a microwave signal detector system provides a visual indication of the relative bearing of a remote source of microwave energy . an antenna for receiving said microwave energy includes a plurality of microwave - sensitive elements arranged in a planar circular array for receiving pulses from all azimuth directions . each microwave sensing element is adapted to monitor energy received in a predetermined angular sectors and includes a horn element and a microwave energy responsive diode disposed within said horn element . the diode is connected as part of a voltage divider to develop a noise signal corresponding to the microwave energy received at each sector resulting from vibrations in the diode which occur at an audio frequency . the resultant developed noise signal is digitized and compared to a predetermined threshold to provide an output control signal when the developed signal exceeds the value of the threshold . the output signal drives an led indicator . an led corresponding to each sensing diode is arranged in a circular display to provide relative bearing information corresponding to the received signal . this system is particularly adapted to provide early warning of vessels in the vicinity so as to avoid possible collisions .