Wikipedia's amateur radio article (also explains why it's called "ham")
DXCC call sign nomenclature
Chirp FOSS for radio programming
flrig to control bigger devices
CQRLOG a ham radio logger
WSJT-X helps with weak-signal communication
The American National Association for Amateur Radio
The global International Amateur Radio Union
The Field Day event on 25 June in the US
The Dublin maker's club
ISM bands - radio bands reserved for industrial, scientific and medical purposes
fldigi turns a sound card into a modem
The Linux in the Ham Shack podcast
Hamvention, a big amateur radio conference
HP Dev One HP laptop sold with Pop!_OS
On the waves he's known as NE4RD
You can listen to him on the Linux in the Ham Shack podcast