New Digital PMR Decoder

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cartman
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New Digital PMR Decoder

Post by cartman » Tue Dec 28, 2010 8:31 pm

I noted on radioreference that Ian Wraith is working on a new windows programme to decode Digital PMR (like a lot of these programmes at the moment you need a disciminator tap). A couple of the regular folk here have posted on this RR thread below and seem to have their head around this much better than me, so they may want to comment further as to its usefulness

http://forums.radioreference.com/trunki ... e-dmr.html

I know this is an early version and there is a lot of work to be done but the version 12 i downloaded seems to be useful it that it works on Motorola TRBO frequencies.


Grant


https://github.com/IanWraith/DMRDecode

README.txt
The aim of this project is to provide a user friendly DMR data decoder for hobbyists.
It is Java based so should run under Microsoft Windows , Apple and Linux PC's.
The only hardware needed will be a radio scanner with a discriminator audio output.

The core of the program is based around the open source DSD program by an unknown author.
This program was written in C and runs under Linux only so the first job is to convert that code to Java and remove all sections that don't relate to DMR.

Milestone 1 - To detect voice and data sync words reached (3rd September 2010)
Milestone 2 - To reliably detect voice and data sync words. (Reached 15th October 2010)
Milestone 3 - To decode the CACH TACT (Reached 22nd October 2010)
Milestone 3.5 (!) - To decode the SLOT TYPE PDU (Reached 4th November 2010)
Milestone 4 - To decode the Short LCs that make up the CACH payload. (Reached 25th November 2010)
Milestone 5 - To work out why and then fix the problem that is causing single bit errors in frames.

Update : I have just added a display bar in build 13 which shows symbol values in a graphical form.
With this I see the program sometimes achieves a good sync with the DMR data stream (you see all
the symbol values clustered around 4 points) but then it looses sync for an unknown reason.

Ian Wraith (23rd December 2010)


This is a few second capture of the TR Corp TRBO system on 474.625 (it makes a racket every 5 secs - hard to miss)

CACH = Common Announcement CHannel
TACT = TDMA Access Channel Type
EMB = EMBedded Signalling Field
PDU = Protocol Data Unit


DMR Decoder V0.00 Build 12 7:07:18 PM DMR Data Frame - Error ! (113394)
CACH : TACT Ch 1 Continuation fragment of LC
7:07:18 PM DMR Data Frame - Error ! (113394)
CACH : TACT Ch 2 Continuation fragment of LC
7:07:18 PM DMR Data Frame - Error !
7:07:18 PM DMR Data Frame - Error ! (78578)
CACH : TACT Ch 2 First fragment of LC
7:07:18 PM DMR Data Frame - Error ! (78578)
CACH : TACT Ch 1 Continuation fragment of LC
7:07:18 PM DMR Data Frame
CACH : TACT Ch 2 Continuation fragment of LC
Slot Type : Colour Code 1 CSBK
7:07:18 PM DMR Data Frame
CACH : TACT Ch 1 Last fragment of LC
Slot Type : Colour Code 1 CSBK
7:07:18 PM Bad Short LC !
7:07:18 PM DMR Data Frame
CACH : TACT Ch 2 First fragment of LC
Slot Type : Colour Code 1 CSBK
7:07:19 PM DMR Data Frame
CACH : TACT Ch 1 Continuation fragment of LC
Slot Type : Colour Code 1 CSBK
7:07:19 PM DMR Data Frame
CACH : TACT Ch 2 Continuation fragment of LC
Slot Type : Colour Code 1 CSBK
7:07:19 PM DMR Data Frame
CACH : TACT Ch 1 Last fragment of LC
Slot Type : Colour Code 1 CSBK
7:07:19 PM Short LC : Unknown SLCO=15 000100000000000100000000
7:07:19 PM DMR Data Frame
CACH : TACT Ch 2 First fragment of LC
Slot Type : Colour Code 1 CSBK
7:07:19 PM DMR Data Frame
CACH : TACT Ch 1 Continuation fragment of LC
Slot Type : Colour Code 1 CSBK
7:07:19 PM DMR Data Frame
CACH : TACT Ch 2 Continuation fragment of LC
Slot Type : Colour Code 1 CSBK
7:07:19 PM DMR Data Frame
CACH : TACT Ch 1 Last fragment of LC
Slot Type : Colour Code 1 CSBK
7:07:19 PM Short LC : Unknown SLCO=15 000100000000000100000000
Last edited by cartman on Tue Dec 28, 2010 10:17 pm, edited 1 time in total.
Professional Scanner nut. Ibis bin chicken of radio scraps
Scanners:
Uniden 325P2, Whistler TRX-1, GRE PSR800 x 2, Uniden 780 x 3, Uniden 796, Uniden 396 x 2, Uniden 246,
Software:
DSD v2.368, Unitrunker, Trunkview

centralcoastscanman
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Re: New Digital PMR Decoder

Post by centralcoastscanman » Tue Dec 28, 2010 9:17 pm

nice, i'll have to give it a go on my windows box as i've not quite gotten around to getting the linux version going yet that does all of the digital stuff...

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