Sea Tel ST88-21 C/Ku-Band TVRO, Installation And Operation Manual

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Maintenance and Troubleshooting ST88-21 C/Ku-Band TVRO
13-18
input is corrupt, not stable or not consistently accurate the tracking errors will become large enough to cause
the antenna to be mis-pointed off satellite.
Satellite Reference Mode will uncouple the gyro reference from the azimuth rate sensor control loop. When
operating in Satellite Reference Mode changes in ships gyro reading will not directly affect the azimuth
control loop. The Pedestal Control Unit will stabilize the antenna based entirely on the azimuth rate sensor
loop and the tracking information from DishScan®. This will keep the azimuth rate sensor position from
eventually drifting away at a rate faster than the tracking loop can correct by using the tracking errors to
regulate the rate sensor bias.
Satellite Reference Mode can be used as a diagnostic mode to determine if tracking errors are caused by
faulty gyro inputs.
I t should normally be
OFF
as long as you have an accurate, reliable, gyro compass input available.
It MUST be OFF when the elevation angle is greater than 75 degrees. Above 75 degrees Elevation, the
ability of Sat Reference tracking to correct the Az Rate sensor bias begins to degrade, especially on a circular
C system.
Satellite Reference Mode
MUST be ON when:
•
No Gyro Compass is available.
•
The Gyro Compass input is noisy, occasionally inaccurate or occasionally unavailable.
•
Frequent or constant ACU Error Code 0001 (Gyro Compass has failed).
•
Using an
uncompensated
Flux Gate Compass.
To view, or change, the Satellite Reference Mode status,
select the SAT REF remote parameter:
1. Press the RIGHT arrow, then press the UP arrow and last press the ENTER key to turn Satellite
Reference Mode ON.
2. Press the RIGHT arrow, then press the DOWN arrow and last press the ENTER key to turn Satellite
Reference Mode OFF.
If you change this remote parameter, you must save the change using REMOTE PARAMETERS.
13.7.11. To Read/Decode an ACU Error Code 0008 (Pedestal Function Error):
An Error Code 8 as reported by the ACU is an indication that the above decks equipment has experienced an
error. One of the functions available within the “
Comm Diagnostics
” tool window provides the means to
read and decode the actual discreet Pedestal Function Error.
1. Select the
“Comm
Diagnostics”
window
under to the Tools
submenu or Press “CTRL +
C”