SDR# TETRA Demodulator Trunk Tracking Demonstration

[thewraith2008]

Is still crash on DMO gateway mode burst . ( do you need IQ data I can make some samples if needed )

Only MS to MS or DM-REP support at the moment. I thought I put a bypass in place for other types. Guess not.

DM-GATE is a lot bigger (documentation wise) than the other two, I've not really looked into it too much.

IQ samples is the only way it will see the light of day. As I've said before, I don't thing DMO is in use here. (near me anyway)

 

[CqDx]

Hi thewraith2008, thanks for the awesome software. It's working beautifully with my SDRsharp with recorded IQ of many TETRA control channels.

One question I have is since this is a TETRA Trunk Tracker, is there ability to:
Lock TTT on a particular traffic channel, or
Lock TTT on a particular timeslot, while keeping the data window available.

The reason being is I am trying to log talkgroups of a very busy system and TTT jumps from MCCH to a timeslot with active voice traffic and I think I have little control over where TTT jumps to.

Best Regards

 

[hamradionl]

CqDx, good suggestion, as a extra function

 

[thewraith2008]

Hi thewraith2008, thanks for the awesome software. It's working beautifully with my SDRsharp with recorded IQ of many TETRA control channels.

One question I have is since this is a TETRA Trunk Tracker, is there ability to:
Lock TTT on a particular traffic channel, or
Lock TTT on a particular timeslot, while keeping the data window available.

The reason being is I am trying to log talkgroups of a very busy system and TTT jumps from MCCH to a timeslot with active voice traffic and I think I have little control over where TTT jumps to.

Best Regards

Best option is not to use TTT. That is all the standalone plug-in does.

Calls are only set-up on MCCH, TTT will only do it's thing after a call set-up is seen.
If you put SDR# on a traffic channel, TTT will put it back to MCCH, this feature can disabled with '-dm' commandline option.
The '-dm' option is for Auto setting the 'Base frequency', 'Offset' and MCCH (will switch).

Using the '-dm' option and placing on a traffic channel, TTT will do nothing (no call setups there to respond too.)

"I am trying to log talkgroups". Why can't you use the GSSI hold or lockouts? Then only those GSSI activity will be seen.

"TTT jumps from MCCH to a timeslot with active voice traffic". That's the whole point of TTT. Trunk Tracking.

 

[CqDx]

Fair point, I just wanted to take advantage of the recording off SDR sharp

 

[thewraith2008]

I've noticed while testing with the IQ samples provided by the helpful users that the SDR# option "Correct IQ" (Under the 'Radio' in the side menu) can make a difference when decoding these samples.

I'm not sure if the difference just comes down to the SDR dongles that where used to create the IQ samples and using the offline file instead of live signal.

I noticed this more so with a IQ sample of a presence beacon for a repeater.
On another sample it had a negative affect.

 

[DarkAngelT]

thewraith2008 today I verified that the tetra demodulator has some problem because it is losing communication. Sometimes it is reading the user as a group and when this happens, the audio is not released. The demodulator is losing communications!

If you can take a look. I recorded the IQ sample and will send you to see what is happening!

 

[thewraith2008]

thewraith2008 today I verified that the tetra demodulator has some problem because it is losing communication. Sometimes it is reading the user as a group and when this happens, the audio is not released. The demodulator is losing communications!

If you can take a look. I recorded the IQ sample and will send you to see what is happening!

This problem happens when you use the old call list. This is code from the original plug-in.

Try using the option "Call list - Alternative generation". It is found in the plug-in "Config > Settings"
The issue you describe does not occur when I tested with your sample.


EDIT: And the 2 occasions where the call suddenly stops is probably the user. Both end with "D_TX_Ceased" "D_Release" PDUs.

 

[hornet1]

thewraith2008 .. things to consider in the next update/fix
1- manual frequency offset (some of the preset offsets shifts around +/- (2 to 8) khz from the main CC Park >> need manual offset).
2-Protocol:Location_information SubType:Location_protocol_with_extension is not showing location data

Thanks ... Great Job .. !!

 

[hamradionl]

@thewraith2008
Possible to use multible SDR# + TTT on busy network. Not using a Call operator (human dispatch who cordinate voice calls)
1x SDR# + TTT - CC and this CC controlling 2x or 3x SDR# + TTT- VC

 

[Ubbe]

2-Protocol:Location_information SubType:Location_protocol_with_extension is not showing location data

As standard there's no location data being transmitted out in a tetra system, it's not a repeater system. It goes directly to a server and you only see the ack. If it has been setup to be transmitted to a remote mobile radio somewhere and there's an application built to handle the map service, then it is transmitted on that particular site that mobile have registrated to.

/Ubbe

 

[hornet1]

As standard there's no location data being transmitted out in a tetra system, it's not a repeater system. It goes directly to a server and you only see the ack. If it has been setup to be transmitted to a remote mobile radio somewhere and there's an application built to handle the map service, then it is transmitted on that particular site that mobile have registrated to.

/Ubbe

.. Thanks that explains it.

