Edited by KENDALL BANNING .MAY 192+ J In thisNumber How to Make an Auctioïfieduency Amplifier that Does Not Distort n for a two tube Mola Radiola III NEW two -tube RADIOLA -designed and A built by world -famed engineers in the At $35 great RCA laboratories -priced at less than you Radiola III. Two Radiotrans WD -I1. Head telephones. In brief, every- could build it for at home! A real RADIOLA thing except the dry batteries and the antenna. -including the tubes and headphones. .A new You Can Add model. Improved in sensitivity and selectivity. Radiola Loudspeaker . $36.50 Getting distance on the headphones, and near Radiola Balanced Amplifier(push -Dull) stations on a loudspeaker. Receiving clearly - toges long distances with a loudspeaker. I Including two RadiotronsWD. 11,$30 reproducing truthfully. Its thirty-five dollar Or Buy Complete price means at last that every home, every- RADIOLA III -A, the amplifier com- where, can tune in on the fun with a small bined with Radiola Ill in one cabinet; w ithfourRadiotrons WD -1 I,heed rcle. receiver built for big performance. phones and RadiolaLoudspeakcr,$ 100 Radio Corporation of America There are many Radiolas at many prices. Sales Offices: Send for free booklet that describes them all. 233 Broadway 10 So. La Salle St. 433 California St. New York Chicago, Ill. SanFrancisco,CaL RADIO CORPORATION OF AMERICA Dept. 15 (Address office nearest your. Please send me your free Radio Booklet. Name Street Address City R. F. D. State Radiola, The Best in Radio Equipment !JJett&r Radio r right through the summer/ Some three million more listeners than there were last year - and they'll all have a. season of real enjoyment! ALL through the country fans are headed straight for the most amus- ing and enlightening season that radio ever offered. Daily treats! Daily helps! Daily marvels! Three Main Developments contribute to the tremendous step-ahead of this summer's radio regime. Better programs - stronger broadcasting - clearer 'reception. Bitter, Programs Selected tnoie keenly -and, chosen according to, the, tastes òf' the vast atìdkeOe whose opinions are molding the quality and tone of the programs. An outstanding, feature will be the coming presi- dential campaign. ' All important messages of all the; 'parties.,will be broadcasted. More churches are planning to send their. services to vácationists. _ Sports- will be vividly and .ade quately. reported.. Áll,rqund: programs -packed with vital interest -art =news -home hints- business -fun -good music! Better - Sending and. Receiving Sending over e diversified wave- lengths to permit greater selectivity. Mtire.powerful sending stations- interconnections of . important .stations, for simultaneous broadcasting of mes- sages of national import- rebroadcastirig'from high power Áll Brandes Prod- stations. throtigh sub -stations located at distant points. All ucts are sold under -these make for more satisfectory reception. And the vast a money -bark improvements in. sets and circuits, in tubes and loudspeakers I 'S guarantee by re- assure clearer and truer rest pttòn. Surely this will be a sea- liable dealers son of jollity -and -interest. Tune in -and get-the good things everywhere. that crowd the air! T6ble Talker. $10.00 see additional men of the Rockies In Canada . $1.4.00 Navy Type Headset 8.00 In Canada . 11.00 Superior Headset 6.00 In Canada . 7.00 © C. Brandes, Inc., 1924 Tie /[Line to know in Radio Ì1 Please refer to POPULAR RADIO when answering advertisements. POPULAR RADIO EDITED by KENDALL BANNING CONTENTS for MAY, 1924 (Cover design by Frank B. Masters) VOLUME V NUMBER 5 Radio -operated Code Machines in a Newspaper Office FRONTISPIECE What is Radio Doing to Our Newspapers? ..... Marten E. Pew Page 423 Melting Metals by Radio. E F. Northrup 430 A Compact Radio Kit for a Spring Hike H. W. Sinclair 438 How to Get the Maximum Radio- frequency Amplification. George Lewis 442 How Radio Locates Ships at Sea S R. Winters 449 Getting Static's Autograph Austin Bailey 450 How to Test Telephone Receivers J T. MacGregor- Morris 454 What Can We Do With 3,000,000 Volts? . Thomas Elway 456 100 Best Hook -ups Technical Editor 463 Installment No. 6 How Radio Saved a Sailing Ship Armstrong Perry 468 A Measurement Chart for Use in Designing a Rheostat Raoul J. Hoffmann 470 Article No. 8 Where Interference Comes From 473 to Make an Audio -frequency Amplifier How 476 That Does Not Distort " "' Laurence M. Cockaday Will Radio Create a New Kind of Dramatic Writing? An Interview with - Edward C. Carpenter 486 Underground Radio Telegraph S R. Winters 490 DEPARTMENTS Broadcasts David Lay 493 What Readers: Ask Laurence M. Cockaday. 