Some Effects of Measurement Errors on Rain Depolarization Experiments

Measurements of rain-produced depolarization for linearly polarized 20- and 30-GHz satellite signals oriented vertically (V) and horizontally (H) and a few degrees either side of V and H are required to determine both the proper polarization orientation for future systems and the depolarization at that orientation. The polarization received from area-coverage satellite beacons will vary considerably for different measuring sites within the coverage area. Calculation of rain-produced depolarization of one pair of orthogonally polarized signals from measurements of depolarization, differential attenuation, and differential phase of a different pair of orthogonally polarized signals will be required. Some effects of measurement errors on these calculations are shown. Accuracies on the order of ± 0.5 dB in differential attenuation and ± 2 degrees in differential phase are required in the measurements. Cross-polarization isolation of 25 dB in the measuring system is inadequate.