User's Manual

UHF Fibre-Fed Remote Site
User Handbook
Handbook N.-60-137601HBK Issue No:-1
Date:-18/03/2005
Page:-
38 of 38
5. INSTALLATION
5.1 Initial Installation Record
When this equipment is initially commissioned, please use the equipment set-up record sheet
in Appendix A. This will help both the installation personnel and AFL should these figures
be needed for future reference or diagnosis.
5.2 Installation & Attenuator Settings
The UHF Fibre Optic System comprises a remote site fibre driven 10Watt bi-direction
amplifier. It is fed from a fibre optic tray which links to the master site fibre optic tray via a
single fibre optic cable. The Tx and Rx signals use different optical frequencies and are
coupled using wave division multiplexers (WDMs). The three BDA will feed either an omni-
directional antenna or leaky feeders to provide UHF radio coverage in areas where signal
levels and reception from the BTS are poor and in which the mobiles are to be served.
The duplexer, fibre optic and BDA trays are all designed to be mounted in standard 19”
equipment racks.
The maximum output from the BDAs is limited by built-in AGC circuits. The gain in both the
downlink and the uplink paths can be adjusted using switched attenuators which can be
accessed from the rear panels of the BDA trays. The master site is also fitted with attenuators
which control the signal levels to and from the master site fibre optic tray. All switched
attenuators are switched to maximum attenuation prior to despatch.
The downlink attenuator in the master site should be adjusted so that -14dBm is available
from the downlink connector when one channel is being driven at maximum power by the
BTS. The uplink attenuator in the master site should be adjusted so that an input signal to the
uplink connector of -5dBm will provide a maximum signal to the coupler of -20dBm.
The downlink attenuator on the 10W BDA should be adjusted so that an input signal of
-10dBm provides an output to the antenna connector of +25dBm. The uplink attenuator on the
10W BDA should be adjusted so that an input signal of -50dBm will provide an output of
0dBm to the Uplink F/O Tray connector.