Page:Electronics Technician - Volume 7 - Antennas and Wave Propagation - NAVEDTRA 14092.pdf/51

 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.

Figure 2-48.—AS-3263/SPS-49(V) antenna. 2-29