Abstract: A non-rotatable radar antenna installation for aircraft for providing 360.degree. azimuthal scanning, which includes a generally triangular radome carried by the aircraft, and three substantially planar radar antennas arranged in a triangular planform within the radome. 360.degree. azimuthal coverage is achieved by the sequential side-to-side scanning of the three antennas. The planform area of the triangular radome and consequently the drag and weight penalty of the radome upon the aircraft is substantially less than equivalent radar antenna installations of circular configuration.