TM 55-1510-222-10
The transmitter and receiver sections of the UHF
unit operate independently, but share the same power
supply and frequency control circuits. Separate cables
route transmit and receive signals to their respective
receiver/transmitter.
The UHF command set is protected by the 7
1/2ampere UHF circuit breaker in the overhead circuit
breaker panel (fig. 2-6). Figure 3-2 illustrates the UHF
command set. The associated blade type antenna is
shown in figure 2-1.
b.
Controls and Functions. UHF control panel
(fig. 3-2):
(1)
Manual frequency selector/indicator
(hundreds). Selects and indicates hundreds digit of
frequency (2 or 3) in MHz.
(2)
Manual frequency selector/indicator
(tens). Selects and indicates tens digit of frequency (O
through 9) in MHz.
(3)
Manual frequency selector/indicator
(units). Selects and indicates units digit of frequency (O
through 9) in MHz.
(4)
Preset channel indicator. Displays
preset channel.
(5)
Manual frequency selector/indicator
(tenths). Selects and indicates tenths digit of frequency
(O through 9) in MHz.
(6)
Preset channel selector. Selects one
of 20 preset channel frequencies.
(7)
Manual
frequency
selector
(hundredths and thousandths). Selects hundredths and
thousandths digits of frequency (00, 25, 50, or 75) in
MHz.
(8)
Mode selector. Selects operating
mode and method of frequency selection.
(a)
MANUAL. Enables the manual
selection of any one of 7,000 frequencies.
(b)
PRESET. Enables selection of
any one of 20 preset channels.
(c)
GUARD.
Selection
automatically tunes the main receiver and transmitter to
the guard frequency and the guard receiver is enabled.
(9)
SQUELCH switch.
Turns
main
receiver squelch on or off.
(10)
VOL control. Adjusts volume.
(11)
TONE pushbutton. When pressed,
transmits a 1,020 Hz tone on the selected frequency.
(12)
Function selector. Selects operating
function.
(a)
OFF. Turns set off.
(b)
MAIN.
Selects
normal
transmission with reception on main receiver.
(c)
BOTH.
Selects
normal
transmission with reception on both the main receiver
and the guard frequency receiver.
(d)
ADF. Not used.
c.
Normal Operation.
(1)
Turn on procedure:
NOTE
It is presumed aircraft power is on and
normally used avionic circuit breakers
remain depressed.
1.
Avionics master power switch
ON.
2.
Function select switch MAIN or
BOTH position, as required.
NOTE
If function selector is at MAIN setting,
only the normal UHF communications
will be received. If selector is at BOTH
position, emergency communications
on the guard channel and normal UHF
communications will both be received.
(2)
Receiver operating procedure:
1.
Transmitter-interphone selector
switch No. 3 position.
2.
UHF audio monitor switch ON,
No. 3 position.
3.
Volume control Mid position.
(3)
To use preset frequency:
1.
Mode selector switch PRESET
position.
3-5
