Bird Technologies 61-89A-50 Series-Manual - Manual (Page 9)

TXRX Systems Inc. Manual 7-9424-1 07/24/06 Page 3
Procedure for 18 MHz Systems
Re-banding kits for systems that originally left the
factory as 18 MHz systems will consist of replace-
ment filters which have the new desired bandwidth,
new tee-connectors, several critical length cables,
as well as a signal sampler. The filters are pre-
tuned at the factory so the position of the tuning
rods should not be changed. The conversion pro-
cess consists of simply replacing the old filters
(duplexer assemblies) with new filters, adding tee-
connectors, cables, and signal samplers. In addi-
tion, the circulators will be attached to the cabinet
mounting plate instead of the duplexer assemblies.
A simplified block diagram for a 18 MHz SB II sys-
tem is shown in Figure 2. Note that the original
duplexer assembly has the tee-connector, critical
length cables, and signal sampler built-in. The re-
banding kit includes these par ts as individual
assemblies.
All work should be performed by a qualified elec-
tronics technician familiar with the communications
system. Refer to the system drawings at the back
of this manual as a guide to the correct placement
of assemblies and cables. Follow the instructions
listed below in a step-by-step fashion.
1) Open the signal booster enclosure and turn
OFF the AC power. Disconnect or turn OFF any
battery back-up DC input.
2) Disconnect and discard the 3 cables connected
to the right and left side duplexer assembly.
Including the thru-hole connectors at the bottom
of the cabinet.
3) Disconnect and discard the remaining cable
connected to the right and left side circulators.
4) Remove the mounting screws for the right and
left side duplexer assemblies and remove them,
with the attached circulators from the cabinet.
Use care when removing the duplexer assem-
blies so as not to damage any of the cables that
are still in the cabinet.
5) Remove the circulators from the duplexer
assemblies, they will be re-used.
6) Install the right and left side replacement filters
(two on each side) making sure that the mount-
ing plates are firmly attached to the cabinet.
7) Install the tee-connectors and associated
cables to the bottom connectors on the right
and left side filters. Refer to the appropriate sys-
tem drawing in the rear of this manual to make
sure you have the correct cables going to the
correct ports. These are length sensitive cables
so it is important to connect them correctly.
Install the 2 thru-hole connectors at the bottom
of the cabinet.
8) Attach the card cage to the right and left filters
with the supplied cables.
9) Attach the signal samplers to the filters as
shown in the drawing.
10) Install the two circulators on the cabinet mount-
ing plate as shown in the drawing.
11) Install cables from the circulators to the power
amps and from the circulators to the signal
samplers.
12) Verify that all filters and cables have been
installed properly. The booster should now
look like the system drawing.
13) Energize the booster and verify correct opera-
tion.