TM 11-6625-2632-14
radio set to be used as a transmitter must be tested first.
such contaminants, but it is best to avoid these
The receiving set is then tested against this transmitter,
conditions.
which is known to be operating properly. The two sets
b. Check to be sure both Radio Sets AN/PRC-90 to
are then reversed and the test procedure is run through
be tested contain batteries in good condition.
again.
to be tested, using wrench supplied with test set.
2-7. Test Setup
a. Select a tes t area which is as free of moisture,
CAUTION
dust, salt spray, snow, or other contaminants as
Do not lose sealing washer from
possible. Testing can be performed in the presence of
Figure 2-1. Antenna removal from Radio Set AN/PRC-90.
d. Install a connector adapter in each of the two
indicates in red area (NO-GO), the transmitting radio is
unsuitable for use and should be replaced.
radio antenna jacks. Avoid cross threading and seat
connector adapters fingertight.
2-9. Beacon Monitor Check
e. Connect transmitter cable of test set to the
connector adapter on one Radio Set AN/PRC-90
(transmitting radio), and connect receiver cable to the
a. Set the function switch of the transmitting radio
connector adapter on the other (receiving radio) (fig. 2-
to the BCN 243.0 position.
b. A beacon tone should be barely audible from the
speaker of the transmitting radio. If the beacon tone is
2-8. Beacon Battery and Transmitter Check
not audible, replace the AN/PRC-90.
2-10. MCW Transmitter Check
transmitting radio to the BCN 243.0 position and observe
the meter of the test set.
a. Set the function switch of the transmitting radio
b. Meter should indicate in the green (GO) area to
to the VOICE/MCW 243.0 position. Depress and hold
indicate that beacon power output is satisfactory and
the MCW button of the radio set and observe the meter
battery is good.
of the test set. Release the MCW button.
c. If meter indicates in the red (NO-GO) area,
b. If meter indicated in the green area (GO) when
beacon power output is not satisfactory. Install a new
the MCW button was pressed, MCW power output is
battery in the transmitting radio.
satisfactory.
d. Repeat step a. If meter now indicates in green
area the problem has been corrected. If meter still
2-2
