TM 55-1510-221-10
Figure 3-2. Marker Beacon Audio Control Panel
NOTE
The PRESET channel selector and man-
ual frequency selectors are inoperative
when the mode selector is set to GUARD
position. The receiver-transmitter will be
set to the emergency frequency only.
The transmitter and receiver sections of the
UHF unit operate independently but share the same
power supply and frequency control circuits. Sepa-
rate cables route transmit and receive signals to their
respective receiver/transmitter.
Complete provisions only are installed for a
TSEC/KY-28 voice security device to be located on
the LH forward avionics rack behind the pilot. The
UHF command set is protected by the 71/2 ampere
UHF circuit breaker on the overhead circuit breaker
panel (fig. 2-26). Figure 3-3 illustrates the UHF
command set. The associated blade type antenna is
shown in figure 2-1.
b.
Controls and Functions. UHF control panel
(fig. 3-3):
(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
(0 through 9) in MHz.
(3.) Manual frequency selector/indicator
(units). Selects and indicates units digit of frequency
(0 through 9) in MHz.
(4.)
Preset channel indicator. Displays pre-
set channel.
(5.) Manual frequency selector/indicator
(tenths). Selects and indicates tenths digit of fre-
quency (0 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 thou-
sandths digits of frequency (00, 25, 50, or 75) in
MHz.
(a.) Mode selector. Selects operating
mode and method of frequency selection.
1. MANUAL.
Enables the
manual selection of any one of 7,000 frequencies.
2. PRESET. Enables selection
of any one of 20 preset channels.
3-5
