LTR systems - help

[n8yid]

Ok, not sure if this is the correct place to Post this; but, here goes...

There are numerous, various LTR systems that have been "mapped" out over the years in my area of Southwest Ohio, and are currently still listed in the Radioreference DB. These systems were fairly active back-in-the-day; but, now that DMR has taken over, there are a lot of unused system entries in the DB.

I have a dedicated radio (Pro-106), programmed with nothing other than these local LTR systems. Running this radio daily, I hear virtually nothing, other than the "hash" of digital users on some of the frequencies that were licensed for the older LTR systems.

My question I want to put out there is this...

What is the definitive method of verifying that these "systems" are no longer in use?

I have monitored/been monitoring with a radio, as I just mentioned; however, now I'm looking for the next step(s) in verifying that a system is truly gone/dead/defunct... I guess, in other words, what would be needed to verify before submitting a "deprecated system" to the DB administrator?

Looking for any help with this,

Dave T.

 

[BC_Scan]

Here where I live the same thing happened , one by one freqs where stripped away, until some became two channel or more, I would remove the offending freq one at a time , we still have a few rental systems in use.
The tell might be wether you hear the open carrier pulse or see the repeater ID which usually ended in eg ;1-01-253
as for definitive , I have no clue, short of calling the service provider and ask them if they still use LTR.
I think most listeners have probably moved on unless they want to listen to Jims Garden service or whatever the case may be.

 

[mtindor]

Ok, not sure if this is the correct place to Post this; but, here goes...

There are numerous, various LTR systems that have been "mapped" out over the years in my area of Southwest Ohio, and are currently still listed in the Radioreference DB. These systems were fairly active back-in-the-day; but, now that DMR has taken over, there are a lot of unused system entries in the DB.

I have a dedicated radio (Pro-106), programmed with nothing other than these local LTR systems. Running this radio daily, I hear virtually nothing, other than the "hash" of digital users on some of the frequencies that were licensed for the older LTR systems.

My question I want to put out there is this...

What is the definitive method of verifying that these "systems" are no longer in use?

I have monitored/been monitoring with a radio, as I just mentioned; however, now I'm looking for the next step(s) in verifying that a system is truly gone/dead/defunct... I guess, in other words, what would be needed to verify before submitting a "deprecated system" to the DB administrator?

Looking for any help with this,

Dave T.

A computer, a dongle, and LTR Analyzer ( Index of /~phoenix/wap/LTR ). Run it from a windows command line. Unless you are using a tapped scanner, you will probably need to use something like SDRSharp + Virtual Audio Cable / VB Cable, then run LTR-Analyzer and select the proper virtual cable.

Then you park on each frequency and wait. Wait til you see low-speed data providing the LTR information. It's been so long since I listened to LTR systems. If a voice comm comes up and you start seeing LTR Analyzer spit out data, that data will tell you a lot of about how big or how small the LTR system is and will tell you the current LCn and show you the talkgroup. Some channels may be active on a system but only used for overload. But usually (if I recall correctly), even if the system is idle, active frequencies usually emit a beacon (probably a better word for it). If you were listening by ear you would essentially think somebody was keying up in periodic short bursts -- but those bursts would contain some info about the system.

When I was last LTR-monitoring, which was somewhere between 2015 and 2019, the active freqs on the LTR system here would beacon and give you some information like what LCNs are active (and you have to hope that the LCN to Freq mapping in the DB is correct), what channels are idle, and a couple other things.

Anyway, I would recommend this. And if you do this and find a system that still is online, and you actually monitor the audio by ear, you'll quickly learn how to easily pick up (by ear) if particular frequency is an LTR freq based upon the short bursts and what it sounds like when the low-speed data is being sent.

Mike

 

[sonm10]

LTR systems will have a short data burst every(30 sec?). It sounds like a short bit of static. If no data bursts are heard, then the system is probably off the air. Simply make a submission to the system in rr and ask to depreciate. Explain that you scanned all frequencies and heard nothing.

If you are hearing DMR on those frequencies instead, which is often the case (and most likely Cap+) submit a separate submission for DMR. (Cap+ has data bursts every few seconds also, but sounds digital.)

 

[MtnBiker2005]

LTRlogger works great with few uniden scanners.

