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RF Technology PA220
1 OPERATING INSTRUCTIONS
1
Operating Instructions
The PA220 is part of the Eclipse range of modular base station equipment. It is a power
amplifier capable of delivering 100 Watts in the VHF frequency range. It is designed
to complement the T220 transmitter, and mounts in a standard Eclipse sub-rack.
1.1 Installation
There are no front panel controls. In normal circumstances no alignment or setup is
required. If mounted in a sub-rack that has not previously been wired for a power
amplifier, the rack connector must be wired according to the guidelines in section 1.1.1
below.
1.1.1
Sub-rack Wiring Guidelines
When installing an Eclipse Power Amplifier in an Eclipse sub-rack, observe the
following guidelines for sub-rack installation:
•
The sub-rack power supply must be capable of delivering the full current
requirements for all modules fitted in the sub-rack, typically 20 Amperes for a 100W
transmitter/amplifier.
•
Owing to the current drain, power supply lines should be cabled to the power
amplifier separately and using heavy gauge wire to minimise voltage drop and
interference via the power supply of other modules in the rack.
•
The ALC line from the power amplifier must be connected to the ALC input of the
exciter. If this connection is not correctly made, no control of the output power
level will be possible. This can result in excessive RF output power, and
consequent breach of licensing authority regulations, or possible overload of the
unit.
With an Eclipse T500, join pin 8 on the exciter and the amplifier.
1.2 Front Panel Indicators
PWR LED
The power (PWR) LED shows that the dc supply is connected to the
transmitter.
RFO LED
The RF output (RFO) LED indicates that the amplifier is being driven
and that the forward output power is above a preset level. This preset indication
level is generally set 1 - 3 dB below the preset output power level. The presetting
potentiometer RV2 is not accessible without removal of the cover plate.
