Continuous-Wave Radio Transmission on a Wave Length of 100 Meters, Using a Special Type of Antenna

The paper describes a method and apparatus for continuouswave transmission on a wave length of 105 meters. An electron tube generating set was used which employed four 50-watt tubes in a tuned-plate primary circuit, coupled to the antenna circuit. The antenna was rectangular in shape, 18 feet (5.5 m.) high by 40 feet (12.4. m.) long, and consisted of 23 wires connected in parallel. The generating set was coupled in on the lower side, and a gap which constituted a condenser was inserted in one of the other sides. The primary circuit and the secondary circuit separately each had a natural wave length of about 105 meters. A special receiving set was developed for this short-wave work. In transmission tests conducted between Washington and Pittsburgh, good signals were received in Pittsburgh during daylight, with 4.8 amperes in the transmitting antenna. Comparatively little variation in transmission was noted from daylight to night, and fading was not so serious as might be expected for somewhat longer wave lengths. The method described would, therefore, seem to have particular advantages for daylight communication. Tests were made at Dayton, Ohio, in transmitting with this set from the ground to an airplane in flight, and directional characteristics of the antenna were determined with the condenser gap in the top side of the antenna, and also in one of the vertical sides.