LTRLogger - LTR trunked radio system data decoder

A Windows commandline application that outputs LTR data from Uniden scanners in a readily human-usable format.

www.ericcarlson.net

 

[n8yid]

Gents,
Thanks for the input and links!!
When I get a spare moment or two from work; I'll give these a shot and see what I can come up with...

Again... Thanks to all,

Dave T.

 

[slicerwizard]

Some channels may be active on a system but only used for overload. But usually (if I recall correctly), even if the system is idle, active frequencies usually emit a beacon (probably a better word for it).

I would think that only home channels would have to broadcast idle bursts. No subscriber radios would be sitting on non- home channels, listening for bursts. I'd expect non- home channels to only key up when calls trunk-off their already in-use home channels.

Although it's possible that all repeaters may be keyed up periodically just to verify that they're still working. Might be a controller setting for that. Generally, repeaters can report a failure back to the controller and controllers can often raise an alarm / send a page to the system operator.

 

[mtindor]

LTR systems will have a short data burst every(30 sec?). It sounds like a short bit of static. If no data bursts are heard, then the system is probably off the air. Simply make a submission to the system in rr and ask to depreciate. Explain that you scanned all frequencies and heard nothing.

If you are hearing DMR on those frequencies instead, which is often the case (and most likely Cap+) submit a separate submission for DMR. (Cap+ has data bursts every few seconds also, but sounds digital.)

You would only submit something about hearing DMR on the freqs if you actually have the information about the DMR system that has replaced it. One can't just assume that because they hear DMR on something that once was LTR, that it is indeed a replacement system (versus signals coming from another county or site location or something). And we would never add anything to the database just because the frequencies our on a license.

If a LTR system is found to be no longer online, then a submission should be made to that LTR system. If it has been determined that a DMR / NXDN / whatever system has replaced it and relevant/useful network/system, site id, etc information is available, then one would make a new submission for a brand new system.

I would think that only home channels would have to broadcast idle bursts. No subscriber radios would be sitting on non- home channels, listening for bursts. I'd expect non- home channels to only key up when calls trunk-off their already in-use home channels.

Although it's possible that all repeaters may be keyed up periodically just to verify that they're still working. Might be a controller setting for that. Generally, repeaters can report a failure back to the controller and controllers can often raise an alarm / send a page to the system operator.

Rgr that. I forgot most of what I thought I knew about LTR. But I do recall that on systems around me, at the time, if a I landed on a home channel and it spewed info about all of the active / free LCNs on the system, if I then went back through and parked on each of the other freqs I would get a burst with some low speed data confirming that the frequency I tuned to was one of the actual LCNs.

I'm still foggy from COVID, and It's just been too long. I just figured that at least I could throw out my preferred software for determining LTR system characteristics, and that was LTR Analyzer

Mike

 

[slicerwizard]

COVID? Yikes! I hope you're back to 100% soon.

 

[mtindor]

COVID? Yikes! I hope you're back to 100% soon.

Thanks, I'm on the mend and am probably at 90-95%!

Mike

 

[MtnBiker2005]

This LTR system changed to NXDN system using the same RRDB page.

White Cloud Communications (NXDN) Trunking System, Various, Idaho

White Cloud Communications (NXDN) Trunking System Profile

www.radioreference.com

If a LTR system is found to be no longer online, then a submission should be made to that LTR system. If it has been determined that a DMR / NXDN / whatever system has replaced it and relevant/useful network/system, site id, etc information is available, then one would make a new submission for a brand new system.
Mike

 

[mtindor]

This LTR system changed to NXDN system using the same page.

White Cloud Communications (NXDN) Trunking System, Various, Idaho

White Cloud Communications (NXDN) Trunking System Profile

www.radioreference.com

I'm really sorry to see that. That just isn't how we are supposed to be doing it. Just glad that system isn't near me.

 

[sonm10]

You would only submit something about hearing DMR on the freqs if you actually have the information about the DMR system that has replaced it. One can't just assume that because they hear DMR on something that once was LTR, that it is indeed a replacement system (versus signals coming from another county or site location or something). And we would never add anything to the database just because the frequencies our on a license.

If a LTR system is found to be no longer online, then a submission should be made to that LTR system. If it has been determined that a DMR / NXDN / whatever system has replaced it and relevant/useful network/system, site id, etc information is available, then one would make a new submission for a brand new system.

Agreed