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> 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). > The NOAA broadcast is a NBFM signal. I am using 2 Signal Hound receivers ( > 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> > 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), 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 >> >
