[Hackrf-dev] Receiving Digital LMR (P25 CAI)

[Rick "Zero_Chaos" Farina]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On 08/25/2013 09:42 PM, Luke Berndt wrote:

> Hi Guys - I have been playing around a bit and found an easy way to receive

> and playback digital LMR. More and more of the radio systems are going from

> narrow band FM to Digital. This makes it tough to listen to them on GQRX.

> DSD is a great program which can decoded the audio you get when you tune in

> a system in GQRX, but you either have to run it on another machine with a

> audio cable in between or figure out how to do a virtual audio cable on

> your machine.

> 

> Luckily, someone wrapped the DSD libraries so they can be accessed as GRC

> blocks. I have put together a GRC file and a Python program that make it a

> little easier to use the block.

> 

> 

> The files and write-up are here: https://github.com/robotastic/gr-dsd


Just for anyone considering packaging this, or redistributing this, or I
suppose using this: The codecs necessary to decode P25 (IMBE) are
proprietary and you can't use them without a license.  You will note
that this code is gpl3, but that doesn't actual give you permission from
the rights owners to use it.  The situation is far better described on
the original dsd page than by me:

http://wiki.radioreference.com/index.php/Digital_Speech_Decoder_(software_package)

- -Zero_Chaos

> 

> If you have a chance, give them a try and let me know if they work. There

> is a good chance I have messed up the values in the filters or else where,

> but I have gotten clean audio out of it.

> 

> 

>  - Luke

> 

> 

> 

> _______________________________________________

> HackRF-dev mailing list

> HackRF-dev at greatscottgadgets.com

> http://nine.pairlist.net/mailman/listinfo/hackrf-dev

> 


-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.20 (GNU/Linux)
Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/
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=j+qb
-----END PGP SIGNATURE-----