signals to guide rescue aircraft to the downed
aircrewman. Although the PRC-90 is a line-of-
sight communications device, it has a voice range
under ideal conditions of 60 nautical miles to
aircraft operating at 10,000 feet. The automatic
direction finder has a range of 50 nautical miles
and atone (code signal) range of 80 nautical miles
to aircraft operating at an altitude of 10,000 feet.
Batteries
The batteries are tested by using Test Set TS
2530/UR. Batteries are considered to have a
maximum shelf life of 36 months from the date
of manufacture. This shelf life is based upon a
storage temperature of 70 ‘F. If the temperature
increases, their storage life is shortened. For
example, if the temperature reaches 130 ‘F, the
storage life can be reduced to as short as 1 month.
When you are in an activity that uses this battery,
you should refer to NAVAIR 16-30PRC 90 for
the most current shelf life information.
Operating Procedure
Refer to table 5-2 for the functions of each
control on the PRC-90. The set is operated as
follows:
1. Free the antenna from its stowed position
by pulling its end from the retaining ring or band
Table 5-2.—Operating Controls and Indicators
Control or
Indicator
Control Position
Function
Function switch
OFF
Completely removes power from radio set.
VOICE/MCW
Turns on the guard channel receiver to
243.0
the emergency frequency of 243.0 MHz. Also
enables voice and MCW guard channel
transmission which are keyed by the PUSH
TO TALK or MCW buttons.
BCN 243.0
Turns on 243.0 MHz guard channel transmit-
ter, and transmits a beacon tone. Swept audio
tone is continuously transmitted for rescue air-
craft to home on.
VOICE 282.8
Turns on alternate channel to receive on 282.8
MHz. Also enables voice transmission on
NOTE
auxiliary channel when PUSH TO TALK
The button, (9, figure
button is depressed.
5-8) must be de-
depressed to place
function switch in the
VOICE 282.8 posi-
tion.
PUSH TO TALK
Depressed
Turns receiver off and turns transmitter on
button
when function switch is in either
VOICE/MCW 243.0 or VOICE 282.8 position.
Best voice transmissions are obtained when
spoken directly into the talk microphone.
Released
Turns off transmitter and turns on receiver;
received signal is heard with ear close to
LISTEN speaker or earphone.
5-8
