the five distinct operations. It is a preci- set and also turn off at such later time as may sion tool, planing and paralleling to within .002 he. designated. The time switch has a time range enamel, trimmed with red striped chrome finished of an inch. It eonverts the normal wood -working press into a most versatile workshop tool. of 21 i , hours. mouldings and handles. Front panel is remov- drill When the lady of the house goes to bridge able and extends 3" front the face of the screen The Barron Multi- Purpose Planer eliminates or the movies, she plugs the electric roaster into cover. Chassis are supplied complete with bot- the need for manual planing and sanding,. It tom plates. Available in 3 chassis sizes: 10 x provides unlimited scope in paneling door and 12 x 3, 10 x 17 x 3, 13 x 17 x 3. Screen covers drawer fronts and special furniture effects. It are 0'/2" high. rabbets with amazing speed and accuracy. It tenons to precision tolerances and it routs and Sonora Radio it Television Corporation, Chi- grooves to serve a variety of purposes. cago announces the introduction of an ingenious new type of radio receiver. Known as the The Transformer Corporation of inierica, "Candid," it has been designed for "America -on- through its nation -wide organization of Sound the-Go." As its name implies, it is a personal Distributors, the Clarion Institute of Sound Engi- type of radio, resembling a camera in appearance neers, has just announced a complete new line of Sound equipment for 1940 designed with individuality, as evidenced by the Model A -95, 71 watt Super power unit illustrated above; having a peak wattage of over 100, facilities for 4

the time switch, sets it, say for ou at 3 and off at 5. and comes home to find dinner ready to serve. If blather likes to waken to music, he tunes in his favorite radio station before he goes lu lied and plugs it into the clock set for the lieur at which he wishes to rise and the time .sw i lch turns on the radio at the desired tinte. Some go to sleep by radio, and let the tinte switch tarn off the instrument. Men-Mints use the time switch to turn ou and off electrically operated displays, window and store lights. The same service is performed for inside and outside lights of homes. Farmers use microphones, 2 phono inputs, all of which may it tu control am almost infinite number of farm be operated simultaneously, maximum gain of deviice. and lights in barns and other farm microphone input, 127 db, individual bass and bui Idi tins. treble equalizers, master gain control, special low The time switch is manufactured by Tite distortion inverse feedback circuit, 4 beam power t trartz Gan ph. Mfg. Co. of Toledo, Ohio. in two tubes, remote control, impedance selector switch. models priced at $5.95 and y+6.95 respectively. optional DB meter or 2" monitor speaker, studio control panel, and optional model with built -on phono table and pick -up. This new Clarion unit The new Ilallieraftera S.0 -;;b "Super Defiant" is claimed to be far ahead of the field. Amplifier Cann nsent ;culinls.c Receive, although selling in the complete with tubes and phono equipment lists medium-In-he class t slightly under a hundred at only $174.90. dollars) a treys an array of features unusual in this class. Included among these are two pre - scleekir stages, four degrees of selectivity includ- Three new dual capacity midget dry electrolytic ing broad and sharp crystal filter circuits, tem- condensers with separate positive and separate perature and line voltage compensation with eon- negative leads have been added to the well - known line of ,Sprague Atoms. These are especially adapted as duplicate replacements for auto radio receivers and common positive condenser. requirements. Like the other Atoms, these new units are un- conditionally guaranteed. Although surprisingly and construction. The sturdy case is molded of Durez, and is available either with carrying handle or shoulder strap. Everything is built - in; plays anywhere- nothing to add or connect. Has built -in batteries; uses the new miniature tubes in a Superheterodyne circuit includes "Sonoraseope" built -in aerial; Dynamic Speaker; Automatic Volume Control. Tunes the standard Broadcast hand. Has headphone plug -in connection for privacy listening or long- distance recep- small, they may be used to replace old -style con- tion. Uses ordinary 'flashlight cells for "A" sup- densers much larger in size and costing a great ply, and regular portable "B" battery; unusually deal more. economical. The "Candid" is the answer to the The new writs include Type TU -220, 20 -20 sequoia freedom front tuning drift, frequency wide demand for a miniature self -playing radio - mfd., 150 volts, 1" x 23/s ", list $1.35; Type calibrated bandspread on ham bands front 80 to an ideal companion for traveling, for out -of- TU -216, 16 -16 mfd., 250 volts, 1" x 2 % ", list

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$1.65 and Type TU -88, 8 -8 mfd., 450 volts, 11/4" coil has its own link the coupling adjustment for All but four are of the hum bucking construc- x 3% ", list $1.35. each band can be left permanently set at the tion type. A new felder listing the complete line of Atom proper value. These units will find widespread application in midget condensers will gladly be sent upon re- All coils in this series fit standard 5 -prong light portable equipment, such as aircraft, por- quest to the Sprague Products Company, North sockets and are designed for operation in stages table broadcasting, marine and any service where Adams, Mass. where the input power does not exceed 50- watts. the rigid government specifications for submer- Coils are available for all amateur bands. sion proof testing are to be maintained. The United Cinephone Corporation, Long Island Complete information and a new catalog can City, N. Y. recently introduced new controls that Currently featured by Allied Radio Corporation, be obtained from the manufacturer. are housed in compact (9" x 61/ " x 414" ) Chicago, is an 8 -Tube Knight Commode radio, battleship grey enclosures, having half -inch Model A10773. This radio strikes a new note Volume controls with serrated shafts, for quick knock -outs in the bottom for power connections, in charming period design. It is housed in a and exact replacement of controls having the and a fourth knock -out on the top as provision beautiful cabinet of choice mahogany veneers, knurl and slot shafts, are announced by Claro- for wiring in an external photo -cell. Rugged finished in a rich high lustre. The doors at the stat Mfg. Co., Inc., 285 -7 North Sixth St., Brook- telephone type relays are ordinarily provided, front, which are fluted on the surface, open to lyn, R, Y. These Series KS controls are of the permitting a maximum non -inductive load of give access to the instrument panel. The speaker popular Clarostat midget type, and permit re- three amperes alternating current at operation grille is at the bottom. placements without having to replace the slip -on speeds up to ten per second; however a Micro - The Knight "8" covers two wave bands from knobs as well. Series KS units are available switch to carry eight amperes, or another con- 5.7 to 18.3 M.C. and from 540 tó1600 K.C. It in all required resistance values, although only tacting device handling fifteen amperes at 110 incorporates the new built -in "Air- Magnet," six values are required in servicing the bulk of volts will fit the same housing, and are available eliminating the need for aerial and ground. Other existing radio sets. at slight additional cost. In Model No. 60, listing for $24.00, the photo- RCA Manufacturing Company, Inc., Harrison, cell is separately housed, making possible the New Jersey, are making available through their convenience of mounting the control as much as transmitting -tube distributors the RCA -829 new, push -pull, beam power amplifier tube having-a a total maximum plate dissipation of 40 watts. A single 829 tube operated in push -pull class C telegraph service is capable of handling a power input of 120 watts with less than a watt of driv-

five feet from the electric eye. Model No. 62 lists at $27.00, and Model No. 64 is priced at $29.00, the latter employing a three inch collec- tor lens to the photocell for applications demand- ing response from as little as one -half foot candle with zero residual illumination. Units utilize a commonly available and inexpensive amplifier type tube (6J5), and the photocell tubes used have life expectancies of upwards of 10,000 hours, making for low maintenance costs. Generally built for operation on 110 volt 50/60 cycle A.C., higher priced models are obtainable to work from 110 volts D.C. or 220 volts A.C. features include: Push- button tuning on six sta- lines. tions; Giant Slide -Rule dial; Electric Eye; Tele- We are also making available at this time a vision Connection; A.V.C.; 5 Watts Output; Big complete line of light sources, designed to be Dynamic Speaker: Bass Compensation. Fully used in conjunction with this new "No. 60 series" licensed by RCA and Hazeltine, uses the following line of photoelectric controls. tubes: 6SA7, 6SK7, 6SQ7, 6SF5, 2 6K6G, 5Y4G, 6U5 (Electric Eye). These are dual -pur- For applications calling for very high capacity pose and triple -purpose tubes. Operation is from values at very low voltages, seven popular values 110 volts, 50 -60 cycles A.C. and voltage ratings are now offered in the midget The Knight 8 -tube Commode Model Radio is a metal -can electrolytics by Aerovox Corporation of product of Allied Radio Corporation, 833 W. Jackson Blvd., Chicago, Illinois. The Kenyon. Transformer Co., Inc., of 840 Barry Street, New York have just announced a complete new series of transformers made in both standard and submersion proof types. They are designed to plug into an 11 prong octal socket and are extremely neat in appearance, being finished in black alumilite. Case sizes are standard, being a round drawn can 21/2" high and 1% " in diameter. Units are manufactured covering the following types of transformers: Line to line. Crystal mike to line, low impedance source to ing power -at frequencies as high as 200 megacycles. The exceptional efficiency of the 829 at the ultra -high frequencies is made possible by the balanced and compact structure of the two units, excellent internal shielding, and close electrode spacing. The internal leads are short and heavy in order to minimize internal lead inductance. The terminal arrangement provides excellent insulation and is designed to facilitate symmetry of circuit layout. New Bedford, Mass. The capacities range from Marked emphasis on modern styling, more cool- 1000 to 3000 mfd., with working voltages of 6, per 12 and 15 D.C. The metal can is full protected ing kilowatt -hour of input, and substantial re- ductions in physical size feature the trend in self - and insulated by the paper sleeve extending for contained room air conditioners as evidenced by the full length and rolled over the can edges, to the three new room coolers -one window -type preclude shorting of leads on the can. Units and two consoles-just announced by the. General are supplied with mounting straps, except for a Electric Company. Meeting the past criticisms of larger can size unit which has a standard mount- interior designers the cabinets are styled in ing ring. simple, modern lines. with exteriors of finished walnut and antique leather over steel backing. The Cinema Engineering Company of Burbank, Taking up about 36 per cent less room than California announces the appointment of Norman previous units of comparable rating, the new B. Neely as exclusive sales representative. This models produce up to 16 per cent more cooling company has been supplying precision attenua- effect per unit of electricity used. tors aald resistors, plugs and patch cords, relays, The window type, which is one -half horse- jacks, jack strips, gain sets and similar units to power, has a net cooling capacity of 5.000 Btu the motion picture industry in Southern California per hour and is 28 inches wide, 19 inches high for several years. Strict adherence to high stan- and projects into the room 9 inches from the dards of quality and accuracy have built a very window sill. The one -half horsepower console good acceptance for Cinema Engineering products model is rated at 6,000 Btu per hour net cooling, and Mr. Neely's appointment as technical sales while the three- quarter horsepower model has a representative marks the beginning of an expan- net cooling capacity of 8.000 Btu. Both consoles sion campaign made possible by increased manu- measure approximately 35 inches high and extend facturing facilities. A new catalogue has just 19 inches from the wall. been released and is available upon request to Norman B. Neely, 5334 Hollywood Boulevard, Simpson Electric Co. of Chicago, announces Hollywood. that. for the first time, a current transformer and an indicating instrument have been combined in A new series of "Airwound" Adjustable Link a small A.C. multi -range ammeter that sells at a Oscillator and Buffer Coils has recently been an- price almost unbelievably low. Known as nounced by Bud Radio Inc. of Cleveland, Ohio. "Micro- Tester" Model 280, this instrument pro- These coils are designed for use in circuits where vides readings in any of five different ranges, it is desirable to adjust excitation or antenna grid, interstage transformers, and output trans- from fractions of an ampere up to 25 amperes, loading by varying the link coupling. formers and chokes with no D.C. in the winding It is housed in a red Bakelite moulded case, with Each coil is individually linked, and coupling is the frequency response is plus or minus 2 db 30 satin -finish steel front panel. Pocket -size, it varied by pushing the link in or out of the to 20,000 cycles. measures only 2 T/s " x 5,4" x 1 %4 ", weighs just main winding. In view of the fact that each 21 new units offer a wide range of applications. 20 ounces.

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This Model 280 is the standard bearer of the air or out -of -doors on its own batteries -or on 174s" thick. It is finished in a rich brushed new line of "Micro -Testers' which Simpson has any ordinary electrical outlet without the slight- chrome which does not scratch easily or show just placed on the market. These companion est battery wear. smudge from handling, yet blends or matches testing instruments, all the same size, can be Other important features of this receiver are: with modern desk and floor stands. It is fur- combined in sets of three to measure current, radio -range plus commercial broadcast reception nished with an S ft. cable set, but a 25 ft. set voltage and resistance for almost every require- or longer can be furnished. A removable con- ment. Kept in a sturdy carrying rase. which has nector is furnished so that cables can be changed room for necessary leads. such a set pros-ides or repaired without opening the mike. measurement on individual meters at a total cost A positive contact slide switch affords easy far below that of the usual combination instru- action on the Hot -D, and permits the off and on ment. The separate nielers. too, allow a flexi- switch to be operated without thumb fatigue. bility never before obtainable. The frequency response of both the crystal and The complete "Micro-Tester" line includes: dynamic models is engineered to be suitable for Model 281 A.C. Voltmeter "illustrated." Ranges: both close speaking (voice application) and for voice and music pickup where the performer may operate at a distance. Voice reproduction is crisp and clear without unnecessary sacrifit e of bass responses. yet feedback problems are held to a surprising minimum. As with all Turner Microphones, each unit is individually tested in a sound pressure room for level and frequency before it is shipped, assuring pnrehascrs that the microphone is in perfect. condition. According to the manufacturer, the Mod- -phone jack for use on aircraft band -external el OD Dynamic Han -D terminal for connection aircraft antenna -bat- should be chosen when tery life of 200 hours or more-weight of only the microphone will be 121/4 pounds complete. subjected to extreme 0 -150, 11- 311(1, 0- 131111 Volts. Model 28° D.C. Ohm- cold humidity or rough meter. Ranges: 0 -100i), 0- 111.01111 am 0- 100,000 Despite the considerable improvement over handling, or where ex- Ohms; 0 -1 und 0 -10 Megohms. Model 283 D.C. previous models, the Tri -Powr is offered at no inin price. tremely long lines are Millianmeter. Ranges: 0 -1. 5, 10. 25. 50, 100. crease necessary. Model 9D '350, 500, 1000 M.A. Model 284 D.C. Microam- Dynamic is available in meter. Ranges 0 -50. 11)0, :;ill. 5(1(1 and 100(1 Model 334 Dtilite,sler- all -purpose compact high impedance 30 -50 Micro -amperes. Model 285 D.C. Ammeter. Ranges: general utility test instrument. 22 ranges. Three ohms, 200, 250 ohms 0 -1, 0 -2.5, 0 -5, 0 -10. 0 -25 Amperes. Model 28(3 inch meter. Resistance 0 to 1 me_'. with in- heavy duty dry cell. Volts 0 to 3000 or 500 ohms. Lines of A.C. Voltmeter. I Rectifier Type). Ranges: 0 -5, ternal 75 feet may be used 10, 25, 50, 100. 25(1, 5011 and 1000 Volts. Model A.C. and D.C. Milliamps O to 300. Decibels with high impedance (i 64. Sensitivity 1000 ohms 887 D.C. Voltmeter. Ranges (1 -1, 2.5, 5, 10, 25, minus to plus per types. Unlimited lines 50, 100, 250, 500, 1000 Volts. volt. All ranges selected by single rotary switch. are possible with other Specially tapered ohms adjust control. Pre -aged impedances. This Dy- Just announced by Iluava'd Radio Company of rectifier. Wire wound shunts and all multiplier namic is Particularly 17:15 Belmont Avenue. Chicago, is the new How- resistors plus or minus 170 (one percent). recommended when the This instrument maltes Leather carrying handle. Black wrinkle case. ard Radio Recorder. raised designations. mike is to be used in an automobile. Model 9D it possible lo record radio programs on phono- Ivory 5j<"metal panel with black with 8 foot cable set, high impedance is listed graph record blanks. By means of the mixer con- Size x 7i/s" x 2% "- Weight 2'/ lbs. at 825.00 Level Hi- Z -54DB. Range (i0 -7000 trol. provision is made to blend the voice or Triumph. Mfg. Co., 4017 -19 W. Lake Street, cycles. Reference level 1 volt per bar. It comes music from the microphone with the radio pro- Chicago, Illinois. packed with chamoisette protector and diagram.,. gram in the background. Music or voice alone The Model 9X Crystal is slightly less ragged " Multivolt'' multi -tap vitreous- enameled Resis- than the 9D, yet withstands a great amount of tors especially suited for cathode modulation abuse, and gives clear cut performance on both radio telephone circuits are offered by the Oliunite voice and music. It also is packed with chamoi- Manufacturing Co., Chicago. sette bag and diagrams, and with 8 ft. cable set, These 50 watt Units (No. 1206 of 10,000 ohms lists at $2.2.50. Response 60 -7000 cycles. Level Resistance and No. 1209 of 25,000 ohms Resis- -50D13. reference level 1 volt per bar. tance) make it possible to secure the proper im- Complete information on these Han -D models may be had by writing the Turner Co., Cedar Rapids, Iowa. Radiotechnic Laboratory. Evanston, Illinois, has announced the Model 120, an innovation in tube testing. The PMT circuit switching is an outstanding feature of this instrument. It is designed to accommodate any possible combination of heater and control elements of all existing' sockets. and for all tubes that may be introduced in the future. pedance match of the modulator to the filament In the event of new sockets. space is provided, or cathode circuit of the final radio frequency and wiring would only be made to an adjacent amplifier. They provide the exact control needed socket. for correct cathode modulation. All tubes, including ]octal, single -end, minia- Ohduite Multivolt Resistors have ten equal ture, Hytron Bantam, Raytheon CR series, Si), 70, sections. The resistance wire is accurately 117 volt series, pilot lamps and Christmas tree wound on a porcelain core and permanently pro- bulbs can be accurately tested on this new instru- to assure long' ment. Gaseous rectifiers are also tested with nay be recorded as well. This unit wilt also tected by Oh-aiile vitreous enamel proper operating' voltages. laplicate standard records or records made by this dependability. have been filed for the PMT - In to their convenience in cathode Patent claims nstrumenl.. An automatic record player is pro adcition (permutations) switch system. R -T -L 'ided for 10" and PI" or mixed sized records. modulation circuits. the Miltis-ol las are also handy states that By means of the microphone and radio receiver, as voltage dividers, etc. They are available in this PMT method is the only way that a flexible a powerful home amplifier system is provided. many resistances in 50, 75 and 150 watt sizes. Two types of radio chassis are available. -a 7 tube two band receiver and a 9 tube three bald The Thordarsou Electric ,llfp. Co. announces a receiver. The cabinet is of authentic Hcpple- new addition to its line, the Tru- Fidelity Studio vhìlc tlesign, available. in Mahogany or Walnut.. Ampli fier. flu( eabinel, dimensions-:3114" lung, :33% " high This new model provides audio amplification and l5((i deep. with superior tone fidelity . tones so per- '' fect that they actually create an illusion of American Phenolic Corporation. 1250 Van presence. This is a quality which especially Buren Street, Chicago. Illinois, announce a new recommends it to broadcast stations, studios, socket for crystal- holders made of transparent owners of extensive libraries of choice phono- ultra-low -loss _I in/Au-not "91'2" a pure polYstY- graph records, and others who appreciate fine music and speech reproduction. - Noticeable among the many features of this new amplifier is the Audio Frequency Equalizer, a refinement of the 2'h ordaraou pioneered Dual Tune Control Circuit.. Actually. it provides an unlimited choice of audio frequency ranges. Although the amplifier is essentially one unit, the IoW level and voltage amplifier stages are isolated from the power stage and power supply, reducing 1111111 to :in absolute minimum. It is available for rack mounting or in a grey rate), which is nun- by _'rnseupie, won't collect cabinet. A beautiful "Brushed Steel" panel frost. and is tough and stronn.. Losses are so maltes this a most attractive instrument in any low as to be negligi tune, and Kermit full crystal conspicious position. switch system can be incorporated in a tube output to be applied to the grid of the oscillator Complete specifications and technical data are tester without going to specially built switches. tube. The phosphor-bronze contacts are silver - available in Bulletin SD -44:3 by writing the Stock switches are used throughout, thereby plated to reduce contact. resistance, 'und are set Thordarnon Electric Mfg. Co., Chicago, Illinois, keeping the cost at a minimum. Three D.C. in long packets extending above and below the or at your local distributor. ranges 0 -10V, 0 -100V, and 0 -1000V are available central rib. for the testing of batteries and D.C. power The mounting arr ingenient is interesting' as it The Turner Co. of Cedar Rapids, Iowa, is an- supplies. can be assembled either on top of a chassis, or nouncing a new low -cost microphone named the The 120 is available in two models: the coun- from underneath, fastening with a single No. 6 "Han -D" because it is shaped to fit the hand, ter, which has a sloping metal case with a slide screw. and also because it is handy for so many pur- drawer to hold the tube chart; the model poses. Available in both erystal and dynamic, portable the Tri -Powr Portable that is mounted in an attractive leatherette case. Leaattclio presents this new microphone fits snugly into the hand, For additional information, write The Radio - operates on AC -DC and Batteries, featuring choice has a hook which allows it to he used as a hang- technic Laboratory, 1328 Sherman Avenue, Evan- of AC -DC or battery operation by merely flipping ing mike for stage work and call systems. and is ston, Illinois. a switch, in response to urgent pilot demand. designed to fit any standard desk or floor stand Pilots asked for a portable receiver they could with r/x -27 thread. A new innovation in merchandising in the radio use indefinitely indoors without the penalty of This new Han -D microphone is 4r/s" long (in- battery loss. The Tri -Pow'r can be used in the cluding the hook), 25/8 " at. snidest point and (Continued on page 57)

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This is the Reader's Page; where he can express his opinions, and where he can find all corrections.

Refer to: High -Fidelity Tuner, RADIO NEWS, parts, provided the requirements of the in a glass of White Rock, with two ice Feb., 1940. tester are met. cubes floating about as a symbol of his An error appears in the schematic dia- Special attention is called to a drafting mission. Sleepless minutes passed (from gram as follows ; Condenser Cl should be error in the diagram. F2, the common 1:01 to 1:03 p.m.) until the reply to the connected on the Rl side of the AVC cir- lead of the filament transformer secondary, kibitzers was ready. cuit, instead of on the coil side. The AVC should be connected to the negative bus. Transformers and other components return goes to the coil direct and then to At the time the tester was built no sock- were hurriedly unbolted from the chassis the first grid. ets were available for the new RCA ban- and mounted on one inch rubber washers. tam tubes. I understand Atiiphenol has The meter was neatly taken care of by a Refer to: Build this modern Oscilloscope, such a socket now, and would include one round rubber teething ring as a support. RADIO NEWS, May, 1940. if building the tester at this time. I have In the right -hand tool compartment, a half The diagram on page 33 shows a by -pass had the instrument in service since last dozen cakes of Ivory Soap, long the Amer- condenser Cl at the tube socket. Actually October, and as there has so far been no ican synonym for floating, were installed. one side of the filament is grounded at the occasion to test these bantams have not The left hand compartment was quickly power supply and condenser Cl is mounted yet made any provision for doing so. Dur- lined with zinc, and with the addition of a right at the tube socket for by -pass pur- ing that time have tested in excess of 2,000 quart of water, became the happy floating poses in case stray fields are set up. This tubes with only one exception the OZ4. ground of two gold fish named Elmer and is required in order to prevent any self - Since this tube requires 300 volts for break- Eloise. l jz inch lengths of coil spring distortion of the pattern on the oscilloscope down, no provision was made for it, since were fastened on each control shaft, and tube screen and therefore should be in- it would defeat the primary purpose of the the knobs attached to the springs. The cluded. article, i.e., construction from stock parts slight nudge is sufficient to cause these obtainable by all. However, the OZ4 either knobs to hob about, simulating the effect Refer to: The 1940 Portable Rig, RADIO rectifies or does not, and the quickest and of stray bits of garbage floating down NEWS, May, 1940. surest is install test to a new one. Anyone Long Island Sound. Little more . was Correction for the parts list on page 17. doing auto work should surely have at needed to float everything else. A length T3 should he a Thordarson T -14R40 trans - least one new OZ4 on hand. of tubing was installed in each corner of former-115v. 50 -60 cycle or 6 v.d.c. vibra- the case, and the last necessity was a six - tor transformer. The part listed as T4 is Refer to: Full Floating the Full Floating Tube foot length of light chain, with four long the one incorrectly shown for T3. This is a Tester, RADIO NEWS, April, 1940. coil springs attached to one end. Thordarson T49C91 choke. The sensation caused by the publication Arriving at the customer's home, the of the details of the writer's latest master- service man throws back the lid of the Refer to: The Full Floating Tube Tester, piece, the "Full Floating Tube Tester," was instrument, which floats to the floor, land- RADIO NEWS, April, 1940. only what might be justly expected in view ing with a crash which will attract the cus- 6 Alden sockets, 4 -5 -6 -7 LS, 8 and ¡octal tomer's 1 wafer socket for 80 of the outstanding merits of this challenge attention. Throwing a few bits of 8 Yaxley 3215J circuit se'. to the domination of the mighty tube trust. fish food to Elmer and Eloise, to demon- I Yaxley 32117) fil. sw. Letters of congratulation poured in, at the strate a kindness to dumb animals, the serv- 9 H & H SPDT push button sw. ice 1 Triplett O -1 ma meter rate of one or two a week; representatives man slips a small flag into each corner I DPDT toggle sw. of the larger equipment manufacturers, bit of tubing. As most modern houses do 1 SPST toggle sw. Easton, Quadruplet, Billion and others bid not provide a breeze, it will lie necessary I No. 465 Yaxley plate No. 1 -15 for the service tnan to anticipate this, and 1 2709 Gordon dial No. 263 frantically for rights to the author's future 1 Yaxley B control No. 1 tamier efforts. The pale faces of downtrodden supply his own breeze with a small electric I Yaxley á7200P potentiometer service men brightened for the first time fan, which may he easily carried around by 1 pin jack hooking 1 400 v. condenser .25 or .5 mf in years, at the realization that here was a over either ear. When the fan is I 1/4 watt neon lamp 115s'. tube tester they could use for a whole -week turned on the flags will float attractively,

I socket for neon lamp - 1/ before it became obsolete. David Sound- adding a gala touch. I 5,000 ohm w. resistor off, president Only one more thing remains- floating 1 400 ohm 1/2w. resistor of the powerful tube trust, 1 Fil. Trans. 1.5 to 115 v. sec. Ar- sylvan -rad, hurriedly announced their the whole ensemble. Leaping lightly on 1 30 r. anode transformer entry into the television field, clearly in- the customer's piano, the service man At the time the tester was constructed dicating their withdrawal from the tube screws a hammock hook in the ceiling, at- (last Oct.) Radio- Wire -Television, Inc. in industry, since the days of easy profits taches the length of chain ; and returning Chicago was the only nearby jobber able were over now that anyone could test tubes. to the floor attaches the four springs to the to supply the filament transformer. It is Bells rang whistles blew, and the writer corners of the case, and behold! everything listed in the last catalog. The 270° dial beheld people hurrying from all directions floats, including the customer's head. When plate may he any make but the writer found toward his door. Unfortunately a big fire the customer is able to speak she will say it necessary to order direct from the Gor- broke out around the corner at this time, "Ooh-what a remarkable whoosit ! ! !" and don Specialties, Park Ridge, Ill. Substi- which distracted the crowd, and by the the service man can proudly reply: tution may be made for any of the above time the fire was out it was time for them "Yessir -its the most fullest floatingest to go back to work. full floating tube tester, they is in these I CAIN'T THIS BUSINESS SURE TAKES YOU PESO HIT ALL-- BUT In the midst of this gen- here parts." I KIN MAKE OUT - TO SOME FUNNY PLACES-. OF COURSE r3 ENOUGH- eral furor of adulation and By R. K. Wheeler, SAFE ENOUGH AMONG THESE HILL BILLY LET'EM HAVE IT, BOYS¡ acclaim, MOONSH INERS. a discordant note Indianapolis, Ind. appeared, which became au- P. S.: After writing the above opus -I dible as a jeering whisper - am for some obscure reason reminded of a " 'Taint DOES full floating, 'taint famous story which you have probably full floating." Stung by I here TRUSTY **, these taunts, originated no heard before, but goes: RADIO SERVICE tori doubt by the low hirelings of A man contemplating a trip through the the tube manufacturers, the desert was discussing his proposed equip- rag writer withdrew to the seclu- ment with a friend, stressing the need for sion of his workshop, to pon- a compass in case he got lost. His friend der over this grave charge. however insisted he did not need a com- His dander rose -his Scotch pass, only a deck of cards, saying : rose, and was quickly mixed (Continued on page 58)

www.americanradiohistory.com 25 R HOEBUI T

1 -10m. RECEIUER

by PAUL POPEIIOE, Jr. Altadena, California

For the very ultra short wave reception, this special set should generally do a much better job than the general receiver.

Compact and efficient is this small unit.

\ODAY it is possible to purchase must be made for these frequencies, but few receivers which go as and the losses throughout the set must - - high as 300 megacycles (1 me- be reduced to a minimum. Taking ter). These receivers are out of the these "must" factors, as well as vari- reach of many experimenters, for they ous factors of less major importance are expensive. This expense is in- but which nevertheless add to the util- curred in trying to maintain electrical ity of the set, into consideration, the efficiency. set here described was built. But, the question may be asked, In choosing the tubes to be used, the what use is a receiver going up to 300 factors both of expense and efficiency mc. anyway ? The most important use were taken into consideration. The of such a receiver is, of course, in re- first tubes designed for ultra high fre- ceiving the amateurs operating on the quencies were acorn tubes, which are 28 mc. band and bands which are har- excellent but expensive. In choosing monics of this band: 56 mc., 112 mc., the tubes used in this receiver a sav- and 224 mc. Between 5 and 10 meters ing of nearly five dollars was made there can be heard various commercial over the price of acorn tubes, when fig- services. Some of these are television, uring the cost of the sockets which Rear view of the receiver. u.h.f. broadcasting and two way Po- must be used with the acorn tubes also. lice phone. Between 1 and 5 meters The detector tube is a Hytron HY615, the services, which are relatively which works efficiently up to 300 mc. scarce, are mostly experimental. An 1851, a tube originally designed for In answer to the need for a low cost television, works very well in the r.f. receiver which would work efficiently stage. between 1 and 10 meters, the author The mechanical construction of the decided to build such a set. What set, which may be seen from the pho- would be the requirements of this re- tographs, is not quite conventional. ceiver? It must be super regenera- The entire set is built up on a 5x9x2 tive, a super -het being too expensive. chassis, using one end of the chassis as It must have an r.f. stage which should the front of the receiver. Mounting not show a loss on the ultra high fre- on the front end of the chassis is a quencies. The tubes of the receiver (Continued on page 54)

1851 C RB HY615 4 CB 6F6 Cn Looking into the baffle -can. 111 ' OUTPUT Cs L3 Cfi 1 R7 h O. O _ C7 Ó O b O Ca a L5 O 'II 9 4 L TUBE SHIELD R2 Cid R9 8+ It.

C C-15 mmf. variable condensers, ganged. R,-500,000 ohm potentiometers. Centralab. Harnmarlund. R, -500 ohm, I watt Aerovox. C,, -100 mmf. variable air trimmer. Hannnarlund. R, -,- 100,000 ohm, 1 watt Aerovox. C, Cw, C,, -.01 mid. fixed condensers. Aerovox. R1 megohm, 1/2 watt Aerovox. C4 -.1 mfd. fixed condenser. Aerovox. R- 250,000 ohm, 1 watt Aerovox. C,-, -.0002 mfd. Aerovox. 12x -400 ohm, 1 watt Aerovox. C -.006 mfd. Aerovox. R0- 10,000 ohm, 1 watt Aerovox. mfd. Aerovox. L,, L_ See coil data. C,,, C.-.5 mfd. Aerovox. L4-5 meter R.F. chokes. Ohmite. R4- 10,000 ohm potentiometer. Centralab. L ,-, -250 henry audio choke. Stancor. Underchassis connection view.

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,;_-_4E.. the Price!"

by HORACE E. EDDY, W8MTZ Oneonta, New York

A rertical antenna is one of the most efficient types of radiators. They are fine for reception, too. Build this one and see.

Vertical antennae do not mar houses:

1EELING that there is a need for can be filed down, insuring a snug fit. To fasten the pole to the chimney 1 an inexpensive, easily- erected, These two sections are joined, with a was a problem. Stack wire and strap - - unguyed, vertical antenna, I de- liberal application of casein glue, and iron bands were rejected because of cided to construct one that fully meets the outside wall is securely wrapped inflexibility. Galvanized metal clothes- these specifications. with heavy fishcord, and given several For line was the final choice and it has an unguyed pole, 33 feet in coats of lacquer. The top section is proved its worth. Three galvanized 3" length, which can be mounted on a added in the same manner, and there turnbuckles were purchased and an housetop, the use of bamboo is prac- results a very sturdy pole which can electrical appliance store provided tically dictated. Rugs are shipped be supported by one hand. small copper cable clamps for secur- wrapped around poles, 8 to 10 feet in The bamboo was then joined to a ing the loops which pass through the length, and of varying diameters. The piece of 2x2, five feet long, by means local eyes of the turnbuckles. furniture store is usually glad to of a pipe fitting consisting of a section Ascending to the roof we cut a piece get rid of a few. One pole, 10' by 11/4" 11/4 " i.d. by l', a reduction joint, and a of clothesline long enough to pass forms the bottom section, another 10' section 134 " i.d. by 1'. The larger sec- once around a piece of 2x2 by 1" and around the middle section, and a piece of tion of pipe was jammed onto the 2x2, the chimney, with the ends joined by fishpole, 16' by %" as the top section. and the butt end of the pole fitted into the The turnbuckles. (The point at which first step in joining, is to saw the 14" section with casein glue. the cable crosses should be at the out- off the small end of the bottom section Finally, the whole structure was given side of just below the 2x2 and not against the the first joint, leaving a several coats of outside white paint, chimney.) Then on the ground two cavity, the walls of which should be small standoff insulators were wired other cables were cut, one to the strong and free from cracks. The butt on at two feet intervals, and the No. length of the model, and one end of the second seven section should have 12 antenna wire was wired to the in- inches shorter. This last length is the a cross wall at the very end. The sulators. The pole was then ready to middle cable, and does not encircle the slight protuberance around this joint be erected. pole. The pole went up much more easily than was expected. BAMBOO It proved easy to POLE hold with one hand, while adjusting the middle cable with the other. This held the pole solidly enough to permit WRAP THIS PORTION the use of PIPE WITH FISH CORD R. both hands in the adjusting I¿I.D.XI LACQUER of the other cables. 2/X2X5' This antenna has been in use for six months, and it is as solid as the day it 3'GALVANIZED d was erected. Three continents, twen- TURNBUCKLE ty -five countries, and an average in- REDUCTION crease of 2 S points per report have JOINT FILL SPACE been added to the previous DX WITH CASEIN achievements, due directly to this an- GWE tenna, and it is for this reason, as well as for that of low cost and ease of construction that I recommend this ver- PIPE tical antenna to the world. I ¿ "I. amateur Parts List One piece bamboo, straight and sturdy, 10'x11/4 ". zícz'x5' One piece bamboo, straight and '^.1111 sturdy, 10'x1 ". (Continued on page 49)

www.americanradiohistory.com 27 r r T r S J _ _

by CLYDE D. KIEBACH Reading, Pennsylvania Those old cabinets which the serviceman talcs in trade can be rebuilt for profit to house phono- graphs and new radio receivers.

