>The ionosphere makes the optical ray-tracing analogy
>inapplicable, in its simplicity. Not wrong..just not sufficient.
>His comments concerning polarization are correct, and impact the problem
>significantly. The suite of optical rays are now a swarm, with varying
>polarization, going through what MAY be a polarized filter (earth). At
>best, the result is a blur.
If you wait long enough and sample enough signals in both directions
you'll find that usual ionospheric propagation is going to be pretty
reciprocal.
The addition of random ionospheric shifts in amplitude and phase
doesn't change the overall reciprocity of the problem.
The appearance of non-reciprocal propagation usually comes from local
noise sources on one end or the other. Most of the time, if you can
hear 'em you can work 'em unless you can't overcome local noise
arriving via different paths on the other guy's end.
>So, yes...you can assume reciprocity. You might be right,
>you might be wrong. It doesn't matter, either way.
>Just put the damned antenna up and get on the air!
If you're sinking tens of thousands into a contest station and think
that putting your tower over near a ridge will let you hear signals
beyond the ridge just fine but make it impossible to transmit equally
back to that point because of diffraction, you might want to clear
this issue up in your mind.
I don't think that folks making heavy use of HFTA just want to throw
the antenna up ;-)
>WHY did we have interesting 10m openings during CQWWSSB, with zero sunspots?
My propagation software shows the MUF still has a small chance to get
above 28MHz sometimes..
Band seems to be open to ZS from 1400 to 2000Z for example. It's
just that no one is on most of the time ;-)
I worked Z29KM on 12m CW a couple weeks ago using 100W and a half
square... I ran the propagation prediction afterward, and the QSO was
right in the middle of the predicted open times to Z2.
If you're trying to optimize your station, this stuff matters.
73,
Dan
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