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7.
Adjust the RF signal generator level until the SINAD
meter reads 12 dB.
8.
Check that the signal generator RF level is less than 0.28
µV EMF.
Noise Quieting Sensitivity
1.
Disconnect the signal generator from the radio.
2.
Set the radio power meter to volts and connect the audio
power meter to the speaker terminals.
3.
Press and hold the monitor button.
4.
Connect the signal generator to the radio
5.
Adjust the VOLume control to obtain a noise reading
of 1 Vrms.
6.
Set the deviation to 3 kHz..
7.
Set the audio generator to 1 kHz.
8.
Adjust the RF level of the signal generator RF level for
a noise reading on the meter of 0.1 Vrms. This is the 20
dB noise quieting point. Check that the RF level is less
than 0.5 µV EMF.
Squelch Sensitivity
1.
Set the RF signal generator to the receive frequency for
the selected channel.
2.
Set the deviation to 3 kHz.
3.
Set the AF generator to 1 kHz.
Set the RF signal generator to 20 dB or 2.0 µV and
4.
verify that an audible tone is heard.
5.
Switch off the RF signal generator and verify that no
audio is heard (received).
AUDIO OUTPUT
1.
Set the RF signal generator to 1 mV EMF and the
deviation to 3 kHz.
2.
Set the audio generator to 1 kHz.
3.
Set the power voltmeter to ac volts.
4.
Connect the power voltmeter to the accessories socket.
5.
Adjust the volume control of the radio under test to fully
clockwise.
6.
The meter should indicate 2.0 V or greater, the power
meter should read 500 mW or greater.
ALIGNMENT PROCEDURES
When performing the transmitter and receiver alignment
prcedures, refer to Figure 6 for location of test points and
adjustment controls.
PLL ALIGNMENT
NOTE
If the Phase Lock Loop (PLL) is out of lock, an audible
warning will be heard and the red LED on the top panel
will flash.
1.
Connect an RF power meter to the ANT socket.
2.
Using the channel switch, select channel with the low-
est receive frequency.
NOTE
If the power save format is programmed and the
squelch is closed (muted), there will be a periodic
voltage change at TP1 unless step 3 below is per-
formed. If the power mode has not been selected in
programming, it is not necessary to perform step 3.
3.
Adjust VR201 to unmute the squelch.
4.
Connect a DC voltmeter to test point 1 (TP1), accessed
through the hole in the VCO cover.
5.
Adjust TC301 for 1.4 (0.05) volts at TP1.
NOTE
The receiver operational bandwidth is typically 10
MHz. There may be some degradation in actual re-
ceiver performance if a bandwidth of more than 10
MHz is used.
6.
Using the channel switch, select channel with the high-
est transmit frequency.
NOTE
Any transmit frequency between 450 MHz and 470
MHz can be programmed and used, however the high-
est transmit frequency can typically be only 8 MHz
above the lowest receive frequency.
7.
Press the PTT switch to transmit.
8.
At TP1 measure and check that the voltage is 6.0 volts
or less. If the voltage is above, 6.0 volts the VCO may
not lock because the frequency is programmed too
high above the lowest receive frequency.
9.
Set the PTT switch to receive.
10. If step 3 was performed, readjust the squelch setting.
AUTOMATIC POWER ADJUSTMENT
NOTE
Transmit periods longer than five minutes are to be
avoided.
1.
Using the channel switch, select the center receive
frequency channel.
2.
Press the PTT switch.
3.
Adjust VR2 to provide rated transmit power.
4.
Release the PTT switch.
DIGITAL CHANNEL GUARD
MODULATION ADJUSTMENT
1.
Connect the test equipment to the radio as shown in
Figure 4.
2.
Using the channel switch select the DCS coded fre-
quency channel.
3.
Press the PTT switch and observe the demodulated
waveform on the oscilloscope. Compare with Figure
6.
4.
If necessary adjust RV403 to achieve the waveform.
Figure 6 - Demodulated DCS Waveform
LBI-38861C
MODULATION DEVIATION ADJUSTMENT
1.
Connect a power meter and a coupler to the radio as
shown in Figure 4.
2.
Connect an audio generator as shown in Figure 4.
3.
Set the audio output level to 60 mV and the audio
frequency to 1 kHz.
4.
Using the channel switch, select the highest transmit
channel without Channel Guard.
5.
Press and hold the PTT switch.
6.
Adjust RV402 for maximum system deviation.
7.
Release the PTT switch.
8.
Using the channel switch, select the lowest transmit
channel without Channel Guard.
9.
Press and hold the PTT switch.
10. Measure the deviation and verify that it is below peak
system deviation. If the deviation is greater than the
peak system deviation adjust RV402 to peak system
deviation.
11. Select channel showing the highest deviation, sweep
the audio frequency between 300 Hz and 3 kHz.
Adjust RV2 to ensure deviation is below peak system
deviation at all frequencies.
12. Disconnect the audio generator and set the PTT
switch to the off position.
CTCSS/DCS DEVIATION ADJUSTMENT
1.
Connect a power meter and modulation meter to the
radio as shown in Figure 4.
2.
Using the channel switch select a transmit channel
with Channel Guard.
3.
Press the PTT switch.
4.
Adjust RV403 for 10% of maximum system devia-
tion (500 to 750 Hz).
5.
Using the oscilloscope check that the positive and
negative peak deviations are equal.
6.
If necessary adjust RV401 to obtain equal and oppo-
site peak deviations.
7.
Release the PTT switch and disconnect the deviation
meter.
11
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