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.
Audio signals are applied through the pilots and
copilots UHF AUDIO switches to the respective
headsets. A separate receiver is incorporated to
provide monitoring capability for the UHF guard
frequency (243.0 MHz).
b. UHF Controls and Functions. Refer to
(1) Manual Frequency Selector (Hundreds)
Selects hundreds digit of frequency (either 2 or 3) in
(2) Manual Frequency Selector (Tens)
Selects tens digit of frequency (0 through 9) in MHz.
(3) Manual Frequency Selector (Units)
Selects units digit for frequency (0 through 9) in MHz.
(4) Preset Channel Indicator Displays
preset channel selected.
(5) Manual Frequency Selector (Tenths)
Selects tenths digit of frequency (0 through 9) in MHz.
(6) Preset Channel Selector Selects 1 of
20 preset channel frequencies.
(7) Manual Frequency Selector (Hundredths
Or Thousandths) Selects hundredths or thousandths
digits of frequency (00, 25, 50, or 75) in MHz.
(8) Mode Selector Selects method of
The GUARD position should not be used
except in actual emergencies. When
operating under emergency conditions, set
the MANUAL / PRESET / GUARD switch to
the GUARD position and the function
switch to MAIN. Do not use the BOTH
position since noise from the two receivers
may make the incoming signal unreadable.
(a) MANUAL Any one of 7,000
frequencies can be manually selected using the five
(b) PRESET Frequency is selected
using the preset channel selector to select any one of
20 preset channels.
(c) GUARD The main receiver and
transmitter are automatically tuned to the guard
frequency and the guard receiver is disabled.
(9) SQUELCH Switch Turns main receiver
squelch circuit on or off.
(10) Volume Control Adjusts volume.
(11) TONE Push Button - When pressed,
transmits a 1020 Hz tone on the selected frequency.
(12) Function Switch Selects operating
(a) OFF Turns set off.
(b) MAIN Turns set on.
(c) BOTH Selects main receiver,
transmitter and guard receiver.
(d) ADF Not used in this installation.