a v a i l a b l e , e a c h l i f e r a f t m u s t h a v e a n
AN/URT-33A beacon or AN/PRC-90 radio set.
We will cover the AN/PRT-5, AN/URT-33A,
and the AN/PRC-90 survival radios in this
chapter.
In addition to the automatic direction finder
(ADF) capability of SAR force aircraft, the
United States government also uses satellites
that monitor guard frequencies for emergency
locator transmitter (ELT) broadcasts.
AN/PRT-5.— The AN/PRT-5 radio transmits
a tone-modulated signal in both high- and
ultrahigh-frequency ranges. The set has an
inflatable collar assembly that allows it to float
at sea or sit upright on land. The radio can operate
continuously for 72 hours at 25°C (77°F). No
provisions for voice or code communications or
for receiving signals from search aircraft are
available with this transmitter. The AN/PRT-5
radio operates on 243.0 and 8364 MHz. The
assembly instructions and the directions for use
are included with each set.
AN/URT-33A.— The AN/URT-33A beacon
radio is a battery-operated radio that transmits
a tone-modulated radio signal. The battery
provides 72 hours of continuous operation.
It must be pointed out that this beacon should
not be used at the same time the AN/PRC-90
is being used, as the AN/URT-33 will inter-
fere with the voice communication signal of
t h e A N / P R C - 9 0 . W h e n y o u a r e u s i n g t he
AN/URT-33, do not point the antenna directly
toward the receiving aircraft because of the
t y p e o f a n t e n n a e m p l o y e d ; a c o n i c a l a r ea
perpendicular to the antenna tip does not radiate
a signal.
Do not attempt to use the telescoping antenna
o n t h e A N / U R T - 3 3 A r a d i o w i t h o u t f i r st
detaching the flexible antenna. Use of both
antennae creates interference in the transmission
patterns of both.
To turn the AN/URT-33A radio on, you
must move the switch to a position where
t h e w o r d O N c a n b e r e a d . T h i s m a y be
c o n f u s i n g t o t h e a i r c r e w m a n , a n d t h e
AN/URT-33A could be on when the aircrewman
thinks it’s OFF.
AN/PRC-90.— The AN/PRC-90 radio set is
a d u a l - c h a n n e l p e r s o n a l e m e r g e n c y r e s c u e
transceiver, used principally for two-way-voice or
modulated-continuous-wave (MCW) communica-
tion between a downed aircrew member and a
rescue aircraft. Provisions are included for
transmitting tone MCW and swept-frequency
homing beacon signals to guide rescue efforts.
The AN/PRC-90 is battery powered and
contains a flexible antenna, an interchangeable
telescopic antenna, a function switch (knob and
indicator), an MCW button for Morse code, a
volume control dial, and an earphone.
When you are using the voice mode, the
AN/PRC-90 is capable of transmitting up to 60
nautical miles (nmi) and up to 80 nmi on beacon
or code. A rule of thumb is that this and other
survival radios are limited to a line-of-sight
Figure 5-37.—Rescue hand signals.
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