PRO-18 Sound Quality

[adams_jb]

Good Evening!

I have recently purchased a PRO-18 scanner to run a local scanner feed and am having problems with the quality of the audio. The audio is very garbled; I have tried making adjustments to the settings with no change. I am monitoring the Charlotte, NC P25 system (particularly Cabarrus County Fire channels). Any thoughts or tricks for anything I can do to improve the sound quality? I currently have a full five bars of signal upon every transmission received.

Any other information that I can provide about my settings or anything else please feel free to ask.

Thanks for your continued support.

My email, jadams@bdvfd.org, may be the quickest way for me to respond (while at work they block any forum and other stuff to keep us working, lol)

Jason

 

[ranger821]

Did not check this but could the frequencies you are trying to listen to be encrypted. Just a thought. Some of my local area ones are like that.

 

[Spitfire8520]

Looking at the Charlotte / Mecklenburg County (Project 25) Trunking System on the database doesn't indicate that any of the talkgroups that is being monitored is encrypted. Based on your statement, I believe you are referring to your Cabarrus County Fire Departments feed (in case anyone wants to listen).

My thought is that you are dealing with something called Simulcast digital distortion. The link goes to our entry in the RadioReference wiki and goes into detail regarding the problem and possible solutions. The short description is that there are 5 different radio towers sending the same signal at roughly the same time that causes multipath. Multipath is a result of distance and other factors causes your Pro-18 to receive the signals at different times, therefore causing conflicting information for the scanner and making it decode the information poorly.

The quickest and easiest ways to attempt to correct the issue (if it is multipath) is to attempt to reduce the signal by attempting to use the attenuation setting in the scanner. It may seem counterproductive to try to weaken the signal when you have poor decoding, but what you are trying to do hit the point where you drown out the other signal paths so that your scanner will receive and decode the strongest of the signal. Some people have reportedly found that replacing the antenna with a metal paperclip has helped them correct the issue due to this thought. Be advised that this solution does not always work for everyone and may require the next solution.

The other and a little bit more complicated/costly way of fixing the issue is to build or purchase a directional antenna (eg. Yagi-Uda antenna) for the scanner. A directional antenna is basically what it sounds like where you can effectively point your antenna at a certain tower to ensure that you are only receiving the signal for that tower and minimize signals from other towers. If you intend on using this method, then it would be helpful to know where the sites are located. It appears that the Cabarrus Simulcast is licensed under WPGT418 (CONCORD, CITY OF). You can basically use the license information to provide a map location of where the reported towers for the Cabarrus Simulcast site are if you want to aim an antenna at it.

I hope that this input was able to provide some insight into the possible problems you are having.