Uniden BC785D Sound QULTY0050, 867.8375 P25 Low Mid Upp 0533 1985, Threshold Adjustment Range

APCO P-25 Sound Quality Fine Tuning

With each APCO Project 25 system, particularly at 800MHz, the sound quality (C4FM Demodulation Threshold) may need to be fine tuned specifically for that system. If the scanner is not adjusted correctly, the P-25 voice transmissions will sound robotic or unintelligible.

To adjust the sound quality to match the P-25 system you want to monitor follow these four steps:

1.While monitoring a specific APCO P-25 frequency, press the ▲/HOLD key. Note: In the Trunking mode, press the TRUNK key instead of the ▲/HOLD key.

2.Press and hold the number 9 key.

3.On Line 1 of the screen you will see SOUND QULTY: 0050 (for example).

SOUND QULTY:0050

867.8375 P25

Low Mid Upp

0533 1985 3342

This shows the Sound Quality. The lower the level the better the Sound Quality. For better Sound Quality rotate the VFO up or down. As the threshold adjusts in increments of 50 at the bottom of the screen watch the Sound Quality level increase or decrease and continue to rotate the VFO until you have achieved the lowest Sound Quality level.

Note: • When APCO P-25 signal is not received, SOUND QULTY: ****

appears on the display.

•You must have the BCi25D card installed and have an APCO P-25 signal during this adjustment.

•You can also use the ▲ and ▼ keys to adjust the sound quality.

- A chart showing the Threshold Adjustment Range is listed below.

Threshold Adjustment Range

		Lower		Mid		Upper
Band	Min	Default	Max	Default	Min	Default	Max
800MHz	33	533	1883	1985	1992	3342	3842
UHF	33	633	1883	1985	1992	3342	3842
VHF	158	658	2058	2085	2190	3590	4090

Note: • The above Min and Max values are the calculated values that can be assigned theoretically, and the values are not to guarantee the operation of the unit.

•The mid threshold value will not change while adjusting the upper and lower limits.

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