User's Manual

Table Of Contents

G3S-800-180-029 Installation & Service Manual

044-05112 Rev. A 4-3 April 2002

for subsequent remote monitoring via the ALARMS connector. Refer to paragraph 2-6 as well as

figure 2-2 and table 2-3 for a description of the ALARMS connector.

4-4.4 Amplifier Module Cooling

Although each amplifier module contains its own heat sink, it is cooled with forced air. Four fans

are used for forced air-cooling and redundancy. The fans, located on the front and rear of the

amplifier module, draw air in through the front of the amplifier and exhaust hot air out the back of

the module. The fans are field replaceable.

4-5 Power Distribution

Primary DC power for the system is provided by the host system to the MCR30829-1-3 Series or

compatible subrack. The subrack supplies each amplifier module with +27 Vdc directly and via

the RF power splitter/combiner. The amplifier module has a DC/DC converter that converts the

+27 Vdc to +15 Vdc, +5 Vdc and -5 Vdc.

4-6 Intermodulation

The G3S-800-180-029 amplifier is designed to deliver a 180-watt nominal composite average

power (210 W max.), multi-carrier signal, occupying a bandwidth less than or equal to 25 MHz, in

the band from 869 to 894 MHz. The maximum average power for linear operation, and thus the

amplifier efficiency, will depend on the type of signal amplified.

Three or more CW tones of equal input power will lower individual intermodulation products. If the

frequencies are not equally spaced, the level of intermodulation products gets very low. When the

frequencies are equally spaced, those products fall on top of each other on the same frequency

grid. The average power of all intermodulation beats falling on the same frequency is called the

composite intermodulation; it is -60 dBc or better.

4-7 Alarms

The presence of several plug-in amplifier alarms can be detected at the DC and logic connector

on the amplifier rear panel. Refer to table 2-3 and figure 2-2 for a description of the connector.