BCD396XT help setting up simulcast P25 system

[joeynshelby]

O.K. I need some help here. I am trying to set this system up in my scanner:
Scanner Frequencies: Palmetto (Project 25) Trunking System, Charleston, South Carolina

I First set it up as P25 Standard Trunk and put in the control channels and the scanner picked up no activity on the system whatsoever and I was well in range. So I changed it to one-frequency trunk. The scanner tracked the system somewhat. It would pickup the control channel (I had two, or three bars) and jump to the voice channel display the talkgroup ID's and sit on that ID for a few seconds as if it was recieving. The display would jump back and forth between LNK and DAT - LNK and DAT but no voice at all. Like I said before I was recieving two to three bars of signal. So...in direct entry I put in the control channel and hit hold. I was intermintently recieving the control channel noise. There were breaks in it and long periods of silence. Any ideas what I am doing wrong?

The scanner works well on this system which is analog and digital.
Scanner Frequencies: Palmetto 800 Trunking System, Various, Multi-State

It decodes the digital on this system like a champ w/no problems at all. So I have pretty much ruled out that the scanner has a defect as far as digital decode goes. So I am assuming I most be programming something wrong on the P25 system. Anybody got any ideas? Upman?

 

[W6KRU]

It sounds like the P25 system is a little out of your range. There shouldn't be any breaks in the control channel "noise".

 

[joeynshelby]

It sounds like the P25 system is a little out of your range. There shouldn't be any breaks in the control channel "noise".

DDan:
The strange thing is I can pickup analog systems in Charleston, SC located all around where this P25 system is, pretty clear. If I can recieve those I don't understand why I can't recieve the P25? Maybe digital requires a little bit better signal to properly decode that analog does?

 

[OriginalJimbo]

Hey Joey-
Not hijacking your thread but I am having nearly the same challenges with York County's P25 Simulcast (9 sites) as well. Scanner Frequencies: York County Public Safety Trunking System, York County, South Carolina

Programmed as:
P25 Single Freq Trunk - 868.7750
P25 LP On
CC Disabled

Only difference is that I have 5 solid bars and have the same symptoms sitting next to the tower on 77S. I can't imagine this to be a signal issue but then again I am a newbie. I would love to discover any 396XT radio settings that improve the listening. Doing the HOLD on Control Channel results in solid 5 bars throughout. Occassional CC noise but long periods of silence as well. I have the same disruptions. Could this be due to the Simulcast issues?

While scanning, I see similar symptoms but I do hear intermittent voice. Display jumps from DAT to LNK and back. Audio is solid, then choppy, then returns to solid. Almost as if I am missing every 3rd word. I see the no voice issue similar to yours on E talkgroups but that is to be expected. The TGs you are locking on aren't encrypted right?

I haven't had much luck with the Simulcast thing. Luckily the smart folks on this forum have alerted me to the threads with similar issues with P25 simulcast systems. Ultimately seems to point to "confusion" of signals from 2 or more towers. There is a really good wiki post at Simulcast digital distortion - The RadioReference Wiki if you haven't seen it.

How far are you located from your tower? Are you closer to one site than another?

Best solution to date:
1) Directional Ant

Sorry I don't have an answer but will certainly keep trying.

-Jim

 

[SCOTTER]

My system in Mishawaka IN. has no bars on the cc channels I pick it up on a voice channel I dont know why. Try a cc search and see if you get a hit on one of them if you do press hold on that channel.All of the system runs off a voice channel and I dont know why I am 3 miles from the city its next to South Bend in St Joe county. The thing that ticks me off is the err rates are higher than the 396t I have the xt now does anyone know why its like that?

 

[UPMan]

Both of the systems mentioned above should be programmed as P25 standard, not P25 single frequency for proper tracking.

 

[w8jjr]

A couple of things to try and report back to us.

Make sure you do not have Weather Priority or Priority Scan turned on.

You say its a simulcast system. You could be between two towers that are competing signals.

