Radio broadcast .. (1922-30)

RADIO BROADCAST JULY, 1928 WILLIS KINGSLEY WING, Editor KEITH HENNEY EDGAR H. FELIX Director of the Laboratory Contributing Editor Vol. XIII. No. 3 Cover Design - - From a Design by Harvey Hopkins Dunn Frontispiece A Giant Radio'Equipped British Passenger Airplane 124 What Hope for Real Television? R. P. Clarion 125 The March of Radio * An Editorial Interpretation 129 Aviation Must Come to the Use of Radio No Innovations or Revolutions for 1928 Broadcast Regulation at a Standstill The Inequalities of "Equalization" Another Non-Radio Man for the Commission The Commission Eliminates Its First Station The Engineers' Plan of Allocation The High-Frequency Spectrum Recent Radio Events A New Principle in Audio Transformer Design Kendall Clough "Radio Broadcast's" Home Study Sheets - - No. i. The Nature of Radio and Electricity No. 2. Determining the Capacity and Induct- ance of a Radio Circuit Making an A-Power Unit From Your Battery Charger Robert Burnhatn New Apparatus »'*-*- Useful Information on J\[ew Products A Good Amplifier-Power Unit for the 250 Tube Howard Barclay "Strays" from the Laboratory Keith Henney New Crystal Control Prices of British "Components" Present Interesting Trends in Radio Radio Gossip Publications Worthy of Note "Skim Milk Masquerades as Cream" 133 135 137 139 141 143 Technical Smoke Screen Recent Interesting Technical Articles Present Compression Type Resistors From a Lab Circuit Fan Who Our Readers Are A Flux for Nichrome Wire An Interesting A-B-C Power Unit and One-Stage Amplifier /. George Uzmann A Universal Set and Tube Tester •'*'-.'• D. A. R. Messenger Broadcast Station Calls with a Past - • William Fenwic\ "Our Readers Suggest" Checking Power Unit Voltages A Convenient Telephone Jack Arrangement Neutralizing the Short-Wave Amplifier Wave Trap Tuned Antenna Combination Additional Amplification for Phonograph Pick-Up To Stop That Whistling As the Broadcaster Sees It • Note on Programs D«ign and Operation of Broadcast Stations 21. Water-Cooled Vacuum Tubes A Space-Charge Amplifier and B Supply A Fine Program You Will Never Hear H. P. Manly John Wallace The Listener's Point of View A Receiver for Short-Wave Broadcast Reception Bert E. Smith Manufacturers' Booklets * - "Radio Broadcast's" Laboratory Information Sheets - - No. 201. Tube Life No. aoa. Farm Lighting Systems No. 103. Tuned Circuits No. 204. Line Voltage Variations No. 205. Electrical Measuring Instruments No. 206. A Screen-Grid Resistance-Coupled Amplifier No. 207. Equalizing Wire Lines for Broad- casting No. 208. Power Values in Radio Receiving Antennas Letters from Readers 145 148 150 151 A Short'Wave Adapter for the R.B. Lab Receiver Hugh S. Knowles 153 How to Build a Beat'Frequency Oscillator - G. F. Lampkin 156 "Radio Broadcast's" Service Data Sheets on Manufactured Receivers 159 No. 3. The Grebe A.C. Six No. 4. The Kolster 6 K A. C. Carl Dreher 161 163 165 167 170 174 179 OTHER THINGS. The contents of this magazine is indexed in The Readers* Guide to Periodical Literature, which is on file at all public libraries. MANY favorable comments have been received about the list of stations throughout the world transmitting below loo meters which occupied three pages of our May, 1928, issue. Although this list was very carefully checked for accuracy against the best lists of stations we could find, some errors undoubtedly crept in. Some of our readers have been kind enough to send us information which should be included when the list is published again in RADIO BROADCAST. In the course of the next four or five months we shall reprint the list, com- pletely revised. We urge our readers to help us by sending in any