• Effective immediately we will be deleting, without notice, any negative threads or posts that deal with the use of encryption and streaming of scanner audio.

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SDR# TETRA Demodulator Trunk Tracking Demonstration

Joined
Nov 22, 2016
Messages
518
#1
I've been messing around with SDR# TETRA Demodulator plug-in to see what I could come up with in regards to trunk tracking TETRA.

I did this as a stop gap until the big players have come up with something.

And in true SDR form, here is the setup.

I used 2 instances of SDR# (for CC and VC):
  • Both CC and VC have 'TETRA Demodulator plug-in' with 'Network Info' windows open.
  • SDR# VC has 'Net Remote' plug-in to allow custom made program to communicate with SDR#
  • SDR# CC has volume muted and is fixed to CC frequency.
  • SDR# VC has 'Remote Net' plug-in enabled, Timeslot auto disabled

The custom made program scrapes data from TETRA Demodulator plug-in to allow trunk tracking.
I has many bugs and requires a bit of messing about to get running but so far things seem to work.

My 1st program just made SDR# scan frequencies when no voice was present, when voice was heard it would stop, when call was over would continued to scan after a delay.

Some features currently are:
  • Auto save seen group# (GSSI) + add label and sort
  • Lockout GSSI from playback
  • LOGs for raw CC and VC data
  • LOG for call events (and other messages for testing mainly)
  • Replication of call details (as seen in the plug-in window)
  • Uses custom list for available carriers (VC frequencies) so tracking does not occur when a VC not seen

A demonstration video is here for anyone to have a look.

Nothing may come of this, but I thought I'd give it a shot.

Thanks for listening.
 
Joined
Nov 22, 2016
Messages
518
#3
Would be nice to see if it works on other networks around the place.

Still very alpha stage. And the SDR# plug-in by TSSDR in still in a state of flux, so any changes to it could impact on this program.

It seems to be working fine so far. It has hardwired parts to it that won't work for anyone but my monitored network. Mainly the accepted carriers. I put it in place so carriers that are not received are not switched too.

I still need to work on how this program obtains the window handles it needs for both SDR#s.
Currently, this is done manually. I need to know which one is CC and which one is VC.

Setup could also be a hassle, but considering what people have done to get OP25 and Telive going, should be easier by comparison.

Some more features added:
  • Auto save SSI list with last seen date and option to add labels
  • GSSI list with labels added priority and last seen date.
  • GSSI Priority. Calls are weighted and will start playing when seen higher than current call.
  • Can edit GSSI priority and labels and SSI labels.
  • Lockouts can be skip if wish, ie. returned to allow call

Here is the latest GUI.
 

Attachments

Joined
Nov 22, 2016
Messages
518
#5
And I'm sure that's not the last mistake.

Image quality is what I got from IrfanView resize/resample with Lanczos and sharpen ON while preserving aspect ratio. I tried with sharpen OFF but it looked blurry.

Only changed from 1047x446 to 800x341 so I could post image.
 

CqDx

Member
Premium Subscriber
Joined
May 15, 2003
Messages
875
Location
US
#6
Very nice, I would be happy to help be a debug user for you.
We have a fairly busy transit network in the area (with another one under deployment) and some SDR Sharp IQ recordings to help validate your program
 
Joined
Sep 19, 2002
Messages
5,108
Location
Toronto, Ontario
#7
Image quality is what I got from IrfanView resize/resample with Lanczos and sharpen ON while preserving aspect ratio. I tried with sharpen OFF but it looked blurry.

Only changed from 1047x446 to 800x341 so I could post image.
No fuzzies if you save a screen grab as a .png (without any resizing) and upload it to an image hosting site (like Imgur), then just link to it in your RR post.
 
Joined
Jun 12, 2013
Messages
93
#8
I use IrfanView and resize "Resample (better quality) and use "Lanczos (slowest)".


Then save as .jpg using 80% compression. Works great for me with no visible reduction in quality.

I hope this helps! IrfanView is a great program.
 
Joined
Nov 22, 2016
Messages
518
#9
Trying to determine if what I've implemented for carrier # to frequency will work for different networks around the place.

I am using a user set base frequency (Fb) for calculation.
So if a base frequency is:
800.0125 and carrier # is 1000 then frequency would be 825.0125​
or
800.0125 and carrier # is 1500 then frequency would be 837.5125​

To get base frequency for a known carrier number/frequency: (as shown in TETRA plug-in)

Carrier# = 1500 and frequency for that carrier # = 837.5125

Fb = 837.5125 - (1500 * 0.025)

So Fb = 800.0125

Question is, does using a calculated base frequency with different carrier # produce the correct frequency for you.

If you don't want to calculate it for me, just post a few of your carrier # and frequency from your network.

NOTE: Versions before the one released on 20th May 2018 may display carrier #/freq wrong.

Thanks for any help
 
Joined
Mar 23, 2014
Messages
281
#10
Sorry i do not understand what you like us to do.

About latest plugin, seem like different (older or newer depending on hardware) network show different output and not show correct. Like the new Hytera network show diff output as first older generation hardware.
 
Joined
Mar 23, 2014
Messages
281
#13
We use 10 MHz duplex space in/out on 400 MHz or do you search the channels being used?
But when plugin output freq in that penal display showing, is wrong? Your method be wrong?
 
Joined
Jun 12, 2013
Messages
93
#14
"Jpegs are for photographs, not computer generated displays."

True. But compression compresses images to a much smaller size for quicker ul / dl. But I get your point! .jpg can be saved with no compression too.
 
Joined
Jan 24, 2004
Messages
872
#15
We use 10 MHz duplex space in/out on 400 MHz or do you search the channels being used?
But when plugin output freq in that penal display showing, is wrong? Your method be wrong?
Are you in Europe....TETRA around 210MHz, 390MHz and (certainly in the UK) some up around 450MHz?
In the USA it's around 460MHz, 810MHz and 860MHz
 
Joined
Mar 4, 2015
Messages
30
#19
Sounds like an Australian Tetra syste judging by the accents.. There is some 800mhz Tetra systems in New Zealand that would probably be using the same set up as this one I imagine if you need further testing done
 
Joined
Nov 22, 2016
Messages
518
#20
I use a Russian (assumed, as it from a Russian forum) developed TETRA plug-in on a AU network.

If people use this plug-in anywhere in the world that uses TETRA and it works for them, then my little program should work for those people. When I get a few replies to the question I posted above I should be able to tell if it would work.

I think what I'm doing might be restricted to English. Not sure.
 
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