 

[intruso]

TTT_Features_and_Usage.pdf
Its a little against logic but if you read, you find out

Hello, yes, I read the manuals.
The priority of a GSSI is set (when Group is in Orange)

But I do not want to block a GSSI, I want to set a group priority.
I translated the manuals into my language and there are incomprehensible paragraphs, maybe that's it.

I have a signal in which there are several services
Then ... Normally there are two transmissions at a time (TS2 and TS3).
Without setting priorities it jumps from TS2 to TS3 and I miss the call that is in TS2.

I want to prioritize so that the GSSI that I choose, when it is in TS2 and receive call in TS3 of another GSSI, does not jump to TS3, but stays in TS2 until the call ends.

My question is: is 8 more priority than 1?

Thank you 73

 

[Ubbe]

Higher number are higher priority but calls will still be interupted by others in the waiting time between user transmission but will revert back to the higher prio one.

You can set hold time and start "record all" to lock out other conversations from breaking up your monitoring for the duration of the hold time.

If a private call console-radio, or radio-radio with users on different sites, take place you'll need the call timeout timer to be set to something like 30 seconds or longer to not have the call clear down while the other party are speaking. You'll never get back to that call if it is cleared down by call timeout as the setup command are only sent once at the start of the call and not repeated continously as with talk groups.

/Ubbe

 

[hamradionl]

Logic will be using High priority-1 = playsound1.wav and Low priorrity-9 = playsound9.wav..... but this is not the way it seem to work
When you install from default you only have 1x priority, thats all priority set to above nummer 5 are play snd_priority5.wav
and when you change/rename snd_priority5.wav to snd_priority1.wav, ALL priority are using snd_priority1.wav
Later stage wish able make different priority using different sound.
For now, this is what it is.

 

[hamradionl]

To preventing any confusion or misunderstanding, in my country are 2x type network operators
1e network)
using 1x real person in the middle who is directing all the calls (dispatching control center) so there be always max 2x users active using 1 slot.
2e network)
there is never a real person in the middle and day time over 1000++ different users using all 4 slots.
For this 2e network to fallow all the importend conversations its handy to make some sound or noise and not have to "block" or "time out" ON / OFF other users because to do this manualy, you need sit behind the screen the whole day

 

[Ubbe]

A wav file are a sound file. If you rename the file it will still produce the same sound. Record or download from internet the wav sound file you want and rename to snd_priority7.wav and it will be played when a call starts that you have set to priority 7.

/Ubbe

 

[intruso]

Well, I'll try to set a higher number for higher priority.

Thanks for answering my message

Very grateful for this extraordinary work to the creators and those who contribute their time to try it and discover errors.
A good for the SWL community

73

 

[thewraith2008]

.. things to consider in the next update/fix
1- manual frequency offset (some of the preset offsets shifts around +/- (2 to 8) khz from the main CC Park >> need manual offset).

The offset used is the one the network defines for carrier selection. This is not a frequency correction offset.
If you have "+/- (2 to 8) KHz" from frequency you need to check your PPM of your dongle. Or get a dongle that doesn't drift so badly.
If you have "+/- (2 to 8) KHz" between MCCH and traffic channels, then not much can be done about this. The network provider needs to check their frequency standards. Maybe try using SDR# "shift" feature to find middle offset for the different frequencies.

 

[thewraith2008]

I have a signal in which there are several services
Then ... Normally there are two transmissions at a time (TS2 and TS3).
Without setting priorities it jumps from TS2 to TS3 and I miss the call that is in TS2.

I want to prioritize so that the GSSI that I choose, when it is in TS2 and receive call in TS3 of another GSSI, does not jump to TS3, but stays in TS2 until the call ends.

Thank you 73

Assuming these are group calls and priorities are ON.
If a call is in TS2 and TTT has set it up and is listening to it, then activity in TS3 should not be heard.
The only reason TTT would switch to TS3 (assuming D_Setup was detected) is because that the call in TS3 (GSSI) has a higher priority value.

It sounds like "Auto" checkbox is enabled.
"Auto" should be "OFF" or Unchecked. This should be disabled by TTT on "Start".


How priorities work with TTT,example:
GSSI: 1234 with priority value of 2
GSSI: 4321 with priority value of 6

Call is current with GSSI: 1234 and all is good in the world.
A "D_Setup" PDU is seen for GSSI: 4321.
Because GSSI: 4321 as higher priority (6) and obviously 6 is greater than 2.
TTT will then release call (GSSI: 1234) then setup the call for GSSI:4321.

And for the use of (call state)/priority snd file with TTT: (from "TTT_Features_and_Usage.pdf")
Only use one priority# WAV file at a time.
If more then one WAV file is used, only the highest number (file name #) will be in effect.

e.g. If snd_priority4.wav and snd_priority5.wav are seen by TTT then only snd_priority5.wav will be used.

When 'snd_priority5.wav' is used, GSSIs with a priority value of 5 and above will play that sound when a priority is triggered.
GSSIs with priority values of 1 to 4 will NOT play any sound when those priorities are triggered.