User's Manual

96/346 Issue 01 - April 2001 - Draft 04 3CC12426AAAA TQ BJA 01
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The downstream path loss is measured from the IBS-TLX card Tx SMA cable to the end of the IF cable
that connects to the X-Pol RBS Tx. The upstream path is measured from the IBS-TLX card Rx SMA
cable to the end of the IF cable that connects to the X-Pol RBS Rx. If the measured upstream or
downstream loss is less than the value required, an attenuator is installed between the 12:2 Combiner/
Splitter and the Bias-T.
Table 27 lists the equipment required to calibrate the upstream and downstream IF cable losses.
Figure 82 shows the equipment setup used to measure upstream or downstream cable loss.
Measurements should be made at the lowest and highest frequencies of the upstream and downstream
IF bands for your system. The average of the pair of measurements is used to determine the nominal
amount of attenuation needed in the upstream and downstream paths.
Table 27: Test equipment required for BS IF system loss calibration
Figure 82 – BS IF cable calibration equipment setup
2.10.2– To calibrating the upstream and downstream cable runs
Perform the following procedure for the downstream and upstream cable runs.
1. Ensure the dc power to the surge protector is disconnected.
2. Disconnect the dc power cables from the Bias-Ts.
3. Disconnect the SMA cables from the IBS card.
4. Disconnect the IF cables from the X-Pol RBS Tx and X-Pol RBS Rx.
Equipment Supplier
Signal generator capable of generating a sine wave at
2050 MHz
Hewlett Packard: Model ESG-4000A
50 W power meter Hewlett Packard: Model E4419A
If dc power is not disconnected from the IF cables, the test equipment will be damaged. To
remove dc power, switch off the appropriate circuit breaker on the power distribution system
to isolate the individual IF channel.