AS-3263/SPS-49(V)

pulse generator (APG), located in the rotary joint, transmits to the radar indicator azimuth information corresponding to beam direction. Polarization of the radiated energy can be remotely switched to either linear or circular polarization. The reflector has a modified parabolic shape designed to produce an approximately cosecant squared beam in the elevation plane. The reflector surface, covered with expanded aluminum screen, is 16.1 feet wide and 9 feet high. The antenna feedhorn, which mounts on the polarizer, provides impedance matching between the waveguide system and free space, and produces the desired feed pattern to illuminate the reflector. A radome over the horn aperture excludes moisture and foreign matter, and provides a pressure seal. pedestal assembly, the feedhorn and feedhorn support boom, and the reflector assembly. The base assembly provides a surface for mounting the antenna to the ship. It also contains the azimuth drive gearbox. The gearbox is driven by the azimuth drive motor, which drives the pedestal in azimuth through a pinion gear mated to a ring gear located at the bottom of the cone-shaped pedestal assembly, The azimuth drive circuits rotate the antenna through 360 degrees at speeds of 6 rpm and 12 rpm. The reflector and the feedhorn support boom are mounted on a trunnion, allowing the elevation angle of the rf beam to be controlled by a jackscrew located behind the reflector. The jackscrew is rotated by the elevation drive gearbox, which is connected to two dc motors. The rf energy to the feedhorn is routed through elevation and azimuth rotary joints located within the pedestal. AS-3263/SPS-49(V) The AS-3263/SPS-49(V) antenna (fig. 2-46) consists of three major sections: the antenna base and Figure 2-46.—AS-3263/SPS-49(V) antenna. 2-27