Thanks, Kevin!
I think that was the issue. I had, in my early days of learning about SDR, installed another version of gnuradio. Also, I was not calling the pybombs-installed gnuradio correctly. Instead of
$ pybombs run gnuradio-companion
I was calling it like so:
$ gnuradio-companion
That is another error.
I have everything working as expected now (i.e., got the OP flowgraph (and more)) working.
I uninstalled all gnuradio-* components (sudo apt-get remove --purge libgnuradio*, and maybe more; try apt list --installed | grep gnuradio) installed by Ubuntu's apt-get and then, using pybombs (see
https://github.com/gnuradio/pybombs), rebuilt gnuradio and added the necessary recipes.
So, here's what I did:
$ apt list --installed | grep gnuradio
$ sudo apt-get remove --purge libgnuradio* # again, do the above and this line for everything else you may have installed using apt-get, e.g., rtl-sdr, osmosdr etc.
$ pybombs -vv rebuild gnuradio
$ pybombs install gr-osmosdr
Marcus, thanks for your on the matter! I hope this helps someone.