JULY 1951 tAl)I K - ea CS LATEST IN TELEVISION SERVICING AUDIO TELECAR SPEEDS TELEGRAMS 30 7J_E FIROAr-sCV,TINCJ AND COMml.micik flON. U.S. and CANADA In this issue: TV Tube Substitutions Field Strength Meter Pocket Superhet www.americanradiohistory.com tt,cea,flUMDNT A UTOMA TI-FOCU S Completely Provides- Eliminates- AUTOMATIC FOCUSING AT ALL TIMES FOCUSING COIL FINE OVERALL FOCUS FOCUSING CONTROLS REPLACES ALL 17" GLASS MECHANICAL FOCUSING RECTANGULARS WHETHER DEVICES ELECTROSTATIC OR ELECTROMAGNETIC 17" NtAvailable soon in other sizes nUM FOR COMPLETE TECHNICAL INFORMATION - WRITE: TUBE DIVISION - ALLEN B. DU MONT LABORATORIES, INC., CLIFTON, N.J. www.americanradiohistory.com RADI:': -TEL E. SMITH. Prea. aanonal gadia Inslilel. 8000 TECHNICIA FREE y N0 SN upoN A1. Americas Fast Growing Industry Offers You M 1. EXTRA MONEY Available to Imo' IN SPARE TIME Many students In 14 t 5, :r,IU a week extra fixing neighbors' Radios VETERANS in spare time while learning. The day you enroll I start sending you SPECIAL BOOKLETS to show you how to do this. Tester Bill you build with parts I send helps you service sets. All equipment under G.I. is yours to keep. 2. GOOD PAY JOB I TRAINED THESE MEN Your next step is a good job installing and servicing Radio- Televi- Mid Wow, Pam bila Wry IMdakes is TMMUM, Soon after finishingg Have am on shop sion sets or beccming boss of your own Radio -Television sales N. R. I course, An auw¡sedtl - h' ked for servicing a 5 large and service shop or getting a good job in a Broadcasting Station. hop. Now 1 am Chief roanufactirers and d, Engineer of N'CUN, xery g or 7 dealers. Today there are over 90,000,000 home and auto Radios. 3100 WNRN. WSPK. w -,.'v FM :. i I. tas enatiedms to build ar Police Radio Itwallatlons.' S.W. bl, ' r in Televi Broadcasting Sta:ions are on the air. Aviation and Police Radio, DINWIDDIE, Jacksonville. 111. nos. F MILLER, Maumee. O. Jew tN Meet seen Tiles Bit gradahMòM SAN, Micro -Wave Relay, Two -Way Radio are all expanding, making 'When I enrolled, had more and better opportunities for servicing and communication do idea it would be so ár 30 as tran mitts learn. .p-nto- Have mo .ouppedi my shop out h -o darbled aalaTi technicians and FCC licensed operators. if spare time earnings. m starting in RadL. I am clearing about San to 860 mks ',debt, N. R. 1. has Full credit to N.R I" - Ith.D. KNIGHT, Denison. Texas. .INwERR. e Caoennd,olaé Pa- 3. BRIGHT FUTURE III week I. gpra Tlwa 1 Yono fern e m. " Refore finishing your E "I onetime my o I earned shop here And t lint. ut t is ilppllrtwuuc ciciiuun! In 1')51) aster much as 510 a week in f'* 00 c beer Radio cing, at rosa runts. about 5,000,000 Television sets were sold. By 1954 authorities estimate home i r my spare raw su: a nth. Ha ve 25,000,000 Television sets will be in use. Over 100 Television Sta- time I recommend N.R.I. to ev- ay.eofdtI N.YI enainiena eryone who shows interest in Ra- nits[ 1 cavai! N.F I. tratang." dio." S.J. PETRUFF, Miami, Fla. t. K AIDER ì0N, Atlanta, Ga. tions are now operating, with experts predicting 1,000. Now is the on IbYYtnn.tL 11.11.1. gr,ua ti bra* MI-n time to get in line for success and a bright future in America's My first Job was op. f.ra pud of m, e n KDLit. Plena. cam.. fast -growing industry. Be a Radio-Television Technician. Mail obtained for me by oumnan ihn N. lt I you Graduate Serv. manse. ie,glddl.n coupon for Lesson and Book-FREE. Dept. I am t it - R1 Chief Engineer of Pobm Radio ta-d see ada r I your t . t.lt,t,,h"; Station T. c NOR- a Tare shop.' TON, Hailton. T K - R, Hi ton T Ilage, Va. I Will Train You at Home Read How You Practice Servicing or Communications t with Many Kits of Parts You Get! Keep your job while training at home. Hun- Mail Coupon For 2 3ooks FFEE dreds I've trained are successful RFDItl TELEVISION TECHNICIANS. Meg had Act Now! Send for my FREE ), BLE YOU SORB this modern Radio ahwek as part no previous experience; many no mor. than OFFER. Coupon entitles you to aetal les- of my Servicing Course. Build tai: empiete, grammar school education. Learn Ladio- son or Servicing; shows Fow you I -a-o Ra- powerful Radio Receiver that briar n kcal and Television principles from illustratd les- cio-Television at home. You'll alst receive distant stations. N.R.I. gives you ALL tie Radio sons. Get PRACTICAL EXPERIENCE- ray 64-page book, "How 4r Be a S _weds in parts . speaker, tubes, chases, trarztorme -, sockets, loop antenna, EVERI'TF I :10 tau need. build valuable Electronic DtultitesUr fo- Radio -Television." You'll read odiat my You use material to get practical