498 Facts You` Hunt For Richard Lord ' - ßp4 Hints for Amateurs Albert G. Craig 506 In the World's Laboratories E E. Free 508 Listening In Kendall Banning 516 "Stations I Have Heard" 521 With the Inventors Thomas Elway 523 NUMBER 5 VOLUME V MAY, 1924 monthly by Popular Radio, Inc., 627 West 43rd St., New York, N. Y., telephone number Published Treasurer. Price, 25 cents Chickering 1906; Douglas II. Cooke, President; Kendall Banning, a year in thè U. S., Canada and all countries within the domestic a copy; subscription, $3.00 News Company postal zone; elsewhere, '$3.50 a year, payable in advance. The International Bldg., London, E. C. 4, sole distributors in England. Entered as second Ltd.,' No. 5 Bream's the act of March 3, class matter April 7, 1922, at the Post Office at New York, N. Y., under title registered as a trade-mark by Popular Radio, Inc. Copyright 1879. Copyright, 1924, and London, Eng- in Great Britain by Popular Radio, Inc., 6 Henrietta St.. Covent Garden, W. C., land. Printed in U. S. A. R.E., Technical Editor E. E. FREE, Ph.D., Contributing Editor LAURENCE M. COCKADAY, For adocrtising rates address E. R. Crowe & Company, Inc. 225 North Michigan Ave. New York: 25 Vanderbilt Ave. Chicago: 2 The Best in Radio Equipment 3 1The gods cannot help one who loses opportunities." - Mencius If you are wise you will lose none of the opportu- nities for entertainment r that a Grebe Broadcast Receiver will bring. Trustworthy Performance WHETHER the evening's feature be the broadcasting of the World's Heavyweight Championship or a Sunday Night Concert, you will an- ticipate it with keen pleasure and con- fidence when you tune in with your Type CR -12. A 4-tube Receiver combining Regener- r, Broadcast ation and Tuned R.F. $175 (Accessories extra) Receiver Made in two easily operated types, in which every detail of craftsmanship is an assurance of trustworthy performance. Each Instrument is the result of more than ten years of radio manufacturing expérience. Ask your Dealer or write us for literature A. H. GREBE & CO., Inc. Van Wyck Blvd., Richmond Hill, N.Y. Western Branch: 451 East 3rd Street, Los Angeles, CaL IIl !!lii:!!Iii.Jlú'IIi:Illii:lll Licensed Under Armstrong U.S. Pat. No. 1,113,149 Type CR -14. A 3 tube dry cell Regenerative $110óo Receiver . (Accessories extra) Please refer to POPULAR RADIO when answering advertisements. PAGES WITH THE EDITOR WITH this number POPULAR RADIO celebrates D. Hubbard, Harold P. Donle, J. C. Gorman, its Second Anniversary-with a bigger and Dr. Clayton H. Sharp, James H. Collins, Dr. (we believe) better magazine than has ever Hereward Carrington, Leroy Scott, Mrs. been issued before. Christine Frederick, Armstrong Perry, Dr. E. * * * E. Slosson, Forrest Crissey, Percy Mackaye, Two years ago this month, POPULAR RADIO Morris S. Strock, E. L. Hall, Dr. Emil Wie- started out as a modest little publication of chert (German), Capt. H. J. Round (British), only 72 pages. This present number that you Dr. Louis Cohen, Gen. Gustave Ferrié have in your hands now contains 220 pages -a (French), Prof. A. M. Low (British), Marten growth of over 300 percent! E. Pew, Orson Lowell, Robert C. Benchley, * George H. Doran, Watson Davis, Dr. Henry Two years ago the well -known amateur, Smith Williams, Major General J. G. Harbord, William Andrew Mackay (2AQB) called per- Robert G. Skerrett, William J. Burns, Clare sonally at our office and paid in cash the first Briggs, Hon. John J. Tigert, T. Commerford subscription to be entered in our books. Today Martin, Edward R. Hewitt, Don Herold, Dr. that list has grown to 34,000 -the largest sub- Edwin G. Northrop, Dr. Willis R. Whitney, scription list of any radio magazine in the Dr. E. E. Free, Capt. Leon Deloy (French, country. C. Francis Jenkins, Commandant René Mesny * * * (French). DURING the last six months of 1923 (accord- s * s ing to the figures of the Audit Bureau of Cir- WITHIN the past seven months POPULAR culation) the total net sales of this magazine RADIO has gained 300 percent in advertising - showed the extraordinary gain of 92 percent - the greatest increase ever achieved by a maga- an increase that (so far as we know) marks zine within an equal period. Now, advertisers POPULAR RADIO as "the fastest growing radio give increasing patronage to a particular mag- magazine in the world." azine for just one reason -because that maga- * * zine pays advertisers best. WHY POPULAR RADIO is leading all other s * * magazines in circtiation gains may be ex- AND this gain of 300 percent is of particu- plained in two ways. lar significance because, within this very period, First; because it is giving the radio amateurs POPULAR RADIO has excluded from its pages and broadcast listeners the practical, helpful a large volume of advertising which it believed and interesting articles that they most want to to be contrary to the best interest of the radio read; fan and of the radio industry for the leading Second; because it includes among its con- radio magazine to continue to carry-general, tributors the foremost scientists, inventors, or non -radio, advertising, cut -rate advertising, writers and radio experts of the world.