Jeff,
Thanks for the interesting posting. I went to the mapping utility of
MINIPROP PLUS and saw that the ionosphere was in FULL ILLUMINATION to the
east of you, from Florida to past India.
On that basis, there is not a snowball's chance in Hell the contact was
made by long-path. That is about 37,000 km in broad daylight, with the
sun practically on the equator. No way. It had to be short-path,
something like 5,300 km to AK.
Everything considered, I have to think your 4-square beaming S/SE was
giving you spurious information, probably from a high angle back lobe.
After all, you were close to dawn at the time and that's when signals,
during the dawn enhancement, come down at higher angles. That is
presumably due to ionospheric tilts driven by solar illumination as dawn
approaches.
As for the propagation mode, you speak of the signals being strong and
with multi-pathing. My best guess is that you were picking up two
ducted modes, at different radiation angles. Those can happen as
ray-tracing with the PropLab Pro program shows that a range of radiation
angles can give rise to ducting. Ducting usually starts at a low angle,
say above the last E-mode, and goes on to higher angles. I've seen more
than one ducting mode up to 25 degrees elevation angle when using PropLab
Pro.
I would be curious as to the magnetic conditions at the time. For two
modes to be coming through like that seems unusual to me. Whether it was
quiet or disturbed conditions would seem to depend on the length of time
you heard multipathing. As I read your posting, it was until 1107 UTC.
Assuming the 1140Z in the first line of your posting should be 1040Z, it
looks like a fairly stable situation lasting 27 minutes. So my hunch is
the magnetic activity was minimal. But let's see what the magnetometers
have to say. I believe them more than my hunches.
Thanks again for the posting; a nice bit of information to start the day.
73,
Bob, NM7M
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