Some observations of anomalous depolarization on 19 and 12 GHz earth-space propagation paths

During the summer of 1976 anomalous depolarization events associated with precipitation have been observed on 19 and 12 GHz earth-space propagation paths. These events are characterized by strong depolarization (> -20 dB) occurring with low signal attenuation (often <1 dB). They are not explained by contemporary atmospheric propagation theory. The anomalous events could significantly affect performance of satellite communications systems using the same frequencies on two orthogonal polarizations.