GQRX : new decodings module (req)

[Pawel Janowski]

Hello,

is it possible to add new decodings module ?
1) APT (NOAA)
2) APRS / Packet Radio
3) ADB-S : http://spench.net/drupal/research/mode-s ( http://www.youtube.com/watch?v=bKzii5K3AqA )
4) OP25 : http://wiki.spench.net/wiki/Gr-baz#op25 , http://op25.osmocom.org/  ( http://www.youtube.com/watch?v=wShOLgW2tmI )
5) Tetra : http://tetra.osmocom.org/trac/wiki/osmo-tetra
6) Pagers (POCSAG) : http://www.youtube.com/watch?v=ZFkk6rkCX40
n) other ;)

most of these based on gnu-radio (.grc files).

with regards
Pawel

[Alexandru Csete]

On Fri, Jun 1, 2012 at 11:50 AM, Pawel Janowski
<pawel.j...@gmail.com> wrote:
> Hello,
>
> is it possible to add new decodings module ?
> 1) APT (NOAA)

There is already some support for NOAA APT in the form of FM parameter
optimizations, see this post:
http://www.oz9aec.net/index.php/gnu-radio/gnu-radio-blog/451-howto-receive-and-decode-noaa-apt-images-with-the-funcube-dongle-and-gqrx
I may create a dedicated receiver with decoder in the future.

> 2) APRS / Packet Radio

Gqrx have had an APRS decoder for a very long time
http://www.youtube.com/watch?v=AZtmA40G794

> 3) ADB-S : http://spench.net/drupal/research/mode-s (
> http://www.youtube.com/watch?v=bKzii5K3AqA )
> 4) OP25 : http://wiki.spench.net/wiki/Gr-baz#op25 ,
> http://op25.osmocom.org/  ( http://www.youtube.com/watch?v=wShOLgW2tmI )
> 5) Tetra : http://tetra.osmocom.org/trac/wiki/osmo-tetra
> 6) Pagers (POCSAG) : http://www.youtube.com/watch?v=ZFkk6rkCX40

I barely know what these are so it is highly unlikely that I will code them.

> n) other ;)

I really don't wish gqrx to become one monstrous application that does
everything. I prefer to have small applications the do few things but
do it well. I trie to make gqrx modular so that other applications can
be created using common/shared building blocks.

> most of these based on gnu-radio (.grc files).

Gqrx is written in C++ and can not use GRC files. You can only run GRC
files via gnuradio-companion. Or one could write and embed an
XML-parser into gqrx that would build flow graphs from the GRC files,
but that's not exactly on my todo list.

Alex

[Pawel Janowski]

Hello Alex!

> 1) APT (NOAA)

There is already some support for NOAA APT in the form of FM parameter
optimizations, see this post:
http://www.oz9aec.net/index.php/gnu-radio/gnu-radio-blog/451-howto-receive-and-decode-noaa-apt-images-with-the-funcube-dongle-and-gqrx
I may create a dedicated receiver with decoder in the future.

 i saw it @ WWW, but I cant run this from compiled GQRX  from GIT src. Into code (qprx/Forms/qtgui/) modules for bpsk1000win, arisssatlm - but these forms not into menu.

> 2) APRS / Packet Radio

Gqrx have had an APRS decoder for a very long time
http://www.youtube.com/watch?v=AZtmA40G794

Yes, thanks.
 

> 3) ADB-S : http://spench.net/drupal/research/mode-s (
> http://www.youtube.com/watch?v=bKzii5K3AqA )
> 4) OP25 : http://wiki.spench.net/wiki/Gr-baz#op25 ,
> http://op25.osmocom.org/  ( http://www.youtube.com/watch?v=wShOLgW2tmI )
> 5) Tetra : http://tetra.osmocom.org/trac/wiki/osmo-tetra
> 6) Pagers (POCSAG) : http://www.youtube.com/watch?v=ZFkk6rkCX40

I barely know what these are so it is highly unlikely that I will code them.

> n) other ;)

I really don't wish gqrx to become one monstrous application that does
everything. I prefer to have small applications the do few things but
do it well. I trie to make gqrx modular so that other applications can
be created using common/shared building blocks.

> most of these based on gnu-radio (.grc files).

Gqrx is written in C++ and can not use GRC files. You can only run GRC
files via gnuradio-companion. Or one could write and embed an
XML-parser into gqrx that would build flow graphs from the GRC files,
but that's not exactly on my todo list.

Ok, Thanks for explanation. Is the ease way to compile .grc to work as external apps/module to GQRX. I want to learn it how its make.

with Regards
Pawel

[Alexandru Csete]

On Sun, Jun 3, 2012 at 8:46 AM, Pawel Janowski <pawel.j...@gmail.com> wrote:
> Hello Alex!
>
>
>> > 1) APT (NOAA)
>>
>> There is already some support for NOAA APT in the form of FM parameter
>> optimizations, see this post:
>>
>> http://www.oz9aec.net/index.php/gnu-radio/gnu-radio-blog/451-howto-receive-and-decode-noaa-apt-images-with-the-funcube-dongle-and-gqrx
>> I may create a dedicated receiver with decoder in the future.
>
>  i saw it @ WWW, but I cant run this from compiled GQRX  from GIT src. Into
> code (qprx/Forms/qtgui/) modules for bpsk1000win, arisssatlm - but these
> forms not into menu.

