Our own Ken (KJ6RZ) has created a web site all about HF communications and Propagation.
“The purpose of this site is the study of HF radio communications. I hope to provide information that bridges the gap between the simple and very complex.
Finally, it is intended that this be an open source website meaning that you are free to use the information provided here for non-commercial applications. Particularly for articles that you may be writing, club newsletters, and club presentations.
It is hoped that you find this web site interesting, informative, and above all useful.“
Visit the site here…