To operate the electro was the same kind as featured in G.E. mechanism, one must modern electric kitchen -a long tubu- have a key which opens lar lamp, size 113/4" x 11/8". The ap- the lock mounted to the proximate value of the candle power right of the illuminator. is 344 lumens with a power rating of The key lock is a Cutler - forty watts. This lamp is mountable Hammer brand and cer- on an aluminum bracket, size 2%" x tainly is a worthy addi- 13 13/16". It is equipped with rotary tion. switch to operate it independently. The music player is a Exact mounting instructions have It would be hard to believe that this cabinet General Industries Rec- not been given since a great amount looked like the one in the lower right corner. ord Changer, Model K, of divergence from this original will playing eight ten -inch have to be made by the serviceman to do with the old cabi- records automatically, repeating or re- installing the record changer and asso- THATnets the serviceman takes in jecting a record at will was built in. ciated equipment in other and different trade on the new radio re- The changer is equipped for record- cabinets. Mostly, the idea is to turn ceivers is a problem. Some of those in ings at 331/3 and 78 speeds. The en- the old cabinet into a money -maker the trade just dispose of them to the closed type motor is used. The unit for the man who owns the "old mon- junk man, while others let them ac- occupies a space of one hundred and strosity." Each and every type of old - cumulate dust in the cellar. A better forty -four square inches, and is fin- time radio cabinet will present a dif- idea would be to put them to some good ished in a highly polished statuary ferent situation to be dealt with ac- use, or better still, convert them to bronze. It retails for forty -seven dol- cording to the problem presented. The source of income. This may be done lars and fifty cents, complete with result must be pleasing to the eye, and by making the old cabinets into fine volume control and switch. it is hoped to the purse. modern "side" phonograph cabinets An Astatic crystal pickup is used of Since most purchasers act on eye - called "phonotronics." the S -type. appeal, it will be necessary to make This phonotronic was constructed Operadio Portable Amplifier Unit, the finished product as good -looking from an old Grebe radio receiver, type model 414 with power rating of four- as possible. The fact that after the 428. The legs were sawed off and teen watts, peak at seventeen watts, renovation, the finished "phonotronic" roller- bearing casters were mounted was installed. It has provisions for re- will cost around $80 -$100 should not on the four posts for easy moving. The mote control, paging switch and head- be a deterrent. 30 antique framework in front of the cab- phone or meter for monitoring; also inet was eliminated and the inside three channel input, electronically woodwork was disposed of. A modern mixes two microphones and one phono- front was made from light oak wood. graph, fully protected, recessed, illum- The glass panel (green opaque) was ination controls, beam power output purchased from a local glass store for tube, and cathode degeneration. The a sum of fifty -three cents. amplifier can be purchased for sixty- One -quarter inch moulding holds the five dollars, designed for use with glass panel and the front in place and P.M. dynamic speaker. was obtained at a nearby lumber yard The electro- acoustic transducer seat one cent per foot, using ten feet. lected was a Jensen, Model PM12B, The decorating of the master music standard type. The loud speaker is maker was done by an expert, who in known for predominating high quality. turn bartered for the repairing of his The diameter of speaker is twelve radio receiver. inches; voice coil has an impedance of The inside of phonotronic which eight ohms, and was readily mountable holds the record changer and the un- in the space provided. used records (former space for radio) The baffle board was made of celotex was lined with and reinforced by roofing laths. Cost one yard of good qual- of celotex, five ity felt, purchased two cents a square foot; at dollars a cost of laths, one cent a foot; size yard, and fastened in place with draftsmen's 16 5/16" in width and 24 13/16" in thumb tacks. length and %" thick. On the back of the modernistic front To illuminate the interior of the was placed the grille cloth (Philco record playing compartment and to make) , using one yard at four dollars provide additional light for reading and twenty -five cents a yard, which purposes without the aid of any other was also fastened with thumb tacks. lamp in the room, the light selected This is what the author rebuilt.

www.americanradiohistory.com 28 MUSlI Whi Yo.. Cycle

by H. G. CISIN New York City, N. Y.

him how to build simpler receivers While slightly bulky, this cycle radio will make your trips more enjoyable. within the scope of his knowledge and attainments. No one, no matter how limited his radio knowledge, should have any dif- You may put a radio receiver on your motor ficulty in building this efficient little set. Although it uses only two tubes and is devoid of any features which enjoy might add complications to the as- or bicycle with comparative ease, and sembly, wiring or operation, it does incorporate practically all the items which the bicycle users themselves all the pleasure of music while you ride. have specified as desirable in a bicycle receiver. The "Ranger" can receive short wave as well as broadcast transmis- HE bicycle radio offers a new There seemed to be some difference sions. Hence, it can be used to pick and fascinating field for set build- of opinion as regards the use of a loud up police calls, messages from ama- - - ers and radio enthusiasts. The speaker. Many insisted that this was teurs, code and other interesting short demand for a simple bicycle receiver necessary, while others indicated that wave signals. If desired, it can be has existed for a long time. The writer earphone reception was more desir- converted in an instant, into a stand- has received hundreds of letters on this able. On one point, however, every- ard broadcast receiver. Although the subject from "bike" owners, asking for one agreed. The bicycle radio set must "Ranger" has been designed primarily circuit designs and outlining their re- be inexpensive in order to meet pres- for use on a bicycle, it can also be quirements. Practically all the letters ent -day economic conditions. used as a portable, due to its small called for a radio set of extreme sim- The writer has been designing radio size, light weight and compactness. plicity. They wanted a radio which sets for home constructors since 1921. During the winter months, it can be any amateur or beginner could build In the early days of radio, these re- installed in the home and under the out of standard, readily obtainable ceivers were simple affairs. As the more favorable circumstances of a radio parts. A second important item radio art progressed, the sets became more efficient antenna system, com- on the list of specifications called for more and more complicated and recent bined with better climatic and atmos- an all wave receiver which would be designs called for 16 -tube receivers pheric conditions, the set should bring able to pick up short wave stations as with automatic volume control, push- in numerous foreign stations on the well as the standard broadcast ones. button tuning, electron ray tuning in- short wave bands. Other important features demanded dicators and many other improve- The "Ranger" uses five plug -in coils by these alert cyclists were low bat- ments. These new sets are beyond the to cover the wave band range from tery drain, efficiency, compactness, capabilities of the average home set 18 to 550 meters. These are arranged light weight and simplicity of opera- constructor who has certainly been in suitable overlapping steps, so that tion. justified in calling for articles telling the single tuning condenser can be

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This cycle radio receiver is not only compact, but is wholly portable.

used in covering the entire band. it has the ability to withstand rough The carrying case is made of '4" Changing from one coil to another is usage. wood, over which a fabric of attractive as simple as inserting a new tube in Antenna control is possible through design has been glued. The fabric is a socket. To bring in the upper por- the use of a variable antenna trimmer, of type now being widely used in the tion of the broadcast band, a coil with which must be tightened when a short popular "airplane" luggage. many turns is inserted in the coil aerial is used and loosened when us- The set itself is mounted on a min- socket. A coil with fewer turns is ing a long aerial. The set is provided iature metal chassis of the new "step" substituted to bring in police calls and with a five inch magnetic speaker type. The chassis is 61/2" wide by 4" lower broadcast stations. Other coils, which gives excellent volume on the deep. The height of the rear step is V', with fewer and fewer turns, are sub- stronger local stations. Miniature tip and that of the front step, 11 ". The stituted to permit the set to receive jacks at the front panel permit the (Continued on page 53) the higher frequencies. use of earphones when set is tuned to The set uses a circuit of simple de- the weaker stations or when it is being sign, but nevertheless, one which has used under adverse conditions. proved to be sensitive and highly effi- The "Ranger" is contained in a cient. This consists of a tuned regen- carrying case which measures 6'4" by erative detector stage and two resist- 71/4" by 63í ". These are overall dimen- ance coupled audio stages. To con- sions. The front cover is 3/4" deep and serve space and also for increased ef- serves, when set is not in use, to pro- ficiency, the dual purpose type 19 two - tect the front panel containing speaker volt tube is employed. One section is grille and control knobs. When set is used as the detector, the other as the in use, this cover opens on hinges and first audio stage. A 33 type tube is may be removed if desired. The rear used in the output stage. This latter cover opens on hinges at the bottom, tube is a two -volt power pentode de- permitting ready access to tubes or veloped especially to afford consider- for changing coils. Underchassis view of the cycle set. able improvement in battery receiver performance. The use of the 33 tube PHONES has made it possible to secure results somewhat comparable with the automobile type tubes. CI Regeneration is obtained through the use of a tickler winding on the plug -in coil. It is controlled quite smoothly and effectively by means of a ri I 75,000 ohm potentiometer shunted Rs across the tickler. The "on -off" switch 761s is mounted on back of the potentiometer, thus being controlled by the same knob. SWITCH ON POT. In order to save space, permit a more A+ A- B- 45V C- 13V. B+ 90- 135V. compact lay -out, shorter leads and Rl-Z meg. 1/2 w., carbon, I.R.C. C, -.0005 mf. mica, CD. hence better results, a new type of R2-1 megohm, 1 w., I.R.C. C OZ mf. tubular, CD. tuning condenser known as RÏ-200,000 ohms, 1 w., I.R.C. Cc -.01 mf. tubular, CD. variable R,-200,000 ohms, 1 w., I.R.C. L1 -Set of 4 Hammarlund cords an "ultra midget" is used. This con- R-1 megohm, 1/2 w., I.R.C. 17-270 meters. SWK -4 R0-75,000 ohms, pot., Yaxley denser has been designed especially for V1 -RCA type 19 portable apparatus such as a bicycle C1-10-70 mmf. trimmer, Hammarlund V2 -RCA type 33 C2-140 mini. var. cond., Hammarlund SPKR -Utah orthovox spkr. and pentode output radio, and although of very small size, C3-.0001 inf. mica, CD. trans.

www.americanradiohistory.com 30

TECHNICAL BOOB & BULLETIN REVIEW

DO YOU WANT TO GET INTO RADIO, by Frank A. Arnold, published by Frederick A. Stokes Co., New York. 140 pp. $1.50. This volume is written for the hundreds of young men and women who would like to get into radio but do not know how to go about WWt'other eve your colyumist was the great strides which had been made in it. It is not intended as a text book or the guest speaker at the Bell Ham the art but deplored the fact that there were Club where he spouted wisdomic not sufficient capable men available to handle a study in psychology: rather as a (not bad, eh) words on the Past, Present television apparatus. His last words to us story of radio broadcasting from the and Future status and possibilities in the were, "I'll be happy to correspond with any standpoint of its career possibilities, radioping field. Our observations were, of one who wishes to learn more about the fu- bearing always in mind the training course, our own opinions and, as such, can ture of television and what it holds for you." be salted considerably. But a few of the Which is very nice, and we'll be happy to and aptitudes required for success in highlights of the address can hear repeating forward any mail to him. this field. Says the author : By force since many of youse guys and gals weren't of circumstances radio has drawn there . . . or was you dere ? Quote . BECAUSE Mates' and Engineers' licenses Whilst pay increases have been considerable are renewable with a minimum of three heavily on workers in other profes- in the past few years due to the efforts of months service and radiops require a service sions- actors, dramatists, directors in the unions, there has been a tremendous drop record of three years in the aggregate or the the theatre and motion pictures, nov- in berths. In 1933 there were 2300 vessels last two years solid for renewal, and because elists, journalists, composers, instru- equipped with radio and radiops ; in 1939 there the renewal of radiop licenses will be almost were only 1300 vessels radio -equipped and impossible due to the unstable operation of mentalists, vocalists -and in short, the manned. And there are fewer vessels today ships under the American flag, it is being entire field of professional entertain- because of the trend towards selling and char- requested by the ARTA that radiops be given ment. These people do not consider ra- tering to foreign buyers and countries. Fur- the same privilege of renewal as other li- thermore, new inventions have cut down the censed officers aboard the American Mer- dio a vocation but simply an oppor- number of men required to stand a 24 hour chant Marine ships. Which is nothing more tunity to market their own special ac- watch such as Auto- alarm. 'phone equipment than fair, especially since the FCC recently complishments. The writer has drawn and Facsimile. This latter, although coin - stated that only six percent of those taking his case examples paratively new, is being used extensively and the new examinations have passed them. So information from has proven practical in Uncle Sammy's Navy. either the FCC will have to soften the exam and personal experience, frankly dis- Under trying conditions and pressure of large questions, or else agree to the ARTA's re- cussing the difficulties and failure as number of radiograms. Facsimile has defi- quest . . . or else. well as the successes which have come nitely set itself up in business. Installation of this equipment is cheap. which adds to MUST wondering what will happen if the as a result of ability and hard work its features. Therefore. radio -grounded and NJ ACA Chicago convention accepts the combined with a well defined aptitude radio -minded men would do well to seek to new divisional plan of East Coast. Pacific for this most exacting profession. study and learn other radio fields where their and Gulf offices. What will happen when out abilities will have more chance for develop- of town shippers wire to the divisional office ment and profit. Of course. there are always for a man and the local phones by long dis- the Airlines and the Department of Coin - tance, trying to sell some beached op the JFD BELT and BALLAST BOOK, merce Airways. But we advocate a look -see idea of taking the vessel which he might published by the J.F.D. Manufacturing into the as yet clear Television field. Un- not like? Co., Brooklyn, N. Y. 78 pp. plus catalog quote. Just an opinion, me hearties, gathered from a perusal of the facts for 14 years. RADIOPS at the head of the assignment items. 15 cents per copy. This booklet list sometimes are particular about a contains a complete listing of all types ND the Bell Hans Club is nothing to billet offered to them. This happened in ARTA of replacement control cables (belts) snicker at. We'll wager there are not Local 7, San Pedro, when it was impossible many Radio Amateur organizations which to get a man to take out the McCormick used in radio receivers. The manufac- can boast of having over 400 paid up mem- boats Brookings and the Charles L. Weever. turer has listed the belts in a manner bers, their own spacious club rooms, their because of the $115 salary. The ships finally will make it easy for the service- own weekly publication. and the fact that had to sail for 'Frisco without radiops, there- that they have never owed a penny for rent or by incurring fines totalling more than $1000. man to find the type required in short other items. And to have been established So what'll be, what'll be? order. The second section of the book- for more than eight years ! And last, but not least, to have had but one President during- BUT there is the case of Ralph Service let is devoted to a complete listing of this entire period, none other than Charles who took a billet en a Norway -bound all types of Ballasts for use in modern Fay (W6EJZ). Charlie, as he is affection- boat after every one else had refused it. radio receivers. Socket pin layouts are ately known to the tribe, proudly told us that When they were out a few days he picked up he has never missed a single meeting in this an SOS from a Greek steamer. They followed also included so that the serviceman length of time, not even when he had all his Service's hearings taken on the doomed boat have some accurate means for identi- teeth yanked out or when several other mis- and finally rescued her, towing her into port. fying a certain ballast that might not haps tried to stop him. These are records The pleasant end of this story is that after that will stand for a long time, unless one Service had returned to the States, he re- bear any marks of identification. of you Hams can prove better ones. To ceived a check for approximately $1100 as close a splendid meeting, a very hoe explana- his share of the salvage money. Which just tion and description of his mobile trans- goes to prove that Gold is not always where IRC VOLUME CONTROL GUIDE ceiver was made by Buddy Rothrock, you look for it, or sumpin'. Catalog, edition No. 2, and W6MYC, which to our way of thinking is and Resistor the finest and neatest job we've ever laid AUNIQUE agreement was signed by Jor- the 1940 SUPPLEMENT, published by these old optics on. He stated that he has dan of the ARTA. and Paramount Pic- the International Resistance Co., Phila- worked as far as Hawaii whilst cruising tures, whereby radiops who work on any assignments must he to 124 46 pp., respectively. around Pasadena. So here's three cheers of their willing wear delphia, Pa., and for an organization of radio -hams which any special costumes furnished by them and Price on application. The supplement has aided in earthquake and flood troubles, that they cannot receive any extra pay for includes information on proper re- and in which there is complete harmony. being thus photographed in a sequence. The for practically all pay will average $10 per day. Can you placement controls CIDEN TALLY, another speaker at the imagine a radiop getting paid to kiss Dorothy 1939 model receivers and for a large Bell Club the sane evening was William Lamour . or does the hero always do that number of early 1940 sets. Standard L. Prager, an oldtimer who reminded us of in the final cut? 3 -9, are our grey hairs when he reminisced of his controls, as listed on pages old wireless club which was formed way E sadly report the silent key of used wherever possible. Special con- back in 1912. Bill has been connected with Brother William Walsh who had been trols that cannot be replaced by Stand- the American Television Laboratories assist- employed by the Wilmington Transportation ing Dr. Lee DeForest and U. A. Sanabria in Company for the past 15 years. All those ard types are listed on pages 44 to 47. furthering the perfection of Television trans- who had known his cheerful smile in the past older models Volume Control mitting and receiving. In his own right he find it all the more difficult to believe that For he shot himself. The msg found beside his Guide Edition No. 2 should be used. has a few patents pending on color television and, from what he said, it will be the last body read . . . Quote . . . signed off 6 :30 -N- word when it hits the airways. He spoke of (More QED? on page 58)

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This breadboard layout still has many followers, and works very well. ubling in OSCILLATOI S by II. W. KLINE TRITET oscillator, using two Schenectady, New York 1- type 6L6 tubes connected in parallel and developing about 60 watts output at the crystal fre- By using two tubes in parallel, the output of quency and about 40 watts output at twice the crystal frequency, has been an oscillator may be doubled if the Ire - installed at W2DKE, Schenectady, queuey is not too high. Makes a nice WEIR rig. N. Y., to drive two type 203A tubes at full class C rating. The oscillator, by itself, constitutes Under full load, the total plate and meter to a point in the circuit where an economical, simplified transmitter screen currents will be of the order of there is no d.c. resistance in series which keys easily and has no cranky 200 milliamperes. The voltage drop with it and the grid. This point must tendencies. across the cathode resistor will then also be at zero r.f. potential. The The type 6L6 tube requires a driving be 200 times 0.2 or 40 volts. This volt- voltmeter, therefore, will read the power of but 0.3 watt. Two tubes in age, subtracted from 500, leaves 460 combined voltage drop across both the parallel would double this rating. At volts on the plates. cathode resistor and the grid leak approximately 0.6 watt, the average If a high resistance voltmeter was which combination is the total grid crystal rides very easily. Due to these connected between V, (negative ter- bias. low driving power requirements, it minal) and V, (positive terminal) it In the case of an amplifier which was decided to try two of these tubes would indicate, under conditions of dynamically operates class C with ex- connected in parallel. The results full loading, about 460 volts, providing (Continued on page 59) turned out to be so gratifying that it the power supply had good regulating was believed that many would like to characteristics. With the positive ter- R, -200 ohms, 10 w. use this arrangement. minal of the instrument on V,, the tap R,- 50,000 ohms, 1 w. The circuit is very similar to a sin- on the screen potential dividing re- R,- 50,000 ohms, 25 w. gle 6L6 tritet oscillator except for the sistor R should be adjusted until the C, -.002 mfd., 1000 v., mica. addition of another 6L6 tube, having voltmeter reads 300 volts, under full mfd., 500 v., mica. all its elements connected in parallel load conditions. C,-.01 mfd., 500 v., mica. with the first tube. This means of measuring grid bias C,-.00025 mfd., 1000 v., mica. The parts are listed according to the voltage, applies to all oscillators or C, C,-.0001 mfd., midget type re- coding of the wiring diagram. The amplifiers, whether grid leak, cathode, ceiving conds. cathode biasing resistor and the or combined grid leak and cathode L L_ -2.5 mh., miniature choke coils. R L, grid leak R_, have been altered, in re- biased amplifiers. L:, Same as recommended in spect to the conventional circuit, for The method of attack, in the case of conventional handbooks for single tube parallel operation. In parallel opera- amplifiers, is to always tritet oscillators. tion, the cathode and grid currents are connect the positive double those of a single tube so the terminal of the volt- resistors are halved. meter to a point in the Instead of a series screen resistor, a cathode circuit where 50,000 ohm divider was used to obtain there is no series d.c. the 300 volts screen potential. A 500 resistance between the ANT volt power supply, of good regulating voltmeter terminal characteristics was used. The actual and the cathode. This plate potential, however, is the power point must be at zero supply voltage (500 volts) minus the r.f. gradient, however. voltage drop across the cathode re- Connect the negative sistor R,. terminal of the volt- KEY 6.3V - 500V.+ PLATE METER

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Schoolmarm YL Joanna W9JWJ Barnes. Married, by gum: W9CHD es W2MBC. 5' tall, wid eyes of blue, -YL ZS1DB. HAM CH TTR AMATEUR BAND AVAILABLE FOR FM TRANSMISSION WE are in receipt of an urgent THE Federal Communications Commission on request for a hamop to be trus- April 13, 1940, modified the rules governing tee for a hamstation at BOYS TOWN, amateur radio operators and stations to Nebraska. It would be entirely un- make available to amateurs the band 58,500 to necessary for us to dwell at length on 60,000 kilocycles for radiotelephone frequency the good that is being done by the modulation transmission. famous Father Flanagan for homeless, Previously amateurs were abandoned boys regardless of race, permitted to use "Wooden Indian Joe," W9WIJ of Iowa. radiotelephone frequency modulation in all color or creed. As we all know, Boys amateur bands above 112,000 kilocycles. The Town is non -sectarian and non -pros- change in the rules will make possible wider elyting, and a thoroughly American experimentation in this type of transmission, Institution in the fullest sense of the since equipment is quite generally word. We feel that +here might be available for the lower band. a ham, or a group of hams, in or The Commission also took the opportunity near Boys Town who would wan+ to to re- arrange, in the interest undertake this fine work and help put of clarity, the other rules which specify the use to be made the Boys Town hamstation across. of the amateur bands, although no changes Father Flanagan is being furnished were made therein. with a complete station, gratis, but needs an op to comply with the OF course you've heard about the ham who regs. died and went to the nether regions where F.C.C. he beheld a mess of ham equipment. Hams If you want to help, and are in were all around the place crying and wailing and Boys Town, Nebraska, drop carrying on something fierce. It was obvious or near that they were not pleased. us a line, c/o Hamchatter Editor, The Newly Arrived Ham stopped one and said, RADIO NEWS, 608 S. Dearborn St., "Watsa matter, no dx?" The other handed him a pair of ear phones. Chicago, and we'll forward your letter CQ's from all parts of the world were pounding to Father Flanagan. Please give your in. "No antenna:" asked the N.A.H. qualifications, age, etc., and the time The other took him to the window, and there you can afford to devote to this work. the N.A.H. saw a maze of 5 element beans, plus some long, perfectly shaped rhombics, beautiful Here is a chance for those hams to behold in the golden glow of the flames. who are in the position to prove that "No transmitter ?" was the next question. The other sorrowfully pointed to a solid row of a ham is a man with a heart, and the most beautiful rack- and-panel jobs that ever that he will lend a helping hand. graced a broadcast station. Watsa gang? The Hamchatter "No power?" He was shown the meters which showed 2000 Editor. volts at 500 MA running into every final. All WhFHQ"s superswellegant rotobeam. buffers were running at full blast. What could i be the trouble. Why were they all so glum?

Hamstation of W5IRH. HI3N visits hamstation W5CIU. Hamstation of WIMKR.

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Hungarian pre -war hamstation HA6Q. Titis beauty belongs to Ohio's W8MSG.

"Well, why don't you work them Y asked our "Why, Harry." she cried, "You got this from N .A .H. the ZYX Hamstore. didn't you:'" 'We can't tune the rigs, every stage is outta "Yes. clear." Harry replied, "And I would have resonance, and no matter what you do to the gotten it lots cheaper except I liad to bid against controls. the states stay outtat resonance, giving- a guy whose number was 0,789 and he kept us not the tiniest Piece of a watt output any - raising me." whores." The XYI, went to the cupboard, took there "All. that must be the Hell of it." commented from her purse and handed the OM a card with- our S.A.H. sadly. out :1 word. It lead: "Dear Mrs. Blank: `E'RE told it's very very old. but we still like We have entered you in our weekly blind the remark heard on one auction, for the Blahblah FXB -76T Receiver: the sissie band the 057871. other ',event. "Are you a :out you have been assigned number ticket ham. or just a Very truly yours. hanti" Ilnunmpummil! THE ZYX HAMSTORE." Now. aint you glad Christmas comes bitt once IT has always been our contention that a year:' The only active Kwantung rig, Christmas came too fete times during the J8Pl:. year. coming only once as it does. and that we IS our free red ? Yousedit. boy yousedit! So ought to have a Christmas every :3 or 4 months the British took the PK's offs the air! to relieve the monotony of not haviut Christmas Hntmnnmm! We didn't know that we had so more often. While we are not invested with the many readers who knew that the PK's weren't power of our !'resident who call and has chanweel British. To tell the troth. the map changes so dales of holidays to suit the will of the People, often nowadays. that we have installed a laose- we are still able to simulate Christmas whenever leaf system to keep track of everything. How- we want to, and write r Kiwis Kringle Story to ever. our correspondent was in error. and IF the heighten the illusion. Such a story is about to PK's are offs the air, taint the fault of the lx terprtralicd on you and, as Maurice English -or is it? A thousand Poddons OMs. Chevalier would apply Put it tight paw' a thousand Poddons fer our igotnee! In the 7th District lived two pions. Unusual, too, was the fact that they were husband and wife. Both had calls, and built used their tiny TRANS -PACIFIC dx reached a new low during rigs for whatever Pleasure yott can get from the past 30 days. .Vans seems to have joined operntina with a tenth watt in the crowded 7mc hands with Old Sol and between them they a band- As receiver's they had a one tube regenera- virtually eliminated (Ix for short period. tive set each. One trouble developed and that The European war, with its accompanying bans was that each could pick up the other's receiver OD ham activities throughout the world has far better than they could ally sits- wiped many countries off the neap so far as Also, in amateur reception is concerned. case 1 forgot to mention it. they were so poor. But to make that the mice in the kitchen were moving- back matters even worse. atmospheric conditions have to the Church. and the Cockroaches were bring- been very poor for the first there weeks of this ing- in their own lunch. month. During the last few days a marked When Christmas approached the OM thought improvement has been noted and the few remain- World- famous Army hamstation NY2AE. things over and derided that there would not be ing active trans- Pacific hams have again become anything quite so nice, quite so weleome to the audible in this country. XYI.. as a fb receiver. Ile had one all spotted. All parts of the British Empire, including seeund -hand. at the local hamstore where they Australia New Zealand. India. Malaya. Hongkong. betel a "blind" auction every week end. You etc, have been silent. A report on VU,!FQ has were assigned it number and then you wrote your been received again. but is still unconfirmed. An number and the amount you offered for the set observer in Western Australia reports hearing a on a card on the wall, and other hangs who FUYSQ tVU2FQ'r) on 14.00 mew.. twice. but the wanted to hid against you wrote their numbers station gives no location and is obviously a and the amount higher than your bid which they Iouey. So far as we know, with only one or two wished to pay for the set. Our Hero started at iulconftrmed exceptions. the British ban has been $5 which he expected to get as a present from carried out thoroughly in all Pats of the Empire. the Simon Le:rec who employed him as dish- not only with regard to amateur activities, but washer in the local hamsltntery. The next day to a great many experimental and commercial he went to the bantstore again during his lunch phone stations as well. VK°ME. VK3ME. hour. VKeME. VPD° and other AMA stations which Sure month- another collide of hams had have now been off the air for several months. raised the price to $8. Our hero added his num- 4. few l'lí tat /. Mere. Gridley) stations are ber and wrote down $8.50. The next clay there still being' reported from several sources. Al- were only two other hams left in the auction and though the 111t e1111w's a severe drop from that of our hero had to eo to $0.75 to top then. The last month, four transmitters in Java and Stmt next day only one other ham was left and our atra have been Heard more than once. hero reluctantly placed his bid in at $10. The PK :AY on 1400 meg., unreported for two either hart raised to $10.50: our Hero raised back months. was again received with surprising vol- to $10.75. The other ham raised to $11: and ume. PKIRI 114.03 met.) was evidently not Danish (German? i I.;n rillsen', hantshark. our hero raised it to $12 to freeze out the other Heard in Americ:l, although two listeners in tua'. He tut the receiver. He stink it home. Honolulu report fair reception. PK3WI ;14.05 "what a present for the XYL." he thought. mew.) is still being logged irreculaly. although Christmas morning- dawned clear, cold and overseas fans state that PK3BD 114.07 met.) cheerful. On the bare table reposed the heavy is the only active PK:3 at the present time. package which represented all our Hero's money, PK4KS 114.04 met.). one of the most rega la his lunches for the next two weeks, and an visitors to America. was the only other East advalre front the Ross. Dalian, and the only representative of Sumatra. His XYI, opened the paetcage. her face lighted to be reported last month. up. then her chin trembled. A few new Nipponese transmitters have been r.V

W5HEJ (L) watches 11-5_1llJ show a loop. OM es XYL hamstation of K4EZR-FKC. Camden, N. J.'s, hamstation W3BYK.

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'Nuther thing. We are gg to run a beauty contest among the YL's. So enter your YL or XYL. Only specification is it while the gal may be a YL or an XYL WITH OR WITH- OUT a ticket, she MUST be sponsored by a licensed ham. Send the pix along to "YL-XYL Beauty Contest, c/o HAMCHATTER ED. RADIO NEWS." If we get enuff entries, we'll give a swell prize. All pix published will be paid fer at our usual rates. So get gg, es lets show up these movie gals. We can do it. VA, EK1AF, YS1MF, YV5ABE, PK3KJ, KA1FH, PK3GD, PK1JR, PK4KS, PK1ZM, YNIIP, LU5AN, OQ5AN, CO2WM, TG9BA, and many W -k Jersey DXer's hamstation W2AIW. K(i, XE, and K4 stations. On the 28 me. band XU8AM, KA1ME, OQJAB, XYL K4ERZ again. Nice shack, isn't it? LU7AZ, HCIJD, NY4AD, CX2CO, CE2BX, ture controlled and the accuracy of the readings LU5AN, YV4ACE and other less consistent phone is about 10 cycles plus or minus on 7 mc. The stations were heard in only a few hours. crystal is kept in step with It'ti'V on a separate added to the leg- this month. J2NQ, Tokyo, and Conditions on the high frequency bands during receiver when measurements are being made. J2KN, also located in Tokyo male their appear- the afternoon and evening of March 24 were As an official observer for the ARM. I would ance after being unreported for five or six weeks. very peculiar. At 9:30 P. M. the 14mc. band like to remind the phone boys that the FCC re- J3CX and .JSCA (Korea) are also coming through was completely dead while the 28mc. band was quires that every station must include the prefix again. All four stations are on the LF side of wide open for Wl, W2, W3, W8, and W9. On when calling another station. Lately a good the 20 meter band. the 7 mc. band there was a great stillness broken many phone stations have been heard using a J7CB (14.08 meg.) needs scarcely be men- by only a few signals from such stations as procedure something like this: this is 9- call- tioned any more. Mr. Hashimoto's rig has been W6QD, W6GRL, W6MVQ, XF1A and XEICM. ing 8 -. This saves very little time and is class- reported by innumerable fans. and is responsible It seems that the west coast boys had the ified by the FCC as the signing of -a false call. for an extremely strong signal most of the time. best dx pickings this year and our money is on 73 de W9RSO. Still no identification of the 40 meter Japanese W6OCH and W6GRL for national high scorers fones which speak only in the native tongue. in the phone and e. w. divisions respectively. XUSRB (14.09 meg.) and XU1B (14.134 We believe that XE1CM and XF1A will have THE postman rang twice and brought from: meg.) are still "tops" in the Chinese part of our the two highest foreign scores. Charlie W5IRH Palmer- log. Both are still extremely active and are Ten meter phone activity has been very pro- On February 28th and 29th, the four ham - reported regularly. nounced around Kansas City. Mo., during the past engineers here at KARK played host to a foreign A station XUSXI was received once or twice, few weeks. The following local stations are well ham known as Tex Andins or HI3N. Tex, who but seems to have vanished almost as such °nly known on the ten meter phone band: flys for a sugar plantation in the Dominican as it appeared. Walt Sullivan's XUSWS Republic, had left home early on the is back again but very irregularly. morning of February 27th bound for A station using the call XUBGK has Wichita, Kansas in a damaged plane. been reported on 14.14 meg. and a SAY, OM, PLEASE LOT Jos .. He maintained contact with his wife XU7HB on 14.08 meg. Neither of these ME KNOW WHEN I'M (HI3N) until he reached the coast of calls are listed. however. and reception Florida. With only ten minutes gasoline has not as yet been confirmed. BACK /N THE BAND supply left in his planes tank, Tex made In addition to an almost endless list ( pl jV a forced landing at Appalachicola, Flor- num- in of 20 meter Philippine stations, a AGAIN So THAT !CAN L 7Lra71LCtJ. _{ ida. Mr. Anding spent the night Ap- ber of 10 meter transmitters have been V palachicola and took off the next morning logged during the past 30 days. Of USE My OWN it for Little Rock, Arkansas. Tex landed these, by far the strongest are KA1LZ CALL at the Little Rock airport around 5::30 and KA1ME, both of which have been AGAIN P.M. C.S.T., and after registering at his reported time and again during the past hotel, he telephoned the HARK studio to several months. locate a ham. KA1GC (ex W6CIN) (14.13 meg.). is Perey Nichols. control operator on duty now on the air quite frequently, and and W5HUQ, invited Tex up to the studio KA1GX (14.07 meg.), another com- and also got yours truly on the phone. parative newcomer, is also being logged After a brief gab -fest at the studio. I by many listeners. KA1EM (14.08 drove Tex out to the home of Gladman meg.) and KA1CS (14.13 meg.), both Upchurch -KARK engineer- W5CIU. 1060 waiters. are now giving KA1LZ Around eleven o'clock HI3N was heard (14.17 meg.) and KA1ME (14.18 on 20, but due to the condition of the meg.) a run for their money, and all band, we were unable to contact her. A four are regular visitors to America QSY was made to 75 -fore in an attempt between 5 and S A. M. to contact an East Coast station for a The balance of this month's Philip- relay to HI3N. W9DOD, Clinton, Indi- pine log includes KA1AG (14.13 meg.), ana, was contacted but could not relay. KA1BB (14.27 meg.). KA1FH (14.18 However. noon comrnetion of the ono, meg.), KA1PI (14.14 meg.), KA1LS we heard W9EWL of West Lafayette, In- (14.11 meg.). KA1AF (14.16 meg.), diana. frantically calling us. W9EWL KA1HR (14.06 meg.). KAIAK (14.14 turned out to be an old friend of Tex, meg.), KA3KK (14.28 meg.), KA1MM and so the qso was not "just another (14.125 meg.). qso." W9EWL promised to contact Tex's Poor receptiom conditions. coupled wife the next day and notify her that Tex with an extreme scarcity of dx stations had landed safely in Little Rock. The has caused many fans to shift the evening finally ended around 2 A.M. after major part of their listening activity pictures were taken of HI3N at the from 20 to 10 meters, with the result W5CIU rig. W5IRH took Tex back to that the 10 meter log for Hawaii has his hotel, and the next morning W5HUQ been vastly increased this month. The and W5DRZ (Bill Atkinson -another following calls have been reported on KAKR engineer) escorted Tex to the tee 'lower waveband during the past few weeks: WOCXU, Liberty, Mo., has a beautiful station airport to see him off. K6NZC, K6RVG. K6ROB, K6PCF, K6OXY, located on top of a hill just west of Liberty. Tex took off at 9:10 A.M. C.S.T. for the KHRDB. K6MVV, K6PIR, K6PRR, K6QMA, Sam uses 800 watts input to a pair of T200's final jump to Wichita. His transmitter was a IÇOPUL, ROTAS, K6GLZ, K6NYD, KOOQE, modulated by a pair of 822's. The receiver is 12 -watt, W.E. job operated on either of two K60QM, K6PIT, K6REF, K6ROK, K6PCF, an SX17 and the antenna is a neat looking 3 crystal frequencies and similar to the Private JuiNEa, K6MVA, K60QH, K6BNR. element beam setting on a tower which is right Flyer's Xratr in the Feb. 1940 RADIO NEWS. Twenty meter Hawaiians have become too on the peale of the hill. All operation is confined numerous to list in their entirety. but the follow- to the ten meter phone band. W>CIU is recovering in the hospital from a ing have been reported most frequently: KONYD, W5FJY /9 is on 7 mc, in Kansas City, where sinus operation and is anxious to get back K(iRVU, K6BNR, K6MVA, K6PIT, K6KGA, he is going to a radio school. Glenn runs about on9' 20 and 75 meter fone. The rig is a T -40 KIOXJ. K60JI, K60QE, KOPAD, KONVJ, 100 watts and has a fine signal on the low end in the final running at 110 watts input and Ií IlPUL. of 40. modulated with a pair of HF -25's. The 20 -meter K4FKC, located in San Juan, has been ex- W9RMI, Webb City, Mo., has put up a new antenna is a half -wave end -fed vertical while the tremely active and reported by almost everyone antenna pole and is active on 80. 40 and 20 75 -meter antenna is a half -wave end -fed hori- lately. It has been heard on 10 meters. 20 meter cw. The transmitter is completely band zontal. meters and 75 meters. switching with a T40 in the final. The receiver W5HUQ is sporting a new 1?.JIE -70 and is K4DDH, K4DSE, and K4ENT have also been is an SX23. heard quite frequently on 20 and 75 -meter lone received quite regularly on the 20 meter band. W9ASV, Joplin. Mo., is the proud father of a running around 70 watts input to a pair of while K4FOW has been on the air very often new junior operator. Congratulations, Charles, HY_Ss. using 10 meters. we hone he makes a fine ham some clay. W 5IRH is the peanut- whistle of Little Rock Es tt is tt. W9ZAW, Fort Scott. Kans., has become a -running 27 watts dyed in the wool 75 meter phone ham. Gene is input to an HY-25 OOKING b a c k becoming well known on 75 here in Mo. Gene final, modulated with over the .12TH will finish high school this spring. a 6N7 in Class 13. ln ARRLL DX Competi- W9QXG. Fort Scott, Kans., has a 2 element case the parts distrib- tion. just finished, we 20 meter rotary beam. Bob has been working utors are interested, find that the hams 20, 40 and 80 meter ew. with regularity for W5I1tH is ex- WOIHD, in the midwest were several years now. and he doesn't need surprised at the dx W5LD who is engineer for Ii I'OA has a very any more new cata- that they heard. Most fine 75 meter phone signal here in the midwest. logs. (3 sets received of us thought that W9RJP. Carthage. Mo., is selling his rig and to date!) The operat- the dx test would be concentrating on his college work. ing frequencies are very dull this year, WPEPV, North Kansas City. has just finished 14,188, 14,304, and but it turned out to building a new frequency standard which is a 28.608. be a rather exciting dandy. The standard uses a crystal that will W 5DRZ is going contest after all. oscillate on 100 lee. or on 1000 ke. The crystal strong on 40 meter On the 14 me. band stage is followed by a 1.0 ke. multivibrator and cw. over in North phone dx was repre- a 1 ke. multivibrator. To get the reading down Little Rock. Bill is sented by such out- to a frog's hair. Ed uses a separa`e calibrated going on phone when standing signals as oscillator of very narrow range which he beats he gets the audio sec- those of PK4.JD, with the signal to be measured and then measures tion of the new rig KA1LB, KA1ME, the beat difference between the 1 kc. points and completed, but for the OM W9TIO es PK1OG, J2NF, PY2- the calibrated oscillator. The crystal is tempera- present he is running his XYL W9ZNU.

