Polarity Encoder Replacement - Sea Tel 4012 GX KU-BAND Technical Manual

Maintenance
NOTE: In this procedure you will use SKEW to
determine the amount of change you need to
make to your Linear Offset value due to the pot
change. This is because SKEW causes immediate
polarity change, whereas Linear Offset drives the
feed much more slowly over a longer time frame.
28. Log into the MXP as a Dealer. Access the
29. Adjust the SKEW parameter value
30. Note the change in SKEW required to
31. Example: Your Skew was zero, in doing
32. Set Skew back to zero.
33. Access the Configuration – Reflector
Example: The amount of change in Skew was +2
degrees, so you need to ADD that amount to
whatever value is currently in the Linear Offset
field. If the change in Skew is a negative value,
you will SUBTRACT from the value in the Linear
Offset field.
34. Save the final Linear Offset value.
35. Log out of the MXP.
21.5.9.
If your polarity encoder has failed, it must be replaced. Follow this procedure to replace the encoder.
CAUTION: Protect all open feed, feedtube and other waveguide ports from being contaminated by debris.
1.
2.
3.
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Tools-Position Antenna page.
UP/DOWN by typing in +/- numbers in 1
degree increments (adjusting polarization
UP/DOWN) to optimize the cross-pol
isolation as directed by the NOC
technician.
achieve optimum cross-pol isolation.
the cross-pol isolation test you end up
with a Skew of +2 (positive 2 degrees),
therefore, +2 degrees of change.
page to adjust the Linear Offset value by
the amount of change in SKEW.

Polarity Encoder Replacement

To replace the polarity encoder, the RF
Cage MUST be removed from the
reflector. Refer to the "Removing the RF
Cage" procedure to remove the RF Cage
and relocate it to a clean, clear, working
area (as shown in this procedure). Retain
all hardware for reinstallation.
Refer to the "Replacing the Co-Pol LNB"
procedure to remove the side bracket
that exposes the polarity encoder. Retain
all hardware for reinstallation.
Cut tie-wrap that bundles the wires
together and unplug the polarity encoder
from the IDC Connection PCB.
4012 GX Dealer Technical Manual
Document. No. 136879 Revision B
21-51