Is it encrypted TRBO signal?

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lesny69

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Hello it's my first post, sorry for my english... I try to decode TRBO signal in my area. I have Uniden BCT15 with discriminator tap connected to my laptop with DSD software. I found MotoTRBO signal in 172.360 freq. In added files (1.zip) i recorded signals I heard in my speaker after dsd. I put here screen from dsd also. I used -fr option in dsd. I would like to know what's wrong that i can't hear "clear" voice?
 

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ilgrant

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Try throwing in -mg as well.

Isn't -fr is Nexedge? That will not work for Mototrbo. I don't have the program with me so I can't check the options to verify that.

When I run it for Mototrbo it is dsd -xr -mg. You may not need the -xr. Try both and see what happens.
 

ilgrant

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-fr is mototrbo. -xr is inverted mototrbo.

You appear to have a good signal. Are you getting garbled voices?

Could also be as simple as someone just keying the button and not talking.
 

lesny69

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I'm sure that it is not just keying the button I have voices like that all the time. I'll try to record voices without any options in dsd but just to show you that there is no diference. When i setup -xr I have somethink like that:
 

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jhampton2000

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lesny69 - your signal does indeed sound like privacy (encryption) has been turned on.

Two things that can help to confirm this:

1. Try downloading Ian Wraith's excellent DMRDecoder (https://github.com/IanWraith/DMRDecode) and run the raw signal against this.

For group calls that don't have privacy enabled, you'll see something like:
Service Options : Non-emergency/No priority

With privacy it'll look like:
Service Options : Non-emergency/Privacy Enabled/No priority

2. If you're strufggling with this, try sending me a sample of the raw traffic.

HTH, Jim
 

jhampton2000

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lesny69: you'll need to change the polarity in DMRDecoder.....go to Main, then toggle the Invert Signal button.

You should start to see the Colour Code decodes come through, and against voice decodes something like:

18:34:23 DMR Data Frame
CACH : TACT Ch 1 Last fragment of LC
Slot Type : Colour Code 1 Terminator with LC
Group Voice Channel User LC
Service Options : Non-emergency/No priority
Group Address : 2 Source Address : 315

or
18:39:39 DMR Data Frame
CACH : TACT Ch 1 Continuation fragment of LC
Slot Type : Colour Code 5 Terminator with LC
Group Voice Channel User LC
Service Options : Non-emergency/Privacy Enabled/No priority
Group Address : 100 Source Address : 1000

Jim
 

jhampton2000

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ok thanks...your Youtube video sounds like MotoTRBO, and confirmed by your screenshots. Your DMRDecode shows that it is setup correctly too now, now that you see Colour Codes displayed. Good.

I think we need to see what DMRDecode says when it decodes some voice. I suggest in DMRDecode go to Main, then enable Save to File. Try running DMRDecode against your MotoTRBO signal for a long period of time when it is active with transmissions. Exit DMRDecode, then search the log file you have created for "Service Options" (no quotes). If you find any, does it say:

Service Options : Non-emergency/No priority
or
Service Options : Non-emergency/Privacy Enabled/No priority
or something else?

Jim
 

Forts

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The only way to truly tell if privacy is enabled is to run DMRDecode as jhampton2000 suggested in post #6. Follow his directions and you should be able to tell in no time at all...
 

vasilpupkin

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I have same trouble, and according to frequency - same location as lesny69 :) This is police MotoTRBO station. What is strange that I can cleary hear public announcement, average 1-2 times per hour, but all other transmits is encrypted. Here is voice data from DRMDecode "Service Options : Non-emergency/Privacy Enabled/No priority", also DSDPlus writing in log "Key ID = X".

Is it possible to decrypt such transmission?
 

Forts

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No... that sort of defeats the purpose of them using encryption in the first place, don't you think? Not to mention (depending on your location) it can be illegal to do so.
 
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