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most likely bn enforced. The Hawaiian stata_ns hrd r K6LKM- 14,225, K60CV. KIPLG, K0MVV 29,000, K60QE -14,- 242. & KOGLZ on 28.650. KC4USC has bn coming- in occasionally on 14,- :330 & 14,360 using- cw. His sigs r R6 & he has a slow facie dwn to R;á. Best time to look for him is 9pm EST. HK3CC is located ill the "Hams Paradise." 1000 ft up in the Andes Mts in Colombia. Any of u follows tt hve wrked him can iuk forward to getting aa. fb QSL card from him. On his card is a beautiful pie of all ornament he found during his wrk of excavating ruins in the Andes. The ornament is made of solid Fold & is over 500 yrs old. It was used in Indian worship. The gird is one to put among ur prize QSL's. XE1GE- :3,890, XE1AI & XE2FC r the more popular Mexican stations tt can be hrd on 75 lone. They come in and) midnite. By the way, 1GE hails Hamop W5IPX at the controls. from N.Y. While on a tour of the states a a while ago he paid a visit to WHIM Be W1AIZ. around 250- watts to the HY -40's in the final. W5GGW IIiLR-I engineer) is going strong on THE South American hams live bn coming in Hamop W9IIS at his hamstation. 20 lone using cathode modulation. Alex and vy well on both 10 & 20 fone. HC1JB has WSDRZ are roommates and use the same receiver bn the most active. on 10 meters. His sigs never at present. WSGGW has a new ¡'re,u«ai. 20- go below 5 -9 & at times is the only S.A. ham low frequency end of 7 mc. He says LU8EN put meter vertical that is going up within the next poking a silt then. He's running abt (i0t) watts one over on him by having one more country few days. input to a pair of defunkt BC bottles and fig - listed in the Century Club. W5FAL is working out on 10 meter fone. ures it he's only getting 100 watts output to a HH2MC wants some clope on AC4AM. The WSFWF, one of the A. T. & T. boys, spends his rotary antenna. Some of the other active S.A. only statiotes on the air in Haiti now are spare time on 20 -meter done rising around 60 hams on ten r: CE2BX, LU7AG. LUSAN, OA4R. HH °_MC. HH3L, HH2ES, and HH2PB with HH2B watts input. PYSAQ, CX2CO. YV1AQ on 28.353, & HC2CC iu on phone. HH1DOJ is phoney. WSGUG operating on 160 fone is being both- the Honduras. ered with complaints from the bet's. CO2DY -the "Little Palooka.' has increased pwr & is nw running 400 watts to HK254's. Here is a little more of the stuff we're hearing on the East Coast: Johnnie was recently visited by a few Chicago from S. America and vicinity: 21) meters -LU- DX The most outstanding station being hrd yd's & he really showed them around the old 1QP, LU2BJ, 14,068, CX2CO 14,067, YN1IP this month is EK1AF in Tangier, S. Africa, on town. They were expert Rumba dancers by the 14.052, YN1FF, HC2QQ, TG9BA 14,29:3, HK3CO, 14,132. Jose is the only active station at the time they had to go back home. 1m told the HH213 14,130, HH4AS, YV1AP, YV1AV, YV4AE, present time in Tangier. He usually puts in the girls really cried when they boarded the ship, 14,173, YV4AB 14,140, YVSACE 14,120, CELAS strongest sign from 5:00 to 10:30 p.m. & his they were so sorci at having to leave beautiful 14.1::3, CE1AC 14.13(1. CE3EX, 14.350. CE3BE, rigs swing from R6 to R8. PY4BK, PY2AB, PY1AB, HIOQ, HI3N, Other African stations hrd r the OQ's. NY4AD, CO7AS. 10 meters HA9K, OQSAD on 14,125 in the Congo puts in a OA5AA (on cw), CE8BW, -CE3DW, FB silt in the early part of the morning, CO °AM, CO2WM. NY4AD, K4FKC, K4- but a w sigs from the KA's do a job on him FOW, K4AC, K4GIG, KSAT, TI3AB, later on. On ten fone the outstanding 00 HR5C, XE2AF, and XE2FL 28,260. is OQSAB and a new comer on the band OQSIM. Both operate arnd 28,275 & can W5ISE is a, new YL ham in New be wrkd by East. coast stations between Orleans. 10 to 13 noon. Altho they can be hrd W5FJW manages to keep busy with a until late afternoon they can't be wrkd new Economy 40. Who said YL's only becuz of a change in skip conditions. go in for fone. WSAKJ and W9AKJ finally got to- THE Far East stations live bn coming gether on 10 meters the other day. in win unusually strong sign. The most W51VF forgot his own call letters in consistent Chinese harm is XU1B on 14.162. the excitement of his first QSO. His sigs peak at R8, XUSAM-14,133, WSIPR is getting started on 40 c. w. XUSRB- 14.100 & XUSCX- 14.025 r the only W5HOS has been having QSL trouble. other hams coming then. They r hid abt Seems the West Monroe postoffice wants 8 in the morn & then start conning in age 3c per on them since the cards are slight- abt 5pnm & reach max strength from 5:áO ly larger than ordinary. Well "floss," to ti:(I(Ipm. They fade out of the picture how about cutting off the edges! at abt 7:15pm. WSHMV and W5ESP are heard consis- On ten meters the only XU is XUSMC tently on 160 fone. on 29,023. His sits r vy wk & r usually WSDRF has a specially printed QSL fading rapidly. He comes thru occasion- from G5QY. "Confirming all our Lb. ally at abt 5pm. J2NF -14.1 me & JSCW r QSO's on 28 mc. and commemorating our the 2 outstanding Japs hr on the coast. On 100th consecutive daily contact." Some several occasions they were hrd win vy record Allen, wonder if anyone can strong sigs, but on the average they r abt beat it) 112 to 5. They r hrd abt the same time ex -WSBFT couldn't stay away from the as the XU's. J2KN can be hrd vy wk on key any longer. He's recently made a the low end of the American ten meter visit to the R. I. Welcome back! lone band abt 7 in the evening. He is the WSEGK is emergency coordinator for only Jap station that can be hrcd on the ARRL in Monroe. band. The East coast hams hve vy little WSIHX was well pleased to learn that chance of wrkiug him becuz the West Uncle Sam is going to build a new and coast stations put strong sign into Japan larger CAA shack in Monroe. during the period he is active. "I ain't got no 115 line plug, the oldest Lewis Slater. although not yet a ham, The most active DX country this month boas,: i got on the line is only 103." keeps Ouachita Valley Amateur Radio is the Philippine Islands. The KA's hve Club members well posted on radio the- MI coming in hr practically all hours of ory. He is professor of Physics and the day wid R9 sits & vy little fde. The best Cuba( not to mention Johnnie). In Cuba the Chemistry at Northeast Junior College and at time tt the East en wrk these fellows is from yd's call him "Valintinito." Johnnie is planning present is teaching CAA students rudiments of 4:30 to abt 7:00pm. to be in the states abt October for a 3 wk radio and navigation in their flying classes. The most outstanding RA's during; the month bisness trip. One of his most prized possessions W SBDJ. WSCRV, and WSCNG hold the only hve bn: KAIME- 14,143, KA1FH- 14.207, KAICS- is a pie of WSDEW, the little dewdrop, in Port Class A tickets in Monroe. What's the matter 14,172. KA) LB- 14,024, & KA1GC on 14.150. Arthur. incidentally. Johnnie is trying to raise with the rest of you fellows) Other Philippine stations hrd r: KA1CW- 14.174. a mustache & is living a little truble in getting W5HUZ visited Ouachita Valley Amateur Radio KA11313- 14,264, KA1LH- 14,113, KA1ML- 14,120, it to bloom as he wild like it to. P.S. Send all Club several times lately. Best wishes for your HA7EF- 14,10:3, & KA4LH on 14,113. helpful hints direct to John. new club in Shreveport, J. E. KA1GC- 28,386 & KAlER-28.383 r the only Forty meter DX has bn vy gd lately ill the WSFWD is one of the few hams in this sec- Philippine hams on ten meters. Their sigs r early mornings. Some of the ltd catches are tion to have a 5 meter rig. fairly gd but due to a rapid fade they r hard to XUSMI 7055. HK.SED 7095. PY1UR 7030, PT- W5HEJ turned loose on 20 c. w. this week. copy. Only time they r hrd is around Spin. 20E 7060. J21 P 7160, J2KN 7023, J2IH 7060, 11e already has friends on 160 and 10 meter lone. Several other Chinese stations tt I forgot to J7CT 7063. The best time to look for the Far WSCRV is building a multi -band rig for use on mention tt hve bn putting gd sigs in r: XU1A, East is from 4 to 7 am EST. Also LU7AZ on 20 and 40 e. w. and 75 fone. XI15AM- 14.1me, XU8MC- 14.1mc, XU8RG- 14.065 6995 who is on daily frm 4 to 7:30 pm EST. WSCNG can copy e. w. at a & XU4HV- sustained speed 14.062. Several gd catches on 26 the past few months: of (35 words per minute for thirty minutes at ZP1LB 14.065. ZP3AC 14. AC4YN 14.268, KF6- a time without error. He puts it all on the mill, The PK's, ( what aye; e?) altho they r sup- JEG 14,202. YS1NS, KCIUSC 14.180 on board too. Where's that old world record, anyway. posed to be oft the air r still on & live bn vy and MX1A on 14.202 ke. active of late on 14mc. Their sig strength of the Snow Cruiser, WSGHJ does his share of traffic handling- on has not Since LU7AZ has just gotten in the Center ?, 160 lone. however bn as gd as usual. PK10G c4vh he has been having some fb QSO's on the WSHXC has a home is by far the most consistent & strongest sig com- made R meter on his ing from Java. Other Slay Champion. E. Indies hams 11W on ex -W5EMF (elec- the air r: PK:3JK- tromotive force) is 14.05me. P IC 1. V M, working for an elec- P K :3 J K , PK:3DD- tric service company 14.01mc, PK1JR -14,- in Monroe and hopes 073. PK4DA- 14,083, to have his ticket in PK3GD- 14,072. PRO - shape again soon. GC- 14.064, PK1AF- W5HEJ needs only 14.06:3. PK1MF -14,- one more to be WAS. 092 & PK8W1 on WSCNG took along 14,000. a portable mobile rig SEVERAL VK sta- when he visited Cali- tions were lied fornia last summer previous to the 1940 and kept the Monroe DX contest, but no gang informed of his stations Were active whereabouts during during or after the the entire trip on 10 contest period. The meter fone. He also Hatnop W2GFW. ban on ham radio lias W8TLI's peewee powerhouse. (Over to page 60) Bill Schuss.

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Reprinted with permission, from RADIO Trouble Shooters Handbook. Copyright, -1 1939, Radio & Technical Publishing Co. : 7 Britain, and S and Great :i EN'S Copyright in Canada all countries subscribing to the Berne Con- vention, by Radio & Technical Publishing SASE HISTORIES Co. All rights reserved. by ALFRED A. GBIRARDI, B.S., E.E. Author of "The Radio Physics Course," "Modern Radio Servicing "; member Radio Servicemen of America, New York Electrical Society, Institute of Radio Engineers.

FRESHMAN G being in opera- Noisy 1) field coil breaking down to tion about an ground Volume control 1) disconnect the volume con- filter of the detunes re- trol lead from the antenna hour High hum level 1) the plate circuit ceiver when coil. Connect a 0.1 -mfd. by- 6F5 or 6C5 tubes by intro- adjusted, pass condenser from the plate GENERAL ELECTRIC (AMERICAN) ducing an additional 50,000 - Selectivity poor terminal of the second r -f *¢RECEIVERS ohm carbon resistor between the plate load re- coil to the "ungrounded ter- sistor and the voltage supply. By -pass the junc- GENERAL ELECTRIC 1937 MODELS tion point of the two resistors to "ground" with minal of volume control a good 0.1 -mfd. condenser 2) loosen the adjustment of the Colorama pilot .1) insert a 150 -ohm resistor in 2) if necessary, shield the con- Equaphase condensers a n d lights burn out the center -tap lead of the trol -grid wire of the '6F5 set for maximum regenera- high -voltage winding. Also tube tion without instability connect a 15 -ohm resistor in Distortion ....1) "open ", or "partially open" 3) align the tuned stages series with the Colorama 250,000 -ohm resistor (R8) 4) if necessary connect a 0.1- bulbs in the plate circuit of the mfd. by -pass condenser from 2) if green lights are on con- each filament terminal of the '6F5 tube stantly, check the rectifier Distortion and .1) "shorted" or "leaky" 0.03 - r -f socket to ground for trouble low volume mfd. tone -control condenser No reception, .1) shorted r -f by -pass condenser Howling 1) blow out any dust particles (low voltage) GENERAL ELECTRIC A -52 Weak or no re- 1) defective pigtail resistors that are lodged between the ception Microphonic ...1) short -wave trimmers do not tuning condenser plates No reception open -circuited output trans- howl have full tension and vibrate 2) see that the oscillator tube ..1) (at 6 mgc.) at this particular frequency prongs all make good con- former -causing the set to ''howl ". tact, and that the oscillator 2N Remove the trimmer screws and i -f tube grid caps fit snugly FRESHMAN to bend the trimmers so they have full tension. 3) dress the short -wave oscilla- Fading 1) loose or corroded connection Put the screws back in place, and realign the tor primary lead against and at connecting terminals in short -wave band - along the r -f short -wave pri- the power pack, making in- mary bus termittent.contact. Go over these terminals and GENERAL ELECTRIC A -53 4) move the r -f broadcast pri- tighten each with a large screwdriver See also the Case History listed for G.E. A -52 mary lead away from the 2) open -circuited filament wind- receiver oscillator short -wave primary ing in power transformer. Inoperative ...1) open or high- resistance con- lead Re- connect the leads from tacts on band switch 5) dress the green rubber -cov- this winding to any of the other windings of the ered lead from the band Distortion, ..1) short - circuited condensers switch to the r -f section of same voltage. If the r -f and audio tubes are 'Sgauwking" C -16 or C -26. Replace with heated from the same winding, replace the 1800 - one gang against and around the front gang con- noise new units denser retaining ohm r -f bias resistor with a 500 -ohm unit, since Noisy recep- ..1) defective type '6K'7 r -f tube bolt there is now more current flowing in this circuit tion, (even though it may test 6) dress the yellow AVC return - Hissing noise, O.K.). Replace with new lead (from the r -f secondary FRESHMAN "PRESIDENT" to the i -f secondary) so it "Birdies" tube does not touch either the twisted filament pair Hum, 1) burned out resistor due to an or the oscillator primary common (white, red No grid voltage internally - shorted tube. " For Case Histories of Canadian General Elec- Check all tubes-then check tric Receivers, see the listings in the "General tracer) resistors Electric (Canadian)" group. This follows im- GENERAL ELECTRIC A -64 2) centertapped resistor c o n - mediately after the General Electric (American) nected across the 1.5 -volt receivers. Severe a -c hum 1) electrostatic shield of the filament winding "shorting" t For a cross -index of the Model numbers of cartridge -type electrolytic by- to chassis American G. E. with those of corresponding pass condenser (C23) touch- Noisy or inter- 1) broken lead on the tickler American RCA and RCA- Victor, Westinghouse, ing the high a -e voltage terminal of the type mittent opera- coil. This coil is mounted on and Graybar receivers, see the list in Section 3 '5Z4 rectifier tube socket. Move the condenser Lion when a can which moves with the of this book. away from the terminal, and wind tape or in- tuning tuning condensers. Replace sulating paper over the shield the broken lead with one GENERAL ELECTRIC A -54 Inoperative ...1) open 8,800 -ohm s e c t i o n which is more flexible Oscillation, ..l) open- circuit or high- resist- (no screen (R -9) in the voltage divider. Distortion (at ance connection at condenser voltage) A 9,000 - ohm replacement FRESHMAN Q -15 low- frequency C27. Resolder connections to may be used See also Case Histories listed for Freshman end of broad- this condenser and note the Intermittent ...1) to determine whether this Q- D -16 -18 cast band with effect reception, condition is caused by "open" tone control Fluttering or high- resistance contacts on FRESHMAN Q -16 at high -fre- signal, the band switch, remove See also Case Histories listed for Freshman quency setting Inoperative chassis from cabinet and set Q- D -16 -18 only) it so the band switch is ac- cessible. Tune the set to a Intermittent re- 1 ) defective type '22 tube bias- GENERAL ELECTRIC A -55 ception, ing resistor. Replace with signal and probe the rotor contacts with a non- Fading net unit Same Case History as that listed for G. E. A -52 conductive rod. It may be found that the springs 2) go over all socket connec- receiver behind the contacts have lost their tension: this tions, and soldered is easily remedied by bending the spring with a contacts GENERAL ELECTRIC A -63 pair of long -nose pliers toward the stationary joints for intermittent con- section of the switch tacts Inoperative on 1) "open" 3600 -mmfd. oscilla - 3) check all flexible pigtail re- short -wave tor condenser C -9. Replace If the relationship of the contact arms is such sistors O.K. that both front and rear arms do not make for fraying and breaks band but contact at the same time, the following proce- on broadcast dure should be FRESHMAN Q- D- 16 -18, 3 -Q -15, 3 -Q -16 band used: Loosen clamp nut on front .. .1) "open" 2,000 -ohm p 1 a t e - of chassis and twist front section of switch in Noisy reception, 1) open -circuiting flexible pig- Inoperative, either direction until both contact arms seat re- resistors Weak reception dropping resistor Intermittent tail 2) replace 0.05 -mfd. by - pass properly. This adjustment is limited due to the ception cond. in grid circuit of 6117 stopping lug, and if it is not sufficient to correct Hum at res- ..1) poor type '22 tube the difficulty, the flat shaft may be bent by using onance 2) check 0.25 -mfd. filament by- i -f tube of pliers Inoperative ...1) if the 0.03 -mfd. 400 -v. tone - two pairs pass condenser for "open" with tone con- control condenser "shorts ", All contacts should be cleaned carefully with Broad tuning, .1) incorrect adjustment of re- trol in "bass" replace it with a 1000 -volt abrasive paper and wiped off afterwards with Oscillation generation control connected position unit cloth. At no time should lubricant of any kind from det. plate to antenna Distortion with 2) check the 8,000 -ohm 1 -watt be used on this switch. If the switch should work stiffly, the trouble will probably be found GABLE 1937 RECEIVERS tone control in resistor in series with the in "treble" posi- condenser. Replace it if nec - the external mechanism of the switch assem- Inoperative ...1) check the wire on low side tion essary bly. Operating arms of the external mechanism tstrong blue of filter choke. Insulation Intermittent re- 1) inspect the lugs of the r -f should be examined for straightness, and all glow in 83 breaks down causing "short" ception and oscillator coils. See that moving parts oiled tube) to ground. Insulate it with (both broad- they do not "short" to the Better recep- 11 open- circuited secondary in spaghetti cast and short- mounting nuts on the trans- tion on local the second i -f transformer bands) formers stations with wave the type '6116 GALVIN High voltage ..1) open- circuit between shield tube removed See receivers listed under "Motorola" between type pin of type '6117 tube and '6A7 or '6A8 socket resulting in an "open" GENERAL ELECTRIC A GAMBLE- SKOGí1IO tube and ground contact. This causes -65 ground the '61I7 to oscillate and See receivers listed under "Coronado" Same Case Histories as those listed for General draw grid current through Electric A -63 R -11, resulting in the ap- receiver GEM A.C. -D.C. pearance of a d-c voltage across it and from the GENERAL ELECTRIC Inoperative ...1) defective speaker coil, usu- type '6K7 or '6A7 tube to the control -grid A -66 ally open - circuited. Since ground Intermittent ...1) see Case History for this the speaker .here cannot be Noisy reception 1) filings in air -gap of speaker reception, same trouble listed for Gen- repaired. the unit should be at high volume eral Electric A -64 receiver replaced causing inter- Loud crackling 1) poor connection at the lug ference in noise after of the filter choke other sets

www.americanradiohistory.com 37 9aSh 2aats s

FTER reading "Simple Loop Con- by CHARLES THOMAN struction" and building one, I Carolina find now that it can be made Eastover, South accurate to a degree that will make it a useful gadget to have around. This is a follow up of the article If a loop antenna is sensitive enough, it can written and published in the April issue of RADIO NEws, 1939, by John X. be used as a direction finder. The author tells Utley out in Tallkeetna, Alaska, under the title of "Simple Loop Construc- tion." To the present loop was added of certain improvements which will do lust this. a balance condenser and a sense antenna and the addition of a ground at the center of the loop. are working, definitely locate an in- center line into degrees running from The balance condenser may be pur- coming signals direction. Now push 0° to 360 °. Draw vertical lines per- chased, but after inquiries it is a bit the switch connecting one side of the pendicular to the center line at each too costly for the average radio experi- loop with the sense antenna. Rotate degree. Now take the greatest error menter. Therefore, we turned to the the loop. On one side of the longitud- you found. For example, let us take junk -box and found a 35 mmfd. which inal axis of the loop we find the signal an extreme case of twenty degrees. did the trick. Take the rotor out of strongest. Set the pointer with the Lay out on the paper twenty lines the condenser and then with a hack- bulged side toward the direction of the above the horizontal center line and saw equipped with two blades together, signal fixing it so the pointer is actu- twenty below. These lines run par- cut the stator in half. Incidentally, ally 90° to the left, as we look down allel to the center line and are spaced this condenser is of the straight line on a compass card. evenly apart. The center line is now capacity type. Since there are many Now release the switch and rotate called the normal or the true compass. different constructions in this type of the loop pointer into the direction of All points taken are located by relat- condenser we shall only say that it the incoming signal until a nul is ing them to the normal compass. If need only be fairly close to being cut heard. Rotating the balance conden- the radio loop bearing reads less than in half in order to work properly. If ser and the loop together we will be the map or normal compass bearing, you have one of the old type it will be able to sharpen the nul to a point of then we must add the difference to the necessary to cut around the bottom absolute zero. This point will be found horizontal center line. mounting bolt, on both sides as shown. to be very sharp. Varying the length If the radio loop is greater than the Add the necessary lugs and insert it of the sense antenna will reduce this normal compass then we must sub- into the circuit. Notice that antenna sharpness. The use of a variable re- tract. Therefore an error point will marked "sense" is brought in and con- sistance such as is used in some types be located as shown. Radio loop gave nected to the rotor of the balance con- of receivers works well, instead of a reading of 25. The correct reading denser, through a single pole double actually rebuilding the sense antenna. should be 45. Difference is plus 20 °. throw momentary contact switch Now for some real accuracy. Di- Another : The radio loop gave a read- similar to the ones used in the present rectly under the pointer on the loop ing of 48 °. The true bearing is 35 °. day testing apparatus. The blade of stem, place a mariner's compass or The difference is 13 °. Suppose from the switch is connected to the antenna magnetic compass of fairly good size. the final curve we were to take a and the normally open contact is con- Now let's take a bearing on a radio radio loop bearing on a signal and we nected to one side of the loop input or station. What does the pointer say? (Continued on page 54) to one side of the balance condenser. Check this on a map showing the var- The normally closed contact is con- ious locations of radio stations. If you 90° 180° nected directly to the rotor plates of find that the bearing you took and the 20°M Ms. woG11 mommtnn.CO. ERROR the balance condenser. actual direction found on the map dif- 15 a" LINES The sense antenna should be about fer than at this point the radio compass C' thirty -five feet long. Various lengths is in error. Remember the map is right Io° ii should be tried. It was found that the and we are going to have to calibrate s° CENTER longer sense antenna gave a much the radio -loop. We can continue to LINE sharper nul point. The average is take bearings, recording their exact 0° v_COMPASS NORMAL about twenty to forty feet. This sense position as show on the map and the Cii antenna has two functions. First, it bearings on which we found they were 5° C is used to determine the direction from loop. , indicated according to the radio 0° G'. which the signal is entering the loop The more we can get in all directions MI /NM1 circuit. To do this requires addi- 15° TERROR the the more accurate the finished curve IIIMMMI MIAMI LINES tion of a pointer on the end of the will be for future use. S. MAMA .11=M11 zó ...-111- loop stem. This pointer has one side, Now lay out a piece of graph paper FIG. -4 90° 180° or the right side bulged. After things for future references. Use a good grade of paper and draw a center line along its longitudinal axis. Divide this NUL POINT SENSE ANTENNA LOOP E BULGE SENSE TO TUNER DIRECTION SWITCH OF RCV R COMPASS FIG. -2 FIG. -3 CARD

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"Which antenna ? ", is the problem which faces every dx fan, ham, or professional engineer.

ductor. We also know from our knowledge of condenser action that the HOW ABOUT charging current is greatest at the instant the condenser is totally discharged and is zero when the condenser is fully charged. IAT Referring then to our condenser in " A1TE1'NA? figure 1, we find that when the electric field is zero (condenser completely discharged) the current is maximum -NNUMERABLE articles have been caused by a movement of countless and the magnetic field is also at max- written concerning antennae; electrons through a conductor. Re- imum and is fully expanded. Since one - - methods of construction, various ferring to our basic laws, such an elec- of our fields is at maximum when the means of excitation, coupling meth- tric field will create a magnetic field other is at minimum, our electric and ods, impedance matching, etc. Almost -this field being at right angles to the magnetic fields are ninety degrees out every conceivable phase of the subject electric field direction of motion, and of time phase, a fact which we shall has been approached from the practi- having a polarity dependent upon the see presently is of vital importance at cal side, but, with the exception of electric field direction of motion. We radio frequencies. textbook treatises, publications on an- can also generate an electric field by This combination of electric and tenna THEORY have been conspicuous the charge and discharge of a con- magnetic fields in space is called the by their absence. denser. In this case, the electric field induction field. We find such a field It is the purpose of this article to will be in SPACE instead of through surrounding every a.c. circuit regard- bridge the gap between theory and a conductor. If we enlarge the space less of frequency. Although theoreti- practice; to bring it within the scope between the plates of our condenser, cally extending to infinity, the induc- of the layman, and to demonstrate we will have a comparatively open tion field at commercial frequencies is that theory and practice are by no field, one which corresponds to that of very limited, and practically all of the means so incompatible as is persistent- an antenna. This is illustrated in fig- energy is returned to the circuit upon ly believed. ure 1. the collapse of the field. An analysis of the fundamental the- Lines AB and CD represent the two As we increase our frequency how- ory underlying wave propagation takes legs of a center fed antenna and in ever, we find that the element of TIME us back to basic laws. These are : our analogy are the two plates of the becomes more and more important. We 1. A moving electric field creates a condenser. The a.c. generator at the know that electricity, and electric and magnetic field. center is the source of energy and cor- magnetic fields, travel with the speed 2. Conversely, a moving magnetic responds to the point at which the of light -300,000,000 meters per second. field creates an electrical field. transmission line would be coupled Therefore as the frequency increases, As we know from our knowledge of in a transmitting antenna. the electric field has less and less time the elementary electric generator, Since the legs of the antenna are in in which to collapse back into the cir- when the conductors of the armature a vertical plane, the electric field is cuit. At radio frequencies, we find sweep by the magnetic field radiated also in a vertical plane and is repre- that the electric field actually does not from the field poles, a difference of sented by the dashed lines in figure 1. have sufficient time in which to col- potential is induced in the conductor. The magnetic field created by the lapse back into the circuit, and we This difference of potential constitutes movement of the electric field, being have the phenomenon of a field iso- an electric strain, or electric field, at right angles to it, is in a horizontal lated in space. This can be more eas- which is always at right angles to the plane, and is represented by the solid ily grasped if we follow the movement magnetic field direction of movement. lines in figure 1. of an imaginary point (X, Figure 1) in Accordingly, this electric field exists We know from our elementary the electric field as the condenser goes whether there is a conductor present electricity and magnetism that the through a cycle of charge and dis- or not. strength of magnetic field is propor- charge. A moving electric field is usually tional to the current flow in the con- As the condenser charges, the field

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Antennae are not lihe To/sy ii ho -Just a:roneal." They require careful planning and engineering if the set they serve is to function at maximum.

.G.cy ERNEST J. VOGT Hialeah, Florida

at point X reaches maximum value at electric field. Since the components From the foregoing it would appear a certain interval of time later than of the radiation field are self- sustain- that maximum radiation could be ob- that portion of the field closer to the ing (a moving magnetic field creating tained by merely increasing power conductors (Point Y, Figure 1). At the an electric field, and vice versa) they input and frequency. Unfortunately instant the condenser is fully charged, will travel through space theoretically however, a number of other factors the current has reached zero and the to infinity. which impose very definite limitations field at point Y is at maximum. Due It has been determined that the in- must be taken into consideration. Only to the time element involved, however, duction field decreases as the square a portion of the power absorbed by the the field at point X has not yet reached of the increase of distance. We know, antenna is radiated usefully in the maximum. too, that the radiation field decreases form of an electromagnetic field. The As the condenser discharges, the directly as the increase of the distance. remainder is consumed in various field commences to collapse. The field Therefore, theoretically both fields ex- ways, and since it contributes nothing at point Y collapses almost instantly. tend to infinity, it can be seen that the toward radiation, represents a com- The field at point X however, not hav- induction field is very weak at a dis- plete loss. ing reached maximum as quickly as tance of a few wavelengths from its It is customary when dealing with that at point Y, does not begin to col- source, while the radiation field falls power absorbed in a circuit, to regard lapse until a certain interval of time off much more slowly. Immediately this power as being expended in a re- later. Immediately upon completion in the vicinity of the antenna the in- sistance. The value of this resistance, of discharge, the condenser begins duction field predominates -i.e., the of course, is such as would consume charging in the opposite direction and magnetic and electric components will the actual power in the circuit at the an electric field opposite in polarity to be ninety degrees out of time phase. same current flow. In antenna cir- the previous collapsing field is built At a long distance from the antenna cuits, this fictitious resistance is up. however, the radiation field predomi- known as the "effective resistance." Because of the time interval, all of nates, and since the induction field will Since all the power expended in an the energy at point X has not been re- be negligible in amplitude, the electric antenna is not usefully consumed as turned to the circuit and is isolated in and magnetic components will be in radiation, the effective resistance is space by the expansion of the second time phase. divided into two components : radia- field of reversed polarity. Energy in If the frequency is kept constant, tion resistance (or useful resistance) space cannot remain stationary. Since the original strength of the radiation and loss resistance. (Next page, please) the field at point X is repulsed by the field will depend directly upon the +A new expanding field of opposite polar- magnitude of the current flow in the ity, it travels outward-still with the radiators (antenna conductors). In \ light. other words, an increase in the power speed of .` . Since, according to our basic laws, a input to the antenna results in an in- \ \ moving electric field creates a mag- crease in antenna conductor charge . x current with consequent \ netic field, our electric field moving and discharge \ \ , field strength. x , through space at the speed of light increased 1 will be accompanied by a magnetic However, since the time element field at right angles to it. This com- and frequency remain unchanged, the III 411 1Bgill bination of electric and magnetic fields net result is an increase in field energy I isolated in space is known as the radi- per unit space, that is to say, the field ation field. The electric and magnetic density is greater. The field density components of the radiation field, un- can also be increased by increasing the like the induction field, are in time frequency. In this case, although the phase with each other. As we know power input to the antenna is the from the study of generator action, a same, there are a greater number of moving electric field of constant veloc- wavelengths in a given unit of space ity produces a magnetic field which with a resultant increase in field en- varies directly as the strength of the ergy per unit space. Figure No. 1.

www.americanradiohistory.com 40

t, If ,, t,

-1-

A B

FIG .3

guy wires are necessary for the support of antenna masts, such guy wires should be properly broken up by insulators. Guy insulators should be if the power input to the antenna is Obviously, for maximum efficiency, spaced so that the intervening sections the loss resistance must be kept at a very high, any precautions taken in of guy wire will not resonate at any avoiding sharp turns and angles in the minimum. A number of factors con- harmonic of the antenna frequency. tribute to the total loss resistance, and antenna system will be worth while. If other antennae are in the vicinity, If reasonable precautions are taken, their importance should not be under- the transmitting antenna should be as estimated. These factors, therefore, the loss resistance can usually be kept far removed from them as possible. down to 5 percent or less of the effec- will be enumerated below and dis- Failing this, the radiating portion of cussed in the order of their impor- tive resistance. If the effective re- the antenna should be erected at right sistance of an antenna system is tance. angles to them, thus minimizing their The total loss resistance is com- known, it is sometimes possible to de- pickup. The increase in eddy current termine the approximate ratio of loss posed of : dielectric loss, resistance loss is directly proportional to the in- resistance to radiation resistance. For loss, eddy current loss, leakage loss crease in frequency, and can assume and corona loss. example, let us assume two amateur serious proportions on many of the transmitters, A and B. Both trans- Dielectric loss occurs in all dielec- amateur bands. trics and varies inversely as the fre- mitters have the same power input- Leakage loss varies directly as the 300 watts, and both antenna systems quency. It is due to the phenomenon square of the voltage. Since the volt- of hysteresis and is especially notice- are current fed and identical physi- age is inversely proportional to the cally. Both amateurs are putting two able in poor dielectrics such as damp frequency, it follows that the leakage wood, concrete, masonry, trees, etc., amperes into their antenna systems. loss varies inversely as the square of From the foregoing, it would appear which are in the field of the antenna. the frequency. Although this loss does Although this loss decreases as the that both installations are operating not assume Herculean proportions on at the same efficiency. However, this frequency increases and is, therefore, the amateur bands, in the interests of comparatively small on the more pop- is not necessarily true. Suppose we efficiency, every effort should be made were to measure the effective antenna ular amateur frequencies, it is still to keep it at a minimum. Leakage one of the most important occurring resistances and found that A had an losses are caused by the flow of leak- effective resistance of 25 ohms and B in a radiating system and should be age currents from antenna to ground, one of 37.5 ohms. Then : kept at a minimum. Special care or between the legs of dipole an- should be taken to keep poor dielec- tennae. The leakage path resistance P =I2R trics away from the ends of an an- is naturally greatly diminished in wet For transmitter A, tenna, since the highest electric grad- weather and the losses, especially on P = 22 X 25 = 4 X 25 = 100 watts. ients usually occur at these points. the lower frequency amateur bands, Output 100 1 Much power loss due to this cause also become noticeably large. Care should Efficiency - - - or occurs at the point of entry of the an- Input 300 3 be taken to make all possible leakage 33% tenna feeders into the radio room. If paths as high resistant as possible, by efficient. For transmitter B, possible, a point of entry should be the choice of proper insulators and chosen where the material immedi- feeder cables. P = 2' X 37.5 = 4 X 37.5 = 150 watts. 150 1 ately surrounding the feeders has high Corona loss, which takes place dielectric properties. at Efficiency = _ - or 50% efficient. high voltages, is caused by partial 300 2 Resistance loss is the easily under- ionization of the air about the antenna standable loss due to the ohmic resis- wires. The ionization causes the air Despite the fact that transmitter B tance of the antenna and feeder con- above is transferring more energy into loss to become a partial conductor and en- its ductors themselves. This can be ables it to carry a current. Because antenna system than transmitter kept a minimum by making use of A, does not necessarily indicate at of the bluish glow which accompanies that wire having a large cross -section and B's signal is "getting out" more effi- good conduction. The largest useful it, corona effect is visible at night. ciently. The greater antenna resis- cross-section can be obtained by using Corona effect begins to take place only tance in B's case may have a larger a number of small wires, properly in- at certain definite voltages, the criti- component of loss resistance, in which terwoven and insulated from each cal voltage varying with the size and case it is possible that A is radiating other, thus minimizing the "skin ef- shape of the conductors, and being more actual watts of useful signal. fect" and reducing the R.F. resistance. smallest at points and corners in the A rough check on this may be ob- In choosing the material for the wire, antenna system. Corona loss varies tained by arranging a schedule with a a happy medium must be reached at inversely as the frequency, and in the third amateur -preferably one several which good conductivity is combined average low -power amateur installa- hundred miles away -to compare the with tensile strength. Phosphor or tion is practically negligible. However, signal strengths of transmitters A and silicon bronze is often used. B. Should it develop that B is putting Eddy current loss is caused by the out a weaker signal than A, despite ( 006`' -' 006` a the greater amount of energy he is current induced in surrounding metal- LiORLz Li OR LE lic objects. Every effort should be transferring to his antenna, this is made to eliminate, as far as is practi- fairly conclusive evidence that the loss cable, all metallic masses from the resistance of B's antenna system is vicinity of the antenna field. If the overly large. The remedy, obviously, method of construction is such that EXCITER FIG.5 (Study further on page 47)

www.americanradiohistory.com 4 all almost handle they'll and fewer they always fobs. tall 1 to ins replacementlacement easierea ' ' midgets re the work mi dard - PiSpeiais of s does thetwol... stock and One botboth to replace eal dependability. size controls. for r size ...Designed' ' Small in by Using MIDGETS

Greatly en- larged view of control Although IRC Controls are made in you are sure will fit -even in the small- interior. every type for every radio need, there est of modern sets. It means easier The Only Midgets With is a fast - growing trend on the part of installations, thanks to the exclusive servicemen and jobbers to concentrate IRC plug -in shaft features. Above all, EVERY STANDARD-SIZE on IRC Midget Controls for every it means real dependability, for IRC replacement need. And it is a logical Midgets have every engineering fea- CONTROL FEATURE move! It means stock simplification in ture of the larger size "standard type" When you buy an IRC Midget you a small of IRC Midgets IRC Controls. get an exact miniature of the famous that supply IRC standard "CS" Control. Noth- equips you for the big majority of jobs. Certainly, it is a trend well worth your ing has been left out. Not a single It means using replacement controls important design feature has been while to investigate. A study of their changed. Exclusive features in- possibilities will quickly convince you clude (1) IRC 5- Finger "Knee - that IRC Midgets offer the biggest Action" Silent Element Contactor; (2) IRC Spiral Spring Connector; savings in time, space and stock sim- (3) IRC Metallized -type Resistance plification, plus the utmost in true Element; and, (4) Thrust Washer dependability. used to avoid end play in shaft.

