RADIO'S LIVES/T MAGAZINE r November 25 Cents Cando 30t HUGO GERNS1L&CK réíter WA DO OU NAT Experiments in Radio Psychometry See Page 264 4 'r Broadcast Station List -A Home Radio Robot-The "Resonator" Loudspeaker Making Transformers and Chokes - "Dry Cell" Tubes in A.C. -D.C. Receivers READR1TE EQUIPMENT ÁMOVED \ WOK., of 9riiz 6 . ciyy OW is the time to cash in on the widespread public interest that is being aroused by the sensa- t.onal Radio Prosperity Campaign. And you, as a Radio Service Engineer, No. 710 can cash in best by using the Readrite READRITE TESTER testers shown here. They will make money for you and save you money! You can afford to standardize on Readrite in- struments. They are popularly priced. They enable you to make more calls at less cost per call ... they make it easy for you to meet every servicing requirement .. they withstand the hardest kind of use and abuse ... they insure that your equipment dollar stretches much farther. No. 710 READRITE TESTER No. 550 This all- purpose tester fills every need of both the ex- READRITE pert service man and the beginner. It is designed for OSCILLATOR the testing of new and old radios. Equipped with a practical selector switch for checking all parts of tube circuits by connecting to the set sockets. Selection for testing voltage of plate, grid, cathode, sup- pressor grid and screen grid is quickly and accurately done. Plate current, filament volts, line and power supply volts, resistance and continuity are Here's measured. Battery is used for continuity testing of transformers, chokes, Proof of etc. Handles most advanced circuits and newest tubes. READRITE The No. 711 Readrite Tester is the same as the No. 710 except that it is Leadership. equipped with the new Triplett D'Arsonval Volt -ohmmeter, which has 1000 ohms per volt resistance. The readings are 0- 15 -60- 300 -600 - --0 to 300,000 Write ohms. Ohmmeter reading is secured with the 4% volt battery, which is furnished. for your copy No. 550 READRITE OSCILLATOR TODAY! This signal generator furnishes a modulated signal of constant frequency for REACH FOR the alignment of all modern radios. It is used to align r. f. transformers, IME JOY OF LIVING No. 410 check oscillator stage, compare gain in tubes and determine the sensitivity TUBE TESTER of a receiver. TIE IN No. 410 TUBE TESTER WITH/ THE NEW Used for checking new old in receiving sets. de- PROSPERITY and tubes Simply let. Pall signed, compactly constructed, this tester is ideal for both outside CAM PAIGN work and for counter use. A push button provides two -plate cur- rent readings for determining the conductance and worth of a tube. For those wanting a longer-scale instrument, the Model 416 Tester, with a Triplett D'Arsonval Flush Mounted Meter is offered. This instrument does not have illuminated dial, but in other respects is the same as the No. 410. I READRITE METER WORKS, I 81 College Ave., A Bluffton, Ohio. YOUR JOBBER CAN SUPPLY YOU Centlemea: See him today, or send the f Send me catalog on Readrite Instrument No. ( 1 u. well as folder giving proofs of Readrite Leadership. coupon for descriptive catalog. Neam READRITE METER WORKS Street Address........ ........ _. City.. State 81 College Ave , Bluffton, Ohio OPPORTUNITIES are many for the Radio Trained Mari Don't spend your life slaving away in some dull. hopeless job! Don't he satis- fied to work for a mere $20 or $30 a week. Let me show you how to get your start in Radio-the fastest -growing, biggest money -making game on earth. Jobs Leading to Salaries of $50 a Week and Up jobs as Designer, Tester Prepare for Inspector and -as Radio Salesman and in G Service and Installation Work -as Operator or Manager of a Broadcasting Station -as Wireless Operator on a Ship or Airplane, or in Talking Picture or Sound Work- HUNDREDS OF OPPORTUNITIES for a real future in Radio! TenWeeks of Shop Trainin - Pay Your Tuition After Graduation g We don't teach by book study. We train you on a great outlay of Radio, Television and Sound equipment-on scores of modern Radio Receivers, huge Broadcasting equipment, the very lat- est and newest Television apparatus, Talking Picture and Sound Reproduction equipment, Code Iractice equipment, etc. You don't need advanced education or previous experience. We give you -RIGHT HERE IN THE COYNE SHOPS -the actual practice and experience you'll need for your start in this great field. And because we cut out all useless theory and only give that which is necessary you get a practical training in 10 weeks. TELEVISION and TALKING PICTURES And Television is already here! Soon there'll be a demand for THOUSANDS of TELEVISION EXPERTS! The man who learns Television now can have a great future in this