https://www.reddit.com/r/amateurradio/wiki/index https://www.reddit.com/r/amateurradio/wiki/index is a pretty good place to start. The ARRL has manuals that wal

https://www.reddit.com/r/amateurradio/wiki/index https://www.reddit.com/r/amateurradio/wiki/index is a pretty good place to start. The ARRL has manuals that walk through the theory behind the exams for the US licences. The extra class book explains the theory of building a modern transceiver, starting with doping silicon to make semiconductors.