Radio mirror (Jan-Oct 1923)

RADIO DIGEST ILL U S T R A T E D U. S. MAY USE AIR PHOTO INVENTION LIFTS VEIL FROM RECENT SECRET TESTS High Officials of Navy Consider Device After Transmission of Pictures from Station NOF (Special to RADIO DIGEST) WASHINGTON. — Plans for the utilization by the government for an invention for the Radio transmission of photographs, half-tones and other pictures are under consideration by high officials of the navy. Secrecy regarding a demonstration on December 12 of the invention of C. Francis Jenkins, a "Washington scientist, has just been removed by the group of navy officials before whom the tests -were then made. Mr. Jenkins' apparatus was described some time ago in Radio Digest. Besides the various members of the navy department, there were present at the demonstration J. C. Edgerton, supervising Radio activities for the post office department, and John M. Joy, representing Will H. Hays and the amalgamated motion picture industry. Send Picture Through NOP During the demonstration photographs and drawings were broadcast through the ether from the Anacostia station, NOF, to the Jenkins laborator3^. The sending unit was superintended by Commander A. Hoyt Taylor, in charge of the Anacostia station, -while the rest of the officials witnessed the reception of the pictures on negative photographic plates at the Jenkins laboratory and watched their printing in the developing room. Four pictures in all -were broadcast. Two were photographs, one of President Harding and the other of Secretary of the Navy Denby. Two penciled sketches, one representing a map and the other comprising written and printed letters, were also sent. Although the original photographs were said to be of fair photographic quality only, the prints made from the receiving plate in the laboratory were pronounced quite clear, the heretofore impossible feat of broadcasting half-tones having been successfully accomplished. Can be Used for Motion Pictures About six minutes was consumed in receiving each picture, but Mr. Jenkins predicted this could be reduced to onesixteenth of a second, the speed necessary to produce motion pictures. A most interesting feature was a demonstration by one of Mr. Jenkins' assistants of his ability to identify the picture being sent by "sound." It had developed in earlier experiments that the picture impulses gave off a series of "groans" and that each picture had its characteristic "sound", which could be recognized after a few repetitions. How Device Operates The sending apparatus, consisting of a stereoptican like machine, projects the picture across a photo-electric cell in steady, downward sweeps. With each sweep the projected image is moved slightly to the side, only a thin slice of the image being drawn across the cell at one time. The varying intensity of light caused by the successive "slice" shadows caused correspondingly varying impulses to be broadcast. At the receiving end an ordinary Radio receiver, on the diaphragm of which a tiny mirror is mounted, -was used. Projected on the mirror was a strong beam of light. Vibrations of the mirror as it oscillated with the diaphragm caused the light beam to fluctuate across a filtering shutter, and thence through rotating prismatic rings onto the sensitive photographic plate. In this manner the light impulses are laid down side by side as they are received from the original' picture. Book Reviews Air Talk Tells Fans Why They Should Make Wills BUFFALO, N. Y. — Make a Will Day was observed in Buffalo recenty by Radio when S. Grove McClellan of the trust department of the Liberty Bank of Buffalo spoke from the Station WGR of the Federal Telephone and Telegraph company, on, . "Why Tou Should Make a Will." DEALERS WRITE FOR DISCOUNTS DUNGAN RADIO CO. Distributors 68 WEST WASHINGTON ST., CHICAGO 1000—1500 MILES ON ONE TUBE ONE CONTROL 150—25,000 METERS m T^"v Rheostat, Storage Battery, V ari ocou pier, l\l f ■ Variometer. 3-eoil Mounting, Variable In£ Y V^ductance, Taps, Dead End Losses or Radio Frequency. Complete hook-up. cuts, instructions, everything. Price $1.00. Nothing left for you to guess about. Build your own Receiver and flase 50% or more and get better results. Radio Experimental Laboratory, Box 194 F, Berkeley, Cat. Radio Receivers for Beginners. By Snodgrass and Camp. Answers the universal question, "How can I receive Radio?" Price, $1.00. The Armstrong Super-Regenerative Circuit. By George J. Eltz, Jr. E. E. This is a De Luxe edition of this famous circuit. Profusely illustrated and fully explained. Fifty-two pages. Price, $1.00. How to Retail Radio. A new book telling of tested plans and methods and policies for the dealer in Radio. Financing, location, store -equipment and arrangement. Price, $2.00. Radio Pirst Aid. Illustrated with working drawings and complete data as to the necessary equipment and cost of constructing from the simplest to the most modern Radio outfits at home. Price, $1. The Radio Amateur's Handbook. By A. Frederick Collins. A new revised edition of this book is just out. It is complete, authentic and -informative work on Radio. Fully illustrated. Price, $1.50. Vacuum Tube Receivers. By O. F. Heslar. A book that tells how to make a simple set. How to make a cabinet. It includes a 27 by 36-inch layout blue print. Price, 75 cents. Home Radio — How to Make It. By A. Hyatt Verrill. This book is particularly adapted for the amateur who desires to know how to make Radiophones. Twelve full page illustrations and diagrams. Price 75c. Elements of Radiotelegraphy. By Elery W. Stone. The text was written for the guidance and 