Radio broadcast .. (1922-30)

RADIO BROADCAST JULY, 1926 WILLIS K. WING, Editor KEITH HENNEY Director of the Laboratory JOHN B. BRENNAN Technical Editor Vol. IX, No. 3 Cover Design From a Painting by Fred J. Edgars Frontispiece Receiving "Photoradiograms" in London Looking Ahead to 1927 Zeh Bouc^ The March of Radio J. H. Morecroft Wavemeters for the Home Laboratory Keith Henney Series and Parallel Connection of Condensers and Re' sistances Homer S. Davis A High Quality Amplifier Arthur H. Lynch Improving the Popular Hammarlund-Roberts Receiver John B. Brennan Where Summer Static Comes From B. Francis Dashiell The Listeners1 Point of View John Wallace The Lightning Arrester H. Melchior Bishop "As the Broadcaster Sees It'1 Carl Dreher Drawings by Stuart Hay Tendencies in Modern Receiver Design Julius G. Aceves The "Radio Broadcast" Laboratory Information Sheets No. Q. Data on the Roberts Four-Tube Rectiver No. No. No. No. No. No. No. o. The Four-Tube Roberts Circuit Diagram . The uX'ioo-A Tube . The ux-i7i Tube . Charging Storapc Batteries on Direct Current . Dry A Batteries Loop Antenn.ts ft. Carrier Wave Arulvsis "Now, I Have Found" Verniers and Their Application to Radio A Lateral Basketweave Form Controlling Regeneration in the "Universal" Loud Speaker Comparison A Constant Non-inductive Resistance Unit An Easy Method of Doping Solenoids Two Ways of Mounting Crystals Improvising Your Own Bus Bar How the Patentee Is Covered by Law Leo T. Par\er Frequency Channels Used by U. S. Radio Stations Adapting the Roberts for Long Waves C. A. Oldroyd The "Radio Broadcast" Laboratory Service ' A Key to Recent Radio Articles E. G. Shalfyhauser Letters from Readers 2,06 207 211 2,2,2 224 228 232 236 241 243 248 258 263 266 267 268 270 272 277 BEHIND EDITORIAL SCENES TDOR those who have been wondering, "Whither is radio •^ design going?" several of the articles in this issue should prove especially interesting. Mr. Zeh Bouck's leading article, for example, shows how the newest products of the manufacturers— which were announced in time to be included in his story — are meeting the new trends in radio design. Professor Morecroft in his always interesting "March of Radio" sketches some of the important engineering problems which are to be met. And in the paper by Mr. Aceves, one finds an extremely good outline of the technical trend of radio receiver design in recent months. So the July issue is really a forecast number — what to expect in receiver design. '"7EH BOUCK, author of the leading article, is well known •^ to old readers of RADIO BROADCAST. For a long time he conducted the department, "In the R. B. Lab." He is now preparing a series of constructional articles which are more than interesting. We shall have something to say about that in a later number. Keith Henney 's article on "Wavemeters for the Home Laboratory," besides showing the many valuable uses of simple Wavemeters, tells something about the use of quartz crystal oscillators. So many experimenters are interested in the uses of quartz and the information is timely. A RTHUR LYNCH'S article describing the construction of •* ^ a high quality amplifier and power supply will interest those who seek good quality and a way to make their i lo-volt a. c. work for them. . . . How many thousands of our readers have built the Hammarlund-Roberts, we do not know, but it is certain that the article on page 228, sketching important, and for the most part, extremely simple improvements in that set, will interest them extremely. Also, there is the interesting story by Mr. Dashiell on where summer static comes from, and a companion story by Mr. Bishop, describing the installation and use of the lightning arrester. Lightning and static are not to be feared, once we know both ogres for what they are. NOTHER Radio Club paper will appear in the August RADIO BROADCAST, one by A. F. Van Dyck, an engineer of the Radio Corporation. The story deals with modern radio and the electrical phonograph. We shall soon publish a story about A batteries. They are not always what they seem, and we learn from this article what to buy and how to avoid being deceived. A host of interesting material for the set con' structor, the general technician, and the casually interested radio person will be found in the August RADIO BROADCAST. Doubleday, Page $r Co. MAGAZINES COUNTRY LIFE WORLD'S WORK GARDEN & HOME Bun HER RADIO BROADCAST SHORT STORIES 1 iii CATIONAL REVIEW LE PETIT JOURNAL EL Eco THE FRONTIER WEST Doubleday, Page & Co. BOOK SHOPS (Rooks of all Publishers) LoRD & TAYLOR BOOK SHOP PENNSYLVANIA TERMINAL (2 Shops) 38 WA*LLST. AND 166 WEST 32ND ST. GRAND CENTRAL TERMINAL 223 NORTH HTH STREET 4914 MARYLAND AVENUE f 920 GRAND AVENUE \ 306 WEST 47TH STREET CLEVELAND' HIGBEE Co. SPRINGFIELD, MASS.: MEEK INS, PACKARD^ WHEAT NEW YORK: ST. Louis: , KANSAS CITY Doubleday, Page Sr Co. OFFICES GARDEN CITY, N. Y. NEW YORK: 285 MADISON AVENUE BOSTON: TREMONT BUILDING CHICAGO: PEOPLES GAS BUILDING SANTA BARBARA, CAI.. LONDON: WM. HEINEMANN, LTD. TORONTO: OXFORD UNIVERSITY PRESS OOUBLEDAT, 'PAGE & COMPACT, Garden Qity, Doubleday, Page & Co. OFFICERS F. N. DOUBLEDAY, President A. W. PAGE, ^'ice-President NELSON DOUBLEDAY, yice-PrestdeiA RUSSELI. DOUBLEDAY, Secretary S. A. EVERITT, Treasurer JOHN J. HESSIAN, Asst. Treasurer . Copyright, 1926, in the United States, Newfoundland, Great Britain, Canada, and other countries by Doubleday, Page & Company. All rights reserved. TERMS: $4.00 a year; single copies 35 cents. I92-2O4