Chapter 5. Antenna Alignment
Vol. III-5-12 Alcatel-Lucent
8. Check the XPD on the RAC 40s at the reference end of the link, which should
be within 1 to 2 dB of the measurements at the adjusted end.
9. On completion ensure feedhead bolts are correctly tightened - check that
XPDs do not change during tightening.
10. Retain feed-head adjustment data for the commissioning records.
Procedure for Protected XPIC Links
When XPIC links are protected, both V and H links must be protected.
• If just one of the co-channel links is 1+1 protected, a failure of XPIC
cross-connect between the 1+0 RAC 40 and its 1+1 XPIC partner may cause
both V and H receive streams to error as the discrimination provided under
XPIC would be lost. An unlikely double-failure event would be needed to cause
the same error if both co-channel links are 1+1 protected.
For 1+1 hot-standby protection of XPIC links a single dual polarized antenna is
normally used at each end, and remote-mounted equal-loss combiners used to
mount the ODUs.
For space diversity XPIC links, separate dual-polarized antennas are installed.
For information on the operation of hot-standby and space diversity protection of
XPIC links, refer to Co-channel Operation, Volume II, Chapter 3.
Hot Standby Protection
Use the alignment procedure for dual polarized antennas, though first ensure the
links are Tx locked to prevent 1+1 switching.
The Rx function does not need to be locked, as the RSSI/RSL indication used for
antenna alignment is available from each RAC/ODU.
Procedure
• Use the CT > Diagnostics > System/Controls screen to check and set online Tx
locks.
• With an equal-loss combiner either Tx can be locked as the online Tx (The
primary designated Tx is the default online Tx).
Ensure that as you adjust the skew angle, the physical antenna alignment does
not shift, which would make it necessary to repeat step 2. Check that antenna
mounting bolts and azimuth and elevation adjuster locks have been correctly
tightened.
The maximum points may be quite sharp, rotate the feedhead slowly to ensure
they are not missed. Data in the performance screen is updated at 1.5 second
intervals.
To Next Page
Loading...
