Phase and amplitude variations in multipath fading of microwave signals

Experimental data on the duration of individual fades in a 4-GHz radio signal are used to derive the rates of change in amplitude and phase of a signal propagated through a 30-mile multipath medium. A by-product is a relation between the rate of change in phase and the effective vertical velocity of the atmospheric irregularities that can be considered to be the cause of the multipath phenomena. The derived distribution of velocities is then used to predict the variations in fade duration over a wide range of frequency and path length.