User's Manual Part 2

Bay Level Offset Calibration
6-76 1X SC480 BTS Hardware Installation, Optimization/ATP, and FRU MAY 2004
PRELIMINARY
Purpose of Bay Level Offset
Calibration
Bay Level Offset (BLO) calibration is the central activity of the
optimization process. BLO calibration compensates for normal
equipment variations within the BTS RF paths and assures the correct
transmit power is available at the BTS antenna connectors to meet site
performance requirements.
What is BLO Calibration?
Description
BLO calibration is the complete title of what is normally referred to as
“calibration.” Calibration identifies the accumulated gain in every
transmit path at the BTS site. The transmit path BLO values determined
during calibration are stored in the LMF calibration data file, and are
subsequently downloaded to each BBX. When transmit path calibration
is performed, receive path BLO values will automatically be set to the
default value in the LMF calibration file and downloaded.
Component Verification During
Calibration
TX Path Calibration
TX path calibration supports verification of correct BTS installation, RF
cabling installation and performance, functionality of all equipment
installed in the transmit RF chain, and the proper functioning of each
transmit RF path. External test equipment is used to calibrate and audit
the TX paths of the BTS.
RX Path Calibration
RX path calibration is not required or supported on CDMA BTS
systems. Default RX calibration values are written to the RX calibration
data files during the TX calibration process. RX functionality is verified
during Frame Erasure Rate (FER) testing.
When to Calibrate BLOs
Calibration to determine BLO:
1. Is required after initial BTS installation.
2. Must be done once each year for an operational BTS site.
3. Is recommended by Motorola for all associated RF paths after
replacing any of the following components:
– BBX card
– CCP2 shelf
– cCLPA
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