Radio broadcast .. (1922-30)

RADIO BROADCAST MAY, 1926 WILLIS K. WING, Editor KEITH HENNEY, Director of the Laboratory JOHN B. BRENNAN Technical Editor Vol. IX, No. 1 =*• Cover Design From a Painting by Fred }. Edgars Frontispiece The Marconi Direction Finder on a British Ship 18 Breaking Into the Wireless Game James M. Basfyerville 19 The March of Radio J. H. Morecroft 23 Shall I Buy a Factory-Built Receiver? Austin C. Lescarboura 28 Will the New Type of Condenser Improve my Set? Kir\ B. Morcross 3 3 The Listeners' Point of View John Wallace 37 The RADIO BROADCAST Local Receiver John B. Brennan 42 The $500 Short' Wave Receiver Contest 46 Trickle Chargers for Your A Battery James Millen 47 Testing and Operating the "Aristocrat" Howard E. Rhodes 52 Easy Ways of Learning the Code Edgar H. Felix 56 As the Broadcaster Sees It Carl Dreher 60 Drawings by F. F. Stratford The Grid — Questions and Answers »*'**** 70 One Way to Sharpen Tuning When to Change Storage-Battery Electrolyte The Western Electric Cone — High or Low Impedance? How to Eliminate a Singing Noise in the Receiver Circuit Diagram for an Interference Finder Eliminating a Buzzing Noise in the Receiver Two-Point Tuning on the Super-Heterodyne Correct Grid Bias Voltage Determining the Best Grid Leak Connection "Now, I Have Found" Using a Cone with the Super-Heterodyne Head Phones With the Roberts Reflex Try Choke Coupling When your Audio Transformer Burns Out Changing the Frequency Range of Your Set A Treble Back-Mounted Tap Switch A Simple Way of Switching from Tube to Crystal Quarterly Prize Award Announcement A Key to Recent Radio Articles Book Review Tall(s About Radio, by Sir Oliver Lodge The Wavelengths of Canadian Stations Letters From Readers '<•**«•* E. G. Shalkhauser Edgar H. Felix 76 79 85 87 88 B£HIA[D EDITORIAL SCENES WITH this number of the magazine, RADIO BROADCAST begins its fifth year. The first copy was dated May, 1922. During the last four weeks, a large volume of correspondence has come in to the editorial offices, commending our policies, praising the quality of the general and the strictly technical articles which we have been publishing, and very decidedly expressing the hope that we will continue along the lines which we have been following. There will be no change of policy and, reviewing our editorial schedules for the next six months, we can promise to our readers some extraordinarily interesting material. OLD timers and new timers of radio will find James M. Baskerville's "Breaking Into the Wireless Game" full of the charm that wireless — now radio — holds for all of us. Mr. Baskerville is especially well qualified to write of those early days, because there are not many who antedate him in point of practical experience. Another one of Austin Lescarboura's articles about the development of the commercial broadcast receiver appears on page 28. Home constructors who build their own will read with interest of the many technical and manufacturing obstacles which must be overcome before the complete factory-built receiver reaches the hands of that much discussed person, the ultimate consumer. Those who are still weighing the advantages of using the new types of condensers recently developed will find Kirk Morcross' article on page 33 of real assistance. Mr. Morcross is a radio research engineer of excellent standing, and we feel that his article is more than usually complete. A LTHOUGH we have no quarrel with the many enthusi-tV asts whose chief radio pleasure is in pulling in stations at a great distance from their homes, there are still a great number of listeners who are interested chiefly in their local program. That is the reason for the design of "RADIO BROADCAST'S Local Receiver." No claims whatever are made for its distance-getting abilities, but the receiver is simple to build and easy to operate, and delivers very excellent audio quality James Millen, who has become known to readers of this magazine as an authority on current supply devices, has in this issue, another of his helpful articles, this time on trickle charging. Carl Dreher, whose comment about broadcasters and broadcasting, always informative and interesting, and frequently humorous, has had something to say recently in his department about the technical methods of broadcasting, how outside wires are rigged, the placement of the microphones, and other valuable notes for the broadcaster. This month he tells more about how the outside wire connections, so essential to every station, are "equalized," and some of the problems which must be solved in their use. THE next RADIO BROADCAST will contain details of a circuit which, while not revolutionary in itself, does contain some very interesting ideas, many of which will provide food for thought and experiment to constructors for many months to come. The second of Howard Rhodes's articles on wavetraps and their use will appear in this number, as well as a report of some extremely interesting observations made by Dr. Greenleaf W. Pickard on radio transmissions in the broadcast band. Many listeners have wondered at the poor long distance reception during the last six months and Dr. Pickard's figures reduce generalities to actual data. Doubleday, Page &• Co. MAGAZINES •COUNTRY LIFE WORLD'S WORK GARDEN & HOME BUILDER RADIO BROADCAST SHORT STORIES EDUCATIONAL REVIEW LE PETIT JOURNAL EL Eco THE FRONTIER WEST Doubleday, Page & Co. BOOK SHOPS (Books of all Publishers) LORD & TAYLOR BOOK SHOP PENNSYLVANIA TERMINAL (2 Shops) 38 WALL ST. AND 166 WEST 32NDST. I GRAND CENTRAL TERMINAL ' 223 NORTH STH STREET ( 4914 MARYLAND AVENUE K.N,., r.TY. ( 920 GRAND AVENUE NSAS UTY. NEW YORK: ST 1 ouis " CLEVELAND HlCBEE Co. SPRINGFIELD. MASS.: MEEKINS, PACKARD& WHEAT Doubleday, Page & Co. OFFICES GARDEN CITY, N. Y. NEW YORK: 28; MADISON AVENUE BOSTON: TREMONT BUILDING CHICAGO: PEOPLES GAS BUILDING SANTA BARBARA, GAL. LONDON: WM. HEINEMANN, LTD. TORONTO: OXFORD UNIVERSITY PRESS Doubleday, Page S* Co. OFFICERS F. N, DOUBLEDAY, President A. W. PAGE, Wee-President NELSON DOUBLEDAY, WeePresident RUSSELL DOUBLEDAY, Secretary S. A. EVERITT, Treasurer JOHN J. HESSIAN, Assl. Treasurer DOUBLEDAT, PAGE & QOMPA^T, Garden Qity, New; Copyright, 1926, in the United Stares, >{«u;/oundland, Great Britain, Canada, and other countries by Doubleday, Page & Company. All rights reserved. TERMS: $4.00 a year; single copiet 35 cents. 16