GE HC HP - Manual (Page 87)

MDS Intrepid-HC HP Installation and Operation 3-13
1. Power up drawer V on both ends of the link and record the RSL reading on one end.
2. Power off drawer V on that end and power on drawer H.
3. Check the RSL obtained on this RFU on H pol, and compare it to the RSL obtained by the RFU installed
on the V pol.
4. Verify that XPI (Cross Polarization Interference) is at least 25 dB
where:
sites. both at used ons polarizati orthogonal with RSL Link RSL
sites. both at used on polarizati same with the RSL Link RSL
XPOL
POL



=
XPOL POL
RSL RSL XPI
5. If XPI is less than 25 dB, adjust the feed polarization by opening the polarization screw and gently rotating
the feed to minimize the RSL
XPOL
.
Note that polarization alignment is not always possible since the RSL
XPOL
may fall below the sensitivity
threshold of the RFU.
It is also recommended to try to maximize the XPI as much as possible, by aligning the polarization.
XPIC Commissioning Tests
Individual Link Verification
Before operating in XPIC configuration, each of the links (V and H) should be commissioned individually in
order to verify its proper operation.
1 Power up only drawer V at both ends and verify its frequency channel and TX power configuration.
2 Verify that the RSL is no more than +/-4 dB from the expected level.
3 Run BER stability test on the link for at least 15 minutes to ensure error-free operation.
4 Power up only drawer H at both ends and verify its frequency channel and TX power configuration.
5 Verify that the RSL is no more than +/-4 dB from the expected level.
6 Run BER stability test on the link for at least 15 minutes to ensure error-free operation.
XPIC Configuration Verification
1 Using the XPIC cable, connect the two RFUs at each end to the TNC connectors. Make sure the
cable is no longer than 3 meters.
2 Configure the drawers to work in XPIC mode.
3 Verify that the RSL at all four RFUs is no more than +/-4 dB from the expected level.
4 Verify that no alarms exist (if a 155 Mbps line is connected).
5 Run BER stability test on each of the 155 Mbps links for at least 1 hour to ensure error-free
operation.
Note: In a 2+2 configuration, repeat each step above for each of the four coupled RFU combinations.