You are mixing two very different things together. NOAA APT is an
analog transmission based on FM, see the link I provided how to
receive and decode it.
The BPSK module you mention was a demodulator and telemetry decoder
specifically designed for ARISSat. AFAIK nothing else uses that format
and in particular the data format was ARISSat specific and since
ARISSat is no longer in orbit I saw no reason for keeping it in the
GUI.

Alex

[Benoittt]

Hello

 

I would like to know if it's possible to add multimon to GQRX. Actualy i'm using it with a GRC in Gnuradio who create a fifo file, this fifo file is decoded by multimon.

 

The easyiest way should be to offer an option to create a *.raw file that can be read with decoding software. This feature will give (i think) to other sofwares this ability to decode datas.

 

Man Multimon http://pwet.fr/man/linux/commandes/multimon

 

Apparently this is the source

http://www.codeforge.com/read/70443/multimon-_-pocsag.c__html 

 

Thanks a lot for GQRX

[Alexandru Csete]

On Mon, Jul 2, 2012 at 11:23 AM, Benoittt <benoi...@googlemail.com> wrote:
> Hello
>
> I would like to know if it's possible to add multimon to GQRX. Actualy i'm
> using it with a GRC in Gnuradio who create a fifo file, this fifo file is
> decoded by multimon.

Hi Benoit,

The funny thing is that when I was looking at multimon some time ago,
I concluded that nobody was using it anymore - otherwise people would
have had it brought more up do date than it was. Therefore, I took the
part that I felt was useful (AFSK1200 decoder) at included it in Gqrx.
I never thought people were actually using any of the other modes and
maybe it's just a new trend?

Anyway, it doesn't matter, because I agree that gqrx needs more hooks
and handles to allow interaction with external data decoders.

> The easyiest way should be to offer an option to create a *.raw file that
> can be read with decoding software. This feature will give (i think) to
> other sofwares this ability to decode datas.

Named pipes (fifos) are one way to do this. Another solution is to
interact with external decoders via their stdin / stdout, i.e. provide
them with input via their stdin and get the decoded output from their
stdout. I tried this method with the ARISSat BPSK1000 decoder and it
worked well. Some work is required to make it work in a generic way
but it's no big deal.

I haven't actually this this, but I think you can already connect gqrx
output to multimon via the pulseaudio link. You can do as described
here: http://www.oz9aec.net/index.php/gnu-radio/gnu-radio-blog/463-gqrx-and-pulseaudio
and use the parec command line recording application to capture the
gqrx output and record "raw sampes" to the fifo that goes to multimon.

You can maybe also bypass the named pipe altogether by piping the
output from parec stdout directly to multimon and use "/dev/fd/0"
(stdin) as input file in multimon. Plenty of things to try :-)

> Man Multimon http://pwet.fr/man/linux/commandes/multimon
>
> Apparently this is the source
> http://www.codeforge.com/read/70443/multimon-_-pocsag.c__html

Original website with source code:
http://www.baycom.org/~tom/ham/linux/multimon.html
Maybe the other site contains some changes, I don't know.

Alex

[Jasper Ragworth]

IME it was easier to get PDW working under Wine to decode POCSAG than it was to get multimon working.

The ZVEI/CCIR [selcall] decoder might be useful. I certainly hear ZVEI on transmissions I pick up, and have used multimon to decode it. It would be great for it to pop up as a label on the waterfall so you can see who was talking to whom. A display with vast amounts [compared to a hard radio] of data overlaid on it like this would be the realisation of the dream of SDR, to me at least.

There is a POCSAG decoder already in gnuradio so probably easier to integrate than the multimon one.

A CTCSS/DCS indicator might be useful, certainly more commonly used than POCSAG or ZVEI I should think. Again, thinking ahead, on the waterfall either as a label or a coloured overlay to the signal would be interesting.

From a slightly broader perspective, how do you intend to tackle modularity in gqrx? It would surely make sense to leverage the existing decode/demod blocks in gnuradio, but how do you go about integrating them in a flexible manner, without effectively reinventing gnuradio-companion?

[Benoittt]

Thanks a lot for both of you answer.

 

I will try what Alexandru said. I've already edit a flowgraph for pager (based on dekar's pager_fifo) for GnuRadio.

 

Pager_GRC_Martin_TSF70.zip



cd /tmp
mkfifo myfifo.raw
cd
lauch gnu-radio companion
Open "pager_fifo_Martin_TSF70.grc"
Run the flowgraph

In a terminal run : multimon -a POCSAG1200 -t raw /tmp/myfifo.raw  I didn't put the scope.
You should have the same thing as the capture below.

 

Enjoy

[Alexandru Csete]

I tried to make gqrx modular; not with the purpose of turning it into
a one-size-fits-all monster application, but to motivate the creation
a small purpose specific applications that share common code. Such
applications have much better chances of fulfilling their very limited
purpose and scope.

As I wrote in my earlier email, I think it is a good idea to add some
general hooks that will allow using external demodulators and
decoders, regardless of whether these decoders are written in GNU
Radio python, grc, or something else. I don't see any point in gqrx
becoming a generic-gnuradio-something; we already have GNU Radio for
that.

In many ways, you can already consider gqrx as a GNU Radio flowgraph
similar to what you have in GRC, but written in C++. For that reason
it may seem different, but if you dig into the source code I'm sure
you will see the similarities between gqrx and regular gnuradio
flowgraphs.

Alex