QUADRUPLE-SITE DIVERSITY EXPERIMENT IN AUSTRIA USING 12 GHZ RADIOMETERS

The paper reports on a quadruple-site diversity experiment using 12 GH z radiometers in Austria. Separations between sites were 10.9 to 26.2 km, providing orthogonal path separations (vertical or horizontal) of between 9.3 and 25.9 km. The radiometers were directed along the futur e look-angle of the ESA satellite OLYMPUS (azimuth 223.16 degrees from true North, elevation 25.43 degrees). The measurements were conducted from May 1980 to April 1983, with dual-site joint up-times exceeding 94.9% for all combinations. The experimental results indicate that, fo r this location and geometry, dual-site diversity performance is insen sitive to separations above 10 km, all pairs achieving similar diversi ty gain statistics. The results were close to those predicted by the H edge model, with the prevailing weather direction having a significant influence on diversity performance. In general triple- and quadruple- site groupings provided better improvement in diversity than the dual- site combinations but, while the statistical improvement was slight, t he number of joint events was significantly reduced from dual-site com binations.