COPOLAR AND COCHANNEL SATELLITE INTERFERENCE DURING RAIN AT 11.6 GHZ ESTIMATED FROM RADAR MEASUREMENTS

This study reports estimated results on copolar and cochannel interfer ence during rain at 11.6 GHz, derived from radar measurements, in two convergent slant paths to fixed receivers at Spine d'Adda (45.4 degree s N), for values of the angular separation (given by the aperture angl e theta of the corresponding orbital diversity configuration) between the interfered and the interfering satellites ranging from 16.1 degree s to 118.7 degrees, with path elevation angles from 31.6 degrees to 15 .6 degrees, respectively. The results, applicable not only to geostati onary satellite systems but also to systems using satellites in lower orbits, have shown that the interference level I-C,I-n = A(C) - A(n), (dB), i.e. the difference between the simultaneous rain attenuations ( dB) in the interfered path (A(C)) and in the interfering path (A(n)), can be significant for any theta and that, for a given maximum rain at tenuation tolerated in the interfered satellite system (i.e. its power margin), I-C,I-n increases as theta increases. The results are applic able to direct TV/audio broadcasting systems, as shown in the paper, o r to fixed systems working in the 12 GHz band, and can be extrapolated to other carrier frequencies. (C) 1997 by John Wiley & Sons, Ltd.