great new field. Get in on the ground -floor of this amazing new Radio development ! Come to COYNE and learn Television on the very latest, newest Television equipment. Talking Picture and Public Address Systems offer opportunities to the Trained Radio Man. Here is a great new Radio field just beginning to grow ! Prepare NOW for these wonderful opportunities ! Learn Radio Sound Work at COYNE on actual Talking Picture and Sound Reproduction equipment. don't waste time on useless theory. We give you the prac- PAY FOR YOUR TRAINING tical training you'll need -in 10 short, pleasant weeks. After You Graduate MANY EARN WHILE LEARNING I am making an offer that no other school has dared You get Free Enii'lo%ntent Service for Life. And don't let lack of money stop you. Many of our students make all or to do. I'll take you here in my shops and give you a good part of their living expenses while going to school this training and you pay your tuition after you and if you should need this help just write to me. Coyne have graduated. Two months after you complete my is 33 years old. Coyne Training is tested -proven beyond all doubt. You can find out everything absolutely free. course you make your first payment, and then you Just have ten months mail coupon for my big free book! to complete your payments. There H. C. Lewis, Pres. are no strings to this offer. I know a lot of honest fel- RADIO DIVISION Founded i1199 lows haven't got a lot of money these days, but still want to prepare themselves for a real job so they COYNE Electrical School won't have to worry about hard times or lay offs. S00 S. Paulina St., Dept. 83 -8H, Chicago, Ill. I've got enough confidence in these fellows and in my Mail Coupon Today for All training to give them the training they need and pay me the Facts back have after they their training. I If you who read this advertisement are really interested H. C. LEWIS, President in your future here is the chance of a life time. Mail the coupon today and I'll give you all the facts. Radio Division, Coyne Electrical School 500 S. Paulina St., Dept. -811, Chicago, III. ALL PRACTICAL WORK Dear Mr. Lewis:- Send me your Big Free Radio Book, and At COYNE in Chicago all details of your Special Offer. ALL ACTUAL, PRACTICAL WORK. You build radio sets, install and service them. You actually operate great Broad- Name casting equipment. You construct Television Receiving Sets and actually transmit your own Television programs over our modern Television equipment. You work on real Talk- Address ing Picture machines and Sound equipment. You learn Wireless Operating on actual Code Practice apparatus. We City State --- RADIO -CRAFT for NOVEMBER, 1933 267 /idio.aft\ FOP THE SERVICE MAN - DEALER RADIOTRICIAN HUGO GERNSBACK, Editor -in -Chief C. W. PALMER R. D. WASHBURNE Associate Editor Technical Editor O, 041117 IN OUR NEXT FEW ISSUES: CONTENTS OF THE MAKING YOUR OWN VELOCITY MICROPHONE. Almost every- one is interested either professionally or experimentally in micro- NOVEMBER, 1933, ISSUE phones. Therefore, we believe that an article giving complete information on the construction of an instrument of the high - VOLUME V NUMBER 5 quality "velocity" type will be received with exceptional interest. Particularly, in view of the fact that the few components which require moderately precise machining will in form Editorial: The Radio Set of 1950 Hugo Gernsback 263 be available kit for the technician who is not blessed with a junior edition of a Radio Psychometry 264 machine shop. Latest in Radio 266 DETAILS FOR MAKING A REAL AUTOMOTIVE RADIO RECEIVER. Although most previous articles concerning the construction of International Radio Review 268 automotive radio sets have been confined to the more essential The New "Resonator" Loudspeaker rudiments of instrument design, this article described every detail. Only standard parts are used. The 7 -tube superheterodyne Pierre Hemardinquer 269 cir- cuit incorporates automatic volume control, variable -mu R.F. pen- A Radio Robot -In the Home todes in the R.F. and I.F. stages, and two pentode tubes in push - Arnold G. Ferdon 270 pull. A 3- section gang condenser with shaped -plate oscillator tuning sections is used. The dimensions of the overall chassis box A Wired -Radio Public Address System are only about 9 x 712 x 7 ins. high. David R. Freeling 272 AN ELECTRO- ACOUSTICAL WAVEMETER. Helmholtz or Koenig An Introduction to- "Servicing the 'Talkies'," Part I resonators have been used to defect sound and to determine the Aaron Nadell 274 pitch, but instruments of this form have the very great disadvan- tage that the ear is employed to determine when The Newest Design in All -Wave Superheterodyne resonance exists.