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NOVEMBER 1951 tAl) 1 o K 11 ime LATEST IN TELEVISION SFRUIcING AUDIO 30( U.S and CANADA In this issue: Black -and -White Plus Color Receiver Q Revolutionary New Speaker Filter Facts www.americanradiohistory.com 's revolutionary! www.americanradiohistory.com Now, you can be sure of your installations with Belden Microphone Be Sure of Your Installations Next Year Cables. They are Aptitude- Tested and rated to give you safe and complete knowledge of their characteristics. Furthermore, Belden Mike Cables are use asaide-yedred built for maximum service. Put them to work for you now -and be sure ... specify Belden. MIKE CABLE Belden Manufacturing Co. 4623 W. Van Buren Street ?kw Chicago 44, Illinois No. 8411 No. 8401 No. 8422 No. 8410 No. 8412 No. 8423 No. 8424 Nominal Capaci- Nominal Capaci- Nominal Capaci- Nominal Capaci- Nominal Capaci- Nominal Capaci- Use for inter- tance 37 mmf per tance 25 mmf per tance 32 mmf per tance 33 mmf per tance 68 mmf per tance 54 mmf per connecting power ft. Use partic- ft. For crystal, ft. Use specially ft. For crystal, ft. Use specially ft. Use particu- cable for all elec- ularly for lapel ribbon, carbon fo- carbon micro- ribbon, carbon for carbon micro- larly for carbon tronic uses. Also microphone. microphones. phones. microphones. phones. microphones. microphone cable. NOV EM BER, I951 www.americanradiohistory.com li Incorporating SHORT WAVE CRAFT TELEVISION NEWS RADIO RADIO & TELEVISION 'l'ru Iernark ra¢iatered U. S. Patent l)mce BER 1/` Iles SOMETHING formerly RADIO -CRAFT AUDIT BUREAU OF CIRCULATIONS RE Hugo Gernsback, Editor -in -Chief ABOUT M. Harvey Gernsback, Editorial Director Fred Shunaman, Managing Editor Robert F. Scott. W2PWG, Technical Editor Angie Pascale, Production Manager I. Queen, Cal:arial Associate SPRAGUE Wm. Lyon McLaughlin, Tech. Illustration Director LOK`tV Lee Robinson, General Manager G. Aliquo, Circulation Manager TWIST- John J. Lamson, Sales Manager Robert Fallath, Promotion Manager CONTENTS NOVEMBER, 1951 CpPpCITORS Editorial (Page 21) Radio -Electronic Giant by Hugo Gernsback 23 Television (Pages 24 -33) CBS-Columbia--First Commercial Color plus Black and White Set by I. J. Melman, E. S. White & S. Kuker 24 Remote Controls for TV Promote Viewer Comfort by Robert F. Scott 28 Television Service Clinic by Matt Mandl 32 Television dx Forecast for November 33 Moreore twist - Servicing -Test Instruments (Pages 34 -38) Audio Signal Generator with Calibrated Output. prong electrolytic capacitors by Lawrence Fleming 34 are made by Sprague than Fundamentals of Voltage Regulation by Allan Lytel 37 by any other manufacturer Theory and Engineering (Pages 39-43) ... And Sprague naturally Discone- Broadband Antenna (Cover Article) lists the largest, most com- by Fred Shunaman 39 Magnetic Phenomenon by Alvin B. Kaufman 41 plete line for exact TV re- New Design (Pages 44-45) placement applications. lonophone by E. Aisberg and M. Bonhomme 44 And when you use a Electronics (Pages 46 -50) Sprague Twist -Lok TV Ca- Ultrasonics and Therapy by Dr. F. Van den Bosch 46 pacitor, you can be sure it's Audio (Pages 52 -74) dependable. No costly Birds and call- Ultrasonics 52 backs will jeopardize Filter Facts and Faddle by James R. Longham 54 your Electronics and Music, Part XVII by Richard H. Dorf 60 profit or your reputation. Audio Feedback Design, Part XIII ..by George Fletcher Cooper 70 Your business judgment will Construction (Pages 78 -80) tell you to accept no sub- Versatile Intercom Unit "Rings Up" Called Party. by Bob White 78 stitutes. Amateur (Pages 85 -89) *Trademark Converting the Mork II by Louis H. Hippo, W6APQ 85 Broadcasting and Communications (Pages 89 -92) Your Tape Recordings Are Not Negotiable Francis George 89 Universal Tester for Field Use by Lyman E. Gray 90 Departments GET YOUR Radio Month 12 Try This One 109 Radio Business 