User's Manual

Table Of Contents

26 Connection TB8100 Installation Guide

2.5 RF Connections

Important The PA may be damaged if the load is removed or switched

while the PA is transmitting.

To protect the PA output stage from load transients (i.e. switching or

removing the load), we recommend that you fit an isolator between the PA

and the load. Fit the isolator as close as possible to the RF output connector

on the PA. Do not connect any switching or combining equipment

between the isolator and the PA.

We recommend that you use dual-screened coaxial cable such as RG223 for

the BNC/TNC connections, and RG214 for the N-type connections.

When the base station is used in simplex mode using a single antenna with

a coaxial changeover relay, the isolation of this relay must be ≥ 40dB.

2.6 System Control Bus

Important In base station systems which use a PMU, the PMU must

be connected to the system control bus at all times. The

C current source is located in the PMU, and if the PMU

is disconnected, the state of much of the bus will be unde-

fined. This may cause corrupted data to be present on the

bus when the reciter reads the states of the switches on the

control panel. This in turn may result in random actuations

of microphone PTT, carrier, or speaker key, causing the

BSS to transmit or the speaker to be actuated incorrectly.