Specifications

Modulation Deviation Adjustment
1. Connect an RF deviation meter to the radio through a power attenuator.
2. Set the CHANNEL selector to a transmit channel which has a DCS code pre-programmed (should be a
mid-frequency channel).
3. Press the PTT switch.
4. Adjust RV3 for proper deviation, typically 750 Hz. Release the PTT switch.
5. Set the CHANNEL selector to a transmit channel which has a low-frequency CTCSS tone (67.0Hz)
preprogrammed.
6. Press the PTT switch and verify that the deviation is between 500 Hz and 1000 Hz. Release the PTT switch.
7. Set the CHANNEL selector to a transmit channel which has a high-frequency CTCSS tone (250.3 Hz)
preprogrammed.
8. Press the PTT switch and verify that the deviation is between 500 Hz and 1000 Hz. Release the PTT switch.
If deviation is above or below 500-1000 Hz, adjust RV 401 (filter) to same level as obtained in Step 6.
9. Connect an audio frequency generator to the MIC input (connected to the white wire in the microphone
cable) of the radio. Set the audio output level for 30 mV. The audio frequency should be 1 kHz.
10. Press the PTT switch.
11. Adjust RV4 (Maximum Deviation Adjustment) for the 4.2 kHz deviation if no CTCSS tones are present,
and 4.8 kHz deviation if CTCSS tones are present.
RECEIVER ALIGNMENT
1. Connect an RF signal generator or communications service monitor to the antenna connector.
2. Connect a SINAD meter and an audio distortion analyzer across the speaker terminals. If an audio
distortion analyzer is not available, connect an oscilloscope across the speaker terminals.
3. Turn the SQUELCH control fully counter-clockwise.
4. Adjust the VOLUME control to the proper level for the sinad meter and audio distortion analyzer.
5. Set the CHANNEL selector to a mid-frequency receive channel.
6. Tune the RF signal generator to the channel frequency. The RF output level should be set for 47 dBm. The
modulation should be set for ± 3 kHz FM deviation of a 1 kHz tone.
7. Adjust T10 for maximum audio output. Readjust the VOLUME control if necessary to avoid clipping on
the output audio wave form. (This adjustment is typically not required.)
8. Decrease the RF generator output and adjust T1 through T5 for maximum sensitivity.
• NOTE: During this adjustment signal generator level should be reduced periodically to keep the Sinad meter
reading near 12 dB.
MONOGRAM SERIES LBI-38864B
ALIGNMENT PROCEDURE
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Nov. 94