Radio age (Jan 1927-Jan 1928)

RADIO AGE for September, 1927 23 200 miles along the airways, in their functioning they are somewhat like marine radio beacons or lighthouses for mariners, in that aviators are thus offered a guiding hand when enveloped in fog or obscured in darkness. This beacon transmits two directed radio beams, continuously sending on each a characteristic signal. The airplane, equipped with an ordinary radio receiving set, if traveling at equal distances from the lines set up by these radio beams will receive signals of equal intensity ; off the well-defined path, there is an inequality of signals and the pilot corrects his course until the signals are again equalized. The marker beacons, established at 25-mile intervals along the 8,234 miles of airways, will serve as mileposts to aviators, indicating the distance already traveled and how many more miles must be traversed before reaching their destination. These marker beacons do not overlap the function of the directive beacon since the former do not define the course of flight. Instead, these very lowpower radio transmitting stations will flash a charactertstic signal and upon being intercepted by the aviator he is automatically informed of his location. Extremely simple transmitting sets have been . designed for this purpose and these mileposts along the air highways instead of conflicting with the function of the directive beacon will materially supplement its effectiveness. Radio-telephone stations, located at 200-mile intervals along the more than 8,000 miles of civil airways, will serve as mediums for imparting weather forecasts, information about landing fields, and other navigational facts, to aircraft in flight. For this purpose, radio telephony is necessary since aviators are not usually trained in the technique of the Morse International telegraph code and are not, therefore, qualified telegraph operators. The use of the radio telephone on aircraft necessitates the adoption of specially armored cable for the engine ignition systems. Once the engines have been shielded to eliminate interference, conversations between pilots in flight Radio installation in aircraft, mail-carrying transport, showing transmitter, reel and control box and persons at ground radio stations may be effected at distances of 100 miles or more. Officials of the Bureau of Standards recently conducted experiments which form the basis of this estimate. The aircraft radio beacon station at College Park, Maryland, is at once the original and model of all future radio aids to air navigation. There, under the direction of Dr. J. H. Dellinger, Chief of the Radio Laboratory of the Bureau of Standards, the first radio beacon was erected under authority of the United States Department of Commerce for the development of civilian aeronautics. A similar installation is being made by the Bureau at Bellefonte, Pennsylvania, and both of these beacon stations will be available for radio service to commercial air lines after July 1. The other four aircraft radio beacon stations available now or soon are : The station of the Army Air Corps at McCook Field, Dayton, Ohio; two stations of the Ford Motor Company, located respectively at Dearborn, Michigan, and Chicago ; and a station installed by the General Electric Company at Hadley Field, New Brunswick, New Jersey. The commercial lines which these radio aids will serve are, respectively, the Pitcairn Company, operating the New York to Atlanta route, and the National Air Transport, Inc., operating the New York to Chicago route; and the Ford Motor Company, operating out of Detroit. The model station at College Park includes a wooden tower, 70 feet high, painted a deep shade of yellow, with a flag at its apex. This towering latticework is the main supporting structure for two triangular loop antennas, from which doublebeam radio waves are emitted for guiding aircraft. A radio room, lOx 14 feet in dimension, containing the vacuum-tube transmitting set, the goniometer, and other necessary radio equipment, is located directly un