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Voltage is then applied to CR801.
This voltage is rectifiud
and operates a slow- operate relay K802.
This relay then closes
and energizes an auxiliary relay K801.
When this occurs the
main contactor.,
K808,
coil circuit is counloted and full line
voltage is applied to the plate transformer,
T801.
At the same time K801 completes the circuit to T802 and screen
voltage is applied to the amplifier.
This step- start tcch-
nique eliminates much of the transients which occur on start-
ing.
S801
1
which is the high- low switch,
switches the input to the
filter from the output section of the rectifiers to the center
tap of the plate transformer, taus giving half voltage output
which is useful in initial tune-up and primary checking of the
transmitter.
A micro-match is used as an indicatin
or sampling device for
the RF output and is also used to indicate the match to the
transmission line and the antenna.
The Micro-match in the
driver and the Micro-match in the amplifier are the same in
their operation, the only difference being the power handling
capabilities.
The Micro-match unit in the 20KW output is modi-
fied to the extent of placing a sampling loop in the output
end,
and this loop can be used for monitoring.
It is also used
for remote output metering for remote control operation.
Since the power contactors are non- circuit breaker type and re-
quire a momentary " on" and a momentary " off" type of function
to energize them, the transmitter is easily remote controlled.
To facilitate easier remote control application the off- on
functions of the transmitter have been brought out to terminal
boards.
To Multiplex the Gates FM-20Bis relatively a simple matter.
The main channel Exciter in the driver side was specifically
designed with Multiplex in mind.
Space has been provided direct-
ly below the Exciter for the placing of the Multiplex unit.
A
minimum amount of connections are necessary to conatict this unit
to the main channel exciter!
Connections necessary are the
coax connectors to the Multiplex exciter in the Multiplex chain.
This is done on the front panel of the two units.
Other conn-
ections necessary are power from 115 volts source.
This can
be taken off of 115 volt terminals of the main channel exciter
and the connecting of the audio to the terminal board on the
Multiplex unit compl,tes the necessary wiring.
The Multiplex
unit is capable of handling t
wo
sub- channels and,
therefore,
there are two audio input terminal arrangements available on
the terminal board of the Multiplex unit,.
6 ,22/61
-8-
FN- 20 B
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