Control of interference between surface microwave and satellite communication systems

Satellite technology can expand global communication by orders of magnitude, but only by sharing frequencies with surface services now occupying the spectrum. Feasibility of frequency sharing with fixed microwave systems is discussed here. Such systems occupy a useful fraction of the spectrum and employ horizontally-beamed low power. Passive and active, stationary and low orbit satellite point-to-point systems are considered. Interference may be “surface” (earth terminal to or from microwave) or “orbital” (to, from, or via satellites). Surface coordination is eased by the minimum elevation angles of terminal antennas, but still requires beyond-horizon separations or topographically protected sites. Interference from satellites is inconsequential. Main-beam interference to satellites can come only from a tangential belt.