It depends on what your background is already and what you want to do. I took some signals courses in school and we used the Oppenheimer textbook, but that's a

It depends on what your background is already and what you want to do. I took some signals courses in school and we used the Oppenheimer textbook, but that's a lot of math if all you want to do is receive some ADSB signals. Lots more recommendations here: https://news.ycombinator.com/item?id=14584377 https://news.ycombinator.com/item?id=14584377