Re: [Discuss-gnuradio] Reception problem with gsm-tvoid and gsmdecode

[Eric Blossom]

On Wed, May 13, 2009 at 12:31:23PM +0200, José Carlos Reyes wrote:
> Hi all,
> 
> I would like to ask you a basic question.
> I receive the BCCH and CCCH (PCH and AGCH) GSM channels with gsm-tvoid and
> gsmdecode. I use USRP. For instance, to do that, I type something like:
> 
> ./gsm_scan.py -p d -r e -c 104 | ../../../gsmdecode/src/gsmdecode -i >
> myfile.txt
> 
> The problem is that a lot of messages are missed. While I am receiving I can
> see warning messages like the followings:
> 
> sch.c:254 ERR: conv_decode 7
> gsmstack.c:162 cannot decode fnr=0x002921c8 ts=0
> gsmstack.c:162 cannot decode fnr=0x002921ce ts=0
> gsmstack.c:162 cannot decode fnr=0x002921e2 ts=0
> gsmstack.c:162 cannot decode fnr=0x002921ed ts=0
> gsmstack.c:162 cannot decode fnr=0x002921f1 ts=0
> ....
> ...
> sch.c:254 ERR: conv_decode 7
> gsmstack.c:162 cannot decode fnr=0x00292229 ts=0
> sch.c:254 ERR: conv_decode 1
> ....
> 
> The BTS (Base Station) from I am receiving is really near my USRP.
> What Could I do to solve this? Any Suggestion?
> 
> Thanks in advance for your time.
> Cheers
> 
> Jose

Jose,

The airprobe list is most likely a better place to ask this question.
AFAIK the people who wrote gsm_scan.py are not on this list, or if
they are they have been very quiet.

Eric