User's Manual

Bay Level Offset Calibration
PRELIMINARY
1X SCt4812ET Lite BTS Optimization/ATP
08/01/2001
3-64
Introduction
Calibration compensates for normal equipment variations within the
BTS and assures maximum measurement accuracy.
RF Path Bay Level Offset
Calibration
Bay Level Offset (BLO) calibration identifies the accumulated gain in
every transmit path (BBX2 slot) at the BTS site and stores that value in
the CDMA LMF CAL file. The BLOs are subsequently downloaded to
each BBX2.
Each transmit path starts at an SCCP shelf backplane BBX2 slot, travels
through the CIO card, trunking module, LPA, trunking module (again),
TX filter or TX filter combiner, DRDC or TRDC, and ends at a BTS TX
antenna port.
Each receive path starts at a BTS RX antenna port, travels through a
DRDC or TRDC, the MPC card, the CIO card, and terminates at a
backplane BBX2 slot.
Calibration identifies the accumulated gain in every transmit path ( by
BBX2 slot) at the BTS site and stores that value in the CAL file. When
the TX path calibration is performed, the RX path BLO will
automatically be set to the default value.
When to Calibrate BLOs
Calibration of BLOs is required after initial BTS installation.
The BLO data of an operational BTS site must be re-calibrated once
each year. Motorola recommends re-calibrating the BLO data for all
associated RF paths after replacing any of the following components or
associated interconnecting RF cabling:
S BBX2 board
S SCCP shelf
S CIO card
S CIO–to–LPA trunking module RF cable
S LPA trunking module
S LPA
S Trunking module–to–TX filter/filter combiner RF cable
S TX filter or TX filter combiner
S TX filter/filter combiner–to–DRDC/TRDC cable
S DRDC or TRDC
3