GRE 800 Garbled Audio

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bdp278

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Monitoring P25 system, and about 50% of the time the audio comes in very garbled. Sounds like a digital audio decode issue. Moving the scanner around seems to help somewhat, but is there a way to adjust the decoding or any other solutions?
 

dpcain

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If the system you're listening to is using CQPSK modulation, you could be hearing some multipathing issues- identical digital signals being received at different times and the scanner without the CQPSK protocol doesn't know how to deal with it.
 

krokus

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bdp278 said:
Monitoring P25 system, and about 50% of the time the audio comes in very garbled. Sounds like a digital audio decode issue. Moving the scanner around seems to help somewhat, but is there a way to adjust the decoding or any other solutions?
What type of system are you monitoring? Is it a stand-alone repeater? A multi-site? Perhaps a simulcast system?

What frequency range? Which antenna are you using? If you are in a building, what type of construction? How far are you from the transmitting station(s)?
 

N0WEF

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Have you upgraded the antenna? If so, switch back to the stock... Mine is HORRIBLE (For the reason listed above) with the Radio Shack 800.

You could also attempt to use the ATT or tighten the thresholds in the software, but the stock ant gives me darn good performance up to 25-30 miles on a 800mhz TRS
 

bdp278

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System is Project 25 Phase 1 (FDMA). Yes, it is a multi site, simulcast system. Freq range 700 & 800 Mhz. Using stock antenna, in apt bldg wood & brick construction.
 

brownlab

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Phase 1 FDMA should not be a big problem but the first thing I did was upgrade the antenna to the RS 800 or something from Scanner Masters (almost anything is better). I have found that the unit is also very sensitive to various interference so one thing is to keep it away from your laptop as far as possible even if you are plug into one (a couple of inches makes a lot of difference). You can purchase a cheap adapter which allows you to plug the other end of the USB cable in to the electrical outlet. This is a common complaint about the 800 so expect a lot of feedback on your post. Good luck.
 

cpetraglia

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I am having the same problem with my PSR600 on the Fx Co P25 system. I am in Fairfax City. I have tried everything from the rubber duck to my roof mounted 800MHZ antenna. I've tried attenuate and expert settings. Nothing makes a difference. Any other P25 system comes in crystal clear. VSP STARS & Arlington Co. I am at a loss here.
 

mikev

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If your signal strength isn't showing very high, then this would be the first thing you would want to work on. If you can improve your reception of the signal, that may fix the issue.

If the signal strength is high, but you're still hearing garbled audio, there is a setting that you can try adjusting. Do note that this setting is a global setting, so it will affect all digital audio decoding in your current VScanner... thus you may need to somehow strike a balance of lower quality audio on one system to get better quality audio on another, or set up different systems in different VScanner setups, and switch between them as needed.

The setting is the "DSP Level Adapt" setting on the Advanced Settings tab in the EZ-Scan software. It's also in the Settings on the scanner, just a few away from the bottom of the list. Changing it just a small amount has the ability to greatly enhance the decoding of digital voice signals. You can take big swings with it, but you could go from bad to bad, and your ideal setting may have been skipped over.
 
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cpetraglia

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I am using PSR Edit and dont see an adjustment for that. I have a PSR600. What software do I use to be able to adjust this setting? FYI You are the first that has made an attempt to help with my problem and Thanks. I still dont know where to go from here. I would need some PSR600 instructions. This is supposed to work, but it is not for me. !!
 

brownlab

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I am using PSR Edit and dont see an adjustment for that. I have a PSR600. What software do I use to be able to adjust this setting? FYI You are the first that has made an attempt to help with my problem and Thanks. I still dont know where to go from here. I would need some PSR600 instructions. This is supposed to work, but it is not for me. !!
RS sells a little rubber duck which people use on portable scanners for NASSCAR. Sounds crazy but that has worked for me in situations where you may be just too close to the transmitter. They only cost a couple of bucks.
 

bdp278

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The setting is the "DSP Level Adapt" setting on the Advanced Settings tab in the EZ-Scan software. It's also in the Settings on the scanner, just a few away from the bottom of the list. Changing it just a small amount has the ability to greatly enhance the decoding of digital voice signals. You can take big swings with it, but you could go from bad to bad, and your ideal setting may have been skipped over.
Thanks will try that setting. Also, if I have multiple sites programmed in the scanner, how do I find those sites in order to lock or unlock sites.
 

mikev

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Thanks will try that setting. Also, if I have multiple sites programmed in the scanner, how do I find those sites in order to lock or unlock sites.
I don't know that there's a way to enable/disable sites on the scanner itself. However, I believe you can do it in the EZ-Scan software when you're on the Trunked Systems tab, looking at the list of sites that are set up for a system.
 

mikev

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I am using PSR Edit and dont see an adjustment for that. I have a PSR600. What software do I use to be able to adjust this setting? FYI You are the first that has made an attempt to help with my problem and Thanks. I still dont know where to go from here. I would need some PSR600 instructions. This is supposed to work, but it is not for me. !!
Well, since this thread is about the PSR-800, which I have and know about, I'm not going to be much help with a PSR-600. I have a PSR-500, which I believe is the handheld version of the PSR-600, but I've never had to look for this setting on it.

Brownlab's suggestion about a short stubby antenna may also help... being in Fairfax, near where the transmitter for the system is located, could be overloading (aka de-sensitizing) the receiver in your scanner. You might also see if there's an attenuation setting in the scanner and try turning that on (there should be; both my 500 and 800 have them). I've not had any problems receiving either of the Fairfax systems on my 500 or my 800 with just regular antennas, but I'm usually listening to them from Chantilly, on the western edge of the county.
 

mike_s104

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Well, since this thread is about the PSR-800, which I have and know about, I'm not going to be much help with a PSR-600. I have a PSR-500, which I believe is the handheld version of the PSR-600, but I've never had to look for this setting on it.

Brownlab's suggestion about a short stubby antenna may also help... being in Fairfax, near where the transmitter for the system is located, could be overloading (aka de-sensitizing) the receiver in your scanner. You might also see if there's an attenuation setting in the scanner and try turning that on (there should be; both my 500 and 800 have them). I've not had any problems receiving either of the Fairfax systems on my 500 or my 800 with just regular antennas, but I'm usually listening to them from Chantilly, on the western edge of the county.
If you want to try something before buying another antenna, just use a paperclip as as test. Unfold it a little and place it in the center of the BNC connector.
 
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