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CTCSS/DCS Deviation Adjustment
•
Note:The following adjustment should be preset with factory alignment. If an adjustment must
be made the following procedures must be followed:
1. Program the radio with a 67.0Hz tone on one channel and 250.3Hz on another channel.
2. Connect a power meter and modulation meter to the radio antenna jack.
3. Adjust RV101 to the center of its adjustment.
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Note:Release the PTT button when changing channels.
4. Alternately select the channel with tone 250.3Hz and the channel with tone 67Hz. Key up and
note the level for each. If necessary, adjust RV101 until a balance occurs between tone 250.3Hz
and tone 67Hz.
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Note:This adjustment also sets DCS balance even if a DCS tone is not programmed at this time.
5. Select tone 250.3Hz or tone 67Hz and adjust RV403 for the tone level, typically between 500Hz
to 1kHz.
6. Release the PTT button.
Modulation Deviation Adjustment
1. Connect a power meter and a coupler to the radio.
2. Connect an AF generator to the test box.
3. Set the audio output to 30mV and the audio frequency to 1kHz .
4. Using the channel switch, select the highest transmit channel that does not have CTCSS or DCS
programmed.
5. Press and hold the PTT switch.
6. Adjust RV402 for 90% of maximum, system deviation.
6a. Adjust RV402 for 2.25kHz for narrow band (12.5kHz).
6b. Adjust RV402 for 4.5kHz for wide band (25kHz).
7. Using the channel switch, select the lowest transmit channel that does not have CTCSS or DCS
programmed.
8. Press and hold the PTT switch.
9. Measure and check that the deviation is not below 3.8k . If the deviation is below 3.8k, adjust
RV402 to 3.8k .
10. Return to highest transmit channel having a sub- audible tone and verify deviation does not exceed
5k.
11. At the channel that highest deviation is found, sweep the audio frequency between 300kHz and
3kHz . Adjust RV402 to ensure deviation is below peak system deviation at all frequencies.
12. Set the PTT switch to the OFF position.
MAXON SM-2000 MOBILE
SM-2150/VHF ALIGNMENT PROCEDURE
Page-25-
December 98