The application of a three dimensional bistatic rainscatter model to radio systems coordination areas

The current CCIR method of assessing the coordination distance between the earth station and terrestrial station considers the worst-case scenario of exact intersection of the two antenna beams for a backscatter geometry. It has long been known that there is asymmetry in the path loss between forward and backscatter. Because the general CCIR model is only two-dimensional, it cannot properly consider three-dimensional path loss contours. The author analyzes the path loss contours at a number of frequencies using a three-dimensional bistatic interference model. Preliminary results show that, even for the extreme worst-case scenario of two antenna beams intersecting exactly, the CCIR overestimates the coordination contours by at least 10%.<>