Maxon SM5102Radio
2.2.2 Receiver Alignment
The receiver is, by design, a broadband
device. It should require no special
alignment unless repairs are performed on
the receiver.
The following alignment may be performed:
a. Select Channel 1 on the radio.
b. Set the RF generator to the receiver
frequency and the RF level to 1mV pd
(-47dBm).
c. Set the AF signal to 1kHz.
d. Set the deviation to:
12.5kHz channel spacing 1.5kHz deviation
or 20kHz channel spacing 2.4kHz deviation
or 25kHz channel spacing 3kHz deviation
e. Monitor the audio output level and the
distortion, setting the volume control to
mid-range.
Squelch
a. Connect the RF signal generator to the
radio.
b. Set the RF signal generator to the
receive frequency of the current channel
on the channel switch.
c. Connect the leads of the SINAD meter
and the speaker via the speaker socket
on the rear panel.
d. Set the volume control to mid-range.
e. Set the deviation to:
12.5kHz channel spacing 1.5kHz
or 20kHz channel spacing 2.4kHz
or 25kHz channel spacing 3kHz
f.
Set the AF generator to 1kHz.
g. With the above setting, reduce the RF
level to –130dBm. The radio should be
mute. It may be necessary to press the
monitor button to achieve mute.
h. Adjust the RF level until the SINAD
meter reads 10dB. The radio should
unmute.
This completes the receiver alignment
process.
2.2.3 Receiver Performance Tests
SINAD or noise quieting sensitivity
performance tests may be used to test the
sensitivity of the receiver. Both tests are
given below.
12dB SINAD Sensitivity
The SINAD performance test may be used to
test the sensitivity of the receiver.
a. Connect the RF signal generator,
modulated with a 1kHz tone, to the
radio.
b. Set the frequency to correspond to the
Rx frequency of one of the channels
programmed into the radio.
c. Using the Test Box, connect the SINAD
voltmeter to the speaker socket on the
radio.
d. Press the monitor button and set the
volume control to mid-range.
e. Set the RF signal generator deviation
to:
12.5kHz channel spacing 1.5kHz dev.
or 20kHz channel spacing 2.4kHz dev.
or 25kHz channel spacing 3kHz dev.
f.
Adjust the RF signal generator level
until the SINAD meter reads 12dB.
g. Check that the signal generator RF
level is < -117dBm (UHF).
Squelch sensitivity
The RF input level to open the squelch is
usually set in the range -123.5 to -117dBm
(0.15 to 0.3mV). The squelch should open at
a. SINAD between 7 and 12dB (no CCITT).
The squelch should close between 2 and
4dB of the value at which it opens.