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

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7;5;6\VWHPV,QF Manual 7-9547-1 12/09/14 Page 7
GENERAL DESCRIPTION
Your Bird Technologies brand Tower Top Amplifier
System provides the highest degree of reliability
available in a Tower Top Amplifier (TTA). The sys-
tem uses quadrature-coupled amplifiers to create a
redundant amplifier configuration. Each quad-
amplifier provides two simultaneously used, essen-
tially parallel paths of amplification. Failure of one
of these paths of amplification results in an overall
gain reduction of only 6 dB.
The system is composed of two components
including a tower top box (TTA) which incorporates
filtering and a pair of low noise amplifiers. These
amplifiers establish superior noise figure prior to
feedline losses. The tower top box is mounted on
the tower close to the antenna. The second com-
ponent of the system is the base control unit which
is located in the control room. Specifications for the
system are listed in
Table 1
.
The system also supplies automatic backup-ampli-
fier switching in the tower top box. Fault detection
circuitry continuously monitors the DC power oper-
ation of the primary quad-amplifier and automati-
cally switches to the identical secondary quad-
amplifier if conditions indicate a primary malfunc-
tion. Fault detection circuitry also provides at-a-
glance status reporting, with front-panel LED’s and
an LCD display.
Test
Line
Main
Line
Ground
Lug
Antenna
Figure 1:
The tower top box.
Parameter Specification
Frequency Band 700 - 800 MHz
NET Gain 15.0 dB typical
Rejection
110 dB min @
776 and 851 MHz
Noise Figure 2.9 dB typical
Total Power Dissipation 17 W
Table 1:
System specifications.
15 dB TTA Net Gain and maximum 6 dB transmission line
loss assumed.