Try turning on Attenuator - You can set the scanner's attenuator to reduce the input strength of strong signals by about 20 dB and see if it improves reception.

try a antenna cut to band you are receiving

 

[joeynshelby]

Hey Joey-
Not hijacking your thread but I am having nearly the same challenges with York County's P25 Simulcast (9 sites) as well. Scanner Frequencies: York County Public Safety Trunking System, York County, South Carolina

Programmed as:
P25 Single Freq Trunk - 868.7750
P25 LP On
CC Disabled

Only difference is that I have 5 solid bars and have the same symptoms sitting next to the tower on 77S. I can't imagine this to be a signal issue but then again I am a newbie. I would love to discover any 396XT radio settings that improve the listening. Doing the HOLD on Control Channel results in solid 5 bars throughout. Occassional CC noise but long periods of silence as well. I have the same disruptions. Could this be due to the Simulcast issues?

While scanning, I see similar symptoms but I do hear intermittent voice. Display jumps from DAT to LNK and back. Audio is solid, then choppy, then returns to solid. Almost as if I am missing every 3rd word. I see the no voice issue similar to yours on E talkgroups but that is to be expected. The TGs you are locking on aren't encrypted right?

I haven't had much luck with the Simulcast thing. Luckily the smart folks on this forum have alerted me to the threads with similar issues with P25 simulcast systems. Ultimately seems to point to "confusion" of signals from 2 or more towers. There is a really good wiki post at Simulcast digital distortion - The RadioReference Wiki if you haven't seen it.

How far are you located from your tower? Are you closer to one site than another?

Best solution to date:
1) Directional Ant

Sorry I don't have an answer but will certainly keep trying.

-Jim

Hey thanks for your reply! What you are describing is almost exactly what I am experiencing. No, the talkgroups I am picking up are not encrypted so I should be hearing voice but I get absolutely nothing I definately believe it almost has to be due to the simulcast. I mean you are sitting right next to the tower there is no way it is a signal issue. Mine decodes digital fine on single site towers. Uniden needs to put some serious thought into working on some firmware to improve decode on P25 multi-site systems because the 396XT does a horrible job!!!!!! More and more of the simulcast P25 systems are coming on-line in the clear and we should be able to monitor them if we want to . That is my challenge to Upman! As a matter of fact I am going to start a new thread and give him that challenge! BTW I had read all the information here in ref to digital distortion issues and attempted all solutions provided with no success. So the scanner maufactures need to step up to the plate .I paid $600 for a digital radio and I want it to the decode the digital I need it. It never said on the box, in any advertisments or in the
manual that the 396XT would have a hard time decoded P25 simulcast sties! I think Uniden needs to start taking a serious look at these issues. And come up with some firmware to make it better!!!!

 

[SCOTTER]

UPMan do you or anybody know why my P25 standard system runs off a voice channel and not a cc? Its got 3 cc s 2 red one blue its not a simulcast system and no bars on all 3 cc s.On my 396t I put all channels in and set it to man 7 and it was clear all the time with err rates 0 to 6. Then I sold it and got the XT to clear up the motorboating on SAFE-T and it did works great but when I tried to set up P25 system I had the same problem he has untill I did a cc search and picked it up on a voice channel # 859.4375 but it has err rates of 8 to 23. I tried putting all channels in order like with the 396t that didnt work then I put them in order and made each one a site that didnt work. What am I doing wrong? The system is Mishawaka public works in Mishawaka IN. St. Joe county. Thanks

 

[scanchs]

@ joeynshelby... Where are you located? I monitor primarily from the N. Charleston, Ladson and Summerville areas, and I'm not seeing the problems you are experiencing. As w8jjr suggested, you may be right in between two towers with similar enough signal levels that that the scanner is having trouble separating them. OriginalJimbo's suggestion of a directional antenna could help if that is the situation. You might also try monitoring while mobile to see if the problem goes away as you move closer to one tower over another. With some additional data, we should be able to figure this out...

