On 01/09/2023 16:39, Marcus Müller wrote:
Ah, nice! yeah, then this would work – but! any oscillator has drift,
so two local oscillators will not stay on the same phase for long; if
your first couple measurements are correct, but suddenly your
directions become very wrong, that's what I'd investigate.
Cheers,
Marcus
Looks like the BB60C supports an external 10MHz reference clock, which
would be utterly mandatory for anything requiring
mutual phase-coherence, whether that's *sufficient* depends very very
much on the internal architecture of the BB60C.
On 01.09.23 19:16, Michael Berman wrote:
The gr-aoa module has a calibration phase where you connect a source
with a splitter and roughly equally lengthened cables to the two
sources and it cross-correlates the two inputs to determine an
initial phase difference. Then, while the script is still running,
you disconnect the calibration source and connect the antenna's,
again with roughly equally lengthened cables to run the MUSIC algorithm.
Thank you very much,
Michael Berman
On Fri, Sep 1, 2023 at 11:00 AM Marcus Müller
<marcus.muel...@ettus.com <mailto:marcus.muel...@ettus.com>> wrote:
If you don't know the relative phase of your two receiver chains,
how are you going to
know the direction of a signal?
On 01.09.23 17:37, Michael Berman wrote:
Marcus,
Thanks for the reply! I apologize, the GR package is gr-aoa,
not gr-music, and can
be found here (https://github.com/MarcinWachowiak/gr-aoa
<https://github.com/MarcinWachowiak/gr-aoa>). The NOAA broadcast
is a NBFM signal. I am using 2 Signal Hound receivers
(https://signalhound.com/products/bb60c/
<https://signalhound.com/products/bb60c/>) with 2 antennas
spaced on a beam. Do I
need to synchronize the 2 receivers with an external clock, or
should they be fine
free running independently?
Thank you very much,
Michael Berman
On Fri, Sep 1, 2023 at 9:25 AM Marcus Müller <mmuel...@gnuradio.org
<mailto:mmuel...@gnuradio.org>> wrote:
Not familiar with the details of NOAA signalling, but isn't
the carrier of an FM
signal
*the FM signal*?
For a DoA estimate, you'd correlate the different receive
chains with each other
to get a
phase; so, as long as the signals do have some bandwidth
that makes the problem
less
ambiguous, it'd work with any signal. I'm sadly not familiar
with gr-music (and
can't find
it on cgran.org <http://cgran.org>), but MUSIC works as long
as the signals at
the different receive antennas
are correlated and noise is not. You do not have to
preprocess your FM signal!
Best,
Marcus
On 01.09.23 17:09, Michael Berman wrote:
> Does anybody know if there is a way to recover a carrier
of an FM signal to
use for an
> Angle of Arrival calculation? I am using GNURadio and
gr-music and I am
trying to use the
> NOAA Weather Radio signals.
>
> Thank you very much,
>
> Michael Berman