Four different plug -in shafts mean easier, simplified installa- lion -save buying many special 401 - controls at higher prices. N. Broad St., Phila., Pa. In Canada: 187 Duchess St., Toronto, Ont. www.americanradiohistory.com 42

-, - r - MAN J: ;ACT J. : ,.F.. : .S' . . A , _ J-

RESISTORS and VOLUME CON- of the sub -headings are : Typical Oper- parts and tools for the servicemen and TROLS, catalog 44, published by the ating Characteristics of the Symmetri- more than 10 pages of interest to the International Resistance Co., 401 cal Doubler, Operating Conditions of "ham," experimenter and television North Broad St., Philadelphia, Pa., is Capacitors in Symmetrical Doubler enthusiast. now off the press. This very complete Circuits, Considerations of Circuit Re- Copies of the Lafayette Spring 1940 line of all types of resistors for use by turns and Power Line Grounding in catalog may be obtained from the radio manufacturers and servicemen the Symmetrical Doubler, Common above company at 100 Sixth Avenue, includes those designed for specific Line or Series Line Feed Type of Dou- New York City, without charge. Copies purposes. Among these are a line of bler Circuit, Typical Operating Char- are also available at any of the follow- Attenuators for broadcast applications acteristics of the Series Line or Half ing branches: 265 Peachtree St., At- or in high -grade sound equipment. The Wave Doubler. Many other para- lanta, Ga.; 110 Federal St., Boston, IRC line also includes volume and tone graphs are contained. Price on appli- Mass.; 901 W. Jackson Blvd., Chicago, controls, special standard controls, cation. (RADIO NEWS No. 6 -102.) Ill.; 542 E. Fordham Rd., Bronx, N. Y.; midget controls, auto radio and re- 90 -08 166th St., Jamaica, L. I.; and 24 placement controls, metallized resis- JENSEN CATALOG NO. 114. The Central Ave., Newark, N. J. Free. tors, wire -wound resistors, insulated Jensen Radio Manufacturing Co., 6601 (RADIO NEWS No. 6 -103.) resistors, metal cabinets, power wire - So. Laramie St., Chicago, recently wound resistors and adjustable types brought out their new catalog on all CLARION SPRING 1940 PUBLIC for all applications. The popular line types of reproducers. These new units ADDRESS CATALOGUE. of precision The Trans- wire -wound resistors is are especially designed for applications former Corporation of America has also included. These offer the radio that require sound projection in large man just announced a new CLARION P. A. accurate units for use in the con- areas or where clean, crisp speech Catalogue for 1940 which struction of must be they claim many test instruments. delivered without blasting or contains the most extensive line of Free. (RADIO NEWS distortion. No. 6 -100.) This company is specializ- Sound Equipment ever offered in a ing in units having the ability to cover book designed CINAUDAGRAPH large arenas, exclusively for the use SPEAKERS, a skating rinks, stadiums, of the agency who sells P. A. equip- new catalog put out by the United etc. Probably the most outstanding ment in the field. Teletone Corp., 100 achievement Varick St., New in the new line of Jensen Featuring a completely new of York, is products is line now available. Formerly the the new type X Loud "designed with individuality" sound Cinaudagraph Corp., this catalog rep- Speaker Unit. These new units are of equipment, this new book contains resents the first published by the new the metal alloy diaphragm, sound amplifiers and complete company. The Linear chamber type but incorporate sound sys- standard units entirely tems ranging in power from 7 to feature High- Fidelity, Low distortion, new principles of design and construc- 100 watts, Efficiency, mobile systems, recorders, Polyfibrous cones, Acim tion. They are, therefore not to be school systems, musicians sound equip- voice coil supports, moisture -proof confused with the more or less conven- ment, record changers, transcription centering, and Curvilinear cones. The tional loud speaker of the metal dia- players, intercommunication phragm type. They systems, latter are used on their Linear stand- employ a small, microphones, speakers, speaker baffles ard speakers to insure maximum fidel- rugged, narrow annular type dia- and horns, and phragm, much in fact everything in sound. ity minimum distortion character- stiffer than the more Copies may be had by writing to the istics. Linear Standard permanent conventional spherical or dome type Clarion Institute of Sound Engineers, diaphragm. The is 21/2" magnet speakers are also being manu- voice coil in care Transformer Corporation of factured with the same features. A diameter and the whole is rug - unit America, 69 W o o s t e r Street, New special series of public gedly constructed and designed speakers for ad- for York, N. Y. Free. (RADIO NEWS No. dress are completely illustrated and maximum life expectancy. Free. 6-104.) described. These are available in (RADIO NEWS, No. 6-107.) diameters up to 18 ". Air Column sound projectors are also described. LAFAYETTE 1940 SPRING CATA- PUBLIC ADDRESS CATALOG re- These may be had complete with LOG. Radio Wire Television Inc. (for- leased by Terminal Radio Corpn., 68 speakers mounted up to 60 watt ca- merly Wholesale Radio Service Co., W. 45th St. and 80 Cortlandt St., N. Y. C. The answer to pacity. Free. ( RADIo NEWS No. 6 -101.) Inc.) announces the publication of the practically every Spring edition of its 1940 catalog. public address and sound amplification MALLORY -YAXLEY RADIO SERV- Comprising 124 pages, this new catalog requirement will be found in the Ter- ICE ENCYCLOPEDIA, supplement of the world's largest radio supply minal Radio Corporation's Public Ad- No. 6 is now ready. This contains in- house includes a comprehensive listing dress Catalog, just released. Hundreds formation on "Half wave and Doubler of the new line of Lafayette radios and of items are listed, including complete Power Supply Systems." The service- radio -phonograph combinations, fea- P. A. systems, amplifiers, tuners, man will find much hard -to -get infor- turing for the first time the Lafayette microphones, speakers, record players mation covering the servicing of all Radiocorder. The Lafayette Radio - and accessories. A free copy may be obtained by types of sets that make use of voltage - corder is a sparkling new addition to writing to the Terminal doubler circuits. The first part is de- the Lafayette line which is sure to win Radio Corporation, 68 West 45th voted to a discussion of Half Wave rec- great favor with the music loving pub- Street, New York City, or by visiting tifier operating characteristics. Typ- lic. It is a highly practical home re- either of the two Terminal Radio Sup- ply stores in ical examples are given for this and cording assembly consisting of an easy - located New York City. the reader may get a complete under- to- operate recorder for acetate rec- Free. (RADIO NEWS No. 6 -105.) standing on the functioning of the ords, a fine radio and phonograph com- power supply in quick manner. The bination and a moderate power public - ALLIED SPRING -SUMMER RA- entire supplement follows the very address system all contained in a DIO CATALOG. Holding to the 17- complete explanation of the subject as handsome console cabinet. year tradition of "one purpose -one di- used by the Mallory -Yaxley Co. in all The new catalog also contains the rection"- Everything in Radio -the of their previous issues and is recom- first listing of the complete new line of new 172 -page Spring- Summer Catalog mended as a valuable addition to the Lafayette Public Address equipment of Allied Radio Corporation, Chicago, serviceman's library. The second por- featuring several innovations in cir- contains complete listings of all the tion is devoted to a complete explana- cuit design as well as new cabinet styl- latest radio equipment. An attractive tion of "The Symmetrical or Full ing. In addition, the Spring edition new 3 -color processed cover is attract - Wave type of Voltage Doubler." Some lists more than 64 pages of equipment, (Continued on page 52)

www.americanradiohistory.com June, 1940 RADIO NEWS 43

Mobile on 10 (Continued from page 18)

To Frank C. Jones must go the cred- it for this receiver as his article "The 1938 Model 222 Receiver" appeared in the June, 1938, issue of Radio. There he introduced, for the first time, the 6J8G hexode converter tube. This tube seemed to have possibilities. So our former experiences somewhat pes- simistically, an experimental converter was made up and hooked ahead of our broadcast radio. While getting it lined up the first signal heard was an ultra -high police transmitter 2500 miles away. Then it was tried ahead of our auto radio and it worked far better than our expectations. Finally, we wound up some five meter coils and when we heard signals on this band we knew we had something. It was then built up in its present form as shown in the photographs and our particular receiver problem was solved. We cannot recommend it too highly as we have nothing but praise for its performance. It has the three primary requisites of any receiver : sensitivity, selectivity and stability. It's gain and conversion ability at the ultra -high frequencies is remarkable. Images, a major problem in many receivers, are the least of our worries. Tuning the auto radio to 1500 kc. makes the combination a "double super -het" with all the inherent advantages. And using Where -ever you go- the auto radio means 90% of the that Whether you travel by rail- strike out on the open road -or take life easy receiver -from I.F. to speaker -is already built up. Finally, inasmuch as in a cabin in the pines -you can have radio with you by including a they have efficient line and hash filters Meissner Portable "5" in your vacation plans. already built in, trying to find the par- Keep abreast of the times -the latest news the minute it happens -it's yours ticular combination for your lay -out with this highly efficient little receiver. It'll take the place of your daily is eliminated. paper. And even if you're one of those who want to forget about the news The converter is a low C (for gain) regenerative first detector and a high for awhile -there'll still be evenings when you'll enjoy musical entertainment C (for stability) reversed feed -back -you won't have to miss those favorite programs you've been keeping oscillator. Regeneration is used in the up with. detector as it greatly increases the The Portable "5" is a sensitive, 5 -tube super -het, using latest types of im- sensitivity and helps to eliminate 1.4 -volt tubes. Completely self- contained, with batteries and built -in loop ages. This regeneration necessitates antenna -just turn it on for reception anywhere! Beautiful the detector trimmer condenser be brown -tone available from the front panel but this aviation luggage style case is only 81/2" x 61/2" x 13" and complete set also assures perfect alinement of the weighs only 15 pounds. front end. Ofttimes when you want And -best of all -this remarkable set is furnished as one of the famous that signal that is "away down in the Meissner Complete Kits! All parts are supplied (except tubes and bat- fading badly it is mud" or mighty help- teries), with Meissner super -clear instructions, pictorial and schematic ful to tune it in "right on the nose ". The reversed feed -back oscillator wiring diagrams. So simple a twelve -year -old could have it working in a seems to give better results on the few hours! No special tools required. higher frequencies and is obtained by See your Meissner Parts Jobber at once and get acquainted with the winding L2 in the opposite direction possibilities of this receiver. Not "just another battery set" but a full- fledged of Li. Unlike ordinary oscillators the portable super with dynamic speaker. A ready companion for any grid is adven- connected to the untuned under any tickler coil. Both coils of the oscil- ture conditions! lator are wound in the same direction SEND FOR COMPLETE MEISSNER CATALOG but be sure that the grid is out one end and the plate out the opposite end Your copy of the big 48 -page general catalog is ready and waiting. Contains com- of the coil form. The high C tank plete listings descriptions and illustrations of the entire line of Meissner Kits, ready- makes the converter very stable and built units and radio accessories. A post -card will bring yours at once! keeps the frequency drift at a minimum. The switch in the antenna cir- s S/ ADDRESS DEPT; N6 cuit is a low capacity double pole double throw one section of which W31 changes the antenna either to the auto radio or to the converter. The antenna input to the converter

www.americanradiohistory.com 11 RADIO NEWS June, 1940

might have been obtained by using a vent any tendency of the oscillator to small trimmer condenser coupled to "jump" while tuning. the grid end of the detector coil but In the front view photograph the in our case we use a loop of Number 12 upper left knob is the detector trim- wire inside of the coil form. This can mer C2 and the upper right knob is A SENSATIONAL NEW SCOTT ! be moved up or down after the con- the oscillator band set condenser C4. verter is in operation until the best In the view of the bottom of the con- OFFERS BOTH coupling is obtained. In all probability verter the 6J8G may be seen mounted coils for other bands will be wound up in rather an unorthodox manner, i.e., and this method assures optimum horizontally. But this certainly makes coupling for each band as the coils are for short leads and in the RF wiring, plugged in- instead of readjusting where it is really important, there an antenna trimmer. In line with our isn't a lead over 114" long -with most policy of ruggedness -after the cir- of them well under this figure. Where cuits are lined up-the coil turns a lead passes through the chassis use should be cemented in place with duco a large rubber grommet with a short cement. heavy piece of spaghetti slipped over With the coil turns and tuning con- the wire to make a snug fit. densers specified the ten meter phone The lips or ears on the front panel band is spread over 30 divisions of a may seem a bit unusual but were made 0 -100 dial. Ultra -high frequency in our particular case so as to pro- broadcast stations operating in the vide an easy mounting in the glove vicinity of 26.500 kc. can be heard at compartment of the car. We suggest the high capacity setting of the tuning that a model of the converter chassis condensers and are often used as a and panel first be made up out of criterion of conditions on that partic- heavy cardboard. We had the discon- ular day. Police stations operating certing experience one time of very around 9 meters can be heard by re- carefully measuring the space it was setting the oscillator band set con- to fit in; the metal chassis was made denser to a slightly lower capacity. up and then discovered it wouldn't go MOST FAR -REACHING INVENTION Individual requirements as to the in without removing some of the auto- IN RADIO FOR TWENTY YEARS! amount of bandspread can be obtained mobile controls. RADIO science now offers a star - by altering the number of turns of L3. The output of the converter is fed cling new invention FRE- Tuning condensers Cl and C3 should through a low capacity shielded cable QUENCY MODULATION. be of the straight line frequency type to the antenna connection of the auto Not just an improvement of our present for easiest tuning. When it is desired radio. Another shielded cable carry- radio system, but an entirely new sys- to "shave" a station, a slight readjusting three wires-grounded A and neg- tem of transmission and reception. ment of the auto radio dial makes a ative B, hot A, and B plus -supplies Static and "noise" have finally been These conquered. Even in the heart of a FB vernier. the converter power. shielded crashing storm, or with X -Ray or other Other methods of coupling the out- cables should be grounded but do not powerful electrical equipment right put of the converter to the auto radio rely upon the shield alone for grounded alongside, reception from the new can be used but with a receiver of A and negative B. For standby pe- Custom Built SCOTT FREQUENCY good sensitivity the parallel feed sys- riods while transmitting and at the MODULATION receiver, within the tem shown has proven to be ample. same time keeping the battery drain service area of the F.M. Stations, re- It also has several other features we at a minimum. The speaker field and mains undisturbed. Only the serene like- First -simplicity with a mini- the primary side of the power trans- and changeless beauty of the inimit- and a shown. able Scott tone is revealed. mum of parts and adjustments former are rewired as consequent reduction of probable A heavy lead is brought out to the TONE UNEQUALLED IN RADIO HISTORY trouble. Second -we like to be able arm of a single pole double throw The very peak of high fidelity -up to 15,- to read CW signals. A very simple switch. In one position the auto radio 000 cycles -is now transmitted on direct studio F.M. broadcasts -a tonal range 2 to method is used in that the auto radio acts perfectly normal while in the 3 times greater than that used in present can be tuned to the side of a broad- other position this lead is connected broadcasting. Programs are reproduced by the new Scott F.M. receiver with such amaz- cast station carrier for the necessary to the receive side of one of the re- ing perfection -so free of static and noise - CW comes through lays. This method cuts out the vi- you are tempted to pinch yourself to make heterodyning and sure you are not actually present in the in fine shape. brator and speaker field current but studio or concert hall. If the auto radio does not have suffi- keeps the receiver filaments hot while 5 YEAR GUARANTEE 30 DAYS TRIAL cient sensitivity one section of an I.F. transmitting. The lead marked X in New F.M. transmitters are being rapidly in- transformer link coupled to the re- the diagram is most important and stalled. Prepare now for this magnificent new reception. The new far advanced Scott ceiver will help. Or in stubborn cases well worth experimenting with in its offers both F.M. and regular receiver on one a separate amplifier made with a pent- termination. In our case 90% of the chassis, or new F.M. Tuner alone, for easy connection with present receivers in F.M. ode and an I.F. transformer tuned to vibrator hash was eliminated by con- service areas. Precision custom built to same of this lead directly to the bat- quality and performance standards that have the operating frequency the auto necting won for the Scott universal recognition as radio will provide all the gain you can tery terminal. On the subject of hash "World's Finest Radio." 30 days home trial will and extended terms in U. S. A. Sold only use. Incidentally, the choke in the and its removal every installation direct from our Laboratories. Be first. Write plate of the first detector is not of the require different treatment. for all details now. short wave type but one designed to While many amateurs can and will GET SPECIAL INTRODUCTORY OFFER! operate at broadcast frequencies. eliminate it, in stubborn cases the Constructional details can be seen help of an experienced serviceman ,,I.Aplcs in the photographs and are self ex- specializing in auto radio installa- l E. H. SCOTT planatory. The detector coil and tions will be of immeasurable value. RADIO LABORATORIES, INC. 4 trimmer condenser are mounted on the However, here are a few suggestions: 4440 Ravenswood Avenue.. left front of the chassis with the os- Adding ordinary filter seems to be of Dept. 51140. Chicago. Ills. W cillator components on the right rear. little help; A chokes of heavy wire ( , Send all facts. special troy. n_ cots record review. and or- The angled shield between sections and pie wound RF chokes usually will der blank. NO obligation. =.oF O BAO serves a double purpose in that it also prove advantageous; try different sizes Name strengthens the front panel and the of mica and /or paper condensers; chassis. The tuning condensers Cl try bringing the hot side of the 6J8G Address and C3 are ganged but should have a filament to different points; instead of receiver's main power lead going STUDIOS: CHICAGO. NEWYORK .0UFFAI.O.DETROIT,LOSANGELES flexible coupling between them to pre- the

www.americanradiohistory.com June, 1940 RADIO NEWS 45 to somewhere on the dash as is usually as a 50 volt drop on the high side. it was possible to mount them. We done, connecting it to the battery ter- And as a possible source of drop don't have carried a collapsible full -wave minal or starter switch instead usually forget the relays. The contacts carry- and even experimented with portable will help. ing low voltage should be heavy and beams. But, undoubtedly you will try The problem of a power supply for adjust them with a thin file so that operation in high places and the wind the transmitter isn't so easy and here they seat perfectly. In wiring up the velocities and weather encountered are several not so well known funda- power cable and sockets connecting usually makes short work of any com- mentals to keep in mind. The use of the filament prong and the adjacent plicated system. A portable -mobile an- another storage battery in addition to prong together makes a heavier con- tenna must have the ability to radiate the regular car battery is highly rec- nection and eliminates a common power without being fussy about it. ommended if you want to eliminate source of grief at this point. And there must be no such thing as battery troubles. While it is true that It is a well known axiom that no bulk with unhandy and unwieldy ap- a storage battery will stand momen- rig is any better than the antenna paratus. And so a quarter -wave Mar - tary overloads -it is also true that a used with it. We are fairly well in- coni working against ground was a steady drain will usually have disas- formed today on the subject of ordi- logical and highly satisfactory choice. trous results as you already know if nary antennas but knowledge on port- Early in our experimentation it be- you ever let the headlights burn over able- mobile antennas is sadly lacking. came apparent that the placement of night. While transmitting the total The author has had antennas fastened an antenna on the car affected the di- drain is a little over 15 amps and on on his car at practically every place rectional pattern to a more or less ex- receiving the drain is about 10 amps. If you anticipate any great amount of operating this is too much of a consistent drain for a single battery unless you do a lot of driving. Most of the later model cars are equipped with a device that maintains an automatic charging rate. If you do not have one better put in something that will conveniently adjust the charging rate. A rheostat installed on the dash and connected in the field of the car generator is such a device. Auto supply stores call this item a "charging regulator" and while you are at it, unless your generator is well cooled, better get a "generator ventilator ". These two items are very inexpensive but are well worth while. There are two general types of power supplies available -v i b r a t o r and motor generator. Both have their good points as well as their bad. The vibrator type is probably the most tricky and erratic. One major fault is that their regulation isn't so good. We are a staunch believer in class B for portable -mobile operation -- simply because it is the most efficient type of modulation. In this respect a motor - generator is ideally suited as the in- ertia of the armature is such that it carries through the Class B peaks with remarkably good regulation. In fact it is better than most power supplies IN THE MOVIES, he -men The RCA trademark is known built for this purpose. In our instal- like the one above mean everywhere. In the minds of lation the voltage barely fluctuates even though the motor -generator is dollars to exhibitors. They your prospects and customers being worked at its rated current with have public acceptance. it means high grade equip- the modulators resting. Most motor -generators are rated so RCA offers you public ac- ment at reasonable cost. It that they can handle a 25 to 30% con- ceptance in the sound busi- means research and engineer- tinuous overload so these temporary speech peaks do not cause any harm. ness. And any man using a ing plus the world's most One thing worth noting is that it is comprehensive experience in our personal observation that the product with this vital ad- more segments there are on the gen- vantage is well on the way to sound. It's another reason why erator side the less hash there will be. And the integral filter system for the new business every time he it will pay you to recommend particular supply -be it motor- gener- approaches a prospect. RCA Commercial Sound. ator or vibrator-is a cheap investment as the manufacturer knows more about the filter constants required than could be determined in hours of cut and try experimentation. All primary or low voltage wiring should use the heaviest wire possible. It will help you to remember this point RCA Mfg. Co., Inc., Camden, N.J. A Service of Radio Corp. of America if you realize that a drop of one voit on the primary side can cause as much FOR FINER SOUND SYSTEM PERFORMANCE -USE RCA TUBES

www.americanradiohistory.com 46 RADIO NEWS June, 1940

tent. For instance, placing the anten- jack and fitting a key into the side of na on the left rear bumper made the the plug. rig transmit best in a line through the A concentric line is undoubtedly the right front fender. And an antenna efficient form of feeder for this -type mounted on the car's radiator trans- of installation and can be cheaply con- mitted best in a backward direction. structed from copper tubing and iso- Field strength tests -with distant sta- lantite beads. These beads should be tions- indicated that a quarter wave fastened on the wire every 4" but this Marconi transmitted best in line with distance should be shortened to about the greater bulk or mass of the car. 2" where bends take place in the line. So the antenna was mounted in the The coupling scheme shown worked middle of the turtle deck between the the most efficient of dozens that were rear window and luggage compart- tried. For some reason I cannot ex- ment hinge line as shown in the photo- plain it seems to "resonate" the en- graph. In this position the directional tire antenna system and reports av- effect is directly straight ahead and erage 2 R's better than other types of has a pattern similar to an ordinary coupling systems. The coupling con- antenna with a reflector behind it. denser, C is a 50 -75 mmf. variable and As an example, if our signal was R8 serves a double purpose in that it is "HE SAYS THEY SHOULD when pointing directly at another dis- also used to adjust the antenna load tant station, simply by turning the to any desired degree. Two or three HAVE USED UTAH SPEAKERS" car around 180 degrees would make turns of insulated wire are wound There are important reasons for this in- the signal drop down to R3 -4. The around the center of the final tank creasing preference for Utah speakers same effect is noted when receiving. coil with one end going to ground and among sound equipment men. They Separate antennas for transmitting the other to the coupling condenser. recognize the time proved dependability, and receiving were not used for the Tuning the transmitter is quite con- uniformity and consistent high quality. same reason that most amateurs today ventional. But we like to clip a 100 When Utah speakers are used, the use the same antenna for both. The mill thermo -galvanometer across two benefit of these outstanding features, as logic being that if you get out best in inches of the middle portion of the an- well as many others are obtained. a certain direction with a certain antenna and then go back over all tuning 1. Special Utah phenolic resin cement tenna the same antenna should be used adjustments. Lacking the galvan- treatment provides an extra sturdy so that you can best hear stations ometer a field strength meter can be voice coil assuring maximum safety from this direction. And too an- under EXTREME then substituted. The most critical adjust- OVERLOADS. other antenna would probably distort ment is the crystal tuning condenser - 2. Completely dust-proofed. the directional pattern and give an er- and a compromise must be met be- 3. All cementing operations completely roneous impression. tween maximum output and stability. cured before final test, assuring per- It is interesting as well as fect centering, made possible THE practical Tuning on the higher capacity side MODERN METHOD use of upon arriving at an unknown location reduces the output slightly but effects THERMO- PLASTIC- cements to tune in a signal and then orient the better stability and minimum drift. If throughout. car for best reception. As to be ex- tuned carefully a ten meter crystal 4. Rugged formed -steel cone housing pected the null point is the sharper will have very little more drift than for maximum strength and rigidity- and more definite. It is difficult to a lower frequency crystal with doub- rust-proofed, aluminum finish. judge when the received signal is ler stages. 5. All diaphragms are lacquer treated to above R6 but by turning the car If you have been putting off building assure minimum moisture absorption. around in a circle and noting the car's a portable -mobile station simply be- 6. Cone and spider assembly selected position when the received signal is cause you thought that flea -power for maximum power handling and weakest then the exact opposite of didn't have a chance then the results tone quality and minimum distortion this will be the direction for maximum obtained with this 15 watts ought to and break-up. signal strength when receiving as well convince the most skeptical. It has There is a Utah Speaker for as transmitting. been a source of never ending amaze- every original equipment or Many persons have asked why I do ment to us to receive the reports that replacement requirement. not use an antenna attached to the we have with this power. If anything Utah speakers are distributed nationally rear bumper as is the usual police car they are better than the reports through carefully selected, recognized installation. If you are only interested gathered with the 260 parts jobbers and dealers. Look for the watt station at famous Utah trade mark on the carton. If in communication where the ground the home QTH. Of one thing we are your supplier can't furnish Utah speakers, wave does most of the work placement very certain -every bit of RF in the write us direct. of the antenna is unimportant. But car's antenna goes places and does UTAH RADIO PRODUCTS CO. for distant contacts fastening the an- things. It has made me wish that I 824 Orleans St.,Chicago,Illinois. Canadian tenna to a bumper does not work out had some sort of an X -ray machine Sales Office: 560 King Street West, To- so good. so that I could see all the parasites ronto, Canada. Cable Address: Utaradio- Details of the antenna installation of power around my home. All the Chicago are shown. We use a collapsible fish - wiring and plumbing of my own house, Three of the 90 different models of Utah Speakers pole for the radiator because it has plus my neighbors' houses, plus the the least wind resistance. It's length various and sundry wires on the street will be more than half the theoretical and in the alley certainly must soak half-wave value and should be at least up a lot of RF even before it has a 8 feet long. It is made plug -in by chance. using the giant type of plug and jack. One last thing: While it is perfectly H-15P P-12P G-1210 The jack is sweated into the end of all right to run any input you care to the radiator. The plug is insulated as long as there is a convenient power from the car body by means of two plug handy it is quite a different thing machined mycalex washers. Due to when you have to carry this power the fact that the turtle deck is slant- with you. For portable- mobile opera- ing at this point of the car the anten- tion inputs up to about 15 watts to na is bent at the bottom end so as to the final are about all that can be run SPEAKERS be vertical when in use. This will if one wishes to experience any VIBRATORS TRANSFORMERS cause a tendency for it to turn around amount of pleasureable operating. Be- with the wind but this can be over- yond this point past experiences of UTAH- CARTER PARTS come by hack -sawing a key way in the others as well as myself indicate

www.americanradiohistory.com 4 June, 1940 RADIO NEWS 47 that the difficulties and troubles en- tance variation method, is based on The experiment is conducted as fol- countered increase all out of propor- equation (9), in which: lows : The antenna circuit is tuned to tion to the increase in signal strength R unknown antenna resistance, resonance with the transmitter and at the other end. But what a pleasure R, value of added resistance. the current, I, carefully noted. A and a surprise this 15 watts can be. I current with no resistance added, known value of resistance, R,, is then 73's and see you most any Sunday Is current with added resistance. inserted in series as shown in Figure 2, afternoon. Several values of added resistance, and the current, I,, again carefully measured. The values obtained, I, I,, Typical Operating Conditions R,, should be used and the results av- Voltage Current eraged for greater accuracy. Every and R. are then substituted in equa- RK34 Plate 280 54 mils. effort should be made to use resistors tion (9). The experiment is then re- RK34 Grid -10 mils under load. 6)75 Plate 190 27 mils. which are as far as possible non -in- peated several times, each time using 79 Plate 290 16 mils resting, 35 -40 peaks. ductive. Other than the resistors, no different values of R, and substituting Total transmitter filament drain -2.3 amps. additional apparatus is necessary to in equation (9). The various values 30 perform the measurement. Some proof R obtained should be averaged for vision should be made to facilitate the final value. 1Iiiis Ahura Thal Anlenna? opening of the antenna circuit to pro- Care should be taken during the vide for the insertion of the resistors. measurements to maintain a constant (Continued from page 40) The arrangement of the apparatus is transmitter power output, since any shown in Figure 2. fluctuation of power transferred to the is to go over the various losses which have been enumerated above and take whatever steps are possible to mini- Two New Instruments -At Record Breaking Low Prices mize these losses. It has been seen above that the THE NEW MODEL 1230 value of effective resistance of an antenna is a very useful factor to have SIGNAL at hand. A practical method of measuring this resistance is outlined. GENERATOR Due to the behavior of electricity at WITH high frequencies, measurements of cir- FIVE STEPS cuit constants are not as easily obtain- OF able as are those at the lower frequencies. Ordinarily, to obtain the SINE -WAVE AUDIO resistance of an alternating current SPECIFICATIONS RADIO FREQUENCIES from 1011 K. circuit, the current and voltage would C. to 90 Megacycles in 7 bands by front panel switch manipulation. All direct be measured at resonance, and Ohm's reading and accurate to within I% on to obtain R. In an an- LR. and Broadcast bands, 2% on higher law applied frequencies. The R.F. is obtainable sep- tenna system, we find that the current arately or modulated by any one of the five Audio Frequencies. is the only factor which can easily be AUDIO FREQUENCIES: 5 steps of SINE -WAVE audio 200. 400. 1000, 5000 measured. However, by measuring the and 7500 cycles WITH OUTPUT OF various resistances OVER 1 VOLT. Any one of the above antenna current at frequencies obtainable separately for of the circuit, several pairs of simple servicing P.A., hard -of- hearing aids, etc. ATTENUATOR: Late design, full - simultaneous equations can be ob- range attenuator used for controlling tained from which the antenna resis- either the pure R.R. or modulated R.F. CI RCUtT: The Model 1230 employs an improved electron coupled oscillator circuit for the R.F. affording positive tance can readily be computed. protection against frequency drift and a Hartley oscillator circuit for the A.F. section. DIAL MANIPULATION: Large 51/2' dial etched directly on front panel, using a new mechanically perfected If our antenna system is tuned to drive for perfect vernier control. APPEA RA NCE: The front panel is etched by a recently perfected process which results in a life -long attractive resonance, according to Ohm's law, finish and the instrument comes housed in a streamlined shielded cabinet. E CURRENT SOURCE: The Model 1230 operates on 90 to 130 Volts A.C. or D.C. any frequency. I = - (1) The Model 1230 comes complete with tubes, shielded cables, moulded carrying handle and in- 2 85 R ,tractions. Size 14' x 6' a It'. Shipping weight 15 pounds. ONLY $i Rearranging: E = IR (2) THE NEW MODEL 1220 If we now add a known value of resistance, R,. in series with our antenna World's Lowest Priced system, we get a new value of current, I,, and according to Ohm's law, 5,000 OHMS E I, - (3) PER VOLTER!! sensi- R R, 1 :xtrm,ely valuable becu,se of its high tivity. the Model 1220 is an all- purpose tester Rearranging: that permits resistance, measurements up to 3 -{- \legohms, with only a 3 V. self- containe,l flu h- E = LR I,R, (4) ligbt battery and reads directly down to 0.2 Since the value of E is the same in "l " "' SPECIFICATIONS both cases, we may combine (2) and * 6 D.C. Voltage Ranges: 0- 3- 10- 50 -250- 500-5,000 volts. '(4) which gives us: * 3 A.G. Voltage Ranges: 0 -15- 150 -1500 volts. IR = I,R I,R, (5) * 4 Resistance Ranges: 0 -3000 ohms, with 15 -ohm center, direct reading to 0.2 Then: oh m; foregoing base range multiplied by IR I,R I.R. (6) 10, by 100 and by 1,000, to read up to 3 - = Meg. with self- contained 3 V. flashlight And: battery. * 4 D.C. Current Ranges: 0 -200 micro- R(I - I,) = I,R, (7) amperes; 0 -2 -20 -200 Milliamperes, using wire -wound shunts. Dividing by (I : - I.) * 3 Output Meter Ranges: Same as A.C. I,R, Voltage Ranges. * 3 Decibel Ranges: From -2 to +58 R - (8) D.B., based on .036 watt in 500 ohms. * Uses full -sized 3' square 0 -200 micro - I - I, ammeter, with 2% accuracy and finely Or: damped movement, contained in a Model 1220 comes complete with cover, self- handsomely- designed, square molded contained battery, test leads and instruc- $1 045 R- R, Bakelite case. tions. ONLY -I -1 (9) I, SUPERIOR INSTRUMENTS CO. This method of obtaining the an- 136 St. Dept. R N 6 New York, N. Y. tenna resistance, known as the resis- Liberty

