Broadcast Electronics FX-50, Instruction Manual

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©2011 Broadcast Electronics
10
RF AMPLIFIER
This section provides general information and specifications relative to the operation of the RF amplifier
assembly.
10.1 DESCRIPTION.
The RF amplifier assembly consists of three stages of amplification to increase the low level RF input signal from
the modulated oscillator to an adjustable level of 3 to 50 watts as required to drive an associated transmitter.
Directional coupler sensing lines on the circuit board provide both forward and reflected power outputs for
monitoring and control of amplifier operation.
10.2 ELECTRICAL SPECIFICATIONS.
Refer to Table 10-1 for electrical specifications of the RF amplifier assembly.
Table 10-1. RF AMPLIFIER ELECTRICAL SPECIFICATIONS
PARAMETER SPECIFICATIONS
SIGNAL LEVELS:
RF AMPLIFIER
INPUT 0.0 dBm at 50 Ohms.
OUTPUT 3 to 50 Watts RF at 50 Ohms.
DIRECTIONAL COUPLER OUTPUT
FORWARD 2.2V DC at 50 Watts RF output.
REFLECTED Less than 1V DC at 50 Watts RF Output at 50
Ohms.
10.3 REMOVAL AND INSTALLATION
This section provides removal and installation procedures for the RF amplifier assembly.
10.3.1 REMOVAL PROCEDURE.
REQUIRED EQUIPMENT. A number 2 Phillips screwdriver with a 4 inch (10.16 cm) shaft is required to remove
the RF amplifier assembly from the exciter chassis.
PROCEDURE. The removal of the RF amplifier assembly requires the exciter be placed on a suitable work
surface. To remove the RF amplifier assembly, proceed as follows:
WARNING
DISCONNECT EXCITER PRIMARY POWER BEFORE
PROCEEDING.
WARNING
A. Disconnect the primary power from the exciter.
B. Remove the exciter top-cover and disconnect J15 from P15 of the RF amplifier power/control cable.