Vern I know of two areas that trap radio waves. Both much higher than 65K feet. <A HREF="http://en.wikipedia.org/wiki/Kennelly-Heaviside_layer" target="_blank">http://en.wikipedia.org/wiki/Kennelly-Heaviside_layer</A> Then there is the more recently found higher layer. <A HREF="http://en.wikipedia.org/wiki/Appleton_layer" target="_blank">http://en.wikipedia.org/wiki/Appleton_layer</A>