There is a P25 repeater frequency in my area that I am attempting to monitor. My problem is that there is also a NXDN site with the same frequency that is in range. The scanner seems to “lock” onto that NXDN site showing signal strength and all. Is there a way to prevent this and only target the P25 repeater?
SDS100/SDS200: SDS100 “locking” onto site?
- Thread starter Vmhl0917
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If the NXDN is the stronger signal that's what you are going to hear. If the P25 is stronger then you need to set it up as a trunking site.
I have the same problem. Anaheim Stadium (what I want to hear) is a NXDN system that has one frequency the same as Anaheim convention center (DMR system). Everytime that repeater keys up I lose the stadium. It helps that I have programmed the stadium as a NXDN trunk system as it tends to block out the DMR convention center until the DMR repeater keys up.
I have the same problem. Anaheim Stadium (what I want to hear) is a NXDN system that has one frequency the same as Anaheim convention center (DMR system). Everytime that repeater keys up I lose the stadium. It helps that I have programmed the stadium as a NXDN trunk system as it tends to block out the DMR convention center until the DMR repeater keys up.
tvengr
Well Known Member
Is the P25 conventional or trunking. If conventional, set the frequency up as P25 with its NAC code. If it is a trunking site, the SDS100 can be programmed with the Site NAC. Which frequencies, systems, and agencies are you trying to monitor?
I am trying to monitor a conventional P25 repeater. Georgia Department of Public Safety, Troop E, Post 25-Grovetown. Frequency is 155.43750 with NAC code 320, which I have programmed in. Scanner keeps homing in on what I believe is the Tattnall County trunked NXDN "reidsville 1" site.
I have a roof mounted discone antenna, and am able to pick up activity from a pretty good distance away, which is great but troublesome at times.
I have a roof mounted discone antenna, and am able to pick up activity from a pretty good distance away, which is great but troublesome at times.
tvengr
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Please export your favorites list file and attach it so that I can take a look at it.
Eng74
Member
If you program the P 25’s NAC code for the site it should ignore the NXDN site then.
tvengr
Well Known Member
It is a conventional frequency. I though about entering it as P25 one frequency trunk to use Site NAC, but that requires a TGID which a conventional frequency does not have.
Actually it does have a talkgroup. Once you program in as a One Frequency Trunk, run it in ID Search mode and I'd suspect you'll see talkgroup(s).
tvengr
Well Known Member
I doubt that would work, but thanks for the suggestion. A conventional P25 frequency is not a control channel. To my knowledge there would be NAC code info, but no talkgroup data to be able to do an ID search. Have you ever tried that?
Yes, I have numerous "conventional P25 systems" set up as One Frequency Trunk, and I'm seeing talkgroups and Radio ID's.
ID:1 seems to work more times than not in my experiences.
I've seen a few different ones, so no set pattern. That's why it's important to change the default System Option from ID Scan to ID Search. You might find other "channels" they use.
You have to create a new system so the P25 One Frequency Trunk option is available in the drop down menu. Then once that's done, create a Site, and put any frequency(ies) that are in use. Write to Scanner...and you should see any talkgroups in use and radio ID's if that's in your display.
tvengr
Well Known Member
Thanks! Do you know if there is any such thing as a P25 TGID wildcard? I have had times that I had to enter a TGID to a talkgroup to avoid the dreaded Nothing to Scan. Then, other TGID's would be displayed in ID Search for any TGID other than the one programmed. The only problem is that the TGID is displayed instead of the alpha tag.
If you are seeing talk groups then they are not conventional systems.
ID Search is the equivalent of the GRE ID Wildcard.
Correct, if you see an unknown talkgroup ID, text tag it in Sentinel and Write it back to the scanner.
Much confusion here with those terms, so when I see a new "conventional P25 system" posted or find it during a custom search, I convert it to One Frequency Trunk and talkgroup ID's and radio ID's are displayed.
In "radio programming world", One Frequency Trunk doesn't exist. In Uniden's world, if you want the added option of text tagging talkgroup ID(s) or radio ID's, it's an "option" but not a necessity if you're not interested.
I have programmed DMR and NXDN systems as One Frequency Trunk and have text tagged radio and talkgroup ID's the same. This is another reason why I don't download database information as my promary source, instead I "self-program" the information and all is good in my scanner world. DMR systems transmit a "rest channel/slot" so conventional system programming isn't a good idea, or your scanner will "hang up" on a frequency. It's a good idea to learn the options that the scanner has to offer in my opinion.
Just to clarify, Yes P25 Conventional do have TG. Motorola default is TG 1.
DMR systems that transmit a "rest channel/slot" as you call it are Motorola Capacity Plus systems. That you will see is a pulse type of transmission, about every few seconds. You can have single channel Cap Plus but most of the time its 2 or more channels for trunking. But technically single channel and that needs to be entered as a DMR trunking system. If its a continuous data transmission its a Connect plus system or cap max system.
For DMR Conventional you want to program it as One Frequency Trunk so you can enter the TG info.
But if your trying to monitor a P25 conventional channel on a scanner program it as P25 Then Nac code. If you leave it as Digital Code Search it will include P25 Nac, DMR and NXDN and thus pass audio for P25 you want and the NXDN you dont want. So make it P25 with a Nac code and it will ignore the NXDN channel. However you may get interference and not get a clean decode depending on if the two channels key up at the same time and power out put and other stuff..
DMR systems that transmit a "rest channel/slot" as you call it are Motorola Capacity Plus systems. That you will see is a pulse type of transmission, about every few seconds. You can have single channel Cap Plus but most of the time its 2 or more channels for trunking. But technically single channel and that needs to be entered as a DMR trunking system. If its a continuous data transmission its a Connect plus system or cap max system.
For DMR Conventional you want to program it as One Frequency Trunk so you can enter the TG info.
But if your trying to monitor a P25 conventional channel on a scanner program it as P25 Then Nac code. If you leave it as Digital Code Search it will include P25 Nac, DMR and NXDN and thus pass audio for P25 you want and the NXDN you dont want. So make it P25 with a Nac code and it will ignore the NXDN channel. However you may get interference and not get a clean decode depending on if the two channels key up at the same time and power out put and other stuff..
tvengr
Well Known Member
I suspect that since a one frequency trunk system does not have to detect which frequency is a control channel, that it may mistake the P25 NAC code on the conventional frequency for a TGID. If that is the case, a different TGID may be generated for different NAC codes and that TGID could be used for the talkgroup. That is the only reason that I can determine to cause TGID's to be displayed by a P25 conventional frequency. It has my curiosity piqued. I am going to have to run a test on a couple of P25 conventional frequencies in my area.
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Good idea, if it works then the problem is resolved. If not..back to the drawing board.
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