d. You have covered the three major components of the AN/GRC-193,
which are the receiver-transmitter RT-1209, the amplifier-converter
AM-6879, and the power amplifier AM 6545.
Now, we will study the
antenna coupler CU-2064, which is e last major component of the
AN/GRC-193.
The antenna coupler automatically matches impedance of
an HF antenna to a 50-ohm coaxial transmission line to maintain a
standing wave ratio (SWR) of 1.2:1 or less over the HF range of 2 to
29,999.9 MHz.
The coupler receives its signal to start tuning from
the RF signal from the power amplifier. The coupler also provides a
ready signal, to the power amplifier, when tuning is complete.
Signals of forward and reflected power and tuning fault indications
are sent to the power amplifier for display on green, yellow, and red
lights on the front panel of the power amplifier. The coupler also
has a pressure relief valve, which opens at 4 psi.
The unit is
cooled by a forced air heat exchanger system that includes a
thermostatically controlled external fan and a continuously operating
internal fan.
The external fan motor will not operate all of the
time.
It will come on only when the internal temperature reaches
55C. All controls and cable connections are on the front panel (Fig
5).
Figure 5.
Antenna coupler CU-2064/GRC-193.
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