TM 11-5895-846-14
(2) The 70-MHz modulated carrier is
a five-cavity klystron to provide a maximum gain of 41.5
converted to 700-MHz by the amplifier/mixer module.
dB to deliver up to 1000 watts of RF power to the
This is accomplished by mixing the signal with a 630-
antenna input terminal. It is tunable over a 500-MHz
MHz signal (LO-2) from the frequency synthesizer. A
range from 7.9 to 8.4 GHz, with a bandwidth of 40 MHz.
second conversion to SHF is achieved in the IF amplifier
Gain is manually adjustable over a 23-dB range. Load
module. Here, the 700-MHz output from the amplifier-
isolation permits the , equipment to operate at full power
mixer is mixed with the LO-1 output from the frequency
into any load mismatch without damage to PA
synthesizer. The resultant output is in the SHF region
components. Internal monitoring functions provide an
from 7900 MHz to 8400 MHz, selectable in 1-kHz
operator with both forward and reflected RF power output
increments by front panel control of the synthesizer LO-1
level information. Monitors of various types allow fault
frequency. The output of the IF amplifier module is
isolation to the module level. A low-level-RF alarm
amplified by an intermediate power amplifier (IPA) which
network with adjustable threshold alerts an operator if
provides drive to the amplifier/mixer or the power
the RF output level falls below a preset value.
amplifier. On the left side of the front panel are the input
(1) A block diagram of the RF amplifier is
and output connectors, power switch, a MONITOR meter
and switch for power supply and operational checks. An
carrier from the upconverter or amplifier/mixer is applied
UPCONV FAULT lamp will illuminate whenever there is a
to a coaxial input network consisting of a ferrite isolator,
failure in the upconverter unit. A TEST OSC switch will
directional coupler, and a front-panel controlled variable
turn on a 70-MHz or 700-MHz oscillator to provide a
attenuator. RF output from the attenuator is used to
signal through the upconverter for self testing. On the
drive a five-cavity klystron amplifier. Another ferrite
right side are the frequency synthesizer controls and
isolator, HY3, is used at the klystron input port for VSWR
monitoring selector switch. When the MONITOR switch
improvement. The klystron output is then sent through a
is in the SYNTH position, the SYNTH MONITOR switch
network composed of a differential circulator, low-pass
selects test points in the frequency synthesizer to be
filter, bandpass filter, and directional coupler. RF from
monitored by the MONITOR meter.
the unattenuated output port of the directional coupler is
f.
The power amplifier
consists of an individually packaged RF amplifier unit
and a high-voltage power supply unit. The amplifier uses
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