The following is a list of useful resources with information related to RF communication.
RF Cafe
http://www.rfcafe.com/Your engineering vehicle on the Information Superhighway. Featuring RF-related headlines, software cafe, and a very large variety of resource links.
SEC's Radio User's Page
http://www.swpc.noaa.gov/SWN/index.htmlProvides radio operators with current data on the state of the ionosphere.
The Nordic HF Conferences
http://www.nordichf.org/index.htm?index2.htm&2A series of Nordic conferences on HF communications was initiated in 1986 when HF 86 was held in Sweden. International interest in contributing with papers, exhibits and participants has grown, and we are now pleased to find that a conference that initially was planned for a limited audience of Nordic countries now has an international acclaim.
IPS Radio & Space Services
http://www.ips.gov.au/Main.php?CatID=6General propagation advice for HF communicators. Information available includes inferred global propagation conditions, real time HF fadeout coverage charts, regional ionospheric vertical MUF maps and Hourly Area Prediction charts.