General Resources
ARRL – American Radio Relay League
QRZ – Call sign lookup, ham radio forums, online swapmeet, online QSL service
eHam – Amateur radio forums
Learning
HamStudy – Online amateur radio license test prep
LCWO – Learn CW Online – Morse code practice and learning
Operating
RepeaterBook – Online repeater database
SOTAwatch – Online spotting network for Summits On The Air (SOTA)
DXWatch – Online DX spotting network
PSKreporter – Reception reporting network
Digital Modes
W1HKJ Software – Home of FLDigi, FLmsg, FLrig, and other similar amateur radio digital mode software
WSJT Home Page – Home of WSJT-X, digital mode software for popular digital modes such as FT8 and JT65.
Just For Fun
Ham Hijinks – Ham Radio Related Humor