ARRL  Many useful regulatory, educational, operating, and technical items and links

AC6V and DX Zone  General-interest websites with many links on all phases of ham radio

QRZ.com  Call sign lookup service and general-interest ham radio portal

eHam.net  News, articles, equipment swap-and-shop, product reviews, and mailing lists

Radiowave Propagation Center  Real-time information on propagation and solar data

Space Weather Prediction Center  Real-time information on space weather and radio communications

TAPR  Information on digital data modes and software-defined radio (SDR)

AMSAT  Main site for information on amateur satellites

WA7BNM Contest   Calendar  Contest calendar and log due dates

YOTA   (Youngsters On the Air)  World-wide group for student and young adult hams, based in Europe

DXMAPS.com  Collection of real-time maps showing worldwide activity on any amateur band

DX Summit  Worldwide DX spotting network