User's Manual

CHA - Channel Amplifier Board for Channel Selective Operation
The cabinet can be equipped with four CHA Channel Amplifier boards.
These are numbered from left to right: CHA1 - CHA4. The board
positions CHA1 - CHA2 are used for downlink and CHA3 - CHA4 for
uplink (see Figure 5-1 on page 5-4). If the repeater is equipped with two
channels only, the board positions 1 and 3 are used.
The two internal channels on each CHA board are located to the left and
to the right on the board.
If a board is to be removed, the RFI filter at the board connector and the
two coaxial connectors must be removed prior to the board removal. No
heat compound is used on the heat sink body or on the chassis.
Coaxial connector P101 is the input of the CHA board fed from the LNA.
Coaxial connector P701 is the output of the board. The output signal is
fed to the duplex filter, either directly or via a CMB combiner, depending
on the repeater configuration.
Connection
Board #1 from the left CHA1/DL:
Port Connected to
P101 OUT1 on the LNA/DL low noise amplifier.
P701 Input on the CMB/DL combiner (at 4 channels) or
HI on the DPX/MS duplex filter (at 2 channels).
Board #2 from the left CHA2/DL:
Port Connected to
P101 OUT2 on the LNA/DL low noise amplifier.
P701 Input on the CMB/DL combiner.
Board #3 from the left CHA3/UL:
Port Connected to
P101 OUT1 on the LNA/UL low noise amplifier.
P701 Input on the CMB/UL combiner (at 4 channels) or
LO on the DPX/BS duplex filter (at 2 channels).
Board #4 from the left CHA4/UL:
Port Connected to
P101 OUT2 on the LNA/UL low noise amplifier.
P701 Input on the CMB/UL combiner.
Caution
BERYLLIUM OXIDE
The CHA Channel Amplifier board power transistors contain beryllium
oxide (BeO) that is poisonous. The power transistors are mounted with
two screws as opposed to other transistors. See Chapter 1, Safety.
ALLGON System AB AR Repeaters & OMT32 Hardware – Functional Description
User’s Manual VD202 90/EN Rev. 1A 1999-07 5 - 19