User guide

95
Pedestal
Elevation Position Feedback
The elevation position feedback is produced by an electronic clinometer and encoder mounted on the output shaft of the
motor. The clinometer has a resolution of 0.1 degrees with the accuracy/linearity of 1% of the 0-45° range and monotonic
in the 45-90° range. The clinometer is rated for an outdoor environment. The encoder also provides precise feedback on
the unit’s position during operation. The limits are controlled by using inputs from the clinometer and optical encoder
together and are set in and controlled by the TracStar controller. The clinometer is mounted on a bracket under the pol
gear cover. The clinometer is covered with an aluminum cover to protect it from the mechanical damage and provide
additional weather protection.
9: Polarization Feed and Drive Assembly
General
The feed assembly consists of the feed boom, feed housing, RF components and polarization drive. The feed boom is
pivoted at the bottom of the reflector. The feed assembly is mounted to the feed boom.
Polarization Drive
The polarization drive motor is a 24DC gear motor. It is attached to the polarization gearbox. Polarization setting is
accomplished by rotation of the reflector.
Polarization Gearbox
The azimuth gearbox is a worm gearbox. The worm gear drive isolates any backlash in the motor drive from the system.
In addition, since it is a 30:1 ratio, it will not back drive, thus eliminating any need for a brake on the drive train. The
gearbox contains synthetic oil. Because of the design capacity of the gearbox, low rpm, and comparative limited cycles
experienced by the system, no wear or maintenance is expected.
Polarization Roto-Lok Cable Drive
The patented azimuth Roto-Lok drive produces a drive system with zero backlash, high stiffness, no wear, no lubrication,
and maximum reliability. The system consists of two 1/16 9x17 stainless steel aircraft control cables, reverse-wrapped
twice around the capstan with solid connections on one end and high force, Belleville springs on the other end occurring
at the polarization spring block. One cable has the capacity to withstand an 80 mph wind load.