Precipitation scatter as an interference source in communication satellite systems

Communication satellite systems operating at frequencies as high as 3 Gc are now in the active planning stage. A number of recent papers have dealt with the interference produced at the ground receiving sites of such systems by tropospheric scatter from sources below the radio horizon. However, theoretical and experimental data from the field of radar meteorology show that scattering by precipitation particles at 3 Gc can easily exceed the tropospheric scatter component by several orders of magnitude. The precipitation scatter is approximately isotropic in most cases and hence the scattering volume need not be on the Great Circle path from the interfering source to the receiver site to be effective. Minimum separations for satellite terminals and interference sources computed considering only tropospheric scatter are therefore completely inadequate to guard against precipitation scatter.