SDRTrunk DMR help

[mtindor]

I will tell you that since you are using the "free" version of DSDPlus, it is very likely that this ancient piece of software does not decode everything about a TIII system that DSDPlus Fastlane would. It may not be able to properly/fully identify all TIII-related stuff in the datastream. The Free version is probably 8 years old by now, long before TIII systems were popular.

I know that ultimately it sounds like you want to get SDRTrunk working. So maybe you don't want to spring for (pay for) the DSDPlus Fast Lane version of DSDPLus. But if you enjoy / planning on using DSDPlus to sleuth out modern trunked systems, I'd highly recommend you get the paid version. The version you are using just isn't going to accurately depict everyything about a TIII system.

 

[williamGB]

I will tell you that since you are using the "free" version of DSDPlus, it is very likely that this ancient piece of software does not decode everything about a TIII system that DSDPlus Fastlane would. It may not be able to properly/fully identify all TIII-related stuff in the datastream. The Free version is probably 8 years old by now, long before TIII systems were popular.

I know that ultimately it sounds like you want to get SDRTrunk working. So maybe you don't want to spring for (pay for) the DSDPlus Fast Lane version of DSDPLus. But if you enjoy / planning on using DSDPlus to sleuth out modern trunked systems, I'd highly recommend you get the paid version. The version you are using just isn't going to accurately depict everyything about a TIII system.

Ahh I see. I'm just wanting to use SDRTrunk to monitor the agency for fun, not looking to spend anymore, however it does sound tempting.

I also did a quick scan of all the frequencies registered to the agency I want to monitor, and the only channel i found which is constantly transmitting is that screen shot I sent before.
I'll sit on this frequency for today and see what pops up (hopefully something)

Thanks so much for your help, I would not of been able to figure this all out on my own haha!

 

[mtindor]

Ahh I see. I'm just wanting to use SDRTrunk to monitor the agency for fun, not looking to spend anymore, however it does sound tempting.

I also did a quick scan of all the frequencies registered to the agency I want to monitor, and the only channel i found which is constantly transmitting is that screen shot I sent before.
I'll sit on this frequency for today and see what pops up (hopefully something)

Thanks so much for your help, I would not of been able to figure this all out on my own haha!

It is sometimes very difficult to figure out TIII systems, especially if they do not adhere to a particular known bandplan when it comes to associating frequencies with LCNs.

Yes, just park on the 24/7 channel. Eventually, Group Calls should show up on it like they did the other frequency -- in the Event Window. But you will likely not HEAR those calls when parked on that control channel. What you would see, in the Channel Activity window, is references to particular channels/LSNs that the group calls are occurring on. How many different ones show up over the course of the day will likely determine how many (at the very least) frequencies are part of that particular site.

Mike

 

[williamGB]

It is sometimes very difficult to figure out TIII systems, especially if they do not adhere to a particular known bandplan when it comes to associating frequencies with LCNs.

Yes, just park on the 24/7 channel. Eventually, Group Calls should show up on it like they did the other frequency -- in the Event Window. But you will likely not HEAR those calls when parked on that control channel. What you would see, in the Channel Activity window, is references to particular channels/LSNs that the group calls are occurring on. How many different ones show up over the course of the day will likely determine how many (at the very least) frequencies are part of that particular site.

Mike

I'm at home all day today anyway, so I'll leave it on all day.

When calls start to show up, do i write down the LSNs? Then do i change the frequency in SDRTrunk to the 24/7 channel i found or do i keep it as is and just add the LSNs?

 

[mtindor]

I'm at home all day today anyway, so I'll leave it on all day.

When calls start to show up, do i write down the LSNs? Then do i change the frequency in SDRTrunk to the 24/7 channel i found or do i keep it as is and just add the LSNs?

Yeah right down the LSNs. Take screenshots throughout the day (if more LSNs show up). You want to be able to document it. And of course, if you are going to enlist help here screenshots are nice.

For any DMR Trunked system, SDRTrunk must have ALL known frequencies in use at that particular site, and must know the LCNs (which are converted from DSDPlus LSNs). You can't trunk a TIII system unless you know all of the frequencies and their associated LCNs.

LCN = Logical Channel number -- it's what is really tied to the frequency
LSN = DSDPlus nomenclature for each timeslot (2 of them) tied to the frequency

So the LSNs must be converted to LCNs.

Of course, just getting information on LCNs / LSNs is one thing. Tying them to particular frequencies is another, more painstaking thing - especially if they aren't assigned based upon a known bandplan.

Mike

 

[williamGB]

Yeah right down the LSNs. Take screenshots throughout the day (if more LSNs show up). You want to be able to document it. And of course, if you are going to enlist help here screenshots are nice.

