Radar interference to microwave communication services

It is the purpose of this paper to discuss the growing problem of interference between radar transmitters and microwave communication systems and the urgent need for the application of measures to enable these two radio services to coexist in the microwave spectrum. The problem basically is a difficult one since the radar transmitters use power outputs measured in megawatts, whereas the microwave transmitters normally use powers of 10 watts or less. The Bell System became aware of this problem as the result of a number of cases of interference to its microwave communication systems from radar operations. Two general types of interference are involved: 1. that resulting from the operation of radars directly on fundamental frequencies used for communication services, and 2. that due to the generation and radiation by the radars of spurious frequencies including harmonics which fall in bands and on frequencies used for communication services. The former type of interference can be eliminated through control of the frequency assignments for both radar and communication purposes. The latter type, however, is not so readily disposed of.