Radio broadcast .. (1922-30)

RADIO BROADCAST NOVEMBER, 1928 WILLIS KINGSLEY WING, Editor KEITH HENNEY EDGAR H. FELIX Director of the Laboratory Contributing Editor Vol.4X. No. i Cover Design - - - From a Design by Haney Hoptyns Dunn Frontispiece Pictures Transmitted in One Minute at Radio World's Fair What Prospects of Television Abroad? - Lawrence W. Corbett New Trends in Radio Design for 1929-30 - - - Keith Henney The March of Radio - An Editorial Interpretation New Wavelength Allocation Plan Need for Defining Television Practice Newspaper Has Radio Picture Transmitter Commercial Broadcasting Increases Here and There Aircraft Radio Radio in Foreign Countries A Two-Tube T.R.F. Short-Wave Receiver William BostwicJ{ and W. T. Thomas "Strays" From the Laboratorv Dynamic vs. Magnetic Speakers Regarding Series-Filament Operation Present Designs Do Not Consider Economy What is Public Interest? The Race for Television Publicity WRNY Television Broadcast* A Milestone in Television New Nationwide Picture Service How to Stabilize Rice Amplifiers New Radio Tubes Needed Keith Henney The "Gyps" Are Still at It New Precision in Quartz Plates Seven New Radio Booklets Portable Radio Sets Underground Aerials B. B. Akorn When the Set Stops Working "Radio Broadcast's" Home Study Sheets - - No. 9. The Effect of an Electric Current No. 10. Alternating Current—Part HI A New Audio System for Dynamic Speaker Reproduction Franl( C. Jones As the Broadcaster Sees It Carl Dreher Sound Motion Pictures—Part II Commercial Publications A and B Power from the D.C. Lines -William B. Doll Building Receivers for Television Zeh Bouci( and James Millen A Modulator for the 1929 Short-Wave Transmitter Robert S. Kru.se "Radio Broadcast's" Service Data Sheet on Manufactured Re- ceivers No. ii. Freshman Model "G" Receivers No. 11. Freed Eisemann Model NR-8o The Improved Knapp A-Power Unit An Amplifier and Power Supply for the "Vivetone 29" R. F. Goodwin "Our Readers Suggest— Short-Wave Plug-in Coils Improving Capacity Feed-Back Circuits Receiving Without an Aerial Tuning-m With a Distant Loud Speaker Polarity Indicators Home-made I. F. Transformers Reducing Hum in the Detector Prolonging the Life of the 171A Reducing Hum in A.C. Sets Special Soldering Irons for Difficult Jobs The "Chronophase" Screen-Grid Receiver - Bert E. Smith The Fellows of the Institute - Carl Dreher New Apparatus - - - Useful Information on New Products Manufacturers' Booklets "Radio Broadcast's" Laboratory Information Sheets - - No. ijj. Balancing Radio Receivers No. 158. Hook-up for Short-Wave and No. 134. The Audio Transformer Broadcast Receivers No. 135. Television No. ajo. Circuit for Short-wave and Broad No. 336. Moving-Coil Loud Speaker* cast Reception No. »j7. Power Output No. 340. Television The contents of this magazine is indexed in The Readers' Guide to Periodical Literature, which is on file at all public libraries. IO II 14 16 ao 27 29 32 34 35 38 43 45 47 49 5i 52 54 56 AMONG OTHER THINGS. . . A FUNDAMENTAL part of the policy of this magazine is the careful scrutiny of everything appearing in its pages, from the smallest advertisement to the most intricate of technical articles. We have always felt that our first duty to the reader was to protect him from misleading statements and in- accuracies of whatever sort. This rr.agaiine is not, however, the expression of one man's opinion, ncr even of the group respon- sible for editing and publishing it. We have frequently given space to articles on technical subjects in which the authors came to conclusions at variance with our own opinions. Almost in- variably after the appearance of the magazine we would be del- uged with letters and telephone calls demanding to know why we "said" this or that. The editorial expressions of this maga- zine, whether general or technical are always definitely identi- fied. Articles from other sources are also indentified, and for the opinions expressed, the author is alone responsible. We wel- come the opportunity of printing controversial articles. '"PO JUDGE from reports which reach us, the motion-picture JL industry is in nearly as complete a turmoil as that in which radio found itself some years ago. The cause of the trouble is, of course, the application of synchronized and non-synchronized sound accompaniment to the "feature picture." This develop- ment is bringing into play practically all of the experience that broadcasters have so laboriously accumulated in the past few years, and is drawing into the movie field many broadcasters and other engineers who have developed apparatus and its uses for this work. In this connection, the pages of Carl Dreher's department, "As the Broadcaster Sees It," are well worth watching, for Mr. Dreher is including much first-hand and practical information on sound motion picture work. Much of this work is being done by expert radio service men. ANEW ZEALAND radio distributor writes us he is in- terested in communicating with American radio manu- facturers who wish New Zealand distribution for kits or com- plete sets, either a.c. or d.c. operated. Manufacturers who are interested may communicate with the editor. "pOR those to whom the news has not yet traveled, we J- repeat the announcement made in this column last month: the bound volume of RADIO BROADCAST Laboratory Information Sheets Nos. 1-190 is now available at $i. Order from your newsdealer or directly from the Circulation Department of Doubleday, Doran. '"HO JUDGE from the comments in many letters, the Home JL Study Sheets are increasing in popularity. It may have escaped the attention of many who are following these Sheets that we are quite willing to examine the answers to the problems in each Study Sheet. These answers will be promptly examined and returned with our comments. THE December issue will contain an interesting article on band-pass filters, an interesting and practical article on television, more good data for the service man and professional set builder, instructions on how to grind quartz crystals, a number- of important constructional articles—and our regular departments. — WILLIS KINGSLEY WING. DOUBLEDAT, DORA7\[ ^ COMPACT, IXC., Garden Qity 9 MAGAZINES COUNTRY LIFE WORLD'S WORK Tin: Awf-KK AN H«»MK RADIO BROADCAST SHORT STORIES LE PETIT JOURNAL FRONTIER STORIES WEST THE AMERICAN SKETCH BOOK SHOPS (Books of all Publishing OFFICES NEW YORK: LORD & TAYLOR; JAMES MCCRKERY & COMPANY GARDEN CITY, N. Y. PENNSYLVANIA TERMINAL AND ifrfi \\ ,• -. i \tm ST. 848 MADISON AVE. AND 51 EAST 44™ STREET 420 AND 526 AND 819 LEXINGTON AVIM t GRAND CENTRAL TERMINAL AND 38 WALL STREET CHICAGO: 75 EAST ADAMS STREET ST. Louis: 223 N. STH ST. AND 4914 MARYLAND AVE. KANSAS CITY: 920 GRAND AVE. AND 206 WEST 47TH ST. CLEVELAND: HIGBEE COMPANY SPRINGFIELD, MASS: MEEKINS, PACKARD & WHEAT NEW YORK: 244 MADISON AVENUE BOSTON: PARK SQUARE BUILDING CHICAGO: PEOPLES GAS BUILDING SANTA BOKHARA. C'\i. LONDON: WM. HF.INEMANN, LTI». OFFICERS , F. N. DOUBLEDAY, Chairman of the Board NELSON DOUBLEDAY, President GEORCV H. DORAN. / ' it e~ President S. A. KVFRITT. 1'ice-Praidfnt RUSSELL DOI:BI.F.IJAY, Secretary JOHN J. HESSIAN, Treasurer LILLIAN A. COMSTOCK, Asst't Secretary TORONTO: Dot HI..-MA\. DORAN & t'u NOV. LTD. L. J. MCNAUCHTON, Asft't Treasurer Copyright, 1928, in the United State** Newfoundland, Great Britain, Canada, and other counties by Doubleday, Doron TERMS: $4.00 a year; single copies J? cent*. 1 Company, Inc. All right* reierved.