Diversity reception of COMSTAR satellite 19/29‐GHz beacons with the Tampa Triad, 1978–1981

Tampa, Florida (28°N, 82.5°W), has about 90 thunderstorm days per year, almost all in summer. These convective events tend to occur in afternoon or early evening. This paper presents results of 19‐GHz downlink rain attenuation diversity studies in Tampa involving site separations of 11, 16, and 20 km and reception at high elevation angle (about 57°), over a period of 29 months, including three rainy seasons. Almost identical long‐term performance with the two larger spacings indicates that for separations above about 15 km, diversity improvement was not sensitive to baseline orientation or length. During a fourth rainy season, using the remaining 29‐GHz beacon, diversity improvement with the 16‐km pair was similar to that predicted by scaling the 19‐GHz results of the previous seasons. Also discussed are the type of attenuation distributions and typical fade durations to be found under persistent convective conditions. For rain climates like Tampa's, site diversity in some form will be required for high‐reliability SHF satellite links. The diversity data may be helpful in designing schemes for resource sharing among numbers of links.