Radio Broadcast (Nov 1926-Apr 1927)

26 RADIO BROADCAST NOVEMBER, 1926 tion from the compass at regular intervals. By checking the visual and radio observations, the directional errors of the radio compass are recorded for future reference. Utilizing the picture transmission apparatus developed by C. Francis Jenkins, the naval radio station naa at Arlington, Virginia, is transmitting weather charts for the use of ships at sea. Two naval vessels have been fitted with the necessary receiving equipment for reproducing the charts. This is the beginning of what will ultimately be an invaluable radio aid to navigation on the sea and in the air. "Cross Talk" in British Telephone Circuits IT MUST give British radio listeners considerable distress or amusement to hear their private telephone conversations broadcast as a result of cross talk into circuits furnished the radio stations of the British Broadcasting Company. Judging from newspaper items, this has occurred on a number of occasions. Cross talk requires most elaborate precautions to avoid, but the radiation of cross talk by a broadcasting system is nothing less than mere carelessness in operation. By constantly monitoring the program of each radio station, broadcasting of cross talk can be prevented by shutting down the radio transmitter until the line is cleared or shifting to another line. When chain broadcasting was first undertaken in the United States, involving lines many times longer than those used in England, cross talk difficulties were en countered but they were avoided by setting up two parallel telephone circuits, offering an alternative path, should one become noisy, without more than an instant's interruption of the program. As routine tests became perfected and the reliability of telephone circuits established by long practice, the necessity for alternate circuits for ordinary interchange of programs has disappeared. Praiseworthy Work by the Victoria B. C. Radio Club THE Radio Club of Victoria, British Columbia, we learn from W. J. M. Griffin of that city, has tackled the problem of power line radiation in a most commendable manner. Mercury arc transformers are used to step down the high voltage used in distribution and these, in some districts, cause destructive interference to radio programs. Loyal members of the radio club personally expended some four hundred dollars to equip the transformers with choke coils so as to rid the populace of this pest to radio reception. When radio listeners actually reach into their pockets to alleviate conditions of radiation, they are aided by the cooperation of the power companies and rewarded by a considerable improvement in reception. More About Toll Broadcasting WE HAVE received many letters commenting favorably on the article by Austin C. Lescarboura, "What Does it Cost to Broadcast?" in this magazine for September, 1926. Every care for accuracy was observed in the preparation and editing of the story, but several inaccurate statements crept in. We have been asked to call attention to several statements which may appear misleading. John Shepard 3rd, of the Shepard Stores of Boston and Providence, writes to say that the two broadcasting stations operated by his company, wnac at Boston, and wean, Providence, have been connected by wire lines for nearly three years. The connection is not occasional as might have been gathered from the phraseology of the article. In referring to another Connecticut station, wtic of Hartford was represented as a commercial stat ion in the sense that broadcasting for hire was a practise. In the map of the present weaf "chain" appearing on page 368 of Radio Broadcast for September, wtic was shown as one of the links, and the caption conveyed the impression that wtic accepted payment for commercial programs. Mr. W. G. Cowles, vice-president in charge of broadcasting, of the Travelers Insurance Company informs us that his station has never received a penny of income from any source. The programs from weaf, heard through wtic are the so-called "sustaining programs" such as the Goldman Band concerts, the grand opera hour, and national events of various kinds for which weaf is paid by wtic. The Month In Radio LIEUT. E. H. KINCAID, navigator of the Navy transport Kiitery, succeeded in plotting the course of a West Indian hurricane by observing, with his radio compass, the direction in which the heaviest static was heard. This ingenious observation suggests a new service for the radio compass which may be of value in our meteorological service. THE Bureau of Standards is conducting experiments at College Park, Maryland, with improved radio beacon systems for the guidance of aircraft. Radio compasses and beacons are used for this purpose or, most of the European commercial routes. THE intensity of radio signals is affected by temperature conditions, according to conclusions reached by Dr. L. \V. Austin and Miss Wymore of the Bureau of Standards. In order to eliminate as far as possible the influence of meteorological phenomena, stations between 125 and 190 miles distant were chosen for the experiments. A greater distance would be subject to the influence of other conditions which would complicate the analysis, while a shorter distance, on the other hand, woud not show the influence of weather changes to a sufficient degree to make for reliable observation. A study of extensive data reveals that, when the temperature rises along the signal path, there is a tendency for the signal strength to fall and, conversely, a falling temperature produces a stronger signal. It should be recognized, however, that this is only one of the many influences which determine signal strength. THE FIRST DEMONSTRATION OF WIRED RADIO A scene in the office of the Chief Signal Officer of the Army when Major General George O. Squier was Chief Signal Officer. Major General Squier has many patents on systems for "wired radio" or "broadcasting" over electric light lines. This photograph was taken on March 24, 1022. In the photograph, left to right: Samuel Isler, assistant radio engineer, Signal Corps; C. E. Bohner, assistant electrical engineer, Signal Corps; R. D. Duncan, Jr., radio engineer, Signal Corps; Louis Cohen, consulting radio engineer; Lieutenant Colonel C. A. Sloane, Signal Corps, U. S Army; Donald Wilhelm; Major General George O. Squier, Chief Signal Officer of the Army; Sergeant E. D. Latta, Signal Corps; Lieutenant Colonel F. J. Griffin, Signal Corps