ST94-21 C/Ku-Band TVRO Maintenance and Troubleshooting
This completes the phases of initialization. At this time the antenna elevation should 45.0 degrees and
Relative azimuth should be at home flag (home switch actuated).
If any of these steps fail, or the ACU reports model "xx97B or xxx00B", re-configure the PCU as described
in the Maintenance section of this manual. If initialization still fails, this indicates a drive or sensor problem.
13.7.4. Troubleshooting using DacRemP
While troubleshooting a Sea Tel 3-Axis Antenna System, you must classify the fault you are dealing with as a
failure within one of 3 major system functions, Targeting, Stabilization, and Tracking. Should there be a
failure with any one of these functions, your system will not operate properly. A few simple checks may help
determine which fault (if any) that you are dealing with. The matrix below lists some test(s) and which of the
DacRemP graph selection would be best to use to identify a fault. The end of this chapter contains examples
on how to use DacRemP to diagnose a fault.
Targeting: is the ability to accurately point the antenna to an angular position in free space and is
controlled by the ACU. (Does the system drive to the Azimuth, Elevation, and Polarity positions within 1
degree of the desired satellite?)
Stabilization: is the process of de-coupling the ships motion from the antenna and is controlled by the
PCU. (Does the system maintain the satellite link after turning off TRACKING?)
Tracking: is the process of issuing fine adjustments to the pointing angle of the antenna to optimize the
received signal level and is controlled by the ACU. (Does the system pass a four quadrant-tracking test?)
Functional Test(s)
DacRemP Graph Selection
System Function(s)
Four Quadrant Tracking. ADMC (Position) Tracking
Azimuth Encoder Verification. ADMC (Position) Targeting
Sea Trial ADMC (Position) Targeting
Tracking
Side Lobe Plots ADMC (Position) Tracking
Targeting Alignment (AZ & EL Trims) ADMC (Position) Targeting
Determine Blockage Mapping ADMC (Position) Tracking
Unwrap recovery (Limited Az systems only) ADMC (Position) Stabilization
Pedestal Gain Verification DISPIVC (Loop Error) Stabilization
Home switch (flag) verification (Unlimited Az
systems only)
DISPV (Ref) Stabilization
Remote Tilt Verification DISPV (Ref) Targeting
Level cage/Level PCB alignment Verification
(sensor alignment)
DISPV (Ref) Targeting
Stabilization
Rate Sensor Output Verification DISPW (Rate) Stabilization
Level and CL fine balance Verification DISPTC (Drive) Stabilization
AZ Friction Torque Test DISPTC (Drive) Stabilization
DishScan® Drive/Phase DishScan® XY Tracking
EAR Controlled - ECCN EAR99
To Next Page
Loading...
