scope:

The principal equipment specified herein is an antenna intended for deployment in the Air Traffic Control Radar Beacon System (ATCRBS). The antenna provides a conventional directional pattern, an integral side-lobe suppression (SLS) pattern, and a monopulse pattern. The directional pattern has a sharp underside cutoff to control ground lobing while the SLS pattern matches the phase center height of the directional pattern in order to assure that the lobing characteristics of the directional and SLS patterns are the same. The purpose of the monopulse pattern is to provide single-pulse estimates of the azimuthal positions of transponders within the main lobe of the directional pattern. This specification also includes a six-path rotary joint intended for use with the ATCRBS antenna.