Scintillation of radio signals from satellites

Radio signals on a frequency of 20 Mc/s from a satellite in a polar orbit over a period of one month were recorded at two sites in. southeastern Australia to locate regions causing scintillation of signals. Very little scintillation was present during daytime transits between 1200 and 1800 h local time, but between 1900 and 2300 h local time it was observed consistently. The indications are that between latitudes 20°S and 40°S the scintillation was patchy, arising in regions a few hundred miles in north-south extent and more than 1000 miles in east-west extent. A marked increase in the incidence of scintillation with increasing latitude began at 38°S and between 40°S and 50°S, the region responsible for scintillation here being apparently more continuous in both time and latitude. Heights of the scintillation region deduced by triangulation from the two sites ranged from 200 to 350 km. It is shown that, although this method of observation imposes some limitation on the accuracy of these values, much of the scintillation observed must have originated within this height range.