BIRD 428B-83H-01-C-110, Инструкция по установке и эксплуатации

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TX RX Systems Inc. Manual 7-9487-3 05/05/11 Page 1
GENERAL DESCRIPTION
Your Bird Technologies Group, TXRX Systems
brand Tower Top Amplifier System provides the
highest degree of reliability available in a Tower
Top Amplifier (TTA). The system uses quadrature-
coupled amplifiers (also called balanced amplifiers)
to create a redundant amplifier configuration. Each
quad-amplifier provides two simultaneously used,
essentially 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.
The system also supplies automatic backup-ampli-
fier switching in the tower top box. Fault detection
Figure 1: Front view of the tower top box. Door removed for clarity.
3-22658
LNA
Assembly
Hinge
8-21183
Lightning
Arrester
8-21514
Lightning
Arrester
8-21549
Lightning
Arrester
8-23273
Filter
Do NOT Adjust
Tuning Rods
Locking
Clasp
Hold-down
Screw
Parameter Specification
Bandwidth 792 - 824 MHz
Noise Figure 3.5 dB max
3rd order IIP > 15.0 dBm
Reserve Gain Fully settable by
electronic attenuator
Rejection <110 dB Min, 120 db Nom
@776 and 851 MHz
AC Current
(model 428B-83H-01-M)
340 mA (typ) @120 VAC
AC Current
(model 428B-83H-01-CG)
215 mA (typ) @ 120 VAC
DC Current
(model 428B-83H-01-M-48)
780 mA (typ) @48 VDC
DC Current
(model 428B-83H-01-CG-48)
550 mA (typ) @ 48 VDC
Table 1: System specifications.
13 dB reserve gain and
maximum 6 dB transmission line loss assumed