* 1940 IO and Ç TELEVISION Data. Book Published by ZIFF-DAVIS PUBLISHING COMPANY 608 South Dearborn Street, Chicago, Illinois RADIO NEWS 1940 RADIO & TELEVISION DATA BOOK 3 1940 RADIO Radio & Television N EWS Data. Book Edited by the staff of CONTENTS RADIO NEWS William B. Ziff, Publisher, TELEVISION SECTION TRANSMITTER SECTION B. G. Davis, Editor, Television Occupations of the Soldering Tubing 5 Future 4 Karl A. Kopetzky, W9QEA, I. C. W. for 5 Meters 5 Television Fundamentals 6 Managing Editor, Crystal Dope 11 Building a Television Receiver.. 8 Learning the Code 14 Oliver Read, W9ETI, Television Words and Terms 10 Rapid Breakin With a Vox System 20 Technical Editor, Amateur Television Transmitter 12 20-W Bandswitch Transmitter 23 E. Stanton Brown, U. S. Government Amateur Radio Associate Editor, SERVICEMEN'S SECTION Regulations 24 Herman Bollin, Art Director, Service Problems: Home Made Banana Plugs 37 Cross -Modulation 33 Selecting Antenna Wire 47 Eugene O. Gleeson, Variable Tone Modulator 47 Engineering Draftsman, Internal Cross-Modulation 33 External Cross -Modulation 35 Changing Crystal Frequency 49 35 Phone QRM 49 S. L. Cahn, Monkey Chatter How to Advertise Your Service INSTRUMENT SECTION Advertising Manager, 36 Shop Visual Deviation Freq. Meter 21 John H. Reardon, 36 Speaker Troubles An Electric Calibrator 27 Circulation Manager. Line Voltage? 37 What's the Home -Built Audio Oscillator 28 Equipment 37 Cushioning Radio A Vacuum Tube Volt Meter 30 Kinks 46 Meter Meter Readings 37 46 Magnified Handy Continuity Tester Increasing Meter Utility 47 46 Volt Home Made Pilot Light Socket.. Low Cost Tester 48 Dollars 46 Fuses Save Sharply Tuned Wave Meter 48 on 47 Published by Tips Radio Noises A.C.-D.C. Receiver Tube Tester.... 50 Plug-in 47 Ziff -Davis Publishing Company, Resistors Building a Good C. P. Oscillator... 50 48 Handy File System High Resistance Volt Meter 51 608 South Dearborn St., Now! 48 Fix It Low Cost Field Strength Meter... 54 Chicago, Illinois Practical Speaker Repair 48 Projection Device for CR 913 Tube 49 GADGETS-GENERAL SECTION Measuring Power Output 49 Fish Pole Antenna 47 Improving Quality 49 Single Tube Announcer 49 Soldering Iron Tip 49 Handles for Phone Cord Tips 50 Neon Lamp Substitute 49 Winterizing the Antenna 50 Copyright, 1939 Mark the Resistors and Save Time. 50 All Wave Tuned Antenna 51 Magnetic 50 Holder Test Leads 54 Ziff -Davis Publishing Company Replacing Speaker for Silent Microphone Ring 54 Concerning Doublet Antennae.... 60 Feverish Activity 56 Adapter for Determining Coil Pet Vs Pest 56 Frequency 60 New Application for 6E5 58 EXPERIMENTERS' SECTION Tinning Soldering Iron 60 Constructing a Polarized Relay... 29 Reaming with Tools Made of Soft Test Leads for the Experimenter. 35 Includes Articles by: Steel 60 Equipped Treasure Locator 42 Cure for Noisy Volume Control 60 Radio Alfred N. Goldsmith, Automatic Frequency Control Dual Diversity Coupler 44 M. W. Thompson, Measurements 60 Home Made Scratch Filter 47 54 Jones, W6AJF, Tubing Antenna Frank C. Home Made Antenna Tuning Raymond P. Adams, RECEIVER SECTION Condenser 60 The Jones 8 -Tube Special Superhet 15 Edmund P. Kelly, W9HPW, Radio Tuner for P. A. Systems.... 17 DATA SECTION Zeh Bouck, Antenna Mast for $7.50 19 Wire Table-Winding Turns Per Ernest A. Zadig, Better Reception with Good Ground 35 Inch 11 Fractional-Decimal Equivalents. 22 Joseph H. Appel, Jr., W2FDA, Increase Efficiency of Detector Tube 48 Common Word Abbreviations 26 S. Gordon Taylor, W2JCR, Reducing Drift in Receivers 59 R -S -T Reporting System 26 Lee Ward, DB 2-4000 Ohm Conversion Chart. 32 32 Chas. E. Chappel, AMPLIFIER SECTION DB -Voltage Power Ratio Chart Prevention of Oscillation in P. A Common Symbols Used in Radio McMurdo Silver, Systems 38 Diagrams 45 Lee Sheldon, Scotchman's Special Amplifier.... 39 Chart of Tap Clearance Drills 46 L. B. Robbins, A.C.-D.C. 4 -Watt Amplifier 40 RMA Color Code 51 56 Alfred Ghirardi, Making Your Own Records 41 International "Q" Signals Twin Triodes in Cascade 49 What is Electricity? 60 and others. Portable P. A. System 52 What is a DB? 63 Practical Remote Amplifier 58 Some International Prefixes .... 64-65 4 RADIO NEWS 161411 RADIO & TELEVISION DATA IiOOK TELEVISION TELEVISION OCCUPATIONS OF THE FUTURE The above shows the operating technique which will be used in putting on the Television Show this spring. ASTUDY of occupational possibilities looking and listening public. But the size of vision transmitters and receivers. Some of in the field of television before that the audience, its purchasing power, and its these men may be university-trained physi- interesting art has made its com- mood will all influence the extent to which cists who are prepared to enter the equally mercial debut is possibly premature and cer- the advertiser can justifiably support tele- complex but more commercial fields of tube tainly hazardous. It savors slightly of plan- vision broadcasting. Accordingly, there