i www.americanradiohistory.com 48 RADIO NEWS June, 1940

antenna will introduce serious error At low frequencies in general the in the results. It is best to check plate current at different points of a circuit current and voltage of the last trans- is the same. If the voltage remains RAIN or, SHINE... mitter stage before each antenna cur- constant, however, the current into a rent reading and to correct any exist- capacitive circuit increases with the ing discrepancy. It is advisable to use frequency. Similarly, if the current an R.F. milliammeter to measure the remains constant, the voltage across antenna current and to adjust the an inductance increases with the fre- transmitter output so that the current quency. At low frequencies, displace- falls well within the meter scale be- ment currents are present only at fore beginning the measurements. those points of a circuit where rela- However, an accurate R.F. ammeter tively large condensers have been in- will serve the purpose if care is taken tentionally inserted. In other words, in making the readings. the inductance and capacity are defi- Another, somewhat simpler, method nitely localized or "lumped." of measuring the antenna resistance is At very high frequencies, however, by means of the so- called "half- deflec- when the dimensions of the circuit be- tion" method. This method is based come comparable to the wavelength, entirely on Ohm's law: the capacities between different parts E = IR of a circuit become important and the It will be apparent from the above current varies appreciably in different simple equation, that, if the voltage E parts of the circuit. This variation of MALLORY is kept constant, current I will vary current through inductances in differ- inversely as the resistance R. In other ent parts of the circuit causes their words, if E is kept constant, and R is inductive effect to vary similarly. At Vibrapacks doubled-then I will be halved. high frequencies, therefore, the equiv- (TRADE MARK REG. U. S. PAT. OFFICE) The apparatus is set up for this alent inductance and capacity of the measurement exactly as in the case of circuit will depend upon the frequency. are always dependable the resistance variation measurement. The separate condensers and induc- The driver, or transmitter, is tuned to tances must be considered with regard Every day is Field Day for resonance with the antenna and an ac- to their position in the circuit. In countless Mallory Vibrapacks. curate measurement of the antenna other words, one must deal with "dis- is made. The In 24- hour -a -day regular opera- current antenna circuit tributed" inductance and capacity. is then opened and enough resistance Such a circuit is shown in Figure 3. tion, these Vibrapacks provide is added to cause the antenna current The circuit represented is composed of unfailing service in police squad to fall to half its former value. When two long parallel lines supplied by an cars, in forest fire control sta- this condition is obtained, the value of alternator at one end and closed at the tions, in airplane communication the added resistance will be exactly far end. The inductance and capacity equal to the antenna, or unknown, re- of the circuit is represented by the equipment, in ship -to -shore sistance. Great care should be taken dashed lines. At low frequencies very telephone and in other similar to maintain a constant power input to little current will flow through the services from fixed stations and the antenna circuit, since any varia- circuit condensers and if ammeters in mobile equipment aboard tion in E will destroy the accuracy. were inserted at points A, B, C and D, automobiles, boats and airplanes. The stability of the power input can the reading of all of them would be be checked by quickly shorting out the essentially the same. As the frequency The selection of Mallory Vibra- added resistance and noting the an- is increased, however, more and more tenna current. If is packs for these applications is the current the current will flow through the condens- same as it was before the resistance ers. Consequently, we would find that logical because of their depend- was added, it can be assumed that the our ammeter readings would decrease ability, lower battery drain and power remained constant during the as we approached the far end of the economy. measurement. circuit. The current reading at point In performing the above measure- A would be highest, point B would be Amateurs want these same ad- ment, the resistance used should be of lower, point C still lower, and the cur- vantages for their Field Day and the non -inductive type. However, rent at point D would be lowest of all. QRR rigs -especially when gen- since no resistance is really perfectly As a result of this varying distribution non -inductive at radio frequencies, of the current in the circuit, it is evi- uine Mallory Vibrapacks cost no there will be a small change in circuit dent that the equivalent inductance, more than other forms of power values of L and C. It will therefore capacity and resistance also varies conversion equipment. Learn the be necessary to make whatever small with frequency. advantages of Mallory Vibra- change in tuning is necessary to regain The mathematical treatment of cur- packs and why they provide the condition of resonance. rents in circuits having distributed in- In both the above measurements of ductance and capacitance (such as an- "Perfect Portable Power" for antenna resistance, it is extremely im- tenna circuits) is generally concerned receivers, transmitters and P.A. portant to maintain the antenna cir- with the theoretical case wherein Systems. Ask your distributor cuit in exact resonance with the oscil- these quantities are uniformly dis- for the technical data booklet, lator or transmitter, otherwise the re- tributed. Because of end effects, this sults will be in error. If the antenna condition can not be strictly obtained form E- 555 -C, or write- is off resonance during any part of a in antenna circuits, except in circuits measurement, the antenna impedance of infinite length -such as two paral- P. R. MALLORY & CO., Inc. will not be equal to the R.F. resistance, lel wires, a single wire with concentric INDIANAPOLIS INDIANA but will be the vector sum of the ca- cylindrical return, or single (or a Cable Address -PELMALLO pacitive and inductive reactances plus number of parallel) wires with ground the resistance. There will also be return. It is evident, therefore, that se error due to phase distortion. At the distributed inductance and capac- resonance, however, the capacitive itance of an antenna system are and inductive reactances will be equal values which are not easily computed. ALLORY and opposite to each other and will However, these values can be meas- APPROVED balance out. The impedance will then ured for a particular antenna system. PRECISION PRODUCTS be equal to the resistance of the cir- When one value has been found, it is cuit. possible to compute the other very

www.americanradiohistory.com i June, 1940 RADIO NEWS 1,) simply. A method of measuring the based and the values of wavelength antenna inductance easily available to and inductance used in the experiment DEALERS the average amateur and experimen- should, for convenience, be substituted SERVICEMEN ter is outlined below. in equation (21). The derivation of This measurement is based on the the formula is given for the benefit of SOUND MEN familiar equation: those interested and need not enter RADIO BUILDERS Wavelength = 1.884 VLC (10) into the calculations for determining The only extra apparatus necessary antenna inductance. All values of L., ,i AMATEURS to perform the measurement is a few L. and L. are in microhenries. standard inductances of known value. It should be understood that in the A couple of 2.5 mh and 5 mh R.F. above measurement, the inductances chokes of reliable make would be suf- should be inserted directly in the radi- ficient. The arrangement of appara- ating portion of the antenna itself, and tus for a simple current fed system is not in the feeder lines if the antenna shown in Figure 4. One of the stand- is fed by some sort of transmission ard inductances, L., is connected in line. Adding inductance to the coup- with series the antenna system. The ling coil at the station end of a trans- SAVE transmitter is then tuned to resonance mission line will result only in lower- ON with the antenna system, and the ing the efficiency of coupling to the EVERYTHING wavelength is measured by means of transmitter output and will not affect IN RADIO the wavemeter. The wavelength can the antenna constants in any way then be substituted in equation (10) whatsoever. If the antenna is coupled which is modified as follows: to the transmitter by means of a tuned or untuned transmission line, A. = 1.884 V (L. + L.)C (11) where, the apparatus for this measurement L, = known inductance inserted in mi- should be set up as illustrated in crohenries, Figure 5 with the inductances inserted L. = unknown antenna inductance in directly in series with the radiating microhenries, portion of the antenna. In this case, it is C = antenna capacitance in micro - best to use two microfarads. inductances of equal value, inserting one in each leg of the antenna, thus The experiment is then repeated us- 1940 RADIO RATS! New "Camera" ing a different value of known induc- preventing serious mismatch to the and standard Portables-new Euro- transmission line. 60 pean reception model.. -new "t nw- tance, L. The wavelength measured Insertion of these pacts"-all types. all sizes. for every inductances in the antenna causes NEW purpose. New plastic phono- radios. this time, L, is again substituted in SETS nrw Reeorder- ltd dins. new auto ra- voltage and current displacements, dio --al! a !he v -c tn,vrst prices- equation (10) which gives us: m tli wets I'Itlil ti'ataln,. which, unless, properly counterbal- A:. = 1.884 V (L, + La) C (12) anced by having equal amounts of We now have a pair of simultaneous lumped inductance in each leg of the quadratic equations, (11) and (12) antenna, would cause enough shift of which can be solved for L.. as follows: the voltage nodes and peaks to seri- A, = 1.884 V (L. + L.) C (11) ously impair the impedance match to the transmission line. A, = 1.884 V (L, + L.)C (12) Once the inductance of the antenna 1, new Politic Address Sys:,aus to 75 watts -for Electioneering, Or- Squaring both sides of both equa- has been ascertained by this measure- chestras, Churches, Schools. Rentals, tions: NEW etc. America's finest P. A. at star- ment, it is a simple matter to compute tling low prices. Easy Time Payment the capacitance. The value of induc- SOUND Plan. Complete accessory listing, new SYSTEMS rerntding equipment. etc. -all in this = (1.884)-(L, + L.)C (13) tance found from equation (21) is urn' Faille- parked Iwluk. substituted in equation (10). In this A = (1.884)2(L., + La)C (14) case, the wavelength used should be Dividing (13) by (L. + L.) : the wavelength of the antenna system without any added inductance at all. In other words, the wavelength - (1.884)2C (15) of the L, + L. antenna system as it is normally used, should be the value Dividing (14) by (I, L.) : substituted in + You'll find Eiet I bina in Radio in equation (10). Equation (10) is rear- this new Catalog. Servicemen -see ranged follows: the new Test Equipment and full re- A. as 15,000 placement parts listings. Amateurs- get a big surprise and the "low- - (1.884) 2C (16) A RADIO down" on the new "clam" receivers. L. + L.. C (22) PARTS And don't miss the special Bargain Equating (15) and (16): Where: Section-There's nothing like it! C = antenna capacity in micro- micro- A. A farads, and (17) L = antenna inductance in microhen- L. + L. L.. + L. By cross products: ries. - nu,.rtt, ut Maud-new See the splendid new HOward exciting kits - new Aron tour Cuminunicatlanc Re- diagrams. Depend on ceivers tM n a 1 435" Illus- A.L. trated/. Get the exciting story +A -L.= A.L. +A.L. "Cheap at Half ALUM) for infor- of the Rearranging: mation a n d advice. bran,IewAteuR eier the Prime!" Send for Free Parts idea - there's never been any- like It before. (Continued from page 26) thing A .L. - A,L. = A.L. - Or: One piece bamboo, straight and 411/ED RADIO 833 W. Jackson Blvd., O. et. La (A' sturdy, 16'x% ". Chicago, Illinois , -A.) =AL.-AL, One piece 2x2 by 5', fir, knot -free. And: Send me your FREE New 172 page Spring Catalog One piece iron pipe, 1'x13/4" i.d. covering Everything in Radio! One piece iron pipe, 1'x1/4" i.d. A?L. A2L, One pipe reduction joint, to Name L. - (21) 13/4" 2 1 Address A. - A. Three 3" galvanized turnbuckles. Equation (21) is the ultimate for- Six Simpson solderless connectors, City State mula upon which the measurement is U- shaped (Cable clamps). - SEND COU1.ON NOWT

www.americanradiohistory.com 50 RADIO NEWS June, 1940

It's RCA All the Way receptacle, and selector switch. Marine Receiver 5. Mount the coil assembly in posi- in (Continued from page 7) tion temporarily. Install, on the front Profitable Service chassis drop, the bushing and nut for by Signal Tracing Receiver unit layout is quite the ex- the extended volume control shaft, pectable thing. The r.f. coil assembly then the receptacle and various con- is below chassis, the gang tuning controls and binding posts. Place the gang denser above -chassis and positioned condenser in proper place, then mark for short stator and rotor leads to the the front panel for a proper line -up for switch mounted coils. The r.f. 6S7G all shafts and for the dial. In doing is forward toward the panel, the 6J8G this, allow for clearance so that panel between it and the i.f. input trans- and chassis, when secured together, former. Positioned between the two will slide into the cabinet evenly and i.f. transformers is the second 6S7G, permit the panel to make a proper and at the rear of the chassis (top- cabinet fit. Using a circle- cutter, drill side) are the 6V6G and the optional out a hole for the dial. Make holes speaker matching component. The for the various shafts, remembering 6T7G second detector is below chassis. that they must be large enough so From the source of the No attempt will be made to point out that the threaded extentions of the the positioning of the various smaller receptacle, switch, controls, etc., will Signal with the components; suffice to say that these protrude. With this job done, assem- are located at or near the tube sockets ble together panel and chassis, check- with which they are associated in cir- ing for dial -hub to condenser shaft RCA SIGNALYST cuit position. alignment and making sure that all Construction threads come through. to the source of the 1. It is first and last necessary for 6. Disassemble panel and chassis, trouble with the the builder to construct, or have con- then remove the r.f. coil assembly and structed for him by some metal parts gang condenser. Install the sockets, manufacturer, two special items: the i.f. transformers, and (if one is not RCA RIDER cabinet, which should be approxi- built onto the speaker frame) output mately 9" wide, 10" high, and 13" deep, transformer. Secure the front drop CHANALYST with removable front panel; and a items temporarily in place. chassis to fit the 9x13" dimension and If you use the separate output or high enough (about 5 ") to accommo- speaker transformer (which may be date the specified all -wave coil assem- anything matching 7,000 ohms to voice bly. It is particularly important that coil but which under any and every the cabinet be of heavy stock, and it is circumstance should be well impreg- suggested that it feature no lift cover. nated and, in addition, shielded), the 2. The interior of the cabinet might 6T7G socket must go below chassis, well be coated with marine lacquer (if preferably placed in such position that unpainted) to prevent rust. A ripple the tube will extend along the 9" finish for the exterior will of course chassis dimension, grid cap toward the provide additional protection and at i.f. transformer side. Any method of the same time give the box profes- rigid mounting will be satisfactory. Your work is quickly done without sional appearance -slate grey or alu- (Shielded tube and socket assembled minum grey being the recommended together, for ins t an c e, might be disturbing any circuit constants! color. mounted by means of an Amphenol magic eye holder somewhat as we THE revolutionary time - saving, 3. The shield box for power supply money- have done making signal tracing method of ser- components may be anything suitable. the job). vicing radios begins with the source of the Like the receiver cabinet it should If you don't use a separate output signal. Here RCA gives you tomorrow's provide ample protection for all parts, component -and there certainly isn't signal generator today...the RCA Signalyst. be of rigid construction, and be of rea- any reason whatsoever for using one Universal in application -all frequencies sonably compact dimensions. A box where the speaker comes equipped in fundamentals RCA Signalyst sets about 5 "x9 "x6" of the general utility with the transformer and that trans- -the is a new high in dollar value for a signal type (such as the Par -Metal UC -596) former especially impregnated for generator. Its range is greater than any would be quite suitable and would pro- marine service -the 6V6G socket may test oscillator ... its accuracy and stability vide ample room for the Vibrapack, be placed conveniently in the spot oc- are tops. relay, fuse, and filter items. cupied in our own layout by the trans- With the RCA Signalyst providing a 4. Drill and stamp the receiver former and the 6T7G socket may logi- metered signal of known value ... you can chassis for installation of the major cally be moved upstairs. This would then follow that signal through the radio you components -r.f. coil assembly, i.f. simplify the business of both construc- are testing with the RCA Rider Chanalyst transformers, gang condenser, sockets, tion and wiring. without disturbing any circuit constants. and output transformer. Drill indi- 7. On the rear chassis wall, posi- And in short order, you'll find the source vidual holes for lead wires to each con- tioned so that the volume control of the trouble. Dollar for dollar, the RCA denser stator and rotor lower lug from (with on -off switch) shaft will line up Rider Chanalyst offers you more utility, the coil assembly. (The leads will accurately (when extended), with the greater flexibility and stability, and greater pass through chassis and the holes for bushing at chassis -front, mount the freedom from complicated circuits. them should be about %" in diameter Yaxley RB -249 bracket, 500,000 ohm and grommeted.) Make sure, by the audio potentiometer, and switch as- RCA Rider Chanalyst RCA Signalyst way, with the condenser sembly- extending the bracket away Net that in posi- $10750 FOB. 4ow $10750 tion, its shaft will extend forward just from the wall sufficiently far by means of metal washers to provide ample Camden, New Jersey O Camden, New Jersey enough to provide a proper fit to the 11 Z dial hub-remembering that the latter switch clearance. This locates the vol- will be mounted directly on the front ume control in the logical place for it panel, scale face fitting into the panel and makes unnecessary any long a.f. cutout for it, and that the panel will leads -providing, of course, that the support the chassis by means of the 6T7 assembly's socket has been itself RCA Manufacturing Company, Int., Camden, N. J. securing nuts for volume and gain con- positioned as indicated in the under - A Service of the Radio Corporation of America trols, binding post assemblies, cable chassis photo. (Continued on page 51)

www.americanradiohistory.com June, 1940 RADIO NEWS 51

8. Before again installing the r.f. former 6 volt secondary should be coil assembly and gang condenser, opened (one side of the filament line complete as much of the receiver wir- being grounded at the receiver). The ing as you possibly can. Mount small i.f. is aligned at 456 kc., exactly. The parts close to associated sockets, make coil assembly is aligned only if and leads short and direct, bring B minus when such alignment seems absolutely and A minus leads from the 5 -prong imperative; proper adjustments have receptacle down the depth of the chas- been made at the factory, and in any sis to a common ground point at case don't attempt trimmer re- settings chassis -rear, and shield the other leads unless a good service oscillator is from this receptacle -i.e. the B plus, available. A hot, and relay circuit line. The cir- 11. If all's well with the receiver, cuit is quite straightforward and will the next step is to build the power be familiar to even the less experienced supply and interconnecting cable sys- builder. We need not go into details tem. No particular layout for the regarding the rest of the wiring; and power components is imperative - shall conclude construction data on though input and output leads should the receiver with simply a few re- be reasonably well separated and the marks regarding the r.f. coil assembly various parts mounted for fairly short and the gang condenser. But as the point -to -point connections. Use two layout is so unusually compact, it receptacles at the power supply can - might well be pointed out that unusual one for battery input and one for B care must be exercised toward the end minus, B plus, and relay circuit con- that all connections be proper in the nections between power and receiver very first place (check them carefully assemblies. As for the cabling itself, against the circuit diagram as you go bear in mind these suggstions : along), that these connections be se- A. Use individual leads. Don't de- curely soldered, and that the various pend upon shield braiding for B minus components be positioned securely. It and A ground, particularly for A will not be the easiest business in the ground. Consider each return a part world to correct errors in the wiring of a separate circuit, calling for a sep- once it has been completed. arate wire. The one exception may be 9. Install the gang condenser, using the return for the relay circuit. The is no speaker of a higher rather long mounting screws and leave B. The A HOT leads from power quality than JENSEN -yet there this quite loose at first so that leads supply to battery and battery to re- no price premium to pay for that from the r.f. coils may be brought up ceiver should run separately from the finality! A JENSEN speaker is available for short to the lower lugs (both stator A HOT terminal, should be of heavy as little as $2.30 less the usual trade and rotor) and soldered. Get the coil duty wire (No. 12 or better), and discount. for and rotors, by the should be as short as convenient ca- The use of bucking coils to reduce leads stators hunt . larger :wire to give more way (these leads are of braided copper, bling will permit. It is advisable to sensitivity . dnstproofing to insure trou ble-free operation . uninsulated, and are related to each keep both A HOT and A GROUND ore JENSEN'S contribution to r.f. assembly stage section) up through leads from battery to power supply your reputation as a technician. the grommeted holes in the chassis abbreviated in length, as voltage drop And then there is a dominant quality, typical of every JENSEN prod- before securing the coil layout in posi- in these leads may affect Vibrapacic uct, inherent by habit and in- tion. Otherwise it will be difficult to output adversely. It is advisable, slinct of those who have been de- sig g and building JENSEN get these leads through for condenser though not particularly imperative, products for ten years or more. connection, due to the very little work- that these leads be shielded: A HOT JENSEN speakers cost more to from to power A HOT ke -but they cost you no nuore ing space. battery unit; because they give satisfaction! Now get the coil assembly in place, from battery to receiver; B PLUS make the condenser connections for from power unit to receiver : A HOT each section, tighten up the condenser relay line from receiver to power unit. (checking for precise dial alignment Installation between shaft and hub), and complete the r.f. wiring. With the securing nuts In marine application, the receiver for the various controls removed, the may be installed in any convenient frame extension of the dial cut away spot aboard ship but should be used to permit this unit to clear the chassis, with as long and as high an antenna and with the dial mounted on the front as may be erected. Where space is panel, we can now complete the assem- limited, the vertical aerial is generally bly. the best bet. The writer has found It is only necessary to secure panel that, for the average private boat, and chassis together, by means of the nothing could be more practical than cable receptacle, the binding post simply a standard Premax or similar transmitting beam element, pulled out units, and the securing nuts for band - switch, potentiometer, volume control to its maximum length of about 17', bushing, and balancer condenser, to self -supported by some sort of suitable connect antenna and ground leads deck insulator, and carefully coated to binding with weather- resistant paint. A sin- from the coil assembly one gle isn't very post unit, and to connect shielded out- beam element expensive, trans- is rigid enough when extended to full put leads from the speaker length (requiring very little or no former (or 6V6G plate circuit) to the guying), may be dropped down to six speaker binding post unit. foot length when that's necessary, and, 10. Alignment might well be effected last but not least, will be right there with the receiver powered by any ready for use as a radiator when you available a.c. pack supplying 250 and decide one of these days to install that 6.3 volts. The pack, of course, should radio telephone. have at least an 80 ma. high voltage In ordinary mobile application, the capacity and the center -tap connection receiver may be installed under the to chassis -ground for the power trans- dash, firmly supported at the firewall.

www.americanradiohistory.com 52 RADIO NEWS June, 1940

Set layout and size have been delib- type filter capacitors in the C19 and erately worked out to facilitate posi- C20 power supply positions. This move tioning in this manner in the car -the is particularly advisable where ex- proportions (long depth and relatively tended service at sea is expected of short width) being such as to take up the receiver. Electrolytics are per- as little under -dash space as possible fectly all right for general application (laterally) and, at the same time, to -marine or otherwise -but the paper bring dial and controls well forward types will as a rule stand up much for convenient handling. longer in humid, salt atmospheres. (It's advisable to remember, inci- 30 dentally, that your city or state may have some very definite ordinance or law limiting auto -radio frequency cov- Manufacturers' Literature erage. If you contemplate installing (Continued from page 42) the set in your car, whether temporarily or permanently, look into the ing much interest. Completeness is DESIGNED for matter carefully by consulting your combined with many new features. local police dept. Each radio field is arranged in indi- APPLICATION Proper Vibrapack output is ob- vidual sections for speedy reference. MODERN SOCKETS for MODERN tained through adjustment of the All sections and all items are clearly TUBES! Long flashover path to chassis switch at the side of the pack. (Ad- defined and carefully indexed. The 32- permits use with transmitting tubes, 866 justments should be made with the page Radio Set Section introduces rectifiers, etc. Ideal for mounting on power turned off and the setting sixty new Knight rugged thick cast aluminum chassis now models, including a should be such that the measured B wide choice of portables, farm radios, being used on much of the better com- plus mercial equipment. Long leakage path at the 6V6 screen is approxi- consoles, table models, phono radios, between contacts. Contacts are type mately 250 volts.) As for hash inter- automatic record changers, "Camera" proven by hundreds of millions already in ference, should it appear in spite of type portables, with new miniature government, commercial and broadcast the fact that power supply and re- tubes, Recorder-Radio combinations, serv';ce, to be extremely dependable. ceiver are physically separate units, and a large selection of phono and re- Sockets may be mounted either with or this may usually be eliminated cording accessories. The 36 -page Pub- without metal flange. Mount in standard through trial and error by- passing of lic Address section includes 18 new size chassis hole. All types have barrier A HOT and B PLUS leads. Some- complete between contacts and chassis. All but systems, ranging from 7 to 75 times mica condensers from these watts, for Electioneering, Orchestras, octal also have barriers between indi- leads to ground the in at points of en- Churches, Schools, Rentals, etc. Pre- vidual contacts addition. trance to the receiver will eliminate Catalogue Upon Request sented are many new units such as: hash where paper types (C17 -C18) do "The Speechmaster," a one -unit sys- no good. Remember, by the way, that tem ideal for speakers; Rental -Type JAMES MILLEN MFG. CO. INC. hash noise is an r.f. effect set up by P. A. Systems for Servicemen; low -cost 150 EXCHANGE ST. MALDEN, MASS. the Vibrapack -noise which no systems for orchestras and musicians; amount of a.f. filtering beyond that Chime Systems for Churches; and a necessary to the smoothing out of Vi- complete line of P. A. accessories. For brapack high voltage output will at- builders and experimenters there is an tenuate. unusually complete section featuring Incidentally, some cases will be the latest kits, accessories, projects, found where no hash noise at all is diagrams, and Allied's new Radio evidenced with antenna and lead -1n Builder's Handbook. The Amateur disconnected, such noise immediately Section features the latest receivers of appears on one, some, or all bands as the country's leading manufacturers the case may be with the aerial tied and the complete story of Allied's new in. The no -noise condition with no separate Exclusively Amateur Cata- antenna indicates that power leads log. Of special interest to the service- into the receiver are adequately man is the big general section cover- shielded and by- passed. Appearance ing 15,000 parts for every radio need. of the noise with antenna connected, There are sections devoted to photo- on the other hand, indicates that the cell equipment; to bargains in brand EI ft&ty,/ iGN noise is picked up by the antenna or new merchandise; and to the latest USE H its lead -in or both. Remedies are to books, manuals and literature cover- -120-X shield the lead -in thoroughly, remove ing every radio field. A copy voltage regulation maintains con- as as possible from of this AUTOMATICstant oscillator plate voltage despite wide the antenna far 172 -page Spring Catalog is available changes in line voltages and a special compensat- the power pack, check the power sup- by writing to Allied Radio Corpora- ing device automatically corrects frequency drift its overall self -shielding, and, during temperature changes. These two outstand- ply for tion, 833 West Jackson Blvd., Chicago, make "HQ-120-X" been made in a ing features the exceptionally if the installation has Illinois. Free. (RADIO stable in operation and results in unusual tuning car, bond all shields to car -ground NEWS No. accuracy. And, these are not the only reasons for 6 -106.) USE COUPON BELOW. its top -notch performance.. .. Ask your jobber or carefully and effect a good short con- write for details. nection between the power supply can WRITE FOR "HQ"¡ BOOKLET! and ground. RADIO NEWS, Catalog Dept. 608 S. Dearborn Street, Chicago, Ill. HAMMARLUND MFG. CO., Inc. RN -6 The power supply unit should in any 424 W. 33 St., N. Y. City and every installation be located close Please send me the literature I have checked to the 6 volt storage battery to elimi- below. If there is any charge I have en- 16 "HQ" booklet closed the money. Please send -page nate long leads. Just as leads of in- ....6 -loo ....6 -102 ....6 -104 ....6 -106 Name sufficient cross sectional area will effect voltage drop and prevent the real- ....6 -101 ....6 -103 ....6 -105 ....6 -107 Address ization of full Vibrapacks output, so I am the following: (please check) will long leads bring about this unde- S'v'cem'n Ham Exp'm'nt'r City State sirable condition. Name One last word -which we perhaps P. 0. Address HAmmARLU1ID should have brought into this writing while discussing matters of construc- City State Canadian Office: 41 West Av. No., Hamilton, Ont. This offer expires July 1, 1940. Export Dept.: 100 Varick St., N. Y. City tion. If you can afford it -use paper

www.americanradiohistory.com June, 1940 RADIO NEWS 53 lutely certain that the batteries are Music While You Cycle connected correctly before inserting tubes in sockets. Do not mishandle or SYLVANIA HELPS (Continued from page 29) drop the tubes. Remember that they are delicate and if the "B" battery is To Help You Sell tuning condenser is mounted on a shorted to the filament circuit, even for a second, the tubes will be burned bracket at the right front of the chas- DEALER N A l`"`'j E. sis. The regeneration control is out and worthless. mounted directly beneath the con- The "Ranger" is tuned by means COMPLETE The five of the variable tuning condenser (sta- denser, but below the chassis. r ; RADIO inch magnetic speaker fits into a recess tion selector). It is adjusted by the SERVICE at the front of the chassis and is regeneration control potentiometer QYFAecwnmand fastened to the front chassis wall. The and the antenna trimmer. The antenna 1NSA 1/1;:,, RADIO TUBES coil socket and the two tube sockets trimmer is used to make the set more are mounted on the rear (lower) step, selective. This is accomplished by Display This Electric Edgebrite with the coil socket directly behind the loosening the adjustable set screw Clock Sign. Made of sturdy, satin- variable tuning condenser and the provided. It is also used to help tune finish metal, illuminated with two lamp power output tube at the extreme left. in weak and distant short wave sta- bulbs. Separate switch controls lights After the chassis is assembled, the tions. The regeneration control is so clock operates at all times. Movement is self- starting. Convenient size, 131/2" the as follows : place one of the wiring is performed according to operated high, 20" wide ... complete with YOUR diagram. It is desirable to wire in the short wave coils in the coil socket. NAME on illuminated glass panel....$6 filament circuit first. Next wire the Turn the station selector until a Without name but with plain glass grid circuits, then the plates, etc. For whistle is heard. Each whistle indi- panel $5 best results and most rapid work, the cates a different station. It may be use of solid push -back wire is recom- necessary to adjust the antenna trim- mended. All joints should be carefully mer to get the whistles. As the sta- soldered with rosin core solder. tion whistle is tuned in, turn the re- The completed set should be tested generation control until the set "spills before installing it in the carrying over," or a distinct hissing sound is case. It should then be secured per- heard. The station selector is then manently within the case, at which turned until a continual whistle is time connections to the earphone jacks heard and should be left at the point COMPLETE should be made. The case may then where the squeal is loudest. The RADIO SERVICE be mounted to the handle bars of the whistle can now be cleared and the bicycle by means of a leather or metal station brought in by turning the re- strap. The batteries, spare coils and generation control knob slowly back. fluYOUTHOaIEn PIAPI M ou rs NINN earphones are contained in a separate A slight further adjustment of the case 11" long by 51/2" wide, by 23/4" station selector knob may be necessary. R NAME HERE high. This is fastened to the frame of A telescoping vertical antenna of the the bicycle and connected to the re- automobile "whip" type is recom- Put Up This Striking Flange Sign. ceiver by means of a 6 wire cable. Of mended for an aerial. This may be Sign is weatherproof baked enamel on course, the battery box dimensions attached quite readily to the handle heavyweight sheet metal. Size, with de- of bicycle. The "Ranger" is tachable name plate, 161/4" x 16 ". With- may be varied to suit the type and bars the out name plate, 161/4" x 113/4". Flange number of batteries employed. sensitive enough to bring in the local Sign complete with YOUR NAME on The "Ranger" requires two 11/2 volt stations with the whip type antenna. name plate in baked enamel $1.00 "A" batteries, two 45 -volt "B" batteries Of course, even better results can be Sign, without name plate 25c and a tapped 221/2 volt "C" battery. obtained when the bicycle is stopped, All of these batteries are available in by connecting the ground terminal to very compact models, designed es- a convenient wire fence, a pipe or simi- COMPLETE metal object. pecially for portable work. Increased lar grounded RADIO SERVICE volume can be obtained by using three It may be of interest to the builder 3ì snma rusFs¿s: 45 volt "B" batteries instead of two. of the "Ranger" Bicycle Receiver to SYIVANIA In this case, the "C" bias of the 33 know that it is possible to obtain a 131/2 which develops 21/2 tube must be increased to minus bicycle generator YOUR NAME HERE volts. volts and produces more than enough A few hints on testing the "Ranger" current to operate the lights of the New Electric Sign Can Increase the fila- may be useful and may serve to pre- bicycle, and also to energize Your Business. Strong metal frame vent the burning out of the tubes in ments of the tubes in the "Ranger" electric sign trimmed in chrome plate making the initial battery connections. Receiver. The use of this generator with glass panel. Flat base for standing If flashlight cells are used for the "A" thus permits elimination of the "A" and adjustable chain for hanging. Size supply, solder small clips to the posi- batteries. 221/2" x 83/4" x 33/4 ". Complete with im- tive terminals at the centers and to the The "Ranger" will furnish its owner printed name plate $2.25 negative metal casings. The clips pro- with pleasant diversion while on a trip Without name plate 1.25 vide an easy means for connecting one and will be a constant source of pride r battery to the other and also for con- to him. One point, which has not been USE THIS VALUABLE COUPON necting the "A" minus and "A" plus sufficiently emphasized, is the fact that Hygrade Sylvania Corporation leads. Having connected the "A" bat- this set can be built for very little Emporium, Pa. teries, put the tubes in the proper money, since it uses only a compara- Enclosed is Please ship the following: Electric Edgebrite Sign sockets and note whether they light up. tively few tubes and other compo- Metal flange sign, without nameplate Now recheck all the wiring and make nents. Metal flange sign, with imprinted nameplate hanger sure all connections are correct. After the "Ranger" has been com- Electric Sign Take out the tubes and connect the pleted and in operation for a while, Imprinted nameplate, separate -Can be used either with flange sign or new "A" batteries. Proceeding with the the builder will be able to add various electric sign. test, connect all batteries, plug in a improvements. For example, it is pos- Name broadcast coil in the coil socket, con- sible to employ a remote control device Address nect antenna, the ground and a single which will permit the entire outfit to State or double earphone, or speaker. When be fastened in back of the saddle and City should be Imprint testing, the earphones used still be controlled and tuned from the (Please print) rather than the speaker. Be abso- handle bars. 30

www.americanradiohistory.com 54 RADIO NEWS June, 1940

is tried, provided the instructions have NEW! 1 -10 Meter Receiver been followed and the set hooked up (Continued from correctly. Being now hooked up the page 25) set is ready for alignment procedure and operation. 3x4x5 shield can, which is used for The first part of the set to get work- housing the r.f. stage. No panel is ing is the detector and, of course, the used as the dial and condenser assem- audio. Operating the audio stage is bly is mounted directly on the shield common procedure, and so I will not can. Tuning condenser assembly C5, give it here. The detector, however, C2 is ganged, as the selectivity of the may require some adjustment. The r.f. stage does not warrant separate values given for the parts in the de- controls. Condenser Cl is mounted di- tector are empirical, but were designed rectly on the shield can with the rotor for use with this detector. They shaft grounded, while C, is mounted on should be changed only under extraor- stand -off insulators, as the rotor must dinary circumstances. In lining up not be grounded. the detector the antenna may be con- While the r.f. stage provides a rela- nected and signals received, although, MILLION tively large amount of gain, it is not of course, an oscillator is easier to use. NEW DF TUBE CHECKER difficult, nor tricky, to build. There is The regeneration control is set to a TESTS THE NEW 7 PIN only one thing to make sure of, this minimum hiss level and a signal is MINIATURE BATTERY TUBES, being the complete shielding of the tuned in. If no signals are received, BALLAST TUBES AND OZ4 GAS RECTIFIERS. plate from the grid. The leads should the receiver may not be hitting the New, with wider application range. Tests emis- be short, and the by -pass condensers band for which the coils was designed. sion of all tubes. Twelve sockets cover all types connected close to the tube contacts. In this case the inductance of the coil from the new Raytheon "hearing aid" tubes and RCA 7 -Pin battery types to new loktals and S The gain control Rl in the cathode cir- can be changed by changing the num- series. Filament switch covers 1.4 to 110 volts cuit is useful on local stations. The ber of turns or the spacing. Different with spare positions for the future. Gives instant "good -bad" readings on oversize D'Arsonval r.f. and detector coils are both mounted arrangements of parts often produce meter. Makes neon short or leak test with tube on small banana plugs which plug into different stray capacities in the set, hot. Tests by -pass condensers, etc. Literature on request. a pair of banana -plug jack type cone and these are important where the MODERN insulators. This provides a quick and tube has a low capacity. ACCURATE 95 simple means of changing from one After the detector is operating, the DEPENDABLE band to another. antenna may be connected to the r.f. ECONOMICAL NET The detector consists of a grid block- stage, and the r.f. stage to the detec- IF YOUR JOBBER CANNOT SUPPLY, WRITE tor. The gain on the r.f. is US DIRECT- GIVING THE NAME OF YOUR ing oscillator using an HY615, which opened JOBBER. works very efficiently. The r.f. stage wide, and the regeneration control on is coupled to the detector advanced to a fairly loud MILLION RADIO AND TELEVISION the detector through C 100 hiss level. Condenser C3 is then cou- 577 No. Union St. Chicago, III. a mmf. variable air trimmer condenser. The tuning assembly of the pled until the detector just goes into detector is similar to that of the r.f. super regeneration. After the receiver TURNER stage except that L, must be a little is working on one frequency, there larger than L owing to the low inter - should be no trouble in getting it to Han -D electrode capacities of the HY615. The operate on the other frequencies. MICROPHONE grid leak and condenser, R,;, C5, are Preferably, the receiver should be critical, and the given values were lined up first on 28 mc. and then on Crystal or found to be the best. If a high pitched each higher frequency band in succes- Dynamic squeal is heard, the value of the grid sion. Now, when the set is all lined Hold It! leak or grid condenser should be low- up, there should be no trouble at all Hang It! ered. About all else that may be said in getting it into regular operation. It will be found that it works excellently Use it on desk or floor about the construction of the detector stand. is that the HY615 has a base shield for this type of receiver. that must be grounded. Coil Data FILLS THE JOB OF SEVERAL MIKES 411 coils wound with No. 12 tinned mire, 5/8" Although it was designed for ear- inside diameter. Whether you want voice, music it for -pick -up or phone reception, the 6F6 audio stage R. F. Detector auto use, the Turner Han -D will fill the bill. 23mc Positive contact slide switch on both crystals and will give enough volume to operate a 14 turns 17 turns dynamics permits off-on 56mc. 6 turns 9 turns switch to be operated magnetic speaker on most signals. 112mc. 3 turns 4 turns 224mc. 1 turn 2 turns without thumb fatigue. Output coupler, L, and C,1 is necessary Voice reproduction is crisp and clear within order to get full value from the out unnecessary sac- rifice of bass re- audio amplifier. In the screen grid sponse. yet feedback Rich circuit there is a filtering arrange- Increasing Loop problems are held to brushed ment, which reduces large of Sensitivity a surmising mini- chrome a amount mum. Will not blast finish hum. This filter consists of a 10,000 (Continued from page 37) from close speaking. Allows one mike to matches ohm resistor, R and a .5 mfd. paper do the work which modern required two or desk condenser, C15. The volume of the set did not know its exact location. The more before. Each and is varied by audio gain control R3. Po- radio loop gave a bearing of 10 °. Re- unit individually floor tested for level and stands. tentiometer R_ is to control the regen- ferring to the graph we find that at 10° frequency in sound of the detector. the correction average is plus 3 °. pressure room be- eration fore shipping. With In wiring up the set there are a few Therefore the true bearing of that sta- 8 ft. removable cation is 13 °. Another : The radio loop ble set and chamois - things to remember. In the portions ette mike pouch. of the set carrying r.f., the condensers gave a reading of 100 °. Checking we 9D hi- impedance Dy- and the tube sockets, etc., should see that 100° the radio loop was in namic, $25 List. all be made of low loss insulation error minus 3 °. The correct 9X Crystal, $22.50 Write to- such as bearing °. List. day f o r isolantite or victron; the fixed con- of this station is 97 The TURNER Complete densers should all be mica. It is im- We may now take bearings on ships CO. Informa- portant that all leads be as short and at sea or other radio stations and even tion and as possible, 908 17th St. N. E. prices on direct not straying around locate interference accurately. It may Cedar Rapids; Iowa these Han - through the set. After the set is all also be used as we do here, for the Cry patentss of D Models. hooked up there should be no trouble tuning out of interfering stations on The Brush Develop- ment Co. in getting it to work the first time it the same frequency. 30

