TX RX Systems 434B-83H-01-M-110/48, Инструкция по установке и эксплуатации, Страница: 20 / 44

7;5;6\VWHPV,QF Manual 7-9547-1 12/09/14 Page 20
2) Connect the base control unit ground lug to the
Equipment Rack Master Ground Bar with a pig-
tail.
3) Connect the main and test transmission cables
to the appropriate connectors at the back of the
deck.
4) If you have a supervisory alarm system, con-
nect its wiring harness to the alarm terminals at
the back of the control unit. Refer to
Figure 13
.
5) Connect the station receivers and optional 16-
port receiver multicoupler expansion deck to the
output ports on the back of the base control unit
with high-quality 50-ohm coaxial cable such as
1/4-inch super flexible transmission line. Some
flexibility in the jumper cables will prevent strain
and possible damage to the connections. We
also recommend the use of quality BNC con-
nectors. Unused receiver outputs need not be
terminated. However an unused expansion port
should be terminated with 50 ohms until con-
nected to an expansion deck.
Interference and IM Considerations
Although Bird Technologies TTA systems are
designed for maximum interference immunity, there
are many factors that can lead to harmful interfer-
ence when using a tower-mounted amplifier. It is
highly recommended that the receiving and trans-
mitting antennas be vertically separated to maxi-
mize antenna isolation.
Although most transmitters are connected to their
antenna through a combiner, it is quite likely that
the combiner does not have enough transmitter
noise filtering to prevent desensitization of the
receivers unless there is significant antenna space
isolation. Large values of antenna isolation are
most easily realized when the antennas are sepa-
rated vertically. This antenna isolation also helps
reduce the possibility of intermodulation interfer-
ence in the receiving system.
One other important factor that can strongly con-
tribute to interference problems is excessive gain,
ahead of the receiver. Excessive gain can cause
overdrive to the station receivers when strong sig-
-
9.000
8.000
.500
1.000
9.063
7.000
6.005
4X O .515
Figure 11
: Tower top box mechanical details.