Tower-Top Amplifier (Optional); Satellite Synchronization Antenna & Feeder; Overview - Huawei Airbridge BTS3612A-1900 Technical Manual

Technical Manual
Airbridge BTS3612A CDMA Base Station
Usually, there are two types of lightning arresters. The first type uses the microwave
principle to conduct the low frequency lightning current to the ground so as to sink the
current. The second one is a discharging tube, when the voltages at both ends of the
discharging tube reach a certain value, the tube conducts to sink the large current.
The second technique is used in BTS3612A. Lightning arrester should be installed
close to the BTS cabinet.

4.2.4 Tower-top Amplifier (Optional)

When the BTS3612A works at 1900MHz band, the tower-top amplifier (TA) is optional,
for the other bands, it is not necessary.
The TA is a low-noise amplification module installed on the tower. It is to amplify the
reverse signal from MS before the transmission loss occurs along the feeder. This
helps improve the receiving sensibility of the BTS system and the reverse coverage of
the system while lowering the transmitting power of MS and improving the conversation
quality.
Usually the triplex TA is configured. It is installed close to the antenna. This type of TA
consists of triplex filter, low-noise amplifier and feeder. The triplex filter is actually the
combination of two duplex filters. The signal from the antenna is first filtered off the
external interference at the triplex filter, and then is amplified by the low-noise amplifier,
and finally sent to the feeder.
Features of the TA include:
The noise factor of TA is very low.
The TA has a wide dynamic range, which is full adaptable to the change of
strength of signal received by antenna caused by different distances between the
MS and the BTS.
The TA has the alarm bypass function.
The TA is fed with feeder, so it has the feeding detection device.
The TA adopts strict water-proof sealing and is adaptable to a wide range of
working temperatures (-40ÿC~70ÿC).
The TA can sustain strong lightning strikes.
4.3 Satellite Synchronization Antenna & Feeder

4.3.1 Overview

Many important features of the CDMA system are closely related to and much
dependent on the global satellite navigation system. If the global satellite navigation
system stops working for a long time, the whole CDMA network will collapse.
Chapter 4 Antenna & Feeder Subsystem
4-4
System Principle