User's Manual

Bay Level Offset Calibration

68P09258A31–A

Oct 2003

1X SCt 4812T BTS Optimization/ATP

3-90

TX Calibration and the LMF

The LMF Tests > TX > TX Calibration... and Tests > All Cal/Audit...

selections perform TX BLO calibration testing for installed BBX(s). The

All Cal/Audit... selection initiates a series of actions to perform TX

calibration, and if calibration is successful, download BLO and perform

TX audit. The TX Calibration... selection performs only TX

calibration. When TX Calibration... is used, BLO download and TX

audit must be performed as separate activities. The CDMA Test

Parameters window which opens when TX Calibration... or All

Cal/Audit... is selected contains several user–selectable features which

are described in the following subsections.

Rate Set Drop-down Pick List

The Rate Set Drop–down Box is enabled if at least one MCC card is

selected for the test. The available options for TX tests are 1 = 9600, and

3 = 9600 1X. Option 3 is only available if 1X cards are selected for the

test. The available transfer rate options for RX tests are 1 = 9600 and

2 = 14400. Option 2 is only available if no 1X cards are selected.

Verify BLO

In both the TX Calibration and All Cal/Audit dialog boxes, a Verify

BLO checkbox is provided and checked by default. After the actual TX

calibration is completed during either the TX Calibration or All

Cal/Audit process, the BLO derived from the calibration is compared to

a standard, acceptable BLO tolerance for the BTS. In some installations,

additional items may be installed in the transmit path. The additional

change in gain from these items could cause BLO verification failure

and, therefore, failure of the entire calibration. In these cases, either the

Verify BLO checkbox should be unchecked or the additional path losses

should be added into each applicable sector using the

Util>Edit>TX Coupler Loss... function.

Single-Sided BLO Checkbox

Another option that appears in the pull–down menu is Single–sided

BLO. Normally valid BLO values are some value plus–or–minus some

offset. The ranges that we currently use for calibration are wider than

necessary to accommodate the redundant BBX. The lower half of that

range is where non–redundant BBXs should be. When Single–sided

BLO is selected, the result is only considered a success if it is in the

lower half of the range. If it was normally a success from 37–47 (which

is 42 "5), Single–sided BLO would make it a success only if the result

was from 37–42. To get the more stringent conditions, the operator

checks Single–sided BLO when calibrating non–redundant transceivers.

Single–sided BLO carries the likelihood of more failures. This option

should only be used by experienced CFEs.