[op25-dev] Re: GRC blocks for OP25 and 4FSK missing / Re: OP25 GRC - Almost but not quite..

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rrgsti bobrich at gmail.com
Mon May 14 18:13:27 UTC 2012


Hi Richard,

Thank you so much for posting this observation (and to your colleague for making it).  I built a vm with Ubuntu 10.04 64-bit, installed gnuradio via the build-gnuradio script, installed op25 using the basic quick install instructions on the wiki, and re-ran my flowgraph and IQ file and (drumroll, please) IT WORKS!

I get proper DUID identification and audio output.

Combined with the difficulty trying to route audio from gnuradio to dsd, and I can confidently say that is *not* one of the high points in my love/hate relationship with linux over the last 15 years...lol.

Finding the problem is way over my head, but I'd be happy to help to whatever extent I can.  The tar file at this URL does provide an example of IQ baseband data that does work on 10.04 and does not work on my install of 11.10:

http://s3.amazonaws.com/public-xrp/p25.tar.bz2

Please note that I don't believe my install on 11.10 was done precisely the same way as above.  It's certainly possible that there's something wrong with the build on my local machine.

Thanks!



--- In op25-dev at yahoogroups.com, Richard Clarke <richard at ...> wrote:
>
> A colleague of mine here has noted that op25 decoder seems to produce no
> audio when compiled and run on anything later than Ubuntu 11.04 for as yet
> undetermined reasons. Building and running on 11.10 or later (other mods
> required for 12.04) and you end up with the no audio problem. I've
> suggested that he post here with any more details he may have.
> 
> Cheers
> Richard
> 
> On 11 May 2012 03:50, rrgsti <bobrich at ...> wrote:
> 
> > **
> >
> >
> > Hi there,
> >
> > AFAIK, the OP25 components do not show up in GRC. As you've found, gr-baz
> > includes an OP25 block for GRC that encapsulates OP25 functionality. Balint
> > also provided an example flowgraph that uses it, so you generally just need
> > to tweak the frequency.
> >
> > I'm having difficulty successfully decoding P25 with my RTL2832, so I'm
> > very interested in your results. If you get no audio output whatsoever,
> > take a look at the 'not quite' thread in here as well. I modified
> > data_unit.cc to force all frames to be detected as LDU1 (voice), which is
> > 100% broken, but I do get chunks of audio.
> >
> > I also ran into the same issue with compilation. If you punch
> > 'op25_imbe_frame.h' into the search function in this group you'll find a
> > couple threads with fixes.
> >
> > Last but not least, there is a discussion today on the rtlsdr subreddit
> > about sampling rates. In short, ensure that your sampling rate is an even
> > divisor of 28.8, such as 2.4 or 1.8msps, or you may get some artifacts in
> > the signal.
> >
> > Good luck!
> >
> >
> > --- In op25-dev at yahoogroups.com, "mungewell" <simon@> wrote:
> > >
> > > Hi all,
> > > Just getting started with GnuRadio and RTL2832 so might be missing some
> > details, by following the instructions here:
> > > http://op25.osmocom.org/wiki/wiki/BuildInstructionsPage
> > >
> > > I was able (with a couple of hacks) to built OP25, IMBE and 4FSK -
> > however these did not appear as selectable blocks in GRC.
> > >
> > > After some time I was able to figure out that they are missing 'xml'
> > definitions in '/usr/local/share/gnuradio/blocks'. Creating a quick/fake
> > '4fsk.xml' made it/something appear.
> > >
> > > So should these exist? Does anyone have examples of what they should
> > be....?
> > >
> > >
> > > BTW the OP25 which did appear, seems to be from Baz install, not the
> > above instructions.
> > >
> > >
> > > I also experienced problems with build against latest GnuRadio git
> > (seems that 'gruel_common.i' has moved) and the include files are not being
> > installed... other than that things are 'peachy' :-)
> > >
> > > --
> > > libtool: compile: g++ -DHAVE_CONFIG_H -I. -I../..
> > > -I/usr/local/include/gnuradio -I/usr/local/include
> > > -I/usr/include/python2.7 -I ../../../imbe_vocoder/src/lib -g -O2 -Wall
> > > -Woverloaded-virtual -pthread -MT _repeater_la-repeater.lo -MD -MP -MF
> > > .deps/_repeater_la-repeater.Tpo -c repeater.cc -fPIC -DPIC -o
> > > .libs/_repeater_la-repeater.o
> > > In file included from repeater.cc:3862:0:
> > > rs.h:8:29: fatal error: op25_imbe_frame.h: No such file or directory
> > > compilation terminated.
> > > make[4]: *** [_repeater_la-repeater.lo] Error 1
> > > make[4]: Leaving directory `/home/simon/op25/repeater/src/lib'
> > > make[3]: *** [all] Error 2
> > > make[3]: Leaving directory `/home/simon/op25/repeater/src/lib'
> > > make[2]: *** [all-recursive] Error 1
> > > make[2]: Leaving directory `/home/simon/op25/repeater/src'
> > > make[1]: *** [all-recursive] Error 1
> > > make[1]: Leaving directory `/home/simon/op25/repeater'
> > > make: *** [all] Error 2
> > > simon at drifter:~/op25/repeater$ find .. -name 'op25_imbe_frame.h'
> > > ../blocks/src/lib/op25_imbe_frame.h
> > > simon at drifter:~/op25/repeater$ find /usr/local/include/ -name
> > > 'op25_imbe_frame.h'
> > > simon at drifter:~/op25/repeater$
> > > --
> > >
> > > Simon
> > >
> >
> >  
> >
> 
> 
> 
> -- 
> *SCOTT ADAMS: Normal people believe that if it ain't broke, don't fix it.
> Engineers believe that if it ain't broke, it doesn't have enough features
> yet.*
>


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