In 2008/2009 Alan Melia G3NYK and Steve Nichols G0KYA wrote a series of features on understanding LF and HF propagation for RadCom, the Radio Society of Great Britain's RSGB magazine. Steve has managed to persuade the RSGB to let him to put them together into a single document, which is now freely available for amateurs worldwide to download. If you don't know much about propagation it is a great place to start exploring its mysteries. Even if, like me, you have the magazines with original articles it is great to have them all together in one place like this. Makes me wonder if buying one of those electronic book devices aka eReader or Kindle is not starting to make a lot of sense. Does Kindle do PDFs? I have no idea!
Steve is also the author of a book on ‘Stealth Antennas’ available from here.