I am trying to learn about radio (and the electric and magnetic fields in general), and I'm following the Great Scott Gadgets' "Software Defined Radio with HackRF" video series. I'm also thinking about getting an amateur radio license. What else could you recommend?
arrl.org and rsgb.org, the US and UK amateur radio organizations, sell a variety of books you might find helpful.
If you are in the US, ARRL sells books that teach to the specifics of the US tests. I used those but found them rather unsatisfying. There are other books which focus on experiments (see Hands-On Radio Experiments) and others on theory.
The ARRL Handbook is also useful. It's updated annually, but you won't miss too much if you save a few dollars by getting an older edition.