For any DMR Trunked system, SDRTrunk must have ALL known frequencies in use at that particular site, and must know the LCNs (which are converted from DSDPlus LSNs). You can't trunk a TIII system unless you know all of the frequencies and their associated LCNs.

LCN = Logical Channel number -- it's what is really tied to the frequency
LSN = DSDPlus nomenclature for each timeslot (2 of them) tied to the frequency

So the LSNs must be converted to LCNs.

Of course, just getting information on LCNs / LSNs is one thing. Tying them to particular frequencies is another, more painstaking thing - especially if they aren't assigned based upon a known bandplan.

Mike

I checked and the agency has 56 frequencies in use.. so SDRTrunk will need to know each one?
Then i gotta figure out which LSNs are tied to each frequency?

Oh boy, I was not expecting it to be this complicated haha

 

[mtindor]

I checked and the agency has 56 frequencies in use.. so SDRTrunk will need to know each one?
Then i gotta figure out which LSNs are tied to each frequency?

Oh boy, I was not expecting it to be this complicated haha

I'm positive they don't have 56 frequencies in use on that particular site alone. Maybe across their whole system.

You need to:
1. Identify all freqs in use at a specific site
2. Gather the LSNs / CHs in use on each site (by monitoring the control channel)
3. Figure out what LCNs/Chs (and eventually LCNs) are associated with each of those frequencies
4. Program those frequencies all into SDRTrunk for that particular site
5. assign proper LCNs to each of those frequencies in the configuration

And, on top of that, as I mentioned before, that version of DSDPlus may or may not be able to get everything you want simply because that version was not written with TIII in mind -- Connect Plus / Capacity Plus were the popular DMR flavors back then.

Mike

 

[williamGB]

I'm positive they don't have 56 frequencies in use on that particular site alone. Maybe across their whole system.

You need to:
1. Identify all freqs in use at a specific site
2. Gather the LSNs / CHs in use on each site (by monitoring the control channel)
3. Figure out what LCNs/Chs (and eventually LCNs) are associated with each of those frequencies
4. Program those frequencies all into SDRTrunk for that particular site
5. assign proper LCNs to each of those frequencies in the configuration

And, on top of that, as I mentioned before, that version of DSDPlus may or may not be able to get everything you want simply because that version was not written with TIII in mind -- Connect Plus / Capacity Plus were the popular DMR flavors back then.

Mike

Ohh okay, I see.
Forgive me for asking but, why does SDRTrunk need the LCNs and all frequencies at the site? Is that for the streaming to broadcastify and sorting out which talk groups should be muted or not? As I am able to hear all the voice traffic using SDRTrunk anyway.

 

[mtindor]

Ohh okay, I see.
Forgive me for asking but, why does SDRTrunk need the LCNs and all frequencies at the site? Is that for the streaming to broadcastify and sorting out which talk groups should be muted or not? As I am able to hear all the voice traffic using SDRTrunk anyway.

Unlike something like the typical P25 system, which broadcasts a bandplan over the control channel that allows for frequencies to be figured out from channel IDs, DMR systems [typically] do not do that. The control channel says "there is a group call occuring on LCN 5". If you don't have a proper frequency <--> LCN configuration configured in SDRTrunk or DSDPlus, then when the control channel says switch to LCN 5 to listen to the group call, SDRTrunk and DSDPlus have no idea where to switch to.

You likely aren't able to hear ALL of the voice traffic. You can hear voice traffic. You can treat a DMR trunked voice channel as a conventional channel if you want. But maybe, when the site gets busy, there are 1,2,3, or more additional frequencies in use to support the load. You don't / won't have them programmed in and thus you won't be guaranteed to hear ALL the traffic.

Do what you want.

 

[williamGB]

Unlike something like the typical P25 system, which broadcasts a bandplan over the control channel that allows for frequencies to be figured out from channel IDs, DMR systems [typically] do not do that. The control channel says "there is a group call occuring on LCN 5". If you don't have a proper frequency <--> LCN configuration configured in SDRTrunk or DSDPlus, then when the control channel says switch to LCN 5 to listen to the group call, SDRTrunk and DSDPlus have no idea where to switch to.

You likely aren't able to hear ALL of the voice traffic. You can hear voice traffic. You can treat a DMR trunked voice channel as a conventional channel if you want. But maybe, when the site gets busy, there are 1,2,3, or more additional frequencies in use to support the load. You don't / won't have them programmed in and thus you won't be guaranteed to hear ALL the traffic.

Do what you want.

Ahh I understand now. Thanks

For now, I'll set SDRTrunk as conventional DMR whilst I figure out all the LCNs and frequencies.
I believe I have programmed it correctly as conventional but its not streaming..