Determine DMR channel order

[rbuxton]

Is there a method to determine the channel order of a DMR trunked system using DSD+ FL?

 

[slicerwizard]

Sure - match the call grants on the control/rest channel with activity on the voice channels.

 

[rbuxton]

Sure - match the call grants on the control/rest channel with activity on the voice channels.

Would you run a separate instance of FMP24 without the -rv flag and sit on a particular frequency listening for activity as the channel grants occur on the -rc flagged DSD+ ?

 

[garys]

I have done exactly this. I run one SDR dongle using FMP24 feeding DSD_CC. Once I see a channel grant, I scroll through the band (in my case 900Mhz) looking for a voice channel to pop up with the same network and site ID.

I listen on to see if the TG IDs of the two match to confirm that I've have the right frequency.

Then, I update DSD.frequencies and run DSD with the -rv flag for a double confirmation.

It can be very time consuming. In some cases I've spent over an hour searching before I found a match.

It helps if you know the location of the transmitter site and can get close by.

Would you run a separate instance of FMP24 without the -rv flag and sit on a particular frequency listening for activity as the channel grants occur on the -rc flagged DSD+ ?

 

[mtindor]

If it were me, I'd program all of the frequencies for a site in as conventional frequencies in a scanner (either as DMR or as analog). I'd then sit on the control channel / rest channel with DSDPlus. When it showed voice calls and your scanner stopped on a frequency and played audio, I'd consider that a match to consider. I'd flag the LCN reported by DSDPlus for the frequency you heard on your scanner.

I'd repeat that ad nauseum until I figured it out. And I'd double/triple check each one.

Alternatively, you have scanners that could do DMR (if you paid for the upgrade), and I'd simply use LCN Finder on those to find the LCN order.

Mike

 

[rbuxton]

I have done exactly this. I run one SDR dongle using FMP24 feeding DSD_CC. Once I see a channel grant, I scroll through the band (in my case 900Mhz) looking for a voice channel to pop up with the same network and site ID.

I listen on to see if the TG IDs of the two match to confirm that I've have the right frequency.

Then, I update DSD.frequencies and run DSD with the -rv flag for a double confirmation.

It can be very time consuming. In some cases I've spent over an hour searching before I found a match.

It helps if you know the location of the transmitter site and can get close by.

Thanks. I will give this a try.

 

[rbuxton]

If it were me, I'd program all of the frequencies for a site in as conventional frequencies in a scanner (either as DMR or as analog). I'd then sit on the control channel / rest channel with DSDPlus. When it showed voice calls and your scanner stopped on a frequency and played audio, I'd consider that a match to consider. I'd flag the LCN reported by DSDPlus for the frequency you heard on your scanner.

I'd repeat that ad nauseum until I figured it out. And I'd double/triple check each one.

Alternatively, you have scanners that could do DMR (if you paid for the upgrade), and I'd simply use LCN Finder on those to find the LCN order.

Mike

Thanks. I'll give this a try too.

 

[dave3825]

I run the cc in fmp24 and dsdplus. Then all the voice freqs I stick in the sdr# scanner plugin. When a match is made, that voice channel gets locked out. And so on down the list. Yes, can take a while especially on a slow system..

 

[slicerwizard]

Would you run a separate instance of FMP24 without the -rv flag and sit on a particular frequency listening for activity as the channel grants occur on the -rc flagged DSD+ ?

If the system was reasonably active, I would press Esc in VC FMP24 to take it out of voice following mode and use it to monitor either specific frequencies or a chunk of spectrum. I'd also enable audible voice call alerts in CC DSD+.

If there was very little voice traffic, I'd use FMP24's spectrum survey mode to watch all relevant chunks of spectrum and then match timestamped call data in the CC DSD+ event log with what Survey.exe displays. That can be left running unattended for hours or days.

 

[rbuxton]

If the system was reasonably active, I would press Esc in VC FMP24 to take it out of voice following mode and use it to monitor either specific frequencies or a chunk of spectrum. I'd also enable audible voice call alerts in CC DSD+.

If there was very little voice traffic, I'd use FMP24's spectrum survey mode to watch all relevant chunks of spectrum and then match timestamped call data in the CC DSD+ event log with what Survey.exe displays. That can be left running unattended for hours or days.

Thanks. I'll give it a try.

 

[rbuxton]

When following a trunked system when would I see a TX Freq in the VC channel activity window?

 

[slicerwizard]

I don't think it ever displays slot or frequency information while following voice calls.

 

[rbuxton]

I don't think it ever displays slot or frequency information while following voice calls.

It does. After my previous post I used my RTL-SDR dongle for the CC source instead of my RSPduo and it displayed freq and slot.