Specifications

APC

This is the most critical point of the transmitter alignment procedures because ACC-

516 (PCB Extender Board) has a voltage drop in transmission mode and so power drop

occurs. That’s the reason why radio outputs higher power than assigned after assembly.

To prevent over-power output, follow below procedure

In case alignment for SD-160 series:

1. Adjust RV4 and set the power at the point of 1.6W.

2. Assemble the radio and then check again RF transmission power is near 2.0W.

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Required alignment point for each radio and proper RF power output when radio is

assembled

① Adjust RV4 for High Power (2W, SD-161, SD-164), (5W, SD-171, SD-174)

② Adjust RV3 for Low Power (1W) (SD-171, SD-174 only)

7.3. SQUELCH ADJUSTMENT

Before squelch adjustment a SQ type should be selected. Squelch level to open or close (un-

mute or mute) is set up by not only software control but also hardware control and programmed

by the system option of the ACC-916 programming software.

SQUELCH Adjustment (Noise SQ only)

1. Select a receiver channel which is programmed for narrow band (12.5kHz) operation.

2. Set the RF signal generator to the receiver frequency.

Set the AF modulation signal to 1 kHz at 1.5kH deviation.

3. Adjust the RF output level of the RF signal generator until the 1kHz signal is heard.

4. Adjust the RF signal to the desired level for squelch sensitivity as you monitor SINAD.

This is usually 8 to 12 dB sinad.

5. On the RF board, adjust RV5 until the squelch is just un-muted (open).

6. Switch off the RF generator (squelch should be closed).

7. Switch on the RF generator, Squelch should be opened at the SINAD point where RV5 was

adjusted.

8. Select a receiver channel that is programmed for wide band operation (25kHz).

9. Set the RF signal generator to the receiver frequency.

Set the AF modulation signal to 1 kHz at 3kH deviation.

10. Adjust the RF output level of the RF signal generator until the 1kHz signal is heard.