is research and design. The usual factory per- ning the Panama Canal shortly before the an action and reaction between economic sonnel will be required for television equip- discovery of America. At best, any voca- conditions and television success. If times ment construction, including test men, super- tional analysis of the television of the future are bad, the programs must be restricted visors, production and manufacturing engi- must be read with several provisos in mind. which, in turn, affects the public response neers, and the like. In the first place, a normal engineering de- that justifies the broadcasting of the pro- Transmitting Station Jobs velopment of television is assumed. That is, grams. Only in reasonably good times can Once the television transmitter has been it is taken for granted that technical knowl- this circle of effects be broken advanta- built and shipped, it must be installed in edge of television will increase apace, en- geously. Accordingly, those contemplating the television transmitting station and there- abling the practical solution of the remaining television as a career will watch closely for after maintained. At this point, an entirely engineering problems of television within a times of general economic recovery since it new series of openings will exist. Television reasonable time. is in such times that arts like television can station engineers will include field -survey In the second place, a normal economic be expected to flourish and to afford oppor- engineers who will determine the best loca- development of television must be regarded tunities for a multitude of new workers. tion for the station and its antenna system as probable in any analysis of its occupa- Opportunities in Manufacturing and who will study the strength and ac- tional possibilities. Television transmitting Let us start at the factory where the nec- ceptability of the signals throughout the and receiving equipment is elaborate and essary equipment for television transmission service range of the station. These men will relatively costly. Television program con- and reception originates. Here are needed also furnish the data which will satisfy the struction will be more complex and expen- apparatus engineers who are capable of governmental authorities that the station sive than radio program construction of to- doing research, development, and design is covering its territory with an adequate day. The television art is a comparatively work in that complicated field. These men service in the physical sense. The equipment luxurious one. Manifestly, such an art can must be technically trained and well -quali- must be maintained in good condition at all hardly be introduced rapidly on a large scale fied along conventional radio lines in order times, and emergencies must be met, and this in times of marked economic depression nor to meet the more difficult problems of tele- is the job of the maintenance staff of the can it be expected to win public favor under vision. These radio engineers are, in fact, station. such circumstances. The television programs electrical engineers with specialized training The television -station studios will require will be paid for, under our present system in the particular field of communications. In a staff of their own of considerable size and of broadcasting operation, by advertising the factory there are also needed tube en- of wide diversity of tasks. Considering sponsors in the main. The sponsors will in gineers who will handle the similar problems the technical men only for the moment, there this way purchase a portion of the purchas- of vacuum -tube and cathoderay-tube produc- will be lighting experts who will arrange ing power and general good will of the tion which are an integral part of the tele - and control the powerful illumination which RADIO NEWS 1940 RADIO & TELEVISION DATA BOOK b to meet the multitude of complicated, partly unfore- IC W for seeable, and sometimes uncontrol;able conditions 5 to be encountered in out- Meters door jobs. The outdoor camera man will neces- IN the old days of "Rock Crushers" and sarily be of somewhat the "Squeak Boxes" (spark transmitters to same type as the present you youngsters), a ham was known by his successful newsreel camera signal, as well as his call. In many cases if man who can meet an he should have forgotten to sign, it would emergency promptly and have made little difference anyway as by effectively. listening to the particular note, you could a fair of Since portion identify the man behind the gun. The dis- television may programs tinctive signal of the particular individual be, as stated above, from was just as much of a label, as his voice film, it will be necessary would be in a conversation. to film program material, recording both picture and No wonder "wireless" in those days had sound in the same way as the glamour and fascination to attract a fol- lowing.