GSM-204-423
Connecting antennas
31st Oct 01
Inst. 3–36
Installation & Configuration: Horizon
macro outdoor
CONTROLLED INTRODUCTION
68P02902W03-A
RF connection
principles
The primary receive path is connected to the A branch of the SURF module,
either directly or from the Rx connector on the Tx block in non-diversity
configurations. The diversity receive path is connected to the B path on the
SURF. This is normally duplexed with the transmit signal on a single antenna,
and fed to the SURF from the Rx connector on the Tx block. Within any single
cabinet the lowest numbered sector is normally connected to amplifier 0
connections, and higher numbered sectors to amplifiers 1 and 2 as appropriate.
For example, sector one is connected to SURF connectors 0A and 0B, sector
two to 1A and 1B, and sector three to 2A and 2B. However, if a sector is split
between two cabinets, the split sector antennas must be connected to amplifier
0, (this is the only path with connection to the extension ports). Extension ports
must be connected to the correct branch at the destination cabinet.
The transmit path feeds from the CTUs to the Tx block or feedthrough plate
immediately above. Two signals are combined in most Tx blocks, A third signal
can be combined using a feedthrough plate and the third input of a DDF. The Tx
blocks then duplex the Tx signal with the diversity Rx signal, before feeding to
the antenna.
Rx/Tx single
antenna
duplexing
Duplexers allow a single antenna to be used for both transmit and receive
operations. Duplexers exist within several of the transmit blocks. Normally
duplexed RF signals are used through one antenna, with a second receive
antenna to provide diversity.
NOTE
If a single antenna (non-diversity) is required, the duplex
antenna RF receive cable from the transmit block must be
connected to the Rx A path at the SURF. Simply switching
off diversity at the OMC-R without the correct SURF
configuration will cause a loss of reception.