Ultra-High-Frequency Radiosonde Direction Finding

A simple radio direction finder, operating at 183 megacycles, for observing the flight of meteorological balloons is described. An Adcock antenna and a single-dipole antenna system, including a corner-type reflector as shield against ground-reflected waves, were used for measuring the azimuthal and the elevation angles of an incoming electromagnetic wave. Shielding characteristics of the corner-type reflector for various wire spacings, focal lengths, and wire lengths are given. The direction finder has an accuracy of ¼ degree in the determination of the azimuthal angles. An accuracy of ½ degree is easily obtained in the determination of the elevation angles when a stationary transmitter is used as target on top of Mt. Wilson at a distance of seven miles. Larger errors in the elevation angles were observed when the target transmitter was sent aloft on balloons.