TM 55-1510-219-10
Figure 3-1. Audio Control Panel (C-499) (Typical pilot, copilot)
d. Emergency Operation. Not applicable.
e. Shutdown.
1. AVIONICS MASTER POWER switch
(overhead panel) -OFF.
2. Leave avionic controls and circuit
breakers positioned for normal operation.
3. Aircraft DC power - OFF.
3-7. RADIO CONTROL PANEL (FIG. 3-2).
a. Description. The radio control panel, located on
the pedestal extension allows the pilot or copilot to
selectively monitor audio signals from the High
Frequency (HF), Marker Beacon (MKR BCN), or ADF
systems. It also has controls for the selection of ADF
voice or range filters. Controls and functions are as
follows:
b. Controls and Indicators.
CONTROL
FUNCTION
HF VOL control
Adjusts volume of high-
frequency radio signals received.
MKR BCN HI/
Selects sensitivity of marker bea-
LO switch
con receiver.
MKR BCN VOL
Adjusts volume of marker bea-
control
con radio signals received.
(2) Automatic Direction Finding (ADF).
FILTER V/OFF
Selects filter to block voice
switch
transmissions from ADF ground
station.
FILTER R/OFF
Selects filter to block range
switch
transmissions from ADF ground
station.
3-8. UHF COMMAND SET (AN/ARC-164).
a. Description. The UHF command set is a line-of-
sight radio transceiver which provides transmission and
reception of amplitude modulated (AM) signals in the
ultra high frequency range of 225.000 to 399.975 MHz
for a distance range of approximately 50 miles.
Channel selection is spaced at 0.025 MHz. A separate
receiver is incorporated to provide monitoring capability
for the UHF guard frequency (243.0 MHz). UHF audio
output is applied to the audio panel where it is routed to
the headsets.
3-4
