[CQ-Contest] Is HF HF propagation reciprocal?

Bill Turner dezrat at copper.net
Mon Jun 4 23:21:47 EDT 2007


On Mon, 4 Jun 2007 19:46:24 -0700, "Tomas Hood (NW7US)"
<nw7us at hfradio.org> wrote:

>I'm working on posting additional texts where I take various HF
>propagation topics, and use modern software to model the concepts. 

------------ REPLY FOLLOWS ------------

IMO, modeling software is only useful when all parameters are known.
That is not the case for so-called one way skip. Your software focuses
on the signal to noise ratio, which is fine, but only part of the

for years, it has been theorized that one way skip is caused by a tilt
of the ionosphere, so that signals going in one direction strike it at
a very shallow angle, whereas signals coming the other way strike it
at a more acute angle. Due to the angle of incidence vs MUF, one
signal will be reflected and the other will not.

I don't know if this has ever been convincingly proven or not, but it
sounds reasonable. Does anyone have any further information?

Bill W6WRT

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