Re: [Discuss-gnuradio] Multi-rtl - making multi-channel receiver out of multiple RTL-SDR dongles

[Piotr Krysik]

Hi Juha,

It wouldn't be as simple as it was for me as a developer and as it
(hopefully) is for the end user without your hardware mod.

Can you say something more about the residual center frequency
difference? Where might it come from? I prepared little test of
coherency between the receivers (multi-rtl/examples/test_multirtl.m).
Among all the figures that it shows there is a plot of relative phase
offset of signals coming from the receivers. In fact I have seen linear
phase change on that plot - that corresponds to some central frequency
offset. If I know what is the source of this offset maybe I will be able
to find some way to fix it in software.

--
Piotr

W dniu 25.05.2016 o 08:24, Juha Vierinen pisze:
> This is awesome! I'll definitely try this out soon. I use one off
> python scripts to find the sample offset and the small residual center
> frequency difference. This simplifies the process significantly. 
>
> This should make it much easier to implement a passive radar block, or
> an interferometry block. 
>
> juha
>
> On Tue, May 24, 2016 at 4:03 PM, Piotr Krysik <address@hidden
> <mailto:address@hidden>> wrote:
>
>     Hi all,
>
>     I want to announce new GNU Radio related project prepared by me -
>     Multi-rtl:
>     https://github.com/ptrkrysik/multi-rtl
>
>     It is a Gnu Radio block that combines multiple RTL-SDR receivers into
>     one multi-channel receiver.
>
>     Only hardware modification to RTL-SDR dongles required is connecting
>     them to a common clock source (i.e. one of the dongles' oscillator as
>     Juha Verinen showed once). Each channel can work on a different
>     central
>     frequency.
>
>     Everyone who wants to know how it was achieved is invited to read my
>     github page:
>
>     https://ptrkrysik.github.io
>
>     Best Regards,
>     Piotr Krysik
>
>     _______________________________________________
>     Discuss-gnuradio mailing list
>     address@hidden <mailto:address@hidden>
>     https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>
>