16 Question Box III New Devices 82 With The Technicians 113 New Patents 101 Miscellany 120 SPRAGUE TV CAPACITOR Technotes 104 People 122 REPLACEMENT MANUAL TODAY! Radio -Electronic Communications 126 Circuits 106 Book Reviews 129 Just off press, this NEW 3rd edi- tion of the famous Sprague Man- ON THE COVER: Paul Chirlian, New York University, and the ual is jam -packed with up- to -the- antenna designed by the university's Electrical minute replacement recommen- for Engineering College to range from 100 kc to dations critical capacitors in 4,000 mc. practically every TV set on the Ektachrome original by Avery Slack market today! FREE from your Sprague parts distributor or send 10¢ directly to Sprague to cover November, 1951 RADIO -ELECTRONICS Vol XXIII, No. 2 handling and mailing costs. Published monthly by Radcraft Publications, Inc., at Erie Ave., F to G Streets, Philaaelpnia 32, Pa. EXECUTIVE. EDITORIAL and ADVERTISING OFFICES: 25 West Broadway. New York 7. N. Y. Telephone 1(Ectur 2 -8630. Hugo Gernsback, President; M. Harvey Gernsback. Vice -President; G. Allow, Secretary. SUBSCRIPTIONS: Address Correspondence to Radio- Electronics. Subscription Dept.. Erie Avenue. F to G Ste., Philadelphia 32. Pa., or 25 West Broadway, New York 7. N. Y. When ordering a change please furnish an address stencil impression from a recent wrapper. Allow one month for change of address. SUBSCRIPTION RATES: 1n U. S. and Canada, in U. S. possessions, Mexico. South and Central American countries. $3.50 for one year, $8.00 for two years; $8.00 for three years; single copies 30c. All other foreign countries $4.50 a year, $8.00 for two years; $11.00 for three years. Entered as second class matter September 27, 1948 at the poet office at Philadelphia, Pa., under the Act of March 3, 1879. Printed in U. S. A Copyright 1951 by Radcraft Publica- tions, Inc. Text and illustrations must not be reproduced without permission of copyright owners. BRANCH ADVERTISING OFFICES: Chicago: 520 N. Michigan Ave. Telephone SUperior 7 -1798. Los Angeles: Ralph W. Harker, 1127 Wilshire Blvd., Tel. MA 6 -1271. San Francisco: Ralph W. Harker. 582 Market St.. Tel, GArfield 1 -2481. FOREIGN AGENTS: Great Britain: Atlas Publishing and Distributing Co., Ltd., London E.C.4. P ODUCTS COMPANY Australia: McGill's Agency. Melbourne. France: Brentano's. Paris 2e. Holland: Trilectron. Heemetede. Greece: International Book & News Agency. Athens. So. Africa: Central News Agency, Ltd., Johannesburg; Capetown: Durban, 81 Marshall Sf. Natal. Universal Book Agency, Johannesburg. Middle East: Steimataky Middle East Agency. Jerusalem. India: Broadway NORTH ?.DAMS, MASSACHUSETTS News Centre, Dador, Bombay 414. K. L. Kannappa Mudallar, Madras 2. Pakistan: Paradise Book Stall. Karachi 3. POSTMASTER: It undeliverable send form 3575 to: RADIO-ELECTRONICS, 25 West Broadway. New York T. N. Y. (Distributors' Division of the Sprague Electric Company) RADIO -ELECTRONICS for www.americanradiohistory.com 7 TRAIN for Security! Good -Paying Jobs! MARE THE MONEY YOU'VE ALWAYS DREAMED OF! LEARN RADIO -TELEVISION AND ELECTRONICS BY EASY SHOP METHOD TRAINING AT HOME! Let NATIONAL SCHOOLS -a resident- training school for nearly 50 years - train you at home for today's unlimited opportunities in Radio -Television-Electronics. National Schools is one of the largest schools of its kind. It is ocated in Los Angeles -the center of Radio and TV world! It has four large buildings of modern shops and labs. Its faculty is considered tops in the business. You You learn from lessons prepared by experienced get instructors and engineers. Men who are successful all the parts -even tubes! - Radio and Television technicians. Men who have 1 II for this modern Superheterodyne Receiver. r Lr1rrfw (( trained 1000's of men like YOU! You learn to build it step by step. And you keep it! 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