The built-in ADC doesn't have a high enough sample rate to decode ADS-B in, so an external one is needed, and USB ADCs are readily available with built-in demodulators, for use as DVB-TV receivers.
Maybe I post the Rust code after some cleanup. Now I am busy build a new database from scratch to compete with them all https://github.com/punnerud/mpedb
…a new database from scratch to compete with them all…
I see you've taken this route: https://xkcd.com/927/