User Manual

Axell Wireless Limited
Technical Literature
15 Channel UHF Hybrid Select Repeater
Document Number 50-157401HBK Issue No. 1 Date 26/03/2008 Page 42 of 50
5. INSTALLATION
5.1 Initial Installation Record
When this equipment is initially commissioned, please use the equipment set-up record sheet in
Appendix B. This will help both the installation personnel and Axell Wireless should these figures be
needed for future reference or diagnosis.
6. Fault Finding & MAINTENANCE
6.1 General Fault Finding Procedures
In the event that the performance of the system is suspect, a methodical and logical approach to the
problem will reveal the cause of the difficulty.
Transmissions from the main base stations are passed though the system to the mobile radio
equipment; this could be a handheld radio or a transceiver in a vehicle. This path is referred to as the
downlink. The return signal path from the mobile radio equipment to the base station is referred to as
the uplink.
The first operation is to check the alarms of each of the active units and determine that the power
supplies to the equipment are connected and active.
This can be achieved remotely (via CEMS, the RS232 Coverage Enhancement Management System,
if fitted), or locally with the front panel LEDs. The green LED on the front panel should be illuminated,
while the red alarm indicator should be off.
If an alarm is on, then that individual shelf/module must be isolated and individually tested against the
original test specification.
The individual amplifier units have a green LED showing through a hole in their case, which is
illuminated if the unit is working correctly.
If an amplifier is suspect, check the DC power supply to the unit. If no other fault is apparent use a
spectrum analyser to measure the incoming signal level at the input and then after reconnecting the
amplifier input, measure the output level. Consult with the system diagram to determine the expected
gain and compare result.
In the event that there are no alarms on and all units appear to be functioning it will be necessary to
test the system in a systematic manner to confirm correct operation.
6.2 Downlink
Confirm that there is a signal at the expected frequency and strength from the base station. If this is
not present then the fault may lay outside the system. To confirm this, inject a downlink frequency
signal from a known source at the master site BTS input and check for output at the remote site
feeder output.
If a signal is not received at the output it will be necessary to follow the downlink path through the
system to find a point at which the signal is lost. The expected downlink output for the given input can
be found in the end-to-end test specification.