www.americanradiohistory.com June, 1940 RADIO NEWS 55

find themselves teaching radio to the men otherwise, reverse the primary leads. in the Government armed forces.. The method of using the instrument Within Earshot Since communications have risen to a (Continued from page 4) is quite simple. When listening in on position of major national prominence, the the r.f. stages the switch on the tuning field of maintenance of the radio end of the tremendous communications network condenser is closed, rendering the would fall upon the able shoulders of the oscillator inoperative. The set under they report that it far surpasses anything serviceman. observation is tuned to the strongest that AM can give. Ho, hum . . . gotta Research, always given additional im- local available and the test set tuned think up something new again to scoop the dailies! petus by a war, will be conducted to a to the same station. Either one wire * * * limited degree by servicemen under the to the voice coil of the set under ob- guidance of Army engineers. servation should be unsoldered or a 5a rule we take very little if any Not alone in the radio field will the jumper should be put across the voice A exception to what the radio column- servicemen find business, but in all the ists write for the newspapers. We feel electrical fields as well. He will branch coil. Then with the r.f. -i.f. test prod that they, too, serve a public, and that that out as electrician, motorman, lineman, re- the quality of the signal can be as- public has its right to demand and know. pairman, and manufacturer. certained throughout the r.f. stages. what is going on in the broadcasting field. No, servicemen, you will need have no If nothing suspicious is disclosed there, But once in a great while these same qualms about what will happen to you in a the test set should be tuned to some gentlemen of the press stick their necks war. Of all trades, yours will be one which place on the low- frequency end of the 'way out to here, on a subject of which they will boom. -KAK. 30 dial where no station whatever can be know very little and generally nothing. Then we ought to, and do lop those collec- heard normally, the oscillator switch tive necks off as short as we can. 1 -Tube Signal Tracer should be opened, and the oscillator A few weeks ago in a big Chicago daily dial set higher than the dial of the test the radio broadcast columnist advised his (Continued from page 9) set by an amount equal to the i.f. of readers that the hams were an anathema to the set in question. The test set will the industry, and advised all broadcasters The leads to the primary will have then receive the i.f. of this set and, who were discommoded by these same to be reversed if the polarity is not still using the r.f. -i.f. probe, the qual- hams to report the matter to the FCC. will ity of the signal can be to Hams, in his opinion, were of low degree, correct, for then the tube not judged up and not worth the powder to blow them oscillate. Satisfactory evidence of the grid of the second detector. to bits. You are very, very wrong, Mr. oscillation will be had by removing the Passing to the audio frequency part Columnist. You would not now be able grid cap from the 6A7 and, with the of the receiver, the audio probe is used to write your column without the same dial of the test set turned to about 60 and the oscillator dial is set to the hams of whom you write so disparagingly. and the volume control turned down same reading as the dial of the test It was they who developed and pioneered low, slowly turning the tuning con- set and the volume of the latter turned your field of endeavor, and it was they denser on the converter. At about the down pretty low. The audio frequen- who are mostly responsible for those same setting of the converter dial a cies will then modulate "scoops," concerning which you write so the oscillator glibly, which you receive on that Scott loud hum should be heard when the carrier wave and can be heard through short wave receiver you own. The hams, finger tip is touched to the control the test set just as if they were being my friend, are the same persons who fur- grid of the 6A7. If no such hum is transmitted to it. nished your paper with reams and reams o f heard and the connections are all right 30 copy during the Ohio Flood; and who are ern now furnishing your paper with most of the news of the Byrd! Antarctic Expedi- tion ; who built up most of NBC, CBS and MBS. You, of all people, should be The larger "duplicate" grateful to the hams. You bring replacement (below) costs should $1.20. Three ATOMS combined about a better understanding between the with ST Strap (left) give the hams and their neighbors, the broadcast same hard -to -get capacities in listeners. You should realize that hauts smaller size for only 96c! were using Frequency Modulation 'way back in 1925, and that their mobile rigs, the forerunners of the Police Radios of today, were operating in 1923. So my fair, fancy friend, consider yourself verbally spanked. Go and be a good boy; before sometime you may find that the hams will no longer he your friends, and you will BETTER CONDENSER lack for material for that precious column of yours. REPLACEMENTS * * * AROUND a table in a dim serviceman's Either Way back shop sat a bunch of the boys. The discussion veered around to what It pays to try Sprague for any exact duplicate condenser would happen to the business should war requirement. As leading suppliers to the largest set makers, we can supply almost any needed unit promptly -and iden- finally come to these United States. While New Manual on it would be futile to record all the opinions tical to the original specifications. which had their airing that evening, the But don't forget, you can save on most hard-to-get re- Radio Interference consensus was that the war might come, placements, simply by combining several Sprague Atom Just the book you've been and Wren might go to it, but the serviceman midget drys. Just strap 'em together (see picture) with looking for. Complete -fully would continue to do business anyway. Sprague ST Mounting Straps- supplied free -and you have illustrated -tells what to do, It was pointed out that air raid precau- a smaller, better unit and actually at less cost than an exact how to do it tions, envisioning the necessity for thou- duplicate! Using ST Straps, you can make up almost any to eliminate sands and thousands of loud speaker sys- combination of capacities and voltages using standard all types of tems and their associated ills would need Sprague Atoms stocked by every Sprague jobber. Big man - made the serviceman to install and maintain catalog of Sprague Condensers radio noise. then. and Koolohm Resistors FREE. 25c net. Not everyone goes to war, and therefore there would be just as many, if not more sales in broadcast and short wave receivers. The interest in radio would increase, and CONDENSERS with it an increase of business. The "farming out" of government KOOLONM RESISTORS schools, already put in effect by the Civil Aeronautics _duthority in the matter of SPRAGU E TEST EQUIPMENT training pilots, would probably be followed. SPRAGUE Thousands of competent servicemen would PRODUCTS CO. NORTH ADAMS, MASS.

www.americanradiohistory.com 56 RADIO NEWS June, 1940 ,,ivotS The transceiver can be checked on AU% 112 MC "transmit" by means of a small neon Transceiver bulb held near or on the coil, or by the (Continued from page 15) /7,77 use of a flashlight bulb (6.3) connected to a two turn coil. The bulb will in- 1941 Model 1696 -A The tuning condenser which has crease in brilliancy with modulation. If the reader wishes he may install MODULATION MONITOR isolantite insulation is mounted on a piece of high frequency type insulation a regeneration control to reduce the and is held off the chassis by two plate voltage to the detector when bakelite rods. The condenser is re- used on receive. This will reduce the moved from the front of the panel to hiss, increase the sensitivity, and cut allow tuning by an insulated shaft to down the radiation. It can be con- eliminate undesirable body capacity nected as shown in Fig. 3. 30 effects. The coil consists of 4 turns of number 14 enameled wire, l4" in diameter For Immediate Release and spaced approximately 14 " between (Continued from page 13) turns. The coil is mounted directly on the condenser. Since your layout a "sponsor" who paid for "time on the air." You've solved your problem of getting maxi- will probably be slightly different, it We thought that such operation was in viola- mum efficiency from your transmitter when may be necessary to prune the coil to tion of the FCC Rules & Regulations which you invest in a Model 1696 -A Modulation hit the band. do not permit unlicensed stations (and WHD Monitor. Plug it into your AC line -make The condenser, which is of the is admittedly unlicensed) to operate and grid specially to have paying "sponsors." simple coupling to the transmitter output and small mica type, is connected from The an- the monitor shows: swer of the Commission is repeated below. on socket to the is Level of Mod- the grid prong the Whether or not it the answer to our in- Carrier Reference Percent quiry, we leave to the reader's interpretation. ulation Instantaneous Neon Flasher (no in- rotor of the variable condenser. be Gentlemen : ertia) indicates when per cent of modulation The r.f. chokes should preferably This is with reference to your has exceeded your predetermined setting. of the u.h.f. type but if care is taken letter of March 4, 1940, concerning Setting can be from 40 to 120 per cent. to keep leads short and too much ca- an article in Time magazine refer- Helps comply with FCC regulations. Has two pacity is not induced in the circuit ring to a low power radio frequency REDDOT Lifetime Guaranteed Triplett in- device used for broadcasting pro- from metal chassis, etc., the regular grams throughout the Russell Sage struments. Modernistic metal case. Model chokes will work fairly well. Dormitory at Dartmouth. 1696 -A- Amateur Net Price $34.84 side of the filament and the The Commission has established Also available as a rack panel mounting One of should be regulations concerning the operation unit. cathode the detector of low power radio frequency devices For More Information-Write Section 156, grounded directly to one of the screws which rely largely on the induction Harmon Drive that goes through the angle bracket field for the operation of remote con- which holds the tube socket off the trol radio receivers, to eliminate wire TRIPLETT ELECTRICAL INSTRUMENT CO. connections between record players chassis. and receivers for wired radio com- Bluffton, Ohio A plug is provided at the rear of the munication systems and for other cabinet for making connection to the similar purposes. A copy of the a.c. or motor - regulations is enclosed herewith. power supply, either The regulations permit operation ADJUSTABLE LINK generator. The plug is so wired that without a license so long as the field the switch on the volume control turns of the device does not exceed 15 on whatever supply you may be using. microvolts per meter at a predeter- 50 WATT OSC. COILS mined distance fixed by the operating The power supply should deliver frequency, and no interference is about 250 volts under load. It can be caused to the reception of signals of ?Oh an old B eliminator and a 6 -volt trans- radio stations. supply may be built Very truly yours, former or a small (Sgd.) T. J. Slowie. ACCURATE for the transceiver and placed inside Secretary. the metal cabinet. COUPLING When installing the unit in the car, AMULTI -CHANNEL radio telephone for be sure to use at least number 12 wire aircraft, which provides for dial- switch ADJUSTMENT selection of any one of ten pre -tuned fre- for the "hot" A lead to the vibrator quencies, has been announced by the Western or motor -generator or you will Electric Company. The new apparatus was EACH supply ON be disappointed at the performance of designed primarily for use by airlines and receive. private planes. To meet the need arising out BAND the rig, both on transmit and of the long -range operation of modern air- With too small an A lead the output liners, the new transmitter develops more from the power source drops quite a than twice the power of conventional equip- output from ment. bit and as a result the The equipment is extremely simple to the oscillator does the same. operate. Both the transmitter and receiver Excitation or output on each band The antenna used in the tests was are simultaneously controlled from a small can be easily and accurately con- a 4 -foot aluminum rod mounted di- switching panel located on the plane's instrument panel. The control is accomplished trolled by moving the link in or out rectly on the standoff insulator on the electrically requiring no mechanical cable or of the coil to achieve the desired front panel. It is coupled to the os- rotating shafts. One dial on this unit gives degree of coupling. cillator tank through a two turn coil the pilot a choice of any one of ten pre - 4 coil. To adjust tuned frequencies. A second dial converts Amateur coupled to the turn the equipment for telephone, telegraph, modu- Cat. No. Capacity Net the coupling, turn the send -rcve lated telegraph, or facsimile operation. An OLS- 10 21 mmfd. $ .90 switch to receive position and couple "on" "off" switch, and a toggle switch for OLS- 20 33 mmfd. .90 the antenna coil to the tank until "send" "receive" when employing telegraph, OLS- 40 50 mmfd. .90 hiss dis- complete the controls. Although the trans- OLS- 80 75 mmfd. .90 the receiver is blocked, or the mitter and receiver are designed to be used OIS-160 95 mmfd. .90 appears. Then pull the coil out slight- as a two -way system, either may be employed so a - latest ly until the hiss is again heard. It alone. When used, separate electrically Ask for your copy of the operated remote control panel may be sup- at your jobber's. be found that this is the point of BUD Catalog will plied for each unit or local control can be greatest sensitivity. For fixed station employed. use, a half wave doublet placed as Other features of the transmitter include high as possible is recommended. It provision of special condenser combinations to practically any type of antenna should be fed with an open wire feed - match or transmission line ; forced draft pressure type line. The feedline is made of number ventilation through a spun glass filter ; and 16 wire, spaced 2" insulated. self- contained MCW oscillator. 30

www.americanradiohistory.com June, 1940 RADIO NEWS 57

to know the meaning of frequency modulation. Bench Notes Would you: (Continued from page 19) (1) Tell her it was too technical for explanation, and describe it by waving your hands? There was a moment of strained si- (2) Explain it was an unusual form of lence. Then Cliff stepped out of char- the art which would be adopted when /if it acter and laughed. was proved its advantages outweighed its cost ? "Ya got me, pal!" he admitted. "The (3) Tell her not to worry until it be- felon is frustrated!" came much commoner than it now is? What did Pete do to prevent the (4) Drive her home in your car so you robbery? could see the set and give an estimate for Preview rewiring it? Or would you Judging from the answers arriving (5) Lend her a text -book and an um- in response to Repairman's Riddle No. brella? 5, many servicemen forgot their prac- First, decide what you would do ; then tical experience as soon as they picked turn to page 60 for the correct answer. up their slide rules. The "Test -it" 3( problem was presented in narrative form, and laid in a radio store -as were previous ones -to bring out the What's New in Radio practical considerations repairmen (Continued from page 23) must face under actual conditions. To have made the problem one for parts industry, will be introduced in a few weeks I Train You Quickly the simple use of the slide rule, or the by the Tilton Electric Corp.. 15 East 26th Street originators of the famous Ee -b' tat Condensers in Your Spare formula book, would have failed to Resistors. Transformers, Antennas. etc. Hours The sales drive, that will be directed to the bring out the practical experience that consumer, dealer and distributor. will feature . . . Right at Home the successful " BONUS -BUYING," as part of an unusual 6- makes serviceman. point plan. For the first time in this industry, You Do Practical Experiments with There was, therefore, included a small co- operative sales participation will prevail for the buyer and seller, to spur sales. Real Equipment nevertheless catch. I offer you a new and altogether different type of -but significant- A host of new products will also be a high - practical 'Training or a money -making career in Radio light of this new and unusual campaign. Among and Television. I teach you in a ai mplified, logical, It was a fair "catch" since your work understandable style all about Television, Elec- the products to be introduced is a patented tronics. Facsimile Radio, Set epair d Installa- in the serviceman or radio field would vertical-rod antenna that is ideal for hotels, tion. I IV E YOU PERSONAL COACHING ALL homes or offices, particularly, where the noise WAY. have easily supplied the answer. The level is exceedingly high. Because of the unique TRAINING PREPARES YOU FOR GOOD condensers could not be electrolytics; design and construction of this antenna, it is not RADIO JOBS . . at Excellent Pay only possible to obtain a 055%, noise reduction, No matter if you desire to BE YOUR OWN ROSS in only paper or mica. but a decided increase in signal level. The base your fowl) business or hold down a good job in Radio, y g will give you the useful information and Electrolytics would have passed cur- of this antenna. containing a. symmetrically wound knowledge to win success. DON'T JUST WISH FOR transformer is of the rotary type. permitting in- MORE MONEY-START TRAINING FOR IT RIGHT NOW. rent on the five "open" d.c. checks, stallation anywhere in any position, without fear of obstruction. A nine -foot collapsible, Read What This Student Says: and would have made the a.c. readings EARNED $250 SINCE STARTING COURSE non -corrosive metal rod is used. Because of its "I have only completed one-third of the Sprayberry collapsible characteristics. it is entirely possible Course and I find it very interesting, which makes it e asy to learn. to use this antenna for ultra high frequencies. as "By devoting several hours of my spare time daily to well as standard high and broadcast frequencies. studying 1 'ou, I have made about $250 gross A The promotional campaign will be opened by since starting the Course." Earl W. Hostetter, R. No. direct mail with broadsides, letters and folders. 4, Lebanon, Pa. This will be followed by co- operative newspaper advertising. Spot broadcasting will also be used, YOU GET Lantern slides will be sent out and featured at lectures and in local motion picture houses. PROFESSIONAL i IMFD. TEST EQUIPMENT PAPER Amplifier PLUS EXPERIMEN- Experimenter's TAL OUTFITS D (Continued from page 8) Includes 146 RA 1 O PARTS building fore 5 -tube Radio Receiver, RADIO TOOLS, 1000 OHMS 2MFD. ALL - WAVE, ALL - PURPOSE AN- reason a 50 mil. choke is shown in ALYZER. Besides its invaluable use the in experimental work, my Equipment 5 WATT St PAPER will enable you to make spare time list of parts. profits while you're learning and serve n your own Service There are just three precautions that RADIO TOOLS businesssiness later on. I give you DATA SHEETS on how to build popular should be kept in mind: Radio circuits. Also y u receive BUSINESS BUILDERS which (1) The chassis is connected to one you how to get and do spare time, neighborhood Radio Service work. side of the 115 volt line and cannot be NO PREVIOUS EXPERIENCE grounded. If the amplifier is to be NEEDED used in the vicinity of grounded ob- ALL PURPOSE ANALYZER My .Training starts right at the beginning of Radio covers all jects, it would be a good idea to en- essential subjects. Ii m akes yno dif- impossible. This distinction is an im- Ito ference shat your education has close it in an insulating cabinet. Of been. I can fit you for an excellent portant one to a serviceman; not many paying job in Radio. Your s course the chassis could be floated Is my full responsibility. Iuknow of us would try to connect a dry elec- how to get Radio s so that (i. e. not connected to one side of the you c understand its trolytic, for instance, across the pri- . . . and remember it. mary of a power transformer, and we line), but this is rather an inconvenience in construction. SERVICEMEN would know instinctively they should I offer Advanced Training for those (2) Remember to insulate the key (ready in Radio. Get complete details not be sealed in pitch. in my FREE 52 -page Book. jack from the chassis; a rubber grom- The resistor in leg D passed 60 mils REMEMBER - THE SPRAYBERRY met will do the trick. COURSE IS SOLD UNDER A a.c. during the given test between D MONEY -BACK AGREEMENT (3) and C. In handling 3.6 watts, a one - Remember to have something or two -watt resistor would have been connected across the output terminals too low; 5 watts is the next higher whenever the amplifier is turned on. common size, so it was of that rating, If the plate circuit is left open, the or higher. (Remember that Cliff screen will have rather an unpleasant DON'T DELAY! ACT NOW! time of it; and there will soon be a "wired a heavy 1,000 ohm resistor" SPRAYBERRY ACADEMY OF RADIO 25L6 reposing in your waste -basket. F. L. Sprayberry, Pres. into the a.c. test leads ? ) 325 -F University Place, N. W., Washington, D. C. If you are at all forgetful, it would be Please send me FREE copy of "HOW TO MAKE Winners will be announced in the MONEY IN RADIO." next issue. How'd you make out? advisable to use a closed- circuit jack in place of the output terminal strip. Name Age Address YOU are busy in your store on a rainy Aside from these three suggestions the unit is practically fool -proof; it's City state afternoon, and a neighboring house- Tear off this coupon, mail io envelope or paste on in first time. not a high -fidelity amplifier. 30 penny postcard. Servicemen -Check here O. wife drops for the She wants -J

www.americanradiohistory.com 58 RADIO NEWS June, 1940

mtr coils which brings in East coast plenty QSA. WSC and WIM vie with KPH for FACTORY-TO -YOU QRD? de Gy sig strength. Heard the SS Aztec several (Continued from page 30) nights ago off Sandy Hook with steering gear SAVES YOU To O% carried away. Imagine if you can, an ex -sea- EASY TEP- -- going man herding cattle around the scenery by day and listening on 600 by night . in PST. No signals heard. . . Walsh 32340 spite of the wife and daughter . . . so 73 to Unquote . Our sincere regrets to his fam- the old gang and I'd like to hear from any ily and his friends. of 'ein. IN a recent issue we suggested to some of AND so another log is despatched into that the boys that they try the Airways for great unknown wherein those with fore- jobs. We received a letter in which a reader sight will find that it will pay to study the said he had written, re- written and again latest developments in the radio art . 73 wrote airline companies for a billet and so ge GY. far all he had received was silence. He also ...... -30 said, in effect, that we shouldn't kid our readers. Well, we just received another let- Foreign Reception ter from oné of said readers, C. J. Bolvin, Remotes Here's our big 20th Anni- who sez . quote got tired of riding (Continued from page 24) versary radio special.. the the car- ferries and decided I wanted a shore 14 1940 - PRESENTtABINET -tube Television job . So I sits me down and wrote a Adapted Midwest! Bril- lotta letters to the various airlines. Carne have liant performance . . and "When you lost your bearings, and amazing foreign reception! lots of application forms which were then there is no sign of any help, sit down, take filled out and returned. Got results so fast 30 Days Trial that it nearly floored me. This outfit (TWA) out the cards, and start a game of solitaire Absolute satisfaction guar- wired so that's the reason I'm here. The -and, it won't be five minutes before some anteed on money - so and so looks over your shoulder, and back basis. Catalog others -four of them -sent letters which I also shows 14 -tube didn't get until I carne back from trying out tells you what card to play next." here in KC. By that time I had this job R. K. W. cabinet console for ADAPTATION only$ 2 9.9 5ccsmplete l and had to turn down the other offers. Any - Other models from 5 to 17 Tubes, and up to 5 Wave Bands. hoo, it was a revelation that there are so Refer to: Hammeter article, RADIO NEWS, Send 10 postcard for FREE 1940 catalog, showing com- many jobs floating around waiting for some April, 1940. plete line. (User- agents make extra money!) guy to come and get 'em . Unquote. Now I have been using a similar meter for See Midwest's Answer to TRADE -INS! won't the other letter writer's face get red. two a is a Incidentally, CJ sez we shouldn't forget the years, but with circuit that bit MIDWEST RADIO CORPORATION CAA is more sensitive and flexible, and adding a Dept. Cincinnati, Ohio which expanding by leaps. There is 11 H some talk of the CAA taking over the small C battery and changing the Diode Alaskan communications system which is at present being handled by the army. About 15 radiops will go up yonder this month and that's just the contingent. So there's ENGINEERING a word to the wise. If one radiop can get RADIO DEGREE INYYEARS billets where he wanted it, others can follow suit. And we ain't playing bridge ! Complete Radio Engineering AL SEGEN (ex -ham W3BGD) writes that Course in 96 weeks. Bachelor of he has changed his tanker job for a Science Degree. Radio (television, yacht berth, the "Elsie Fenimore," to go on talking pictures and the vast elec- an extended cruise around the Caribbean. tronic field) offers unusual oppor- Johnny Yarns (barn WSHCZ) has moved tunities for trained radio engineers. into the chief's job at WHBB, Selma. Ala- Courses also in Civil, Electrical, Me- bama. Bill Tullis, formerly at WUE, Ft. chanical, Chemical, Aeronautical Geo. Wright, Washington, is now with the Engineering, Business Administra- CAA at Evanston, Wyoming, but will move tion and Accounting. Tuition, living to Sheridan, Wyoming, soon with the sane costs low. World famous for techni- outfit. cal two -year courses. Spe- cial preparatory depart- INCIDENTALLY, we are a bit buoyed up circuit to a Vacuum Tube Voltmeter. I ment for those who lack by the information of our nose- for -news use a 0 -200 microammeter but the 0 -1 mil - required high school work. reporter, CJ, who tells us that there is an liammeter will work almost as well. Students from all parts of association of radiops around TWA known By EARLE OPPENHEIMER W2IZT, the world. Enter June, as the Skyline Assn. of Radio Operators. Sept., Jan., March. We've always been wondering why some one Refer to: Wireless mike, RADIO NEWS, / hadn't tried to unionize these lone wolves of December, 1939. Write for catalog. Burton the field and here is a functioning organiza- Handy, Pres. tion which has in its constitution the provi- One of the elements in the 1A7 tube was sion that it can include ops from other air- omitted. A corrected diagram appears here- TRI -SSTATE COLLEGE lines as well. Jack Stone, Secretary of 1650 Col Ave., Angola, Ind. SARO. sez he'll be happy to hear from any IA7 one interested in j'inin' up. This should be looked into by ops interested in the airways. 4 YOU CAN BECOME ELL, we've received fan mail from W former radiops who are now doing A CODE EXPERT! everything else but radio work, but the hat goes off to Jim Caldwell who is now Manager Learn the Quick of the Antelope Ranch at Willcox, Arizona. Herding msgs to herding steers is really a CANDLER WAY! stretch of the imagination, even for one like Candler doesn't care if you're He sez . . . . Since I used lust a beginner or if you've ours. quote tried to develop your speed up six tickets your column has afforded me without success. If you follow considerable interest as there is little contact the simple Candler System B+ you will learn code right, with with the seagoing fraternity out in these h'ar the correct fundamentals. It's BOOK F Crs parts . . . I've often wondered where the a mental process: you must with. All numbers refer to socket pin learn soured consciousness; Radio rotor old timers have gravitated to. Such as old markings. and this Candler will teach MacCarty of KSF and KSH (Finland and you as he has taught thou- Kroonland), the old Minnekanda, KDKK. sands upon thousands of others, including such Refer to: Cover, April, 1940, issue, RADIO operators as T. R. McElroy, World's Champ- Geo. Dill, Johnny Flagg. Ernest Hawkings, NEWS. ion and World's Record Holder. Goldsmith and the others . and Charlie So many of our readers had the neces- In a short time after you've started Candler Harn . and Charlie Guthrie. Whatever training you'll find yourself reading code as sary technical knowledge to tell us that the easily as you read the printed page, without became of Carl Langvin? The present day strain or conscious effort. A few weeks of Can- turmoil reminds me of the time the USSB scene shown was not the final amplifier of dler training are equivalent to months of un- Conejos struck a mine in the Black Sea and station KNX, that we were at once amazed directed practice. Write today for FREE 1940 "Book of Facts." Learn how the Candler sys- went down in 20 minutes. Fred Selim was and pleased. All of you who caught that, tem works, read what highly paid commercial op on her and I well remember the rag chew- operators say about the Candler system. Send were right. The buffer was what was for your ing he carried on until the last second. We copy today! for at the time shown. The information which appeared were bound Constantinople on the cover was furnished us by our cor- and we were still in the Mediterranean. . CANDLER SYSTEM CO. respondent at the West Coast. He was in Dept. N -5, Asheville, N. Carolina, U . S. A. I have tried to locate a good 600 meter receiver such as the Sargent but so far unable error, and so were we. A thousand par- to do so. So I use a National SW3 with 600 dons, gentlemen. 30

www.americanradiohistory.com June, 1940 RADIO NEWS 59 Modernizing Old Receivers Serviceman's Experiences (Continued from page 13) (Continued from page 14) due to this improved circuit and the "So I figured," Al went on, "the more efficient tubes. best thing to do was to let them keep Provision is made to connect three the cabinet and sell them a new different aerials, one for 5 meters, one chassis. The new angle got them, and for 10 meters and a general aerial, I sold them a new chassis and speaker controlled by a three position switch. for fifty bucks, cash. They didn't want In the latter position, the converter is the Colonial chassis, so I allowed them disconnected and the general aerial a fiver for it. How'd you make out connected directly. 30 with Ben ?" "Aw, he wouldn't listen to reason," lexaa '7vy11VVIVVVvyvvV I said. "That will be an easy job on , - Ken's set knobs 31 EXPERIENCED RADIO MEN WILL -the on the don't KK (/'¡ come through the front of the cabinet, so there won't be any wood -working You don't need to gaze into a crystal globe 00 - just look around you. Television - radio 5 i involved." facsimile - electronics in industry; these and "Surprised that you noticed," Al re- other developments are crystallizing right E LAFAYETTE CATALOG marked. "Ben said you left his house under your very nose TODAY. Here lies the R al future of the servicing industry, here lies in a hurry." YOUR future in radio . . . IF you are ready Experience has taught men in radio that a new to capitalize. Know as much about these Lafayette catalog means news . . buys . "That reminds me," I laughed, "we developments as you know about a superhet savings) Send for the Lafayette catalog -just pub- are getting Ken and Ben to do some- - OR ELSE see the most profitable part of lished -and see for yourself. Have this guide to the thing different. Hope it doesn't break your business go to a competitor. Read best buys handy -buy everything you need from up the team!" carefully the contents of the following books one source -save valuable time and money! Get - and Order Today! your copy today. Its FREE. "It won't," Al said. "After you left, Ken 'phoned Ben and made him order SERVICING BY SIGNAL TRACING LAFAYETTE RADIO a duplicate chassis!" 30 Dept. 2F -100 Sixth Ave., New York, N. Y. By John F. Rider Use the system of servicing which is proved and endorsed - fastest - most modern - the Doubling in Oscillators system you can apply to all receivers regard- AMATEUR LICENSES (Continued from page 31) less of age, type or make. Servicing by RADIO Signal Tracing operates independently of Day and Evening Classes in Code and Theory every limiting factor heretofore encountered. HOME STUDY COURSES citation, and using a combination of In this new book you learn how all receivers Reasonable, Efficient and Thorough, are brought to a common servicing level. Hundreds of Licensed Students cathode and grid leak biasing, opti- You learn how components receive a func- Now on the Air mum adjustment can be made by re- tional check while the circuits are in an American Radio Institute, 1123 Broadway, moving the excitation and adjusting operative condition. Over 360 pages - hard New York, N. Y. the cathode resistor to bias the tube or covers - only $2.00. tubes a little under class A operation. THE OSCILLATOR AT WORK This can be determined by observing By John the plate current and adjusting it, by F. Rider means of the cathode resistor, to a lit- LUST OFF THE PRESS! tle under the recommended value for Get your money's worth - KNOW! This class A operation. new book tells all about ALL oscillators. It explains the theory by means of simple illus- Additional grid leak may then be in- trations, diagrams and curves. It gives you Vat% 3 serted, so that when excitation is ap- the practical facts you need to combine çtt plied, the total bias voltage, measured theory and practice. Get your copy TODAY! 256 pages illustrated $1.50. by the high resistance voltmeter, is - - no more nor less than the rated bias OTHER RIDER BOOKS YOU NEED S?tw (ASIAN for class C operation. A little trim- ming, between the grid leak and ca- The Cathode Ray Tube at Work - 336 pages - 450 illustrations - $2.50 Hour a thode resistor, will give optimum re- Day with Rider Books on subjects you should ® sults without imposing too much on know - Hard Covers - 60c each. And of either the plate supply voltage or the course - All Eleven Rider Manuals. r.f. excitation. It is more certain than a grid milli - 4NOE4WFOYUORRTKH Have you a few spare minutes a day? JOHN F. RIDER,Publisher CITI Then you can very easily ammeter. When a grid current meter earn plenty of is extra cash! You could add $10-$25 used, one has to stop to figure the - i.r. drop across the or even $50 a month to your income. cathode resistor How? Simply by joining the Radio News and that across the grid leak and add EASYTO LEARN CODE Booster's Club and discussing RADIO these results together in order to de- It is easy and pleasant to learn the termine the actual bias on the modern way -with an Instructograph NEWS with your amateur or servicemen grid. Code Teacher. Ideal for the beginner or friends. Send The voltmeter method presupposes advanced student. Many tapes available for subscription supplies ranging from alphabet for begin- and detailed information on how to in- that the amplifier has been properly ners to typical messages on all subjects. Speed range 5 to 40 crease your income! Do it now! neutralized, however. WPM. Always ready, no QRM, If for any reason it should be de- beats having someone send to you. FOR SALE OR RENT SEND COUPON TODAY! sired to read the total grid bias volt- STANDARD with 10 tapes, book age, connect the positive terminal of of instructions, A.C. motor.$24.50 Booster's Club, RADIO NEWS with spring -wound motor.$18.50 the voltmeter to V, and the negative JUNIOR with 5 tapes and book 608 S. Dearborn St., Chicago, Ill. of instructions (not rented).$12.00 terminal to V, The grid bias voltage RENTAL Standard with 10 tapes Gentlemen: Please send subscription and book of instructions $3.00 first month, $2.25 each will be of the order of 60 to 80 volts additional month. References or 310 deposit required. supplies and detailed information on in of All rental payments may be applied on the purchase how fo increase my income. but the case this oscillator, it is price should you decide to buy the equipment. not necessary to adjust it further or Write for details today NAME even to measure it. ADDRESS The parts are all mounted on a INSTRUCTOGRAPH COMPANY CITY & STATE breadboard as shown in the photo- Dept. NR, 912 Lakeside Place, Chicago, Illinois Representatives for Canada: graphs. The board measures 10" long Radio College of Canada, 54 Bloor St., West, Toronto

www.americanradiohistory.com GO RADIO NEWS June, 1940

and 8" in depth. A sheet of metal, preferably brass, copper or lead, 10" Hamchatter by 6 ", is attached to the forward surface of the board. All ground con- (Continued from page 35) nections, shown on the wiring, go directly to the metal plate. The parts are easily recognized in the pictures. got to work a few stations over W6USA. The W5AKT doesn't have a 5 meter rig yes. but two fixed condensers between the he knows what it's all about. He expiained a tubes and the tank capacitors, on the 56 mc. rig from construction to actual operation at a Ouachita Valley Amateur Radio Club meet- top of the board, are : on the left of ing recently. the tubes, the grid's by WSADJ brought a loop antenna to Monroe, screen -pass and when he finished demonstrating its selective condenser; and, on the right of the powers several local hams declared they had to build one too. tubes, the plate tank d.c. isolation con- W5IRO is a new ham in Hodge. denser. 30 W7GAE, W6MBD, K6NYD, K4FKC, LU5AN, 0A4R, OA4K, YV1AQ, CE3CZ, CO2WN, just to mention a few whose signals are consistently heard in Monroe, La. W5DRF brought an e.c.o. rig to a Ouachita RADIO PHYSICS COURSE Valley Amateur^Radio Club meeting and demon- strated its adaptability to different frequencies. W5DXL is all set to start working 40 e. w. by Alfred A. Ghirardi He won't have any trouble keeping up with the best of them for his speed is about 45 words (Continued from May issue) per minute.