Radi_ experi- conducting tests; also practice servicirg Ra- graduates are doing, earning; see casettes of ence. Make EXTRA money fixing eeyhbrs' Ra- dios or operating Transmitters -- eoper men_ equipment you practice no th at home. Send while dios in spare time training. with circuits common to Radio and T.levin- coupon in envelope or paste on postal. YOU MEASURE current, voltage 1/ C DC and RFh ion. At left is just part of the equipment err J. E. SMITH, Pres., resistance and impedance in circuit,. warn I_ootronie students build with many kits of parts I fur- Dept. IGF. National Stultitester (above right) you bulk! as put of my Servicing or Communications Cows, nish. All equipment is yours to keep. Stan: Radio Institute, Wash - students make $5, $10 a week extra fixing ington 9. D. C... You WILD this Transmitter (:ne. ' neighbors' Our 56th year. part of my Communications Course. I EN Radios in spare time. YOU parts to build this low-power troad- noting transmitter. You learn how no nu' a station "on the air," perform proaderes cm mended of Broadcast Station ,peato,. make many practical tats. YOU BUILD this Wavemeter (baba) in ay Caen - munlcationa Course with pans I and yea. Um it Mr. 3. E. SMITH, President, Dep :.',,1 GF, to determine frequency of opeWtlat Had make National Radio Institute, Washlrgtor 9, D. C. other testa on transmitter cormn-a. 'ou eondurt Mail me Sample Lesson and I4 -page Bok abut How to Win many tote . ing experiments. Success in Radio-Television. Both FREE. (No ..alesnaa will nil. Please write plainly.) Nam Age Address City Zola Stase Approved Under G. 1. Bill www.americanradiohistory.com 4 Incorporating SNORT WAVE TELEVISION NEWS RAMO RADIO & TELEVISION - Trademark registered U. S. Patent Office I:I.I:I. ICl/ti11 :S formerly RADIO -CRAFT MEMBER AUDIT BUREAU OF CIRCULATIONS Hugo Gernsback, Editor -in -Chief M. Harvey Gernsback, Editorial Director Fred Shunaman, Managing Robert Editor F. Scott, W2PWG, Technical Editor Angie Pascale, Production Manager I. Queen, Editorial Associate Wm. Lyon McLaughlin, Tech. Illustration Director Lee Robinson, General Manager G. Aliquo, Circulation Manager John J. Lamson, Sales Manager Robert Fallath, Promotion Manager CONTENTS JULY, 1951 Editorial (Page 211 Service Bombshe' By Hugo Gernsback 21 Broadcasting and Communications (Pages 22 -24) Telecar Speeds Telegrams (Cover Feature) ..by Fred Shunaman 22 Servicing -Test Instruments (Pages 25 -32) Signal Generat;r Powered by Buzzer by John A. Dewar 25 BC -453 as a Service Aid by Joseph Zelle 26 The Customer is ALWAYS Right by Eric Wahleen 27 TV Tube Substitutions by Edward J. Locke 28 TV Field Strength Meter is Helpful by H. O. Maxwell 31 Money in TV Servicirg by Oliver Horning 32 Television (Pages 33 -38) Replacing Tuners for Higher Gain and Interference New Edition Rejection by Matt Mandl 33 Television Service Clini_ Conductedcted by Robert F. Scott 35 TV DX Predictions 36 SPRAGUE V Beam for Dx by L. A. Duck 36 TV Trouble Lexiccn by John B. Ledbetter 37 TV CAPACITOR Audio (Pages 39 -46) Audio Feedback Design, Part IX.... by George Fletcher Cooper 39 REPLACEMENT MANUAL Electronics and Music, Part XIII by Richard H. Dorf 42 Here -just off press the Rico Amplifier Operation by Jacinto Sugrates 45 -is Manual that tells Universal Hi -Fi Preamplifier by M. G. O'Leary 46 new Sprague Electronics (Pages 48 -65) you in a jiffy just what capacitor Radar Tracks Shooting Stars....by Professor A. C. B. Lovell and to use on practically any tele- J. G. Davies 48 vision replacement job. In- How an Electrcric Brain Works, Part X..by Edmund C. Berkeley 56 cludes complete electrolytic Construction (Pages 66 -69) capacitor replacement data on Five -Tube Superhet Fits Pocket by W. D. Penn 66 Departments 964 TV receivers -saves you Radio Month 10 Question Box 79 time, paves the way to better Radio Business 14 Miscellany 82 work on practically every job! New Devices 70 With the Technician 86 New Patents 72 Technotes 88 Radio Electronic People 90 Circuits 741 Communication 92 GET YOURS...TODAY! Try This One 761 Book Reviews 93 Ask your Sprague distributor for o FREE copy of this new Manual ON TN[ COVER: Western Union Telecar in typical residential M -473. Or, write your nome on area, with pioneer Telecar operator Wallace the attached coupon and en- Woodward at the wheel. Note microphone on close 10c to cover handling and steering column. Recorder cover was removed mailing and we will rush for photography, would normally be in place.; your copy directly Kodachrome by Avery S lack to you! Mail lo: rots, 1951 RADIO- ELECTRONICS Vol.