> David K1TTT,
>
> In your reply to NM7M's posting, you said
>
> "consider a transmission from a vertical ionospheric sounder, the wave front
> is essentially a plane when it encounters the ionsphere. now assuming that
> the ionopshere is quiet and uniformly ionized above the sounder the wave
> front will not see any gradients, but can still be reflected back down to
> the receiver."
>
> Huh??? Are you saying that the reason the signal from a vertical sounder
> returns to earth is because it's REFLECTED from a uniform ionopshere? Like
> a mirror?
>
> Hopefully I misunderstood your comment. Because the reason the signal
> returns to earth is because it's REFRACTED (bent, turned, etc) in the
> ever-increasing (up to the F region peak, of course) electron density. If
> that doesn't constitute a gradient, I don't know what does.
>
> Carl K9LA
What's the actual difference between reflection and refraction except that
reflection takes place over a very short distance? (i.e., close to or less
than one-wavelength)
Reflection could be said to take place at "step" type discontinuities in
the media through which the waves travel. How "steep" a gradient is
required before refraction becomes reflection?
73, Ward N0AX
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