Squelch - Motorola MCS 2000 Service Instructions Manual

Select 5 Transmit
Deviation
(GVN6011 only)
Note

Squelch

This tuning sequence is ONLY for radios with Conventional
Note
Select 5 Signaling software being tuned with the RSS
GVN6011.
The Select 5 Deviation Softpot is used to tune the FFSK signaling deviation.
Tuning is performed at one frequency and for 25 kHz channel spacing. The
radio generates a Select 5 signal for tuning. Values for other frequencies and
channel spacings are calculated by the radio software.
Alignment of the Transmit Deviation Limit Reference MUST immediately
PRECEDE the Select 5 Alignment Procedure.
1. From the RADIO TUNE menu, press F4 to select SIGNALING alignment.
2. Press F5 again to select the Select 5 softpot.
3. Press F6 to key the radio on the test frequency. The screen will indicate
that the radio is transmitting.
4. Measure the Select 5 deviation on your service monitor.
5. Use the UP/DOWN arrow keys to adjust the Select 5 deviation to be
between 3.30 and 3.70 kHz.
6. Press F6 again to dekey the radio.
7. Press F8 to program the softpot value; press F10 twice to return to the
SERVICE menu.
The squelch softpots set the signal to noise ratio at which the squelch opens.
The 25/30 kHz squelch value needs to be set at 7 frequencies across the
frequency range. In 800 MHz and 900 MHz radios the 6th and 7th frequency
are always the same, so only 6 frequencies are being tuned. For some models,
the 20 kHz and 12.5 kHz values are then set at one frequency and the other
frequency settings are calculated by the radio software. For other models the
20 kHz and 12.5 kHz squelch settings are also tuned for all 7 frequencies across
the band.
1. From the SERVICE menu, press F3 to select RECEIVER alignment.
2. Channel spacing determines the next key press. Press F4, F5, or F6 (as
applicable) to select the SQUELCH softpot.
3. Select the first test frequency shown, and adjust the UP/DOWN arrow
key to the minimum squelch value.
4. With Test Box RLN4460A: Set the RF test generator to the test frequency
plus the following offset: VHF: +200 Hz, UHF: +200 Hz, 800 MHz:
+500 Hz.
With Test Box GTF180B: Set the RF test generator to the test frequency
and modulate the signal generator at 3.0 kHz deviation, 1 kHz tone.
Adjust the generator for an 8-10 dB SINAD level.
5. Adjust the UP/DOWN arrow key until the squelch just closes.
6. Monitor for squelch chatter; if chatter is present, repeat step 4.
7. When no chatter is detected, press F8 to program this value. Press
"ENTER" to select next softpot adjustment.
8. Repeat steps 3 - 6 for all test frequencies shown on the screen.
9. Press F10, F10 to return to the Service menu.
Radio Tuning Procedure 6-9