'instruction of Radio students in the communication service of the Navy. It is an instruction book for Radio schools. Price, $2.50. Radio for the Amateur. By A. H. Packer and R. R. Haugh. The underlying principles of Radio thoroughly explained in simple language and understandable illustrations. This book will teach you how to construct and operate a receiving set successfully. Price, $1.50. Letters of a Radio Engineer to His Son. By John Mills. A series of interesting letters written to a boy. Each letter is full and complete and the most advanced student can skip over some of the letters and get just the information he desires. Price, $2.00. The book department of the Radio Digest is prepared to send you any of the books on Radio published, -whether listed in our Book Review of not, Let us know what book you want, send us your check and we will see that the book is mailed to you. Postage stamps in payments for books not accepted. Send money order or check. Radio Book Department, Radio Digest Illustrated, 123 W. Madison St., Chicago, HI. Make First Step to Cross Pacific Vessel 120 Miles Off Coast of China Hears Amateur Broadcasts ; U. S. Surprised HARTFORD, CONN. — Not content With sending Radio waves across the Atlantic Ocean with the same power that it would take to heat the filament on a 100-watt light and having the voice heard, via Radiophone, by listeners in London, American amateurs have taken, unwittingly perhaps, the first step toward conquering the Pacific as well. The best evidence that they are really capable of doing this is the report received by the American Radio Relay League headquarters here, that four west coast stations have been heard in Asiaticwaters. American amateur signals have been heard now off the coast of every continent. What this will do toward linking up U. S. amateurs in a new bond of relationship with every country where Radio amateurs ar' 'le found, is a prob""adio this next , to TO 1L jS China ma . -ir ignals by a =s o:i the coast of biggest surprises lem which progyear may only t Heard by Sli. The reception i ship operator 120 China was one of RADIOPHANS ORGANIZE WCX RED APPLE CLUB WCX Gives Prizes to First Listener In Reporting DETROIT. — The Red Apple club has been organized by WCX, the Detroit Free Press station here. The club was formed for the benefit of Radiophans in the Middle West, West and the South. The club holds a "frolic" every Tuesday evening from 11 to 12 o'clock midnight. At a recent entertainment a prize of a fountain pen was awarded the first listener from each state and Canadian province who wired in that he heard WCX. In a few minutes messages began coming from all parts of the country. "Keep the Fleet Mobile" is the Navy's motto, based upon the theory that efficient and uninterrupted communication between all units of the Navy makes for mobility of our sea defense. KELLOGG SWITCHBOARD & SUPPLY COMPANY Chicago that developed during 'he transatlantic amateur tests. Not only were the signals from U. S. stations heard clearly, but the operator, in a postal card mailed from San Francisco, stated that he could hear the signals a distance of twelve feet from the headset. The best previous record for amateur long distance transmission via the Pacific was Yokohama, 900 mi'es this side of the point where the amateur signals were heard. 6ZZ and 6EA Rate as Stars Of the stations heard off the coast of China, two were heard across both the Atlantic and Pacific Oceans during the transatlantic amateur test conducted under the auspices of the American Radio Relay League. "With all due credit to the list of successful stations, we think 6ZZ and 6KA are the stars," said Kenneth B. Warner, league secretary, "for they are in the China list and they also got over to Europe, including all -the long 2,500 mile drag over the Rockies and across the United States." WOAI STAND AGAINST "AIR CLUBS" PRAISED Revoke "Guilty" Stations' Licenses, Fan Advocates SAN ANTONIO, TEX. — Another Radtophan has expressed his approval of the anti-club policy of WOAI, as outlined recently by Ellis Chaney, vice president of the Southern Equipment Company, oper, ators of WOAI. He is H. W. Tribble. of Rogers, Ark. Many Radiophans throughout the country have commended the stand WOAI has taken in the abolishment of station clubs and organizations as boresome and uninteresting to the majority of Radio listeners. Mr. Tribble writes as follows: "You are to be commended in the stand you have taken with regards to such Radio broadcast organizations as several now in existence and others. Such stations should have their licenses taken from them. If I understand it, the Radio laws require first-class entertainment, and that is only foolishness. "Yours for better broadcasting, "H. W. TRIBBLE." Alexandra Carlisle and Wm. A. Brady on Program NEWARK, N. J. — Miss Alexandra Carlisle, the charming classic actress of international fame, and William A. Brady, the eminent theatrical manager, were the recent headliners on the program of the L. Bamberger & Company station, WOE, of Newark, N. J. FLEWELLING ALL PARTS NECESSARY DEALERS: WRITE FOR DISCOUNTS Radio is finding its way into college curriculae. According to a report from Philadelphia the University of Pennsylvania plans courses in Radio this spring. DON'T bore holes m your window or wall! Use "Hearwell" flat lead-in. One minute to install, no nails or tools required. Window shuts onto it. Safe, efficient, guaranteed, inconspicuous. A unique device. (Patented.) Sample 50c in stamps. Dealers wanted, good discounts, quick seller. 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