Java program to decode DMR

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Forts

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Thats the first time I have heard a report of an actual encrypted DMR system. No one over here in the UK has come across one yet.

Any idea who the owner of the system is ?

Ian

I have a handful of them in my area actually. My local PD are encrypted... and in the city of Sarnia (about 70km from me) they are using TRBO for city fire, public works and transit. They are all encrypted as well.
 

TampaTyron

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A correction to my previous post about total encryption keys for the 2 types of enc. The enhanced privacy is 40 bit and has millions of possible keys. The basic privacy has a total of 255 keys (and should be garbled audio with dsd or mototrbo capable radio). Thanks to a poster here who pointed out my error. I was essentially trying to show the difference between the 2 systems in terms of total keys and over simplified it a little too much. 255 is still a doable number, but I do not recomment trying it if it is against your local laws (like here in the US). TT
 

MattSR

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Another correction - The sound of the two types of encryption is no different. They both will just sound like "crickets in a blender" or R2D2.
 

Forts

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Really? According to the MotoTRBO System Planner in the case of a missing key (or key mismatch) Basic privacy will sound like 'unintelligible audio or digital warble' played thru the speaker, whereas with Advanced privacy will either keep the speaker muted or will just produce unintelligible audio.
 

MattSR

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Exactly - What they're saying is both crypto methods will sound like unintelligable audio (R2D2) and, if you've got Advanced privacy in your radio - it might just keep the speaker muted if you're lucky.

Either way both systems just produce pseudorandom numbers which when fed through the AMBE code just sounds like gibberish. theres no "digital hash" or "white noise" as suggested above.
 

TampaTyron

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MattSR,
what you had said now seems accurate (by the reports I have been receiving). Unfortunately, I am not able to determine exactly why I get the results I poseted above, but that others are getting the results you are speaking of. I am interested in the firmware differences (on my end) that are producing this. TT
 

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Hi TT,

Can you make a recording? I might be able to work out whats going on if you can create an MP3 or similar.

Cheers,
Matt
 

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Hi Folks
Just a note to let you know I have just put build 24 on Github ..

https://github.com/IanWraith/DMRDecode/downloads

This new version has improved demodulation and should give you far fewer frames with errors. I have discovered one problem which is that because the program is decoding more frames per second I find that after a couple of hours the program begins to slow down which I'm pretty sure is due to memory problems. I think I know how to fix this but might not have time until later next week so thought I would release build 24 for you to test out.

As ever please post any reports (bug or otherwise) plus feature suggestions to this forum please.

Regards

Ian
 

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Actually I meant to post a comment about that last night and forgot. I had release 23 running all day yesterday and when I got home from work it appeared to be running, but was unresponsive. I had to end the program via the task manager.
 

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Actually I meant to post a comment about that last night and forgot. I had release 23 running all day yesterday and when I got home from work it appeared to be running, but was unresponsive. I had to end the program via the task manager.

Yes you should find that build 24 runs a little longer than 23. All being well build 25 should fix these problems but it looks like I'm going to have a busy week so might not have time to work on it.

Regards

Ian
 

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I have a question - does JavaDMR support decoding of simplex transmissions? I've borrowed MotoTRBO radio and cannot get any frame decoded. When tuned to DMR repeater everything works great.
 

TampaTyron

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Matt,
are you asking for a recording of the dmr signal itself from the tap? DSD decoded audio sample? Trbo radio decoded audio sample? Any specific type of encryption? I can mimic a good bit of setups, but the more I dig into the dsd, the more I realize that my setup may not have been behaving properly (which is why I gravitated towards the Mototrbo radio instead). Thank you, TT.
 

IanWraith

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Hi

I have a question - does JavaDMR support decoding of simplex transmissions? I've borrowed MotoTRBO radio and cannot get any frame decoded. When tuned to DMR repeater everything works great.

No it doesn't yet I'm afraid. Simplex DMR frames have a different sync sequence.

Ian
 

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AOR 5000 discriminator out bad result

After months testing sound cards , pc , settings with same results, I made a discriminator modification on my very old AR2001 .

Immediade results : decoding is good . so AR5000 discriminator output is bad for me :

My question is : what would be the best scanner with discriminator modification ? Alinco XJ11 with build in modification .? other

thanks for advice
 

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According to dsdauthor's comments in the wiki; digital scanners seem to do better. This is speculation on my part but they probably have tighter specifications for the local oscillator.
 

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After months testing sound cards , pc , settings with same results, I made a discriminator modification on my very old AR2001 .

Immediade results : decoding is good . so AR5000 discriminator output is bad for me :

My question is : what would be the best scanner with discriminator modification ? Alinco XJ11 with build in modification .? other

thanks for advice

OK that does surprise me but its good you have found the problem. I use an old AOR3000 with a discriminator mod with pretty good results.

Regards

Ian
 

IanWraith

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Hi Folks

Just a quick update on progress. I found that the Java display class I was using for previous versions of the program was heavy on CPU time and steadily ate through a PC's memory (I was using the class for something I shouldn't have been). I'm working on build 26 now and have halved the CPU capacity the program uses , stopped the memory usage creep and found that the number of error frames I receiving has fallen from 20% to 5% so big progress. However plenty remains to be done and the build may not be ready until next week.

Regards

Ian
 
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IanWraith

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Hello All

I have just uploaded build 26 to Github ..

https://github.com/IanWraith/DMRDecode/downloads

This latest version has the following improvements ..

1) It uses less CPU time so *should* run on less powerful PC's. Please post here to say if it still won't run on yours.

2) It uses less memory and I have fixed the bug where the program used more and more memory until everything came to a standstill.

3) It should now decode frames with less errors. This is especially noticeable on systems that transmit in long bursts but less so on one which send brief bursts of data.

As ever bug reports and suggestions to this forum please. Also my thanks to all those people who sent me bug and usage reports for previous versions.

Regards

Ian
 
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