Explaining how radio beams bend around the Earth for HF communications has always been a bit of a task to convey for me. Radio waves, which are in the same domain as light waves, don't "reflect" - they actually refract, or bend.


One way to see the bending is to place a pencil in a clear measure cup-- you will notice it appear to bend at the water line. Rays of light, and indeed radio waves-- do the same.


What you see is not always what actually happens. The arrow appears to reverse direction- and radio waves can do the same when traversing a medium such as the ether.

This video shows an even more dramatic demonstration of refraction:
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These visual cues may help you to understand how our ionosphere shapes and bends signals around the globe.  Here is some more info on the effect including a better explanation.  So the next time you hear a person stating signals reflect off the ionosphere- you have a couple quick and easy ways to show that they refract-- not reflect. The ionosphere is not a mirror. If you would like to learn more about ham radio and how we communicate around the world-- and how you can get a license to do the same. Please feel free to contact our club to find out about a ham radio license class near you.