Alcatel-Lucent 9500 MXC, User Manual, Page: 257 / 916

9500 MXC User Manual
3DB 23063 ADAA - Rev 004 July 2007 Vol. III-2-15
• For unequal loss the attenuation is nominally 1.5/6.5 dB. They have application
on rain-affected bands, 13 GHz and above.
When using a coupler to combine two ODUs onto a single polarization the
operating channels must be chosen from within the same diplexer option. If the
two ODUs are not from the same tuning/diplexer option then interference may
occur, resulting in degraded link performance.
The rationale for using unequal ratios is that they can be shown to lower annual
outage due to rain fades as compared to links deployed with equal loss couplers.
For band-specific coupler loss data refer to Coupler Losses, Volume IV,
Chapter 7.
Coupler Installation Procedure
The following procedure summarizes installation of a direct-mounted coupler. A
coupler may also be remote-mounted, with a single flexible waveguide used to
connect the coupler to its antenna.
Attaching a Direct-Mounted Coupler
Before installing a coupler check there will be sufficient mechanical clearance
for the coupler and its ODUs. There should be no clearance issues using
approved antennas when installed correctly on its mount with the appropriate left
or right offset. However care must be taken at locations where a non-standard
antenna installation is required.
The ODUs are attached to the coupler as if attaching to an antenna except that
there is no polarization rotator associated with each ODU. Rather the
coupler
polarization is set to match the V or H antenna polarization using 0 degree or 90
degree coupler interfaces, which are supplied with the coupler. Couplers are
default fitted with the vertical polarization interface.
A coupler must always be installed onto its antenna before ODUs are attached to
the coupler.
To install a coupler:
For a vertically polarized antenna proceed to step 2. For a horizontally polarized
antenna begin at step 1. (
Antenna polarization setting is described in Setting the
Polarization on page 2-5)
1. To change the coupler interface, remove by unscrewing its four retaining
screws. Replace with the required interface, ensuring correct alignment
between the interface and coupler body alignment indicators. Relocate the
O-ring to the newly fitted interface.
A coupler installation procedure is included with each coupler