Frequency-modulation radar for use in the mercantile marine

The principles of f.m. radar are outlined and a comparison is made between pulse and f.m. techniques, particularly with respect to the requirements of the merchant service. It is concluded that multi-gate f.m. radars are too complex for this application and methods are outlined for overcoming the inherently low scanning rate of single sweeping-gate systems. Equipment is described which has an aerial beamwidth of 1.7° and a rotation rate of 10 r.p.m. with a fractional range resolution of 1/30. The future of f.m. radar for mercantile marine use is critically examined, the conclusion being that it will be most useful where very-short-range high-resolution pictures are required. Before such equipment is economically available further developments in transmitting valves must take place.