User's Manual

Bay Level Offset Calibration
PRELIMINARY
SC 4812ETL BTS Optimization/ATP
08/15/2000
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Introduction
Calibration compensates for normal equipment variations within the
BTS and assures maximum measurement accuracy.
RF Path Bay Level Offset
Calibration
Calibration identifies the accumulated gain in every transmit path
(BBX2 slot) at the BTS site and stores that value in the CAL file. The
BLOs are subsequently downloaded to each BBX2.
Each receive path starts at a BTS RX antenna port and terminates at a
backplane BBX2 slot. Each transmit path starts at a BBX2 backplane
slot, travels through the LPA, and terminates at a BTS TX antenna port.
Calibration identifies the accumulated gain in every transmit path
(BBX2 slot) at the BTS site and stores that value in the CAL file. Each
transmit path starts at a C–CCP shelf backplane BBX2 slot, travels
through the LPA, and ends at a BTS TX antenna port. 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 backplane RF cable
S LPA backplane
S LPA
S TX filter / TX filter combiner
S TX thru-port cable to the RF Interface Panel
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