TM 55-1510-219-10
Figure 3-4. VHF-AM Control Panel (VHF-20B)
(2) Receiver operating procedure.
1. Transmitter-interphone selector (audio
panel, fig. 3-1) - #1 position. or Audio
monitor control #1 - ON.
2. Frequency selector - Set desired
frequency.
3. VOL control - As required.
(3) Transmitter operating procedure.
1. Transmitter-interphone selector (audio
panel, fig. 3-1) - #1 position.
2. Microphone switch - Press.
(4) Shutdown procedure. VOL control -
Counter-clockwise (OFF).
d. VHF-AM Set - Emergency Operation.
NOTE
Transmissions
on
frequency
(121.500 MHz) are restricted to
emergencies only. Emergency
frequency 243.000 MHz (guard
channel) is also available on the
UHF command radio.
1. Transmitter-interphone selector (audio panel, fig. 3-
1) - #1 position.
2. Frequency selector (VHF panel) - 121.
500 MHz (emergency frequency).
3. Microphone switch - Press.
3-11. VHF AM/FM COMMAND SET (AN/ARC-186).
a. Description. The VHF AM/FM Command Set
provides
for
normal
and
secure
2-way
voice
communication: AM in the very high frequency range of
116.000 to 151.975 MHz and FM in the 30. 000 to
87.975 MHz band. Twenty channels may be preset.
Audio signals are applied through pilot and copilot
transmitter select switches No. 2 position and through
the pilot and copilot No. 2 receiver audio switches to
their respective headsets. Complete provisions only are
installed for voice security device KY-28 or KY-58.
Circuits are protected by a 10-ampere VHF AM/FM
circuit breaker on the overhead circuit breaker panel
(fig. 2-26). Figure 3-5 illustrates the VHF AM/FM
control panel. The associated antenna is shown in
figure 2-1.
3-9