corrections which should be included at that time. IN THIS issue we begin a new feature, "RADIO BROADCAST'S Home Study Sheets" prepared by Keith Henney, director of the Laboratory. Back in September, 1925, Mr. Henney's first article, "New Fields for the Home Experimenter" under- took to lead the radio experimenter who had tired of merely building radio sets and who desired to learn more about what makes the wheels go 'round. Since that time, many articles of a similar nature have been published in these pages. With this issue we begin the "Home Study Sheets," which are arranged so that the interested readers can remove them with a razor blade and keep a complete file. The Sheets to follow will contain a great deal of practical information in what we believe is the most useful form. We shall be glad to have our readers' opinions on the innovation. It is a policy of RADIO BROADCAST to print as much useful information as possible with due thought to the form in which it is presented. The "Lab Sheets" — the 2o8th appears in this issue — were the first in this series. Next follow the "Service Data Sheets on Manfactured Receivers" and we have now added the "Home Study Sheets." Still other ser- vices, similarly valuable, are in prospect. UNLESS we are greatly mistaken, several of the articles in this issue are going to excite a great deal of interest. The leading article by R. P. Clarkson, "What Hope for Real Tele- vision 7 " attempts to explain television systems in general and to point out what now seems to be the only possibility of suc- cess. OUR August issue will contain, among other things, a description of the d.c. operated "Lab" circuit, another timely article on television, a really fine article by David Grimes on phonograph pick-up units, a constructional and operation article on the Cooley Rayfoto system, first introduced to our readers in our September, 1927, issue, a story on a new short- wave receiver, and the first article of a series by Robert S. Kruse. Mr. Kruse for a number of years was technical editor of S^ST. His first article deals with the mystery of 5-meter work and will be of especial interest to all our amateur friends who read RADIO BROADCAST. All the regular features will appear in our August issue as well. AS THIS issue goes to press, a correction has been noted in the list of parts (p. 142) for the article "A Good Amplifier-Power Unit for the 250 Tube" The Dongan Con- denser Unit, Ci, is listed at $16.50, instead of $23.00, as printed in the list. — WILLIS KINGSLEY WING. OOUBLEDAT, DORAN & COMPACT, INC., Garden Qity, J^ew MAGAZINES COUNTRY LIFE WORLD'S WORK GARDEN & HOME BUILDER RADIO BROADCAST SHORT STORIES EDUCATIONAL REVIEW LE PETIT JOURNAL EL Eco FRONTIER STORIES WEST THE AMERICAN SKETCH BOOK SHOPS (Books of all Publishers') t LORD & TAYLOR; JAMKS MCCREERY & COMPANY l PENNSYLVANIA TERMINAL AND 166 WEST 32ND ST. NEW YORK: < 848 MADISON AVE. AND 51 EAST 44TH STREET i 420 AND 526 AND 819 LEXINGTON AVENUE ' 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 OFFICES GARDEN CITY, N. Y. NEW YORK: 244 MADISON AVENUE BOSTON: PARK SQUARE BUILDING CHICAGO: PEOPLES GAS BUILDING SANTA BARBARA, CAL. LONDON: WM, HEINEMANN, LTD. OFFICERS F. N. DOUBLEDAY, Chairman of the Board NELSON DOUBLEDAY, President GEORGE H. DORAN, rice-President S. A. EVERITT, rice-President RUSSELL DOUBLEDAY, Secretary JOHN J. HESSIAN, Treasurer LILLIAN A. COMSTOCK, Asst't Secretary TORONTO: DOUBLEDAY, DORAN & GUNDY, LTD. L. J. McNAUGHTON, Asst't Treasurer Copyright, 1928, in the United States. Newfoundland, Great Britain, Canada, and other countries by Doubleday. Doran & Company, Inc. All right* r«en*d, TERMS: $4.00 a year; single copies J5 cents. 122