ScanCHS

 

[OriginalJimbo]

You are correct UPMan. I misrepresented there. I have the system programmed as "P25 Standard". What I meant to say was that I have the site set to CC Only and have my 4 CCs listed. My bad.

Both of the systems mentioned above should be programmed as P25 standard, not P25 single frequency for proper tracking.

 

[rdale]

UPMan do you or anybody know why my P25 standard system runs off a voice channel and not a cc?

That's impossible... Might be better to post in the Indiana forum.

 

[UPMan]

Hmmm. If you set to P25 Standard, the scanner has no option for "CC Only." (But maybe some of the software packages show such an option...if they do those settings are not actually used in the scanner.) For P25 systems, you always only ever need to enter the control channels.

If you are sitting right next to the tower, then too much signal could be the issue (at least at that location). Try turning on attenuation.

 

[OriginalJimbo]

Thanks UPMan. You are correct again I am using FreeScan so the option to select CC Only is there but I don't see it in the radio when on P25. I set ATT and I see some improvements but still choppy audio around the tower. My station location is a probably a perfect storm for the simulcast issue as it is exactly in the middle of two ant sites. I see the same choppiness as I do near one of the towers.

I am imagining that this could "simply" be a system that is not in standard spec rather than a scanner issue.

 

[rdale]

It's not a problem with the system or the scanner, it's just a fact of life.

 

[UPMan]

It could also be related (as others have mentioned) to multipath* and other interference / reception factors (i.e. not a decode problem, but a reception problem). Multipath would ideally be handled using a diversity antenna scheme, but that isn't practical for a multiband receiver like a scanner. Some other ideas and explanations might be gleaned from TV Antenna Fixes (which is written for HDTV, but would apply to public safety, as well).

* I know that the issue technically is not Multipath...or at least not traditional multipath caused by the signal from a single source taking multiple paths to the receiver. What else to call it, though? Multisource interference?

 

[joeynshelby]

@ joeynshelby... Where are you located? I monitor primarily from the N. Charleston, Ladson and Summerville areas, and I'm not seeing the problems you are experiencing. As w8jjr suggested, you may be right in between two towers with similar enough signal levels that that the scanner is having trouble separating them. OriginalJimbo's suggestion of a directional antenna could help if that is the situation. You might also try monitoring while mobile to see if the problem goes away as you move closer to one tower over another. With some additional data, we should be able to figure this out...

ScanCHS

I am in the Moncks Corner area. The scanner show two bars as far as signal strength goes. However, I have been as close as Goose Creek and digital decode still has been horrible!

 

[joeynshelby]

@ joeynshelby... Where are you located? I monitor primarily from the N. Charleston, Ladson and Summerville areas, and I'm not seeing the problems you are experiencing. As w8jjr suggested, you may be right in between two towers with similar enough signal levels that that the scanner is having trouble separating them. OriginalJimbo's suggestion of a directional antenna could help if that is the situation. You might also try monitoring while mobile to see if the problem goes away as you move closer to one tower over another. With some additional data, we should be able to figure this out...

ScanCHS

I am in the Moncks Corner area. The scanner show two bars as far as signal strength goes. However, I have been as close as Goose Creek and digital decode still has been horrible!

 

[scanchs]

Double Post

 

[scanchs]

I am in the Moncks Corner area. The scanner show two bars as far as signal strength goes. However, I have been as close as Goose Creek and digital decode still has been horrible!

OK, being in the Moncks Corner area adds another piece to the puzzle. The Palmetto Project 25 system does not have as big a footprint as the Palmetto 800 system in the tri-county area. The P25 system currently targets mainly Charleston County. There is a P25 tower in downtown Summerville to cover the northern part of Charleston County. I don't know of any similar P25 towers in Berkeley County.

As N_Jay suggested in your other thread, you may very well be outside of the design area of the P25 system up in Moncks Corner. A high gain, directional antenna pointed at Summerville or McClellanville may work if there's enough signal to capture up there. The simulcast system towers are designed to cover a fairly limited area, and the signal drops off sharply outside of the design area.