As long as the filament voltage of `t7 9ECC and W9RSR are students at the Uni- versity of Wisconsin. Training YOUR DOG a tube is normal and is not raised over W9APP is a new operator at Kewaskum, Wis. 10% above the rated value, the evap- (that makes two). properly is essential if you are to get full W9PPV works for the Bell Telephone Co. He enjoyment and comfort from him. POPU- oration and replenishing continues at likes to operate on 75 fone and often used to work crossband wid W9QXI on 160 f. LAR PETS, the sensational new magazine an equilibrium rate, so that a con- W9QQL heretofore on CW is now being heard for animal lovers, shows you exactly how to stant layer of thorium is maintained on 160 m. fone. W9QXI has modernized the ole rig and in- teach your dog to obey your commands or on the surface. corporated everything into a relay rack, receiver signals. Easy-to -read and easy-to-under- If too high a filament voltage is used, and all. One night we saw shadowy forms climb- ing in the night and it turned out to be QXI stand, POPULAR PETS brings complete, the rate of evaporation of thorium is repairing the skyhook in the middle of the night. authoritative counsel by America's leading increased more rapidly than the rate W9GSG who is a doctor at a sanitarium would trainers and breeders, men and women who like to operate on 160, but says that it would of diffusion of the thorium to the sur- cause to much QRM on the patients' sets. are tops in their fields. Treat yourself to this W9wSY the DX hound is now playing on 160 grand magazine today! face, the thorium surface layer is par- m. fone, he sounds funny though, these CW men tially or destroyed, the all have to learn something about fone. But totally and Lee gets out fine b. Runs 20 watts and puts emission drops to that of pure tung- R9 into Mich., Ohio and Etc. from Wis. sten (which is zero W9OBT had quite a party, while he was on the POPULAR NOW ON SALE AT practically at these air, one night. We could heard all the YL's and temperatures) and the tube operation the XYL's titter and laugh in the background. It wasn't anything funny that OBT said though, ALL NEWSSTANDS is impaired. If the tubes are operated then what was it? at very low voltages, the filament tem- W9TPY says that Beaver Dam is the city of Pets 19 manholes wid 18 covers (Don't ever visit perature is so low that the process of TPY) hi hi. Some time when you all hook up wid W9DDD, boiling out the thorium from the in- ask him to tell you abt the time that he tried of filament becomes abnor- to get on ten meters and how he landed in the terior the 13 meter band. mally retarded, and the layer is slowly Speaking of off band operation, W9KOL had quite a fine b. sig on 80 meters. Fact was that used up. he got better reports on 80 m. fone than on The great majority of thoriated 160 m. fone where he was operating. It happens to the best of them. tubes die a natural death, in that their W9ZGK is planning to put up a beam, says with Serahs BIG that HP stuff is nice. And that he is itching for life continues until all of the thorium some DX. in the filament is used up. Obviously, W9JPU is using cathode Modulation in his 1- Volume Radio e.c.o. says that it works all o.k. so far. nothing further can be done with them. W9CQO has just received his class A ticket Training Course Tubes which decrease in operating effi- and is ready to go to town on 20. Fit yourself, at home in spare ume, for a good-paying having some of job. Yes, you can t Radio ciency after suffered THE only radio fraternity of its kind, Rho Ghirardi to help you, as he has helped thousands of others, the abuses mentioned above can Epsilon, has recently granted a charter to the who got their basic training Newark College of Engineering. This new chap- in Radio from h i s world- usually have their thorium layer and famous Radio Physics Course. ter will be known as the theta chapter. One pur- Because you see he has full efficiency restored by the simple pose of the organization is to raise the prestige clrus for making it all vividly of the radio clubs in our colleges and universities. ear and easy to understand. "rejuvena- You need no "background" to process of "reactivation" or Founded some years ago at Washington State Col- prepare you for this intensive consists of clean- lege, Rho Epsilon Fraternity has grown immense- noarse of technical training - tion." Reactivation ly, gone National with chapters in some dozen col- t even a knowledge of math! Ghirardi will see you ing the surface and reducing some of leges all over the United States, and continue to through" from elementary prosper. The secretaries of any accredited Col- Electricity right through Radio, the thorium oxide in the wire to metal- lege Radio Clubs are invited to write the National Sound, Television, Cathode - Ray Tubes, etc., etc. It's all lic by heating the filament of Secretary for detailed information concerning explained here- complete-in one big handy thorium the grant of a charter at their school. Address $4 volume. the tube (with plate and grid circuit Mr. Nulo E. Koski, W7LD, 582.2 E. Green Lake- USED BY U. S. ARMY Way, Seattle, Washington. Yes, because of its ellence, Radio Physics disconnected) to a higher temperature Course has been given the rare honor of being Chet Warren, Ex -3AVX for some years, had a selected as a training text for radio courses conducted time, by the peculiar glint in his eye as he looked over the by the U. S. Army and Navy. In fact, it's recom- than normal, for a short mended and praised everywhere as "tops" -it's used rig here and as he tuned the receiver over the by u radio schools and students than any other application of specified high voltages. band. Could it be that he is thinking of start- radio textthe rld! ing. . No ! Couldn't be. hi. 36 VOLUMES IN 1 -972 PAGES -50S ILLUS. This is known as "flashing." Then it 1. Radio Broadcasting System. 2. Sound. Speech, ilosic. 3. What is the matter with the boys at City Col- Electron Theory; Elec. Current. 4. Elec. Units; Ohm's Law; Re- is operated for a longer time at a lower lege of New York? Why not get a transmitter sistance. 5. Elec. Circuits; Batteries. 6. Magnetism. 7. Electro- on the air over there? N. Y. U. is on with magnetism. 8. Electromagnetic Induction. 9. Inductance. 10. out additional Capacitance; Condensers. U. A. C. Circuits. 12. Filters. 13. Measur- temperature. This boils W2HJ, Columbia Univ. with W2AEE, and N. C. E. ing Instruments. 14. Radio Waves. 15. Broadcasting. 16. Receiv- of the with W2JPK, so what say about a sked some- e. 17. Vacuum Tube Principles. 18. Vacuum Tube Characteristics. thorium atoms from the interior 19. Voraum 'rube Construction. 20. Vacuum Tube Detector and time? Amplifier Action. 21. Radio Frequency Amplification. 22. "Super - filament and a new active layer is I read in RN where W1GFW is a champion hetu." 23. R. F. Amplifiers; Tuning Coils. 24. Audio Amplifiers. antenna putter- upper. How about coming down 25. Speakers. 26. Battery Operated Receivers. 27. Power -Supply formed on the surface. This is known Units. 28. Elec. Receivers. 29. Automobile and Aircraft Radio. here and giving your namesake W2GFW a hand 30. Phan, Pickups; Sound Systems. 31. Short Wave. 32. Photo- OM? electric Cells; Cathode -Ray Pubes. 33. Television. 3d. Antennas is "ageing." is FB and Grounds. 35. Testing; Servicing. 36. Sound Motion Pictures 15- year -old W2MRZ getting out with his .. 856 Self-Review Questions! (To be continued) 7 -watt rig. A 6LOG xtal oscillator and a 2 -tube Test It 5 Days -OUR Risk! blooper are all that Bill use to put out a swell Send for itl -Read Itl -Use it! If not completely satisfied, sig on 80 and 160. return the book within 5 days and your money will beuppromptly refunded. You risk nothing-but you'll lose The most consistent signal from Africa since your great opportunity, unless you at least SEE this book! the ZS's left the air is OQSAV. He can be to Problem on page 57 found every Sunday on (14.312 kc. T8). L' MAIL THIS COUPON NOW I. IM Answer HC1JB is very active on ten meter phone 'RADIO & TECHNICAL PUBLISHING CO., 45 Astor Place, New York. Dept. RN -60. and works his father in the WO district. He is THere is my $4 ($4.50 foreign). Send operator of a new broadcast transmitter there RADIO PHYSICS COURSE postpaid, with NUMBER two. She'd understand that, in Quito. The call used is HCJB and the station your money -back guarantee. she had sense enough to come in out is for missionary purposes. I if From Cuba, the isle of pearl. we find that NAME of the rain, and you could lead up naturally CO2GY is really full of humor. He claims that I ADDRESS , fact you stood ready to make any he is the Johnny in Oli. Johnny. When Johnny to the isn't using tt kw. he is making Neon signs. He I CITY STATE set changes in the future. Present Send me free descriptive illustrated literature. necessary sent W5DEW a neon sign with her call letters ! in beautiful color. [Thee gals get all the breaks!] SEI a------m s m m m mmm ones too, for that matter

www.americanradiohistory.com June, 1940 RADIO NEWS 61

W2CZS has a 60 -watt Pone on 160 meters. W2HZY tried 10 meter fosse and only had one Stan is secretary for the forth -coming Hudson QSO. (With a chap in the same town. at that) Division Convention to be sponsored by the Union George promptly gave that band up as a loss Colony Amateur Radio _lssociolion. and came back to 80 c. w. His ECO sounds very W2J.GV is still trying to be heard at the much like xtal. Newark College of Engineering. He only lives Art at W2LVO is using 6 watts input to a 6L0 about 20 miles away but so far none of the skeds oscillator with an end -fed hertz antenna. This have gone through. Harry is a sophomore. seems to be the vogue around here, as all the Besides having a big' fune rig on 75 meters. younger fellers are using them. W°GQM has a 20 -watt portable rig on 160. Paul W3AKV has had such good results with his VARIABLE recently moved to Roselle Park. 25 -watt portable rig that he is going to give it Flea- powered W2LOP can often be heard on a try on 75 fosse too! 160 fone with a swell signal. Hank tried a RK- W2MUE is another beginner doing big things CRYSTAL :34 on five meters in a mobile rig but was un- with his little rig. With thirty watts to a 6L6. successful. He expects to start at the University Owen has hunched off North Dakota and Oregon. OSCILLATOR of Idaho next yea', and will have a little rig His .sky -Champion receiver nutst help on the pull - with him to try to talk back home. ling -iii end. WIMTI was only a awl when he won an SX -23 W2LBG keeps Linden, N. J. on the map by receiver at a haul -feat but now Pat has his ticket. working out on 80 c. w. Dan said the ORM His rig uses a SLUG final and a 6L6G modulator. was terrible on us the other night on 3505 ke. Sounds plenty loud here. We shifted to 3636 kc. but it was still terrible! W °KKO had a thrilling experience recently, hi. when he noticed that his ticket was soon to ex- W2FNT is dividing time between 80 c. w. and pire! Phil had to rush to get it renewed in time. 160 fone. Oh Johnny, how you can OSO! In- It seems that phonograph records occupy a lot put is 30 watts with no dx to report at FNT. of time at W2KKO and he doesn't get on the air W2CEJ has to keep his rig on e. c. o. frequency flexibility so much wife's the air any more. as well as his own. Both he and Mary (W2JLL) with quartz crystal W2LSX recently got the flu. He is recuperat- have tickets at their home. Bill's rig works on stability ing now and mom, active than ever. 40 -meter CW and Mary works fosse on 160 meters W:3AAL surprised us by saying his input was most of the time. Their son is also learning The Vari -X is a full crystal controlled variable 2 watts! He has worked 19 states with the little the code! frequency exciter for 40 and 80 meters. See your rig on 40 e. w. His frequency is about 7020 and One of the few 160 -meter sips we've heard Bliley Distributor at once for complete details. is Irving to work the west. coast. comes from W3HXN. Ed has a hundred and No qsl cards ever get lost in Jersey City. Why? thirty watts input to an Einhac Because 35 T. ASK FOR CIRCULAR D -2 W3CFW works in the post office and IV2MKN uses about 80 watts input on 80 c. w. he keeps SIl eye out for them. Bill is pounding and 160 fone. Frank keeps 1918 lcc. busy here brass on SO c. w. again. with his swell sign. W'lHXI has his outfit We also worked him from perking on 20, 40. and the college radio club. BLILEY ELECTRIC CO., ERIE, 80 meters. Bob claims he'd like to try it on W2MPQ undoubtedly owes his success to his PA. 10 also. but doesn't have time. By the sound 40- ureter zepp of and (30' counterpoise. Chan's out- ten CW, we could use a few more men down fit uses a 6L6G and a 210 amplifier with 35 than. waits input. Receiver is a Fit -7 and works good. The rig at W2MQP is a ßL6 -6L6 with 60 watts Another "6L6 fiend" is W°_MNA who uses two input.. Receiver 'l 6 -tube super and the antenna. of 'em. However it won't be long is a Marconi. Herb says before Bill "CASE that altho his street gets about a 41 -KW going on 160 fone. It doesn't is called Vassar Ave., it is purely a coincidence, seem to worth the trouble to put anymore power and there are no pretty coeds around. Shux. on tho' because with a 6L6 you can wrk all HISTORIES" W2ANW has a new bug and is Irving to get locals. the 3 used to it. Tom's set uses an RCA 809 with 55 watts input. Compiled by Comes spring and W2DY0's fancy turns to THE mail bag says: Alfred A. halft handling. Julius says that with no dx Well om we want our say in the RN s nd nothing, he's going in for tfc again. Some fro this part. of the country so hr goes. GHIRARDI of the nets on 80 meters certainly do operate Ten members hr in this club es most of them smoothly. The boys sound like commercials ex sips of some kind either navy. R. R., or ham 'ith their snappy bk in. there are 3 tickets es one comming up in a few days or wen the fee puts the old oh on it. Rest are willing fr them. Seems there is a station wid the call 7HJT by name Shirley who contemplates joining the YL ALL league watch out fer (him) girls. hi. RADIO NEEDS Also 7HJK who wants to wrk dx Here stay awake but can't in this one big later than 0 Px. hi! Watsa matter will find book you doe, frail that little 53 ose will go to sleep everything you WI on u. in radio . need I beat the boys to a 1:6 hr awhile back supplies parts and on 80 who was calling co tk a cple gsp's fer him syste public address es tux to W2MHD got them on the east coast in ment amateur equip- gd time then they all piled in on K6 frm Pa. ... testers and to the west coast hi. national! .. - Where's EJS Y known th of 160 fone man. vorites at fle Bn lots of gin hr in Mts. this winter but still prices. Writeme this we wrk the East coast ok but sure wish u boys big today for this who owe us cards valuable catalog out lar wud qsl as we want save money. and our WAS to so wat sa boys dont be proud even that of penny post card will do it so 73s from the All in PROMPT Wallowa Mts. W7J1JJ. SERVICE RADIO . GOOD o1e Keith W4ARX Mathis comes thru, sis per usual, wid: W4FPI at Opp, Ala., comes up with the news BURSTEIN-APPLEBEE COMPANY that he has been very busy which explains his `nie-itsui'ten's 1012 -14 McGEE absence from the air. You had better watch STREET, KANSAS CITY, MISSOURI those YLs over at Damascus, Taylor, they are HANDBOOK school teachers, you know. GET the complete book of Servicemen's "Case Histories " -rho world's biggest co llectiop II sham bled W4EAB at Opp, Ala., reports that he and his and classified for you i father recently Chirardi'.s handy data book Now you can "lick" every Lough servic- Websfer Rim Driven suffered from a. disastrous fire ing job that comes along. For here, in a few seconds, you can see what ?r. Motor which destroyed their warehouse and seed store. all the likely trouble sources are for practically any set you will be W4FDJ reports that he is tlled on 1.,, service today -for 3,313 models in all, representing 177 78 R.P.M. rebuilding and will different , nnlaN.urersl what's more.c Foil ll learn how to remedy operate on iho ore s Ne V. ten meters mostly during summer. tr ,obi -,sit with a lot of but according to the A,C 60 Cycle successful experience of W4FDE at Cordele is on ten with a new the cou,,,ry'e leading.. New Design, self coning, rig and tions. P t 17"-you bet it is!- practical front t o ,, constant peed, mpact reports that the band is really open down Think what th book do pr6o i. his will for yawl-the servicing TIME you will way. -the headaches avoided-the customers ssatisfied -yes, find Limp Pric with Cu i Ship. lb s. you'll find yourself Price t W4DSB at Americus has doing better work and getting more money for it. List $6.00. Price (Plus P r recently put up a new 25% Deposit quired with Order. Write for antenna and his 75 meter phone signals are More Time- Saving Data Besides! Latest Radio Parts Bulletin. much better. That's ion one section of this great Ghirardi Trouble Shooting Handbook! But yo«11 find 50 more of them when you open the ARROW SALES COMPANY W4GHU at Albany recently had his picture in hook-every one 619 W, Randolph St. the Atlanta in ,st chock full of valuable data of 11 kinds hicl, Chicago, Illinois Journal regards to his work there Sou need in your s everyday .orrice work-I. F. Peaks (aver 15,000 in disaster. listings!); Auto -Rodin Data for Installation and Servicing, Inter- Did yorse guys glim the recent ference Elimination, Car Wiring, etc.; Trouble -Shooting Charts, remarks of one Trade Directories; and over 30 ethos tables , d harts. Get this so called editor of this magazine in regards to book -it'sa real time saver! Mail coupon TODAY! Otis. never failing. What may I Iislc do you ex- 518 PAGES, 134 ILLUS. Standard Manual Sint. Qa CQUALITY ABOVE ALL pect out of a good Special Combination Offer rel:orter such as we are. Hi! Both Books -$6.50 -it purchased togetherT `1tY W4F00, Fender. Georgia near Tifton is a new ham on one sixty with a fb .six watt rig. Alvin MODERN RADIO SERVICING says that he _ O L;CR. can really work ens with this nower. The rampant= volume to the Handbook - W4EZI, Selma. Ala., is putting out a swell fone it gives you a thorough aroumllllg course In signal the baste theory and fundamentals of mod- A P A C I T O R S on 100. These Ala. hams gets better all ern radio service work and servicing instru- Write the time Hi. toments-all made wonderfully clear and easy for Catalog W4FEQ. Dothan, mlleratand -Test Instrument.. Trouble- Ala., says that hams there Shooting. Bemiring. etc.. ete. SOLAR MFG. CORP. are thick but not many active at one time. He 1300 PAGES. 706 ILLUS. $4. BAYONNE, N. J. has rebuilt recently and his signal shows nice results. Earl is a. grocery store operator and that means plenty of eats hi. RADIO 8, TECHNICAL E W4FDZ wants to know I PUBL. CO., Dept. RN -60, if 1V4FJM at Panama 45 Astor Place, New York. City, Florida has jumped in the bay but we IPlease send postpaid: MIN didn't Below and our idea is that mebbe the XYL RA$DIOO TROeUIC.E SHOOTER'S HANDBOOK $3. RADIO COURSES there decided that the OM needed some sleep. I MODERN RADIO SERVICING $4. ($4.50 foreign.)' Start September However, Ilocns Pocus. let's hear from you so BOTH BOOKS $6.50. ($7.00 foreign.) RADIO OPERATING -BROADCASTING we can keep up the good word about you. I Name RADIO SERVICING - a practical course "Howcome," writes in a well meaning friend. Address RADIO AMATEUR CODE TELEVISION "do von remember all about how buildings looked I City State. ELECTRONICS-1 yr. day course, 2 yrs. eve. in the last (wat'dya mean, last) World War? Please send free illus- Day and Evening Classes. Booklet Upon Request. Gosh," continued the letter, "we know that you Use it 5 days trated literature descrlb look old Ing detailed cHeks. m Y. M. but having went to some schooling bo servicing New York C. A. Schools wid you we don't -OUR RISK! boo of 7 W. 63rd St. New York City think that they let rompered babies fight that there war." All of this referred to our recent dispatch from Albany, Ga., and MONEY BACK GUARANTEE

www.americanradiohistory.com 62 RADIO NEWS June, 1940

that, my friend, wuz just a figger of speech that boys on 40 meters. Rumors have it that "Tony' all of us better known writers use. is going to build a ten meter rotary beam. Some day we guys in the fourth are going to W7CRE has built a new exciter using a 616 C1RlrSTAl. wake up and realize that our yankee brothern are and a T -20 for use in that kilowatt rig of his. using five meters more than we are and then The new exciter is taking the place of a Collins. mebbe that band will be used for plenty of W7EQH has a very fine 160 meter phone trans- Informative Bulletin No. 1 hamming. mitter and it really gets out. W4GHY at Anniston, Ala., has a DX record of W7BUG is contemplating building a new rig over 47 countries on contacts on the various CW using a 616 oscilator and an 807 final. bands and has recently made his first phone W7AQH is going to take a fling at 160 meter transmitter using it on 160 meters. phone one of these days with a super deluxe 'yi]]ur-i i W4AJI who is going to school at Yale recently compact rig. Jar! paid his home state of Georgia a visit. Sid says The other night W7HRP had a very interesting "WHAT MAKES A LOW DRIFT CRYSTAL ?" that the northern boys are very active. experience. He was pounding the brass on 40 W4FMS, Savannah, has been off the air due to meters and on almost the same frequency as he Regardless of whether the curt of a crystal is called being sick but reports that he now is able to was operating, he heard a CQ by W9FMN. He A, X, Q or Z, if it is cut at an angle from the optical chew the rag once more. answered and "low and behold" on exactly the axis, on the mechanical axis of a piece of quartz, and Your scribe hopes to make the hamfest in same frequency, has a temperature coefficient of 0 to 77 cycles per de- the W7FMN replied. There was no gree centigrade per megacycle, it is a low drift crystal. fourth this year so if you have one coming up possibility of an error in reading code because The degree of the angle determines the amount of drop us a card so that we can be there. (Heck, later W9FMN was heard on exactly the same drift with temperature change. don't let my reputation for eating scare you). frequency. HIPOWEIt W4BZD, at Fitzgerald, Georgia, is still DXing W7HVV located at Sidney, Montana is really "Rubies" are cut at an angle which al- on twenty and has promised your scribe to get getting out with his rig built of 616s and 616gs. lows us to guarantee them to have a drift with tem- back on a good band. All the perature change of less than 4 cycles per degree centi- of boys are giving him 599x reports. per megacycle. Mounted in holders, especially W4FNA, Macon, Ga., has a fb cathode modu- W7EIH is really going to town getting new dgradeesigned to dissipate heat. they present an outstanding lated rig on ten meters. equipment. Be is building a Stancor 20P trans- example of an active low drift crystal unit. W4CQR another Macon ham also has a nice mitter for use as an exciter, and this is going to rig on ten and is very active with his DX work. drive a rig- using a 24 as a final. On The HIPOWER CRYSTAL CO\tl'ANY, one of the top of this. oldest and W4FZE at Macon is trying to get the honors he is building a 10 and 20 meter rotary beam. largest manufacturers of crystal units for away from W4GIA as regards YLs as he has a Broadcast. Commercial, Aviation :end Laboratory use, Es 73 de W7HUJ. is able new one with him on every contact that he to offer the amateur low drift precision crystal makes. Boy single , pikes Uecense sr their large produc- -you guys just won't learn, VIA The Radio: tion end ti, exclusive HIi'OWEIt grinding process. hi. News of the K5's: _4T is still wrestling- W4GOA, Jacksonville, Florida, active on 40 with that fore xmtr and kinda disgusted with "EMERALDS" "RUBIES" meter CW is a new ham and is brother of W4FFI. the sky hook. M's OPS now in no man's Reports that he will get the phone fever soon. country, their company Guaranteed to have F f s t amateur W4FPF. Brunswick, Ga.. has again rebuilt his having been dissolved in a drift with tern- crystaÌ it avaita- the Canal Dept. shakeup. AC not being heard perature orange of b 1 e. Guaranteed FB phone rig and now says that he can run 200 vy often these days; less than 30 CY. drift of less than watts. that is. sometimes, hi. probably too busy with °C. p e r MC. 4 CY. per C. per maintenance work on those army sets on maneu- With holder. Mr. With holder. W4CUS. Orlando. Florida. is very active on vers! Ham radio came to the rescue when the 160 -80 -40 160 -80 -40 160 meter phone and the signal is worth listen- 2d Field Artillery got bogged down in the jungle meters....$335 meters... $4.50 ing to. during heavy rains here: S (a cial 20 Special 20 W4FYF Montgomery a broadcasting on 3530 meter unit.55.50 meter unit.S7.25 at has nice signal on kc., the Artillery hams hooked up with ,I N 160 meter phone and is very active on that band. and got vital info through. AS (formerly Available at Your Parts Distributor W4BOL. Cochran, Georgia. another ole time W1LLE /W1KLM/WA1) will soon be on with 60 ham rafter being on various CW bands has built watts on 20 lone and e. w. and hopes to conic a low powered job for 160. Lamar says that through o. k. W2's and W3's come through his brother Clyde. a former ham, has the avia- here COMPANY tion fever at present time. fine. Following are the times when stations HIPOWER CRYSTAL W4FNY, at Brunswick, Georgia will soon have are authorized to be on air down here: 10 M.- 71135- CHARLESTON ST. CHICAGO, ILL. 3 P.M. to 5 P.M. 20 M. P.M. to 8 P.M.; a xmitser. 40 -5 W4GHK at Savannah. Georgia. drops in a post- M. -8 P.M. to 11 P.M. card and says that he is having trouble getting R. F. Gaudreault (K3AS) his phone rig to work down to ten meters. Knowles says that his cathode modulator works KA1CS, Frank Spier, of Manila, uses a Spray fb. gun and an acetylene torch, draws copper W4VF. Rome. Georgia. has a fine signal on 75 wire through the acetylene torch, sprays it out meters. He is one of the gentlemen responsible over bamboo poles, thus making a bamboo rotary SEND EXERT for the FB hamfest there which is an annual beam. The whole cost came to 810.50. and cer- CODE affair looked forward to by all Georgia hams. tainty puts in a tremendous signal here into the W4IFT is working portable on 160 at Toccoa West Coast. Frank says he worked W2ICA, Learn Quickly at Home Get Real Speed Falls. Georgia and says that he likes the south. WSCNA. W3's, W6's, and W7DX with his 100 //, - bamboo W4GHU, W4GLB, Albany. Ga., and W4GHW antenna. The way Frank has it fixed. It's easy, fascinating, to become a good op. with the NEW at Damascus are new recruits in Georgia Army the three element beam supports itself. It ends ALL ELECTRIC MASTER TELEPLEX CODE TEACHER net.. three and one -half feet off of his roof, so it just to help you. Only instrument ever produced which records W4FCW, "Doctor Charte" says that he thinks clears the roof. As near as we can figure Frank your sending in visible dots and dashes -then sends back that we otter mention the fact that the Crisp still feeds it with a twisted pair. Frank's friends to you at any speed you desire. County Radio Club is the only one that he knows will be glad to know that he is now enroute that meets every day except Saturday in a local to the States, and will be visiting us all before Also sends practice work, recorded long. by an expert. That is why so many cafe in Cordele. Ga. If any others can beat this Master he wants to see it in RN. W6BF, as president of the Oakland Radio Club schools teaching code prefer Florida reports that he is doing a this job. It meets twice a month Teleplex, why thousands agree this W4GAA at Tallahasee. - has a new Defiant receiver which is the eats - that is the second and fourth Tuesdays at the method is surest and quickest. whiskers. Also says that he don't know why we Alden Library, 52nd Street and Telegraph Avenue, FREE BOOK mentioned his DX in a recent column. Well Oakland, California. We furnish Complete Course, Tommie keep up the good work with ur twenty - W6KW, Johnny Griggs, is doing a fine job lend you Master Teleplex, five watts. working the Byrd Expedition. Johnny's super - give you personal instruction ham transmitter, and diamond antenna, is work- with a MONEY -BACK W7HUJ is a new ham in Anaconda and is on ing just the way it should. GUARANTEE. Low cost. 40 meters with a 47 -46 transmitter and a W6NWG. makes a fine 160 meter stepping Send today for booklet RN6, National Sa'8 receiver. stone between Los Angeles, and San Diego, at no obligation. W7FL purchased a new car last fall and re- Oceanside. for daytime relays. 67 -69 PARK PLACE ports it to be very fb. business. The 1940 Northwest Division Convention will NEW YORK W7CUK has built a new xmtr, using a 616 -807 be held at Walla Walla, Washington, August 24, TELEPLEX COMPANY exciter and driving a pair of 809's modulated by and 25. The Convention Committee is as follows: In Canada write: a pair of 616gs. He has the exciter finished Wilbur Beale. W7FCG- Chairman CANADIAN ELECTRONIC INSTITUTE, TORONTO, ONT. and is getting some very fine reports from the Dick Rose, W7GMC- Program Chairman Ed Williams, W7HPG- Publicity Chair- man It is sponsored by the Walla Walla Amateur Radio Club. and those that were there before remember with a great deal of pleasure the fine times we all had. W6LPZ will be found down on Cahuenga Boule- vard. Hollywood, from now on. His round -the- world relays on 40 meters certainly used to be interesting to listen to during the evening. Centralab We are all wondering if the Treasure Island Amateur Station will be opened again. W6USA certainly worked out fine, and undoubtedly the Keeps late hours fine equipment had a lot to do with it. because the noise level there from all of the exhibits was trem endous. with the Serviceman W6ITH does not cone in as loudly in Southern California at his new location as he did when he weary and worn was on the eleven- hundred foot hill out there With fingers near Berkely, but Reg does get out in his usual the poor lad probes for trouble good style. No doubt it is much better for the of some nice noise, sar- amateurs in the east bay too, because Reg's in the shape signal also skips over them in arriving at the castic shorts, "lousy" leaks and open remote places. W6IXZ, Bob Reimus. although he was married circuits. last year. is now an "oldtimer" at the marriage When he finds them . Centralab re- game, and has more time to be on the air. again. placement parts end his worries. KA1CS is a very helpful chap. By discussing or set builders Asia DX with him some of the boys may still Hams ... servicemen ... work a, few countries over there, bes'des the ones a g r e e on CENTRALAB ... FIXED that are coming in regularly. such as the C O N - Philippines. Japan. and China. RESISTORS ... VOLUME The Whitcomb Hotel S.F. is still a pretty good TROLS ... CERAMIC CAPACITORS radio location for Hams visiting San Francisco, although they took down the 200 foot broadcast ... SWITCHES. towers on top of the hotel. which formerly made ideal suoports for portable ham rig antennas. "always specify W7BVO, as usual makes his equipment look Globe Union Inc:, Milwaukee beautiful, and if we did not know it were an CENTRALAB" Div: of amateur station. we might think it were one of the broadcast stations. (Neat page. 031 )

www.americanradiohistory.com June, 1940 RADIO NEWS 63

W7AHX, the original long wire antenna man will no doubt be at the Oregon Amateur Radio Association Convention at Salem, Oregon, during April. DE The Cheyenne Hams will be glad to know that Clutek Houge, is well under way with his amateur Riad HowThis Min license again. so may join thetas on the air soon. Wally Leeland, W7GCO, is on 20 CW these A Whole Tool Shop in your hand clays. His good old ex -navy fist sounds fine. Smooth, steady power at "Doc" of W7GGG. and W9ESA have been your finger tips. Uses 305 keeping a daily schedule on 7150 KC. for years accessories to grind, drill. and years. GotGood PayJobs polish, rout, cut, cane. W7FDV was reminiscing the other day. and sand, saw, sharpen, en- renteinbered the night. just before the shut -down, grave, etc. flags in any when he worked k 3CY, D3FZI, F8OY, VP7, VP5, )0- AC or DC socket. and an OZ4C, all in one evening. 10 Days' Money -back Trial Save W7CEO. of Cheyenne, certainly rolls in fine in RADIO Hours Order today. Standard of Hand down here its Southern California, on 160 meter Model (illustrated) 18,- Work phone. which is really nice dx. Some HAS OWN' RADIO BUSINESS EXTRA SPARE TIME PROFITS' 000 r.p.m. 111 oz. $111.75 of the other Cheyenne amateurs. W7- postpaid with 3 Acces- BAlf. and W7BCL, come in well on the higher sories De Luxe FREE 64 -PAGE CATALOG frequency bands, 20 and 40. I EARN CO 10.115 Model I HAVE BEEN IN BUSINESS 25,000 r.p.m. 12 Complete information on Hendee W7BVV has a large diamond for 10 meters A WEEK IN SPARE ne 310.50 Products and their wide app0ca- FOR MYSELF FOR TWO with G ACCee- phone, but due to his being on the wrong. slope TIME AND ALWAYS series, tion Icrafts work and industry YEARS, MAKING BETWEEN all of the hill, his rotary RAVE PLENTY 10 ,, f over the world. very often beats it. The $200 AND 5300 A slope of the hill has been a DO. ONLY TRAINED Chicago Wheel & Mtg. Co., 11111 W. MonroeSt, Dept. RN, Chicago, ILL very sati sta etory MONTH. BUSINESS adjunct to diamonds for some time, and a hill MEN CAN ris RADIO HAS STEADILY SETS NOWADAYS. I is quite effective when - they use them with half INCREASED. OWE MY SUCCESS wave antennas. using the side of the hill as a sort TO N. R.I. or reflector into the sky, both for receiving AWE . FROEHNER and ,100 W. TEXAS AVE. R tisi: i tti rig. tra 000SE CREEK, TEX. WOEJC, has a nice rotary beam now, and we E/R./AL Burroughs expect him to add to his 73 countries, and 260 foreign contacts. JOB RADIO Now that KA1AW, has resigned as SC3 /. for GOOD RADIO STORE AVIATION OPERATOR CASH Manila, we are wondering who the next SCM REGISTERS will be. 1 WAS WORKING IN A NR.1. TRAINING. WtiGRL is still up more GARAGE WHEN I ENROLLED putting diamond an- HELPED ME GET LOW PRICES -EASY TERMS tennas. The sky's the limit! WITH N.R.I. I AM NOW Ernie Brown, WBKNZ. is President of the RADIOISERVICE MANAGER AND HOLD MY JOB. FOR M I AM NOW IN CHARGE 1/arin. Count ?, Radio .1mafeite association, COLORS TO HARMONIZE and FURNITURE CO. Of THE 'RADIO DE- has helped make a lot of new amateurs, and his code classes FOR THEIR PARTMENT TOR THE are very well handled. 4 STORES AMERICAN AIRLINES. WITH SURROUNDINGS Mars Lusinehi, W6PVC. is editor of the Marin Coun.iy Amateur "QSA JAMES E. RYAN AT CLEVELAND. 5," and certainly puts out //9 PEBBLE se. WALTER A. MURRAY For a free demonstration call the nearest a fine rag. AUG RIVER, RAN. i AullOn Alt Roland Zehr, W6BFZ, as Secretary and Treas- Burroughs office or write - urer. reminds one of the late Will Rogers. W6EY, ye good old director, McCoys-rat', never BROADCAST STATION OPERATOR LOUD SPEAKER SYSTEM BURROUGHS ADDING MACHINE CO. misses an RM Nite nor an RM Meeting, W6CIS can be counted on to show up during any MY LOUDSPEAKER of the CW Contests. AFTER COMPLETING 20 LESSONS I SYSTEM PAYS ME DETROIT, MICHIGAN W7HDO has moved to San Anselmo, is now OBTAINED MY BROADCAST and ABOUT SYS A WEEK. on 160 meters. OPERATORS LICENCE ,K IF IT HAD NOT W6MWK is building AND JOINED STATION his own modulator trans- BEEN FOR YOUR former, and of course by the time this WMPC WHERE I 2,,, gets to COURSE I WOULD press, will have it completed and operating in AM NOW CHIEF M Î OPERATOR. STILL BE MAKING fine shape. COMMON WAGES. Sans Houston (watsina name ?) W6ZM is doing Halals R )IAYES M/LTON oz. extra good work on the American Legion Net, on 791.9.01, ñw Intensive, specialized course including strong basis in 1825 IRC. .t. mathematics and electrical engineering, advanced Some of the boys thought the net was to be Radio Theory and Design. Modern laboratory. Low on 1820 KC. and tuition. Self -help opportunities. Also 2-year courses in bought crystals there, and Aeronautical, Chemical, Civil, Electrical and Me- others bought 1826 KC.. but now Sam Houston chanical Engineering. Participation in Civilian Pilot has now settled down on 1825 KC. As yet the Training Program. Enter June, September, Decem- American Legion Net does not have the superb ber, March. Catalog. organization of the Mission Trail Net. but inas- Be a RadioTechnician INDIANA TECHNICAL COLLEGE much as Sans is an old Mission Trail Man, it will 760 E. Washington Blvd.. Fort Ind. doubtless work out to the satisfaction of all. Learn at Home -Make Good Money Wayne, W6GPB is going in for beams; W6DIX sounds speedy on his bug; W6OZT is fine on his 20 Do you avant to make more money to be successful like meter the man above? Then find out how you can train at home bean. nights to be a Radio Technician. W6ZI is back on the air after 14 years' ab- RADIO TECHNOLOGY sence, is RCA Institutes offer an intensive course and certainly going strong on :3512 KC. of high standard embracing all phases This frequency incidentally is a very fine "rag - Many Radio Technicians Make of Radio and Television. Practical chewing" net, and it is a pleasure to .join with training with modern equipment at New them once in a while. $30, $40, $50 a Week W6OKB has a. fine location; W6PAZ is York and Chicago schools. Also special. active Radio Broadcasting Stations employ engineers,operators Ized courses and Home Study Courses "No as usual. under W6TI, Horace Greer, as usual gets from one to technicians. Radio manufacturers employ testers, in- obligation" plan. Catalog Dept. RN -40. QSL spectors, foremen, servicemen in good-pay jobs. Radio 56 pounds of cards a day. for his Q,SL jobbery and dealers employ installation and service men. RCA INSTITUTES, Inc. Bureau. The rate at which he distributes them Many Radio technicians open their own full-time Radio A Radio Corporation of America Service is a marvel to all who behold. First he distri- businesses and make $30, $40, $50 a week. Some hold 75 Verlok St.. New York 1154 Merchandise Mart. Chicano butes them as "A, B, C, etc." into tubby holes. jobs in other lines and make $5 to $10 a week fixing Radios Then he takes each group and redistributes them in spare time. Others make extra money fixing radios while as "AA. AB, AC. etc." Horace figures about two learning. Automobile, Police, Aviation, Commercial Ra- hours a day, even with this speedy system based dio, Public Address Systems, Electronic Devices are other on post office procedure. If envelopes are there, fields offering opportunities for Radio Technicians. the cards go right back. Those with - several No. 10 envelopes get fast service. It is really RADIO a tremendous job. and we all owe a Get Sample Lesson and 64-Page vote of thanks to Horace Greer, for the fine work that ENGINEERING, he is doing there. He now has between ten and Book Free -Mail Coupon broadcasting, aviation and police radio, servicing, marine fifteen thousand cards on hand some of them Act today. Mail the coupon now for Sample Lesson and radio telegraphy and telephony, Morse telegraphy and going back as far as 1931 and 1932. 64 -Page Book Free. They point out Radio's spare time railway accounting taught thoroughly. 48 weeks' Engi- W6PAZ is nearly ready: W6OEI has a very and full time opportunities and those coming in Tele- neering course equivalent to 3 years of college radio work. active XYL. (Active. now. is it ?) vision; tell about my Course in Radio and Television: All expenses low. free. School established 1874. The Associated Radio Technicians show more than 100 letters from men I have trained, tell- Catalog of British ing what they are doing Institute, Oak St., Valparaiso, Ind. Colntahio. although made up of about half ama- and earning. Fine out What Dodge's teurs. shun the idea- of mentioning amateur Radio offers YOU! MAIL COUPON in an envelope or activities in their meetings. The little groups paste on a postcard -NOWT get off on the side, however. because "once a J. E. Smith, President Hans, always a Ham," and even though they try Dept. OFR National Radio Institute to keep it out of their meetings and out of their Washington, D. C. literature, they know their hearts and souls are in amateur radio as usual. W6I3JN likes 40 meters best; WSJTP is 160 l meter phone: W6AOF is working both 160 and Mail this Now RADIOp_,,,2, Get 64 -page Book 80 meters; W6GPB is trying to increase his FREE nower; W6FVK likes the high end of the 14 me. TELEVISION,/VrRv band. J. E. Smith, President No matter where you are or hat you do, Dept. OFR has a complete training plan for W7FXM is quite an editor and does quite a you-toNational lot of writing for the Northern Publications. National Radio Institute is for thosec seeking immediate i shop - all hope Washington, D. C. training as well as for those who cannot give We that the ARRL will have another up present employment and income. Mail board meeting in San Francisco. It is the first Mail me sample lesson and coupon below. Find out how you can get time that the beard ever met out on the West 64-page book "Rich Rewards the finest in radio and television training. Coast, and it certainly gave the boys a good in Radio "FREE. (No sales- NATIONAL SCHOOLS viewpoint of the directors in Hartford. Many man will call. Write Plainly.) of them feel that they know the directors and AGE NATIONAL SCHOOLS, Dept. RN -6 officers of the League personally. and are very 1000 So. F,necro. St., Lot Anodes, Calif. enthusiastic about them. I guess the board members will remember for a long time the reception NAME I Please send free Literature and full details. put on by W6EY. AGE l NAME It seems like the Morin County Radio Ama- ADDRESS teurs can get about 70 hams out about every ADDRESS meeting. More power to them ! CITY KA1QL, now W6QL, is traveling six states, at- LCITY STATE tends Ham meetings everywhere, and visits all

