User Manual
Fibre Optic Master and Remote Site
User Handbook
Document Number: 60-212701HBK - Issue No. 1 Page 40 of 50
5.5 Commissioning
Once all connections are made the equipment is ready for commissioning.
To commission the system the test equipment detailed in Section 6.2. will be required.
Using the system diagrams and the end-to-end test specification (supplied with the equipment), the
equipment should be tested to ensure correct operation. Typical RF levels that are not listed in the
end-to-end specification, such as input levels to the fibre transmitters are detailed in the maintenance
section of this manual.
On initial power up the system alarm indicators on the front panels of the equipment should be
checked. A red LED illuminated indicates a fault in that particular tray that must be investigated before
proceeding with the commissioning. A green LED on each shelf illuminates, to indicate that the power
supply is connected to the shelf
In the event that any part of the system does not function correctly as expected, check all connections
to ensure that they are to the correct port, that the interconnecting cables are not faulty and that they
are tightened. The majority of commissioning difficulties arise from problems with the interconnecting
cables and connectors.
5.6 Antenna Installation & Gain Calculations
A The equipment requires two antennas, one a highly directional Yagi or similar directed towards
the donor cell base station, and one a leaky feeder, omni-directional antenna or Yagi to cover
the area in which the mobiles are to be served.
B The maximum gain at which the equipment can be set is limited by the isolation that can be
achieved between these two antennas. Therefore when the antennas have been installed,
inject a signal (at a known power level) into one of them and measure the signal level received
by the other antenna on a spectrum analyser. The isolation can then be calculated as the
difference between these two figures. The gain in each path of the equipment should be set at
least 10 dB below this figure, using attenuators as described below in paragraph 5.
C Also measure the received signal from the donor cell at the input to the equipment (base port).
The gain of the equipment downlink path should be set such the donor site will not overload
the equipment amplifiers. It is recommended that the input level should be less than -50dBm
at the input of the equipment (Base Port). (This figure is assuming maximum gain, and may be
increased by the value of the attenuator fitted in the downlink path.)
D Ensure that the mobile facing antenna has at least 70dB isolation from the nearest mobile.
(This is usually easily achieved when using a leaky feeder.)
E The equipment gain is set by setting the variable switched attenuators in each path (uplink and
downlink) refer to the photographs and layout drawings for the exact attenuator locations).
Note that the uplink (mobile to base) and downlink (base to mobile) path gains are set
independently. This allows the paths to have different gains if required to set the correct output
power levels.
F It is recommended that the gains are set such that the Downlink channel output levels from the
equipment are typically +30dBm per channel
(Input level + Gain = Output level).