The Propagation of Low Power Short Waves in the 1000-Kilometer Range

A description is given of a series of experiments carried out between two ground stations, and between an airplane and a ground station, to determine whether it is possible to obtain with relatively low power reliable short-wave communication over distances of 500 km, or more. Continuous-wave transmitters supplying a constant power of two watts were employed throughout the experiments. Results at fixed distances are recorded and discussed, particularly with regard to fading in summer and winter. An airplane installation, operating into a fixed dipole antenna is described, and the results of a large number of observations at ground receiving stations, of the signals received from the airplane in flight are presented.