The remarkable properties of a unique resonant circular array are applied to provide a microwave beacon to supplement warning flashing lights, lighthouses, and bells in coastal shipping. Following a description of the structure and properties of the array of antennas, the design of a special form of the array is explained, and its radiation field is described. This consists of 90 very sharp spikes between 90 equally sharp nulls. In the suggested array, the single driven element is excited at a microwave frequency. By rotating the array a sequence of microwave pulses is radiated that can be made equal to the frequency of flashes from any flashing light.