The long-range propagation of radio waves at 10 cm wavelength

A survey is presented of the results obtained in a series of short-term experiments on the propagation of 10cm radiation over clear sea paths to distances well beyond the diffraction region, under a variety of weather conditions. Very slowly attenuated signals have been received consistently, under normal atmospheric conditions, from an initial threshold beyond the horizon when the diffracted signal is some 50dB below the corresponding free-space level. Analysis of the amplitude distributions of some of the received signals confirms that propagation to ranges in the extra-diffraction region was due to a scattering process.