"Owen Duffy" wrote in message
...
On Sat, 01 Jul 2006 16:11:42 -0700, Richard Clark
wrote:


On the other hand, at HF the ratio between reflection and refraction
varies. There are times when both occur. During those times the
portion of the incident ray that is reflected returns to earth, while
the portion that is refracted continues on through the ionosphere into
space and never returns. I'm not sufficiently knowledgeable on the

But is it actually reflection?

no, it is actually a refraction. but it is useful sometimes to model it as
a reflection from a slightly higher level. that makes computation of angles
of incidence and height a bit easier.