Martin Lornton KD8LON has produced two tutorial videos explaining radio progagation.

Concepts covered in this Ham Radio tutorial:

* Ground wave propagation
* Sky wave propagation
* Ionosphere layers D, E, F
* Radio wave skip and hop zones
* Pedersen Ray
* E-M-E Earth Moon Earth radio communications
* Long path and short path radio waves

In part 3a Martin goes through the theory of HF radio wave propagation. In part 3b of this video he does a practical demonstation of shortwave radio reception through various radios and antennas / antenna tuner.

Watch Radio – HAM – Antenna: Part 3a – Radio Wave Propogation and Short Wave Listening

Watch Radio – HAM – Antenna: Part 3b – Radio Wave Propogation and Short Wave Listening