www.americanradiohistory.com 64 RADIO NEWS June, 1940

the parts jobbers, as a sort of poor hour occupa- tion. W6LMD is running for SCM, and presumably got it, because W6SG resigned. W6DWR took his beam down, and is now putting it up again after cleaning it, and eliminating considerable corrosion. W6DGE has a new Minis Rotary Antenna, which is surely a "peach." It is on top of an eighty foot telephone pole, on a little rise of ground at the East end of Long Beach, just before the drop -off into Belmont Shore, with its salty subsoil. Jim Larsen, W7DZL, can now be found at Ninth and Burnside. Portland. We all remember the snappy little portable he had up at Mount Rainier. Temp Ehmsen, W7VS, certainly is making the instantaneously operating 60 watt mobile transmitters these days. Frank C. Jones, W6AJF, is on the air whenever he builds a new transmitter. Hi! "XU1D is coming in quite consistently," says W6RRE; W6FJX is working portable; W6DEP has a new Mims Rotary Antenna, he is planning to put up. W7VS, W7DNP, and W7FU had a busy time on ten meters. Their gear shift lever came out while they were on a trip throughout the city of Portland. so they kept on describing the trouble and talking while being towed in (we were wondering if the FCC has a ruling about amateur stations being towed). GET A 'BREAK' W 7AXR has worked 41 states on his 10 meter YOUTH shout mobile. The cards are plastered all over the in- I11IN ®ED others. Young men side of the car. AIR me, it ought to interest his boyhood is so interesting to how much easier W7FDU has a swell "gasoline buggy" wheel "If flying fly properly." Realizing G. Allan Han- chair. We were trying to get him to put a . . learn to millionaire a it . a helping hand, the past mobile rig right on it. He is a member of the had someone lentle him in 1928. During Chairwomen' Club. wouldkfound have College of AeronauticsAer who lacked the Santa Maria deserving young men Some of the Long Beach amateurs are very cock founded of Here's intensely interested in television, and are watching the years he has helped education. programs which come nightly from Don Lee in twelve e a thorough aeronautical prominentent and colorfult Los Angeles. They use a variety of beams. funds ical of California's most interests s about one Roger Howell, an -ex -W7 has a three element biographical sketch beam in his home, and a six element down town. interesting The six element (two layers of three element figures. beams a half -wave apart) practically eliminates Churchill QRM as the beam itself works against itself, by Edward thus forms an effective shield against street PATRON SAINT noise. AVIATION'S W6PFA is a good convention Ham. He handled sixteen hundred Wanderbird messages while the Wanderbird was down at the South Pole last year, and plans on doing it again this year. This will be the fourth year. INTERESTING commentary on the stages to which the belligerent dictatorships will go to disseminate their propaganda is to be found in " "50ÚP"5 the columns of Quesstee which faithfully reports on!" that certain German hamstations will be re- A few years ago airline passengers licensed to operate during the present war. Most lucky to get a were significant of all, is the statement attributed to thermos jug of coffee! D4BIU. "Please notify they are served delicious Today all interested." second six -course dinners In view of the well -taken program promulgated to none. The type of by the ARRL for the benefit of the American . meals served Hans, and in further view . - how menus are determined of the fact that the air ... effect newspapers have been full of the German "White travel on passengers' appetites of Paper" alleging that we, of all people, started are just a few of the ... these this war, we wonder who might be the persons phases many interesting who are "interested." The policy laid down by of airline food problems the ARRL not to communicate with the belliger- in this unique article discussed ents, and agreed to by many of the remaining hams on the air today, whether here or else- where, cannot allow that by the mere permission of the German Government to sanction the "D's" by DE WITT WENDELL being on the air, we should thereby drop our ideas that belligerents are to be watched from the side -lines and not "spoken." Then, too, there is always the risk that the "D's" might at some future date print their own "White Paper" accusing the American Ham with starting the war. Hi. While we sympathize with the German Hams. ever mindful of the fact that they, too, had little to do with the rupture in the general good - fellowship which had prevailed among the hams, prior to this war, we feel that the ARRL edict "THE PERFECT should stand and that we should continue to mind our own business and refrain from QSO'ing the "D's " -at least until the end of the hostili- ties. Let us remember that by doing this we will best serve our country in maintaining its AIRPLANE neutrality, TEN meters won't be completely outdone, and the for the first time in many months there is affected enough 28MC DX get along," WINGhas profoundly the to devote a separate paragraph fellow trying to riddle which defied to it. - With everyone using ECO's it is tough giv- R. Davis, " just a little solved an aviation read ing frequencies. so you will have to dig 'em out David This modest genius yourself. Active of aerodynamics. event at Kitty Hawk! Dos and during the past month were: study minds since that enemy, air resistance,'great CX1FB; LUPAX LU2FC; LU2DH; HC1VT K6- most brilliant aeronautical flight's article, AYD; K6SCB; K6PAH: PY2AC; K6QZL; K6- this "nut greatest SBL' /K6- K4DTH; XESAM: ZP1AA: LU7AZ: how aviwoo d con hatedPe your P. A. PY1HQ K4FKC; K6FFL; CO2AM: CE1AO; K6- the Harold Keen, on page 36 of JLV; COSIM: NY4AD; K6PLZ; K6BNR LUIDA: AIßFOIL by TLIAV: HP1A; and KA1GC. While it isn't DX MYSTERY one of those unusual things came though on 28- MC. CW during the DX contest. In order to make public their achievement here is a partial list of stations active on 78MC. CW during the ISSUE DX contest. W1TS; BPN; 2BDK; LRI APT of the JUNE IMF; WC; EEN; UK; CJM; AIW; 3EMM- 4BZ Copy CDE ECI; F5S; 10; 5AVF; FGB; DWO; 6QQL Get Your QD; POZ; 7EZX; GBW; of modern aviation Up; FRS; EHL: DRF Follow the march tion 80XG; ERA; ZY; 9FYY- WTW. Of course there goals . were numerous others active who are not listed, toward greater Magazine but this at least proves there is something rarer Leading Aviation than a ten meter CW signal -no it's not a 160 World's meter CW signal. month. The June W4FVR is ex -W2AAL and is now engineering every at TVBT. John out at W9CSI really works out AT ALL NEWSSTANDS using a 250 watt final with an HF200. Antenna is a Johnson Q. Incidentally W9CSI has 97 countries on CW, but is not on 20 phone. W6HSV /2 is none other than Fritz of NY2AE,

www.americanradiohistory.com June, 1940 RADIO NEWS 65

etc. Now stationed at the Brooklyn Navy Yard now sitting back to enjoy life. W6QQL is back in New York he'll be signing a W2 call real at Boulder City. Nevada, to make the boys soon. Newcomer W2MUO makes himself heard happy. W2IOP is rebuilding completely again. with 60 watts on 20 meters. Frank didn't waste Remember the little piece about old timers and any time getting on the air. First contact for young ones in the Frankford Radio Club? W^_MUO outside of the U. S. was HH2MC. W3KT got mad that we said the reason it is W2HP is the local supply for Long Island pole such a club is the young live wires keep it at masts. John is with the local power company top Jessie went out and won the club WAS if that means anything to you. contest producing the 48 cards early in Febru- Almost overlooked, but not quite is a DX list ary. for the first two days of the month, logged on the W'2EOA /W2HXQ are selling out. Why? W2- East coast. Phone: XU1B; PK1OG: KC4USC; JDG /W2JZX will soon be back on the air with EK1AF; K7HCX: LU1BA; and a slew of K6's. their highpower on 20 meter phone. W2GT, CW: 4C/I',V. IC'4.IS; TA1AR; KC4USC; X1:6- DX'er de -luxe. lost his rotary during the freak MK: XUtiAL: D4BIU; HA4P; OK3ID; PY2NO: ice storm which hit the East recently. KB6RWZ; CE3BG; LU9CZ; J20V; J2KG; K6- WIHSA and W1MFC are co- operating at MIT SCB;; CE3CB; J2KN; HK5ED; XUOK; HH3DN: with some of their projects. W2EWH /4 manages HH2MC; OQ5BF; OQ5AV; U9ML: U8I11; HA4H: to enjoy some real Florida sun while working LY1S; all on 14MC. On 40 there were ample down there. W9UUA /7 is operating at Rock Hawaiians, HA4H; several K5's; and HH2PB. Springs, Wyoming. 80 was good also, but no DX was heard except DX men have been working overtime to pro- four Spanish speaking phones in un- identified duce a list that looks like old times. The DX Put Your Valuable Radio tountries. Add on HP1G; CM2BF; CM2PW; contest brought out a few new ones, but gen- CM° LC; CO7CX and you have the DX story for erally it was just good "digging." You'll notice ties month. numerous European stations listed. but best dope Experience to Work for You! W9MSX runs 150 waits into an 852 using an on hand indicates that the FCC does not approve Your indoor antenna and a NC101X receiver. Burt's of contacts with Europe. experience is a valuable asset in preparing first qso with the setup was IMIR. W9FS, the The 20 meter phone band outshone every for a career in the professional field. Many top DX'er, contest is trying- to snag AC4YN for zone thin;' to give up: LY1J; EA7BA; EK1AF; KC4 engineers and in radio today number you -know -what. AC4YN-KBORWZ-W5- USCt COIRA; IITAK; K7I3UB; XUBAM; XU1A others turned their ECA-WhIOP supply a fast route to Tibet if you XU1B: YN1.IP: YN1FF; YN1OP; XU1AA "ha-0,y into a career" and now enjoy good have any traffic to friends or relatives there. LY1S; HA6Q; HA9Q: HA6T; LZ1ID; LX1RB technical jobs. You have the same opportunity, by WSDG is running a kilowatt on 40. HH3DN ESSD; ES5G; K4FKC; KALME; KA1AF; MR- says to QSL to Gabrial Dorce; Quarters General: 2CC, KA1SM; KOOJI K7HUZ; KOBNR: KO- applying your inherent love for radio to a planned, Haiti. CMfJC asks you to ship his pasteboard MGA : CO2BA; EASF; YVSAA; CO2AM; C060M; proven course of training. C.R.E.I, courses are to Julio Martinez; Oquendo 204: Havana, Cuba. YVIAQ: YVSACE: CO2JMt XE2IY; TI5JAS: W7HNY over Portland way runs 100 watts HKIPAA: Ti(9HP; XE1FF; and YV4AE. selected by men in the industry who realize that into his VFO 809. KC4USC won't work anyone 20 meter CW isn't too bad, but mainly because technical training is the difference between "just on hi" frequency is -which the latest way to of AC4YN. W2GTZ and W2AIW are two recent a job" and a real future in radio! Among our get rid of QRM. Too bad for the boys who have worker's of Fox. WOHLF steeds AC4YN daily, as their only crystal on his frequency. but that's does KBORWZ on the Tibet -New York traffic line students are many amateurs who are now heading DX. WSI?Z in Cincinnati. Ohio pounds through The following DX may be found from 14300 KC into good engineering jobs . . . hundreds of men in using a 30 watt rig. Nothing to 1 portable startling -)400. J2IX; J2NF; J2KN; HA9U; K4KD more than until we learn it's on 14MC. phone! The line up K4DTH K4FCV; LU7AZ; KBORWZ; PY2NO 300 broadcasting stations . . . more is a 6L6 into an 807. modulated by a 6J7 into XEIAM: HI3C: PY2AL: PY1GJ; HH2MC; LU than 700 radiomen in the Navy . scores of a (3C5 driving a pair of 6N7's. The complete 4N13; CM2AP; PY50G; KSAE: KA1FG KA1HR airways rig is on one small chassis and according to PY2GS; OA4U PY1HQ: LU2AG: LU4AG men. C.R.E.I. training must bring results. George runs his HK254 PA plenty of competi- LYISS; CPI XA; HC1VT; PY2AG; LU5FB May we show you why? tion. HL3F; CM"AO; CX2BK; PY2KT HK2BD; PY- WIICA hit. the 110 mark in the DX CC and is IDS; PY1HC: PY1DW; and D4BIU; OK3ID; OQSIM; OQ5AV. Write for Free Book, "A Tested Plan"

To enable us to send you complete infor- 'KWP has recently slipped down from mation, please state briefly your back- 29600 ke to 29060 ke, so that he doesn't ground, education and present positi have to yell so long per QSO. Bill is with the n- Newark Pollee Radio. and whether you are interested in home - Rafe I 5c per word. Minimum, I O words. W2FGJ has an AX -T7 receiver. Hank has one study or residence training. of the best -sounding cathode -modulated outfits CORRESPONDENCE COURSES around town. and runs 140 watts. CAPITOL RADIO W2EDJ isn't being heard so much of late be- USED Correspondence Courses and Educational cause Jack is having trouble with his modulator. Engineering Institute Books sold or rented. Inexpensive. Money -back XE2FL is XE2FC's brother. guarantee. Write for Free Catalog listing 4000 Our last QSO of 1939 was with XE2FC in Tampico. and climaxed Dept. RN -6, 3224 16th bargains. (Courses Bought.) Lee Mountain, another year full of many swell QSOs. St., N. W., WASH., D. C. Pisgah, Alabama. In the News ¡Newark's only evening paper) CORRESPONDENCE courses and educational Kay Caldwell writes a column for the adolescents books, slightly used. Sold. Rented. Exchanged. called "Youth Talks it Over." Her advice to 1L-Es Correspondence All young girls who despair of their less- amorous Courses In subjects. Satisfaction guaranteed. Cash paid sure for usent courses. Complete details and bargain swains is disheartening. She says that RADIO dfld L£CTRICAL £NGIN££RING catalog free. Send naine. Nelson Company, when the lad prefers to talk about his Short -wave radio all the time. ELECTRICAL ENGINEERING F-237 Manhattan Bldg., Chicago. it isn't due to the girls fail- Caen a: ing' electrical field. Prepare ayourself at i charms but is just a sign of his (the ham's) Low Coet. fur re 8 ei plfied nyoaeen can understand quickly. INSTRUCTION immaturity! Oh well . . . we've been accused Es r ear ,e a r.,di,,, ,mho of everything else. RADIModern GINEERING -tube service r Tratue AMATEUR Radio Licenses, complete Say Ed. to be.aunr- men, real vacddm techn¡c wn training in don't forget that Limelight! hi. kite furnished. Diploma Ex perimental code and theory. Hundreds of licensed students WUBFL leas a 3- on eomplotto,,. element beam that is a joy to Either c,a , only 325. payment on the air. American Radio Institute, 1123 beho'd. and with a hundred in. Tony's working pl[,,t avallabte. onntc fer free f,,l o[ sohool Broadway. New York. fine. magazine full details; out As f25 BEÑJaNOÑ °dent W"KRA has been on for some time working LINCOLN ENGINEERING SCHOOL Box 931 -R 18, LINCOLN Nebr. PATENT ATTORNEYS DX on 10 and 20 meters. Barry has a neat INVENTORS- Before disclosing your invention rack & panel job which is responsible for a good send to any one for Form "Evidence of Concep- eW °LUX who is sophomoring tion"; "Schedule of Government and Attorneys' at Rutgers Uni- EVERY Fees" and instructions. Sent free. versity reports little harm activity- because of LATEST Lancaster, studies. At claims they have a swell gang at the Allwine & Rommel, 414 Bowen Building, Wash- radio ington. D. C. club, and that he will have his own ,junk PROFIT going soon after the marking period. (Better not GUIDE PATENTS -Advice and booklet free. Highest before!) references. Best results. Promptness assured. W2CF is beginning to feel the ham -itch again. r K. Watson E. Coleman. Patent Lawyer. 724 9th After ten years off. Roy is setting up a new lay- Street, Washington. D. C. out. and with the help of his pal 2ACZ, will be PATENTS Secured. Two valuable working out on ten lone. Something on the RADIO! booklets sent roof wad work bet.ter'n that indoor antenna, Roy. free. 'Write immediately. Victor J. Evans & Co., We in Northern 58:3 -G Victor Building, Washington, D. C. Jersey welcome W2MTJ to our midst. Ken who is ex -ALNO has just moved in from points west. He has a dandy layout using COMPLETE SELECTIONS RADIO ENGINEERING a grid- modulated T200 with 2.35 watts innut. RADIO Engineering, broadcasting, aviation and With a "Couple O' Kilowatts" W:3COK is bang- GUARANTEED QUALITY police radio. servicing, marine and Morse teleg- ing out on ten -meter phone. Bill is up of the Faster Delivery raphy taught thoroughly. All expenses low. Cat- high -freq end of the band where he finds the Most complete stocks of Uni- alog free. Dodge's Institute, Elm St., Valpa- OEM situation less acute. (lad! II-otta vocabn- versal and Exact Duplicate Re- raiso. Ind. Irtra. placement and Repair Parts, Even the much -scoffed at town of Weehawken, Tubes, Aerials, Cabinets, Radio RADIO N. J., boasts of an amateur. He's W2KXS. Sets, and Amateur Equipment. works on ton forte, and also in the post office. P. A. EQUIPMENT WE buy and sell used radio testing equipment. Howdy Ray! Separate amplifiers or complete Harold Davis, Inc.. Jackson, Miss. Another confirmed CW systems with any desired assort- man gone "phoney" is ment of speakers, W2FTL. Johnny has a new cathode -modulated horns, baffles outfit using a TZ -40 and microphones. Everything HAM STUFF final and a pair of 45's as from 5 to 100 watts. Prices MUST sell all modulators. He's still using the same 40 -meter that save money for you. transmitting and receiving equip- zepp. but a Ilallicrafter's recur ment. Write for list. Carl A. Kowalski, 1.239 has supplanted Kinnmoor Ave., Ft. Wayne, Ind. the S11- -.1. ELECTRICAL APPLIANCES W2LUJ who is still portable -two. built Extra profits for your Standard Brand Electric Irons, SELL: McMurdo Silver "1.5 -17" receiver with Johnny's rig, and is working out swell with his Grills, Toasters, Percolators, Wattle Irons, Vacuum Clifton console, $110. Gay Morrison, Jr., Box own pea- powered ECO outfit. How about a call Cleaners, Clocks, Mixers, etc., at lowest prices. 123. Conway, Ark. sometime. Art? WOMUM's QSL card gave us quite a BARGAINS. Used sets, equipment, tubes. J. C. surprise. Thi mitan. Lake City. Minn. But Mum's the word. Baird. MAIL THIS COUPON TODAY The Newark College of Fnpineerinn Radio The RADOLEK Co. (Taub has a new- National NC-100X receiver. MISCELLANEOUS has This 601 W. Randolph St., Chicago, Dept. P-42 lob full range coverage and it was decided Send the latest Radio Profit Guide FREE. SONGWRITERS, Authors, Inventors! Protect that it would be an asset to have something to your Ideas. Total cost do a lit listenin' to expeditions, commercials, Name $2.00. Request free book- etc. let. Evidence Bureau, F1501 Broadway. N. Y. C. Conspicuous by his absence on 160 -meter phone Address - Dealer? PHONOGRAPH Records -twelve, $1.00. Para- is W2IBX. How's about mount, FA -358 East Market, Wilkes- Barre, getting the heap going Serviceman? Amateur? Pa. again Paul? (Pee QSY next page, OM) LExperimentor?

www.americanradiohistory.com 66 RADIO NEWS June, 1940

W2KGZ has joined the gang around town who fone rig, is experimenting with a high -fidelity are trying to get a little activity stirring on 23/4 amplifier for his symphonic records. meters. What with work and night school, Mike doesn't get too much time for ham radio. T IA W4EVX: It seems to us that the W -hams would get an ` Since spring is here at last the whole gang awful kick out of getting "calls heard" reports of W4's are brushing up their rigs, putting up from some of the DX boys who are off right new antennas and getting ready for newer ac- now. So make 'em voluminous boys, and in- tivities. clude all those S2 sigs like mine. (Conceited eh? A new club has been formed in Nashville, All right then, Sl.) Tennessee and under the club call of W4GN. Another of the 160 -meter phone boys, W2HFB, About five different bands are covered including seems to be in the doldrums at this time. Watsa five meters with a maximum of 500 watts on Bill? That YL can't be taking up all your the lower frequency bands. All of the Tennes- spare time. see hams can participate by making schedules, That guy on the cover of Mar. '40 RV has a reporting activities and by showing operating peachy final tank. procedure that will help in time of emergency. W2MPQ went over to neighbor W2IDU's house This club is expected to be the center of traffic for a visit, and succeeded in talking George out handling for Tennessee. Some of the organizers of his bug. By the by, 2IDU has a new Pontiac are W4AYE, W4BAF and W4DDF. Listen for convertible coupe. W4GNN every Monday night on 3550 kc. at [Tnt to W2GFW fer the above. Ed.] 8:00 p.m. ' W4DRZ of Fort Lauderdale, Fla. has become 2EFI and W2IFX both are now working aquainted enough with PK1OG to receive a pack for the American Airlines at North Beach of cards from him to forward to the boys Airport. throughout the fourth district who have worked W2MWK new ham located in Ozone Park in- PK1 OG. tends to install ten and two es one half gear W4FNS, the "freckle- faced" Kid of S. C. (age in his gas buggy for this summer. 15) is doing FB. He has WAC. WAS, WBE, W2JWE has pair of 809s in final on twenty and has worked 60 countries with confirmations and forty cw and is thinking of cranking the of 45. rig up an eighty cw. Reaching out into spots where such glamorous WHIN /2 that tall feller working in local ham activities are unheard of we find that W1BLO house in NYC hails from Boston. Mass. can show us how easy it is for him to receive W2KIK piled up a nice score in the 1940 R9 from YU7LX on c. w. while W1BLO is on ARRL DX contest. phone with only a kw. W2CKQ is waiting for the New York World's W3FJU is back on 20 meter phone again after Fair to open so he can handle tic at W2USA. being on '75 this winter. So conditions must Wat sa. WZHXQ? be getting better for DX. He already wants to W2KPE is the Voice of Canarsie on 160 fone. know the Qth of EA7AV. As radio marches on to a still more W2KYV active on twenty, forty, eighty cw W7AYO is giving W1AW some competition in with 125 watts. transmitting official ARRL messages. You might critical technique, there are new and W2LUX can't seem to work out so good on ten think so when he does it for the benefit of the more precise requirements to be met fone so is trying his luck on two es a half. South Americans besides the whole W gang. W2LGS doing nicely on two es a half working Stan is a real pal to any of the well known by mica condensers. Which accounts into N.J. hams down there. for several new items in the AERO- W2MQA on 160 fone in Flatbush "Yowzah." Since W6PH of Salinas, Calif. received a card W2GGN using a single 801 ose on two es from Tennessee, he only needs Mississippi and VOX mica line. a half. S. D. for WAS now. W2KXG not active due to nite school work. W8CRA, the old Century Club man who has [Tux to IV2IIBO for the above. -Ed] more countries than any other station in several W districts is on regular now with a CQ with AN East Providence, R. I., 21/ meter SWL XUPZ at the other end. reports We find W5CTW rotating a minis beam... Yes, The following is a list of 21/ meter stations with one shout at KC4USC that 4USC came back heard operating more or less consistantly in and so quick giving 5CTW, 589X that it kinda scared Push -button tuning and other critical ap- around Providence, R. I., during the last several him. but since 5CTW gets R9 from all of these plications are taken care of by the AERO- months. DX honeys he didn't take it so serious at that. VOX Silver Mica Condensers now gen- W 1 BOM, CDI, CNJ. DBA, EBA, GUD, GWL, W3HTF says he thought this best DX was a erally available. These units have long HJB, HQR. HXV, INM, JP, JAA, JUN. KItE, VK3 on 40 meters, but since Berm worked been used by set manufacturers. Pure KOA, KUX, KVB, LKH LNK, LPY, LQE, MHB, HC1FG and HC1VT in one night on 20 he is silver is deposited and firmly bonded on MKL, MLA, MLI, MOT, MXA, MXB, MXO, OAD, going to stick to 20. mica sheets. A remarkably low tempera- OEX, OJF, RAD. RAG, RUS. ture coefficient is attained -only plus One of the local 112 me. hams is off the air ROLL out the DX and we'll have a band full .0022 per degree F. These condensers temporarily due to a new kind of interference of fun. Who said DX was a minimum have excellent retrace characteristics. problem. A bellicose neighbor, who plays an nowadays? Even if it is falling off a bit, fellas, Practically no capacity drift with time. electric guitar. complained that instead of Aloha the fever is as strong as ever and the way cards Exceptionally high "Q." Tolerance limits Oe all he could bring forth was "W one Blub are coming through lately it shows that some of can be held to as close as 1% if required. Blub Blut calling See Cue" Hi! the best QSers for WAC are ZSGBJ, ZS6EU, While visiting the other day ran across a ham ZS1AC, ZS1DB, ZS2G, ZS5CU, ZS4AA, XU8MI, Available in usual brown bakelite, or who was using a temperature gauge. From the yellow XM low -loss bakelite. .000005 LZ1ID, LU8DJ. and VK5AJ. an extinct auto instrument panel for a plate To the editor: Your dope telling some of the to .005 mfd. 500 v. D.C. Test. milliammeter. He was running a type 10 long South Carolina stations to wake up and listen line oscillator with 500 volts at 185° F. input. for the CE's in the April issue of R.N really Hi! brought results, listen to this: Most of the receivers are of the self- quenched CE3AG and CE3BF have been active trying to type. (56 or 76) with one of two stages of work WAS lately. Both have had cards from audio, while the Xmtrs vary from 45's to HK24's . 47 different states years ago, but for three years in all the usual circuits. they have been calling CQ S. C. every night. At the same time the other day two letters were FROM W3EEW. received from Chile. one from 3AG and the W3FZI, opping portable while on a job in other from 3BF. CE3AG said, "Ah ! at last I Baltimore, plans to keep in touch with Phila. worked W4CQG in S. C. on ten meter phone." The dozen and a half bakelite molded re- friends via 80 and 40 ese, using the popular CE3BF says `I worked W4EMT in S. C. and got his card." Congrats boys and FB ! CE3BF ceiving and transmitting types of AERO- 6L6G xtal ose. now Clara VOX mica condensers are now available Two of his buddies down there with him. is on board the Santa taking a voy- up some high - age to Antafagasta (CE1) where he is making in yellow XM low-loss bakelite at only W3GBQ and W3EEJ, are talking negotiations for the DX Century Club. He says 25 cents added to list. Meter- mounting- class 2% meter plans. '7 me. his weekly that he has an album which contains the cards bracket units are also available for r.f. W3RR heard on enjoying of the countries that he has worked and all the And when it comes ragchew skeds with W2JDC and W1BDU. shunting of meters. A well know Phila. contest man is having fun Chilean amateurs look at it because he is near- to handling considerable power at ele- chuckling over his "no- handed" contest setup. est to the DX C.C. He hopes to be the first vated frequencies, there are the porce- Rigging up a small speech amplifier, he dit dit South American Member of the DX C.C. He lain -case units. dit dabs into the mike and operates a relay will be back in Santiago in a month and start which keys the rig. Doggened if it doesn't work, pounding brass again. leaving hands free for receiver and log! What CE3CB is Chile's best rag-chewer. He QSL's 0000 next! 100% and sends a separate card for each QSO. \ Another veteran c. w. man planning on a 2%/ meter vacation is W3DPU, Phila.'s emergency AND tt ab+ winds up another colyum fer coordinator. With a fb eco and good fist, W3GKO is drag- this mn +h. Sure hs bn a lot of info being 0000 ging in plenty of traffic on 80 and 40 these days. passed around here- HMCHTTR continues to Being an active station in a transeon traffic net means work, discovers W3HRS. Over 100 top them all fer gossip es such. But it en be messages direct from Calif. in one night is no made much bigger. So long as the publisher . picnic, hi! * Ask Your Jobber .. W3QV's new rhombic. backed by his powerful of RN will give us the space why not use if? He can show you any mica condensers transmitter. is to be relied on for lots of work Need lots of dope fm the following places: you may require, from the extensive with the Byrd Expedition. Maine, Vermont, Upper New York, Ken- AEROVOX line. Ask to see them. Ask A certain SO meter AARS man is getting quite and free subscrip- expert at playing "America" on his eco. Super- tucky, South es North Carolina, Missouri, for new 1940 catalog patriot? tion to monthly RESEARCH WORKER. Or Three of Phila.'s be stations are reported Texas, Arizona, New Mexico, Utah, Idaho, The write us direct. readying for new frequencies this summer, and Dakotas, Oregon, Washington, Nebraska, what pleases us is the fact that they are moving to even hundred kc. spots. making it fb for those West Virginia, Washington, D. C., and Kansas. J9 using 100 kc. freq. standards. Watsa youse guys? Don't you want your W3EEW builds eco's for others but spent two pay the info, es months trouble -shooting in his own, hi! state represented? We fer W3AGV and W3BES heard boasting about the pix. Es if the pix is one of your shack excellent results in the Jan. ORS Party. They you can have it free, after publication, for the usually have good reason to. WSTNA /8, now doing oil research work at asking. Cuts dwn the cost of personalized VPI, says the ym /yl ratio is too high down there! QSL's like no- body's biz. Es hw abt your va- CORPORATION Has to go after "dx yls !" June is a long way off but lots of Field Day cation trips? Wat, no rdio? We don't be- NEW BEDFORD, MASS. plans are being carried on already. Prepardness lieve it! Send along all the dcpe. counts a lot, it seems. IN CANADA: - AEROVOX CANADA. Limited Hamilton. Ón1. W3FFL, besides fooling with his 10 meter BCNU es sk fer nw. Ye Ed. 3Q-

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www.americanradiohistory.com THE THE NEW Combines NEW CHANNEL- NA YZER MODEL. Models 1240 Follows the SIGNAL from Antenna fo Speaker 1280 EllES,,!TE and 1250 A complete teat1n , laboratory in o n e unit, the Model 1280 combines the Models 1250 Multitester and 1240 Tube Tester. (See specifications of each below.) *Instantaneous Snap Switches Reduce A c t u al Testing Time to S-`-,R+mem.. Absolute Mini- mum. a( * Spare Socket and Filament Voltages Up to 120 Volts, Make t h e Model 1280 Obsolescence Proof. * Latest Design 41/2" D'Arsonval Type Meter. The well established and authentic SIGNAL TRACING METHOD o lo- * Works on 90 to cating the very circuit in which there is trouble, and the very com- 125 Volts 60 Cycles ponent ti at causes the trouble, is now for the first time available at a price any radio serviceman can afford. A.C. TILE Even those servicemen who through past purchases know they can always get SUPER - VALUES from Superior, will be amazed and delighted when they read the specifications CHANNEL -ANALYZER will of this all- purpose instrument and then note the unbelievably loiv price. The Model 1280 features a 41/2" D'Arsonval type meter for easy reading of the various scales, and in Follow signal from antenna to speaker through all stages of any receiver new * ever made. line with our new policy of stressing appearance as well as serviceability in our * Instantly track down exact c usO of intermittent operation. 1200 line of test equipment, our Model 1280 utilizes an aluminum etched panel, designed * Measure both Automatic. Volume- Control and Automatic- Frequency -Con- for beauty as well as ruggedness. The primary function of an instrument is, of course. trol. voltages and circuits without appreciably loadin the circuit, using to make measurements accurately and when designing test equipment this is our first built -in highly s r itive Vacuum -Tube Voltr40ter. important the appearance an Check exact gain e .0 every individual stage ih iver. thought. however, we also appreciate the part of instru- Track down and locate cause of distortion in 1 R.F., I.F., and A.F. am- ment plays in the impression a serviceman makes on his customers, especially on home calls. We have, therefore. paid special attention to the outward design of all of our * Check exact operating voltage of each tube. For instance, the panel of this Model 1280 is made of heavy -gauge locate leaky condensers and all high -resistance shorts. also show opens. new instruments. * Measure exact frequencies, amount of drift and comparative output of aluminum and etched by a radically new process which results in a beautiful, con- Toscillators in superhets. fidence- inspiring appearance. * rack down exact cause of noise. Model 1280 comes complete with test leads, tabular data and instruc- The Superior Channel- Analyzer comes housed in shieldetl ab- fir, net and features an attractive etched luminun panel. Sup- tions. Shipping weight 18 pounds. Size 13 "all "a61 ". Our net plied complete withth tubes, three specially engineered shielded $ 75v price iput cables, each identified as to its pure. Also full op - cratingrating i tructions. Size 13 "x1O "x6 ". Shipping weight 19 $1.00 additional pounds. Only Portable cover THE NEW MODEL 1250 THE NEW MODEL 1240 MULTITESTER SLOPING PANEL FOR PRECISE Instantaneous RAPID Snap Switches SERVICING Reduce Actual Testing Tinte to Absolute Minimum

Tests All Tubes Etched Aluminum 1.4 to 117 Panel Volts

A Specially Designed Electronic Rectifier for All Enables Linear A.C. Sockets Scale. High Stabil- Tubes - ity and Little or no No Adapters Temperature Drift. Here is an opportunity to acquire a Multi- Service, Precision Engineered A Instrument, for less than you would have to pay for an ordinary Volt- Ohm Milliammeter. Besides making the usual volt, resistance and cur- Superior is proud to offer the rent measurements (both A.C. and D.C.) this unit accurately measures newest and most practical tube the CAPACITIES of Mica, paper and electrolytic condensers, INDUC- tester ever designed. Unbe- TANCE of coils, chokes and transformers, DECIBEL gain or loss, of lievably low in price- unbeliev- power amplifiers and public address systems, WATTS output of am- ably high in performance. plifiers, receivers, etc. *Tests all tubes, 1.4 to 117 Volts, including 4, 5, 6, 7, 7L, octals. loctats. Ban- SPECIFICATIONS tam Jr., Peanut, single ended, floating filament, Mercury Vapor Rectifiers, the Complete A.C. and D.C. Voltage High and Low Capacity Scales new S series, in fact, every tube designed to date. and Current Ranges *Spare socket included on front panel for any future tubes. .0005 to 1 mfd. and .05 to 50 mfd. *Tests by the well -established emission method for tube quality directly reati on D.C. Voltage : - 0 -15, 0 -150, 0 -750 3 Decibel Ranges the GOOD i BAD scale of the meter. volts *Jea el protected neon. A.C. Voltage : 0 -15, 0 -150, 0 -750 - -10 to +19, -10 to +38, -10 to *Tests shorts and leakages up to 2 megohms in all tubes. volts *Tests leakages and shorts in all elements AGAINST all elements in all tubes. D.C. Current: - 0.1, 0 -15, 0 -150, + 53 *Tests BOTH plates in rectifiers. 0 -750 nia. *Tests individual sections such as diodes, triodes, pentodes, etc., in multipur- A.C. Current: -0 -15, 0 -150, 0 -750 Inductance : 1 to 700 Henries pose tubes. ma. *Latest type voltage regulator. Watts: Based on 6 mw. at 0 D.B. 2 Resistance Ranges *Features an attractive etched aluminum panel. 0 -500 ohn.s, 500 -5 megohms in 500 ohms .006000 to 600 Watts *Works on 90 to 125 volts 60 cycles A.C. A.C. Comes coin- Model 1240 comes complete with instructions and tabular data Model 1250 works on 90 -120 volts 60 cycles , for every known type of receiving tube. Shipping weight 12 Mete with test leads. tabular charts and instructions. Ship- 85 $ 8J pounds. Size 6 "x71/2"x10% . Our Net Price ping weight 9 lbs. Size 91f2"x11 "x61A ". Our net price Portable Cover S1.00 Additional Portable Cover $1.00 Additional 136 I S U P E R I t R IN R U M E N T S CO. NEW YORK, hÌ(.