Fairfax County P-25 distortion

[RS8]

I am monitoring Fairfax County FD.The old system is clear but the new P-25 system is distorted when there is tranmissions.Is there something I can do about this issue? I am sure they will switch over completely to P-25 and I would like better reception.
Any input appreciated.

 

[steve888]

When Did They Switch Over?

I haven't heard a single fire/EMS call in two days on any of the dispatch or response channels (on a PSR-800). Do you know how to program the new frequencies? Sorry I don't have an answer to your distortion issue!

 

[RS8]

Fairfax FD

Steve,
I had the same issue and I am in Loudoun County so it isn't distance.
Today (Tuesday) I picked up the old system and the P-25 system.I can't figure out
what was going on. Of course the old system is very clear. They had a worker in Reston last night which I would have heard. and taken in on the second. But you can't catch them all.
Let me know if you figure out what is going on.

 

[steve888]

Steve,
I had the same issue and I am in Loudoun County so it isn't distance.
Today (Tuesday) I picked up the old system and the P-25 system.I can't figure out
what was going on. Of course the old system is very clear. They had a worker in Reston last night which I would have heard. and taken in on the second. But you can't catch them all.
Let me know if you figure out what is going on.

Thanks for the info. There must have been some kind of switch over this week because I haven't heard a single Fire/EMS call in 48 hours. FCPD did something like this about a month ago but I was still able to pick up everything even though they moved over to something new (not really sure what it was they did though).

Here's a thread about it: http://forums.radioreference.com/vi...40451-fairfax-county-fire-police-changes.html

I'll try to find out what's going on with the Fire/EMS channels and will post back here. Don't worry, there are some very sharp people on these boards and someone will be able to fill us in if we can't figure it out!

 

[j2brown]

The PSR500 providing the FCFRD feed is programmed with the P25 information from the RR database (as of a few weeks ago, anyway). It's still got the old system programmed as well, so I can't tell which one it's receiving unless I'm looking at it. It experienced the same issues until this morning when I replaced the antenna in my attic with a rubber ducky antenna. The stream is currently carrying at least some radio traffic at the moment that sounds better that what I've been hearing. Perhaps it's an attenuation issue? Just a thought. I'll post more if I get anything more definative.

jeff
sdg

 

[fyrman7263]

Same issue

I have been having the same issue. Sometimes it is crystal clear otheres not so much. It was working great on the Reston 2 alarm but since then breaking up alot. Any help ??

 

[RS8]

Fairfax P-25

Same issue today so I switched back to the old system.It worked well for a short period.Then no traffic.Could be heat related.

 

[fyrman7263]

humm

Not sure if its heat related. They are in the process of switching over to the p25 system. 4a is just distorted alot if the time. Its like my 500 cant lock on the system

 

[fyrman7263]

ffx and gre500

Turned on super track option and got a 3.5 db gain antenna. Cleared up all issues

 

[j2brown]

Thanks, fyrman. I'll give that a shot when I'm at the radio next and see if it makes a difference.

 

[steve888]

I'm getting the same distortion on both the new Fire/EMS and Police P-25 frequencies using a PSR-800. Is there anything I can adjust on my scanner to improve the reception?

 

[j2brown]

I already had Super Track on, so I was unable to use that to increase the quality of the signal, and thus the FCFRD feed here at RR. I'm looking for a better location to host the radio in hopes of getting the quality of the feed restored to something worth listening to.

jeff
sdg

 

[fredva]

I'm getting the same distortion on both the new Fire/EMS and Police P-25 frequencies using a PSR-800. Is there anything I can adjust on my scanner to improve the reception?

You can try adjusting the DSP Level Adapt number slightly up or down. I've not had much success with that though trying to monitor Stafford's P25 system when mobile with my PRO-18. But some people have claimed it has helped.

 

[j2brown]

My PSR-800, which is in my car using the car frame as an antenna (far from ideal in almost any circumstances), does a better job than the PSR-500 at my house providing the RR feed. The audio is understadable and very listenable. I haven't made any changes to the default settings on my PSR-800. Not sure if that's helpful, but I'll provide it as anecdotal evidence that the brain trust at RR may be able to use in figuring out how to improve the situation.

jeff
sdg

 

[freqhopping]

I receive the new system outside at ground level (including in my truck) better than I do on the 5th floor of a building next to a window. At home, inside it's bad even though it shows 5 bars.

At least the 3 and 5 stations are still on the old system. That's what I care to listen to the most.

 

[steve888]

Thanks!

Thanks a lot for all of the suggestions. I'll see what the P25 reception is like outdoors tomorrow morning. I have my PSR-800 about two feet away from a window indoors and the reception is pretty bad. The old system is crystal clear. I hope this isn't a sign of things to come when other agencies start switching over to P25!!

 

[freqhopping]

Something has got to be screwed up with the system. When it first came online I had no problem tracking it, home or anywhere. I can't even reliably run Pro96Com on it now to see if something has changed.

 

[fredva]

If the problem is caused by P-25 simulcast distortion, your problem could be too much signal, as in strong, slightly out-of-sync signals from two or more towers coming at your receiver during the same radio transmission. One way to try to overcome the problem is to get an OK signal from the nearest tower and a relatively weak signal from any other towers. That may be why standing in a spot where you might not normally expect good radio reception could produce better results.

The most consistently clear reception I've gotten with Stafford's system was one day when I was replacing a faucet in a bathroom located in the middle of my house and I brought my scanner in there for an hour or so. I've been meaning to check the scanner there again to make sure it wasn't a fluke, but haven't gotten around to it. Even if it works well there...that's not where I'm going to keep a scanner.

I've read that the expensive two-way radios used on these systems have sophisticated software that corrects the errors caused by the simulcast. A $400 scanner does not have software that sophisticated.

Not all P25 systems have this problem. It's P25 SIMULCAST.

 

[steve888]

P25 Seems Better Outdoors

I had my PSR-800 with me today for a few hours running some errands and the reception on the P25 broadcasts was definitely much better than indoors yesterday. I would say that indoors maybe 30% of the traffic is good and 70% is garbled. However, outdoors it's about 70% good and 30% distorted...and that's with the scanner laying flat on the passenger seat with an Austin Condor antenna on it (inside the car, no antenna on the roof). Of the 30% garbled traffic, most of it seemed to be on the fire channels for some reason (maybe because a lot of those guys are using handhelds while the police are using their in-car radios for the most part)?

So, it's definitely better outdoors but it's still not as good as the old system (where a good 90% - 95% of the traffic is crystal clear).

Anyway, thanks for all the suggestions. I'll play around with the placement of the radio indoors...two feet from the window equals bad reception on anything P25 so maybe I'll stick it in a closet or something!

 

[j2brown]

The simulcast distortion fredva described is what killed the original with the Loudoun County system. The only way we're getting the great sound we are for the RR feed is because we have a location that can only see one tower. I suspect that I'll have to find a similar "one tower" location for the FCFRD feed radio as well.

jeff
sdg