Investigations of radar interference to satellite earth stations and terrestrial microwave communication sites

Fixed-satellite service earth stations and terrestrial fixed-microwave communication links often experience electromagnetic interference from radar systems operating in adjacent frequency bands. This paper summarizes the results from investigations into a large number of such interference cases by the National Telecommunications and Information Administration (NTIA) and the NTIA Institute for Telecommunication Sciences (ITS). Current Federal standards that limit radar out-of-band emissions are summarized. NTIA/ITS investigations have found approximately equal numbers of interference cases caused by out-of-band radar emissions and nonlinear receiver responses. Since mitigation methods are completely different for these two interference mechanisms, it is crucial that the interference mechanism be identified before mitigation efforts are undertaken. Mitigation procedures are described, and critical parameters necessary for the identification of interfering radars are discussed