SECTION 3. TUNING PROCEDURES
a. General. You are now familiar with connecting the components of the radio set and
the location of its controls and indicators. The next task you will learn is tuning the transmitter
and receiver to get the radio on the air.
Before you begin to tune the AN/GRC-103, there are several precautions you should take. One
is not to turn the equipment on unless all connections are made properly and the radio set output
is connected to the antenna or the dummy load. The dummy load is a device that is connected to
the output of the transmitter in place of an antenna. This device will act as a load for the
transmitter without radiating a signal. Figure 3 shows the dummy load used with the AN/GRC-
Figure 3. Dummy Load, Electrical DA-437.
Another precaution is that when the radio Set is connected to the antenna, do not set the
transmitter AC POWER switch to ON/RESET unless the transmitter XMTR CHANNEL and
XMTR TUNE controls are set for the assigned frequency. Failure to observe this precaution will
result in transmitting over an unauthorized frequency.