User's Manual Part 3

RFDS Setup and Calibration continued
Apr 2001
3-75
SC4812ET BTS Optimization/ATP CDMA LMF
DRAFT
Measuring Directional Coupler
Loss
Uas the following procedure to calibrate directional couplers associated
with RFDS installation. The procedure involves measuring the forward
port loss and the antenna port loss to find the directional coupler loss.
Prerequisites
RFDS installed
Table 3-41: Measuring Directional Coupler Loss
Step Action
1 Connect the test set or power meter to the BTS Coupled (forward) port of the directional coupler.
2 Login to the BTS.
3 Select the BBX.
4 Select Device>Key XCVR.
The BBX window appears.
5 In the XCVR Gain field, enter the following value: 20
Verify that the XCVR Carrier and Channel fields are correct and that the Use BLO box is checked.
Click OK.
6 The status report window appears. Click OK.
7 Observe the power reading and record the value measured at the BTS Coupled (forward) port. The
value should be between 34 and 27 dBm.
If the reading is not within these values, adjust the value in the XCVR Gain field until the value is
approximately 30 dBm.
8 Select the BBX.
9 Select Device>Dekey XCVR. The status report window appears verifying the action has passed (the
XCVR is no longer keyed up). Click OK
10 Disconnect the antenna cable from the ANT port.
11 Disconnect the test set cable from the BTS Coupled (forward) port and connect it to the ANT
(antenna) port.
12 Select the BBX.
13 Select Device>Key XCVR.
The BBX window appears.
14 In the XCVR Gain field, ensure the value entered is the same as used for the recorded value in the
forward port portion of the procedure. (Note that a value of 20 was used is step 5.)
Verify that the XCVR Carrier and Channel fields are correct and that the Use BLO box is checked.
Click OK.
15 The status report window appears. Click OK.
. . . continued on next page
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