The antenna pedestal contains these items:
· Scan motors
· Antenna position monitors
· Elevation and scan disable switches.
There is a horizontal scan motor to move the antenna +/- 90 degrees from the airplane centerline. There is also an elevation scan motor to move the antenna +/- 40 degrees up or down. This value includes manual tilt selection from the WXR control panel.
There is a zero position monitor and an incremental monitor for each motor. These monitors send antenna horizontal scan and elevation scan position data to the WXR R / T. There are elevation and azimuth scales that permit a visual measurement of the tilt and scan angles.
There are elevation and azimuth synchros. These synchros send the antenna positions to the WXR R / T. The WXR R / T gets antenna position data from the synchros. The WXR R / T also has a command position. The monitor circuit in the R / T tells when there is a difference between the two values. Then it sets an antenna failure.
There are elevation and scan disable switches on the antenna pedestal. They remove power to the scan and elevation motors. Use these switches to prevent movement of the antenna during maintenance. The switches do not stop RF transmissions from the WXR R / T.
A torque spring in the antenna pedestal balances the weight of the antenna. When you remove the antenna, the torque spring moves the elevation drive to the upper position.
Abbreviations and Acronyms | Antenna | WXR System Components | Air Data Inertial Reference System | WXR Output Data and Display | Sweep Patterns | WXR System Fail Messages and Display | General | Predictive Windshear Inputs | WXR Central Processor Unit |