Alfred Lorona wrote:
Is there a site that explores/explains the latest theories on one way
propagation? The ARRL antenna book is not much help on the subject.

tnx, AL

One way propagation is possible if there is an anisotropic medium in
between (like the ionosphere).

A polarized wave may get rotated in passing through the ionized medium,
then refracted differently depending on the polarization. If you
envision your launching a beam up to the ionosphere, the place on the
ground that it hits after "reflecting" would be different depending on
the polarization. If someone in the "reflected spot" sent a beam back
to you, it too would get rotated on the way, and might propagate to a
spot other than yours.


A good practical example is the glare reducing filters that rely on a
linear polarizer followed by a rotator that rotates the polarization 45
degrees. Unpolarized light coming from the display gets rotated and
then polarized, and you see half of it. Light coming from behind you
gets polarized, rotated, reflected, rotated again, so now it's 90
degrees to the linear polarizer, and blocked.