Cumulative fade distributions and frequency scaling techniques at 20 GHz from the Advanced Communications Technology Satellite and at 12 GHz from the digital satellite system

Cumulative fade distributions were derived from measured transmissions at 20 GHz emanating from the geostationary Advanced Communications Technology Satellite (ACTS) and at 12 GHz from the television broadcasting digital satellite system (DSS) over the one-year period September 1, 1995-August 31, 1996. The transmissions were acquired at two collocated receivers at the Applied Physics Laboratory of The Johns Hopkins University (central Maryland). Since both geostationary satellites are positioned within 1° from one another, the geometric pointing parameters at the receiver locations are approximately coincident (e.g., 38° elevation angle). The 20-GHz fades were noted to be two-four times larger than those measured at 12 GHz. Two frequency scaling techniques were employed for estimating the distribution at one frequency given a measurement at the other. The methods pertained to the frequency scaling formulation of the radiocommunications sector of the International Telecommunications Union and the ratio of attenuations in terms of an equal probability rain rate along an effective path. The latter method gave agreement to within 1 dB when adjusted for antenna-wetting signal degradation