Underwater sounds

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1586

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I just purchased a 396T, updated the firmware to the latest version and while scanning my local county digital system the frequencies sound like they are basically under water. I can half hear the broadcasts but many are broken and hard to understand. I am using the ARC396 program and uploading the systems from the RadioReference.com site which automatically adds the system settings.

I am listening to Charles County, MD. which shows as a trunked Motorola Type 2 800 Mhz system. Is there maybe something in the system settings that is causing the audio issue?

Any insight would be appreciated.

Thx
 

ka3jjz

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I don't know whether there are any Charles County folks in our Maryland forum (which is where I'm going to recommend this be moved to, since it's system specific), but depending on what firmware you have, there are a couple of things to try here. Make sure your P25 mode is set to manual; you will need to fiddle with the P25 threshold. Here in central Maryland 8 or 9 seems to be pretty good. There's also a digital AGC setting(which to be honest I've never been able to access, even though I've used the procedure outlined in the wiki) which is in a hidden menu that can be adjusted.

Here are 2 articles from our wiki which addresses the audio decoding (anything in blue and/or underlined is a link);

http://wiki.radioreference.com/index.php/P25_audio_decode_level_adjustment_(BCD396T)

http://wiki.radioreference.com/index.php/Uniden_Digital_AGC_Tweak_Procedures

The newest firmware (which is what I now have) seems to improve the audio, but I don't believe you will completely get rid of the 'underwater' sound. But it will get much better. The Uniden forum has extensive threads on where to get the new updates and applying them.

73 Mike
 
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1586

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Thanks!

I tried both methods and the motorboating cleared up somewhat. What I don't understand is why the volume is so much lower on the Charles County system vs. PG County.

Any thoughts?

Also, I was able to tweak the AGC based on the link that you sent me using the controls on the unit itself. There is no menu in the ARC software that I could find that would emmulate using the scanner.

Thanks again....
 

ka3jjz

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I can't get Charles from where I am, so I can't try it myself, but I suspect your analog AGC is off?

73 Mike
 

policefreak

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1586, how is your reception of the system? How many bars of signal strength do you get? Does the signal seem to be unstable (5 bars one second 1 or none bars the next)? I set my P-25 gain, using the hidden menu to the highest it can go, while setting analog gain to almost the lowest it can go. Now, their almost about even. I always thought digital sounded kinda crappy anyway. Obviously I'm from Jersey, so I don't get Charles County either, but the new firmware worked with my 396 and I try to monitor digital systems from a spot in the house where the signal is the steadiest.
 
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jkahn

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Hey, Mike

"There's also a digital AGC setting(which to be honest I've never been able to access, even though I've used the procedure outlined in the wiki) which is in a hidden menu that can be adjusted. "


This probably belongs in the procedures forum, but if we all share the special little things we have discovered, it helps us all:

To adjust the AGC:
1. turn on radio while holding "hold" to access the hidden menus.
2. hold soft function key in while pressing down the scroll knob, TWICE. (first is squelch, 2nd is new AGC gain adj/P25 Res Time adj)
3 You can hold soft function and twist the scroll knob to alternate between res time and AGC adjust functions.
3. Adjust P25 AGC gain up or down by turning scrol knob. Display on bottom line right corner will change (+2, +3/ -1 etc). Same if you are in P25 Res Time screen-twist knob to adjust up/down. This will also clear some of the motorboating, but seems to clear the "underwater" sound more than the AGC adjust does.
4. press scroll knob to lock in change.

This works better under the "fixed" 2.01.01 version available from Paul O.
 
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