SCHEMATIC DIAGRAM AND PARTS LIST - The schematic diagram for the antenna pedestal is contained
component location. The parts list for the azimuth drive assembly is contained in Table 5-4.
GENERAL DESCRIPTION AND THEORY OF OPERATION - The elevation drive assembly, which consists
essentially of a yoke assembly (item 8), a housing (item 2), and a drive motor (item 3), supports the antenna and tilts it in
elevation. The yoke assembly, a nonrotatable assembly with a stationary drive gear, is bolted to an elevation drive
support casting which couples the azimuth drives to the elevation drive. The elevation housing, a U-shaped casting
which is bolted to and supports the antenna, is supported through roller bearings in the yoke assembly. The drive motor,
when powered, drives the elevation housing around the yoke assembly. An angle scale, graduated from 0 to 360
degrees, affixed to the movable housing and an index marker affixed to the stable elevation yoke, provides a visual
indication of the elevation angle of the antenna and, during installation, allows orientation of the antenna to O-degree
elevation. Two mechanical limit stop assemblies (item 9) prevent movement of the elevation housing below -18 degrees
and above +98 degrees. An electrical limit switch (item 7), which acts as a buffer for the mechanical stops, makes
contact 3 degrees before the mechanical stops. Two synchros (items 4 and 5) provide control and data signals for the
elevation axis. An electric pressure brake (item 6), which is released when power is applied to the system, prevents
movement of the antenna in elevation when the system is not operating. The detail theory of operation of the circuits in
the elevation drive assembly is contained in Section I.
ADJUSTMENT AND REPAIR - The components requiring adjustment on the antenna pedestal are the
synchros, electrical limit switch, and the electric brake. The synchro adjustment procedures are contained in paragraph
2, this section, and the electric brake adjustment procedures in paragraph 7.B(3), this section. Procedures for adjustment
of the electrical limit switch are contained in the following paragraph.
LIMIT SWITCH ADJUSTMENT
Release the electric brake.
Connect an ohmmeter between pins k and d on receptacle connector J1 on the elevation drive
Position the elevation housing to 345 (-15) degrees, as indicated on the elevation vernier.