I'm weighing in with Tom here. The reciprocity theorem in electromagnetism is well known, and it shows that no amount of focusing, defocusing, scattering, refraction, or reflection will by themselves cause one way propagation. If you take away the earth's magnetic field and its attendant Faraday rotation, I do not see any other reason for one-way propagation if noise levels at both ends of the path are equal.
See http://en.wikipedia.org/wiki/Reciprocity_(electromagnetism) and http://en.wikipedia.org/wiki/Faraday_effect#Faraday_rotation_in_the_ionosphere . 73, Carl WS7L Tom, > > It is a known that the ionosphere is not a perfect sphere. It is always > moving and it is lumpy and tilted. Together these occurrences can cause > focusing and defocusing of the wave due to deformities especially if they > are concave or convex. One-way-propagation can reveal itself as a deep > and/or prolonged fade on only one end of the link because of the > aforementioned reasons. Of course fades can be caused by other reasons, > such as multiple paths, etc. > _______________________________________________ Topband reflector - [email protected]
