Organizations American Radio Relay League (ARRL) ARRL is the national association for Amateur Radio in the US. Federal Communications Commission (FCC) University of California, Santa Barbara Santa Barbara Amateur Radio Club License Exam Prep HAM study KB6NU’s No-Nonsense Guide Resources HAM Radio Resources by DXZone Amateur Radio Subreddit Wiki Callsign Lookup on QRZ DX Maps VOACAP HF Propagation Prediction and Ionospheric Communications Analysis HAM Radio Glossary by ARRL