Topband: Re: SSW propagation on 160m

[Robert Brown]

Eric,

Many thanks for your note and thoughts about the SSW problem.  I think you
will see that my approach has been to stay close to the more conventional
aspects of propagation, particularly the parts that have been totally
ignored in proposing the guidance of signals by the terminator.  In doing
that, I think I have demonstrated terminator guidance is not a viable
solution to the problem.  The turbulent scatter mechanism occured to me as
I was working on the ozone problem and saw good evidence that the lower
ionosphere was not static; indeed, the turbulence of regions around
weather fronts would seem to support the idea of scattering regions
developing during winter.

I limited my discussion to the SSW path as that was the only part that
I had any ozone data for and, also, because there was no great supply of
negative ions in the evening hours for the VLF method to work on.  I was
not keen on speculating without data to go on; there has been enough of
that already and everybody is repeating themselves, ad infinitum.

I do believe there are plenty of observations along conventional
short-paths.  Of course, they are highly variable, as we see from all the
postings on the Top Band Reflector.  In a general way, I think of that as
due to meteorological effects on the ionization in the D-E regions, being
tilted, etc.  The ionization probably stays intact, as far as number
densities are concerned, but turbulence can make it "lumpy", into
scattering regions.

As for conjugate work, I am familiar with some parts of it.  While at
Berkley, my reseach group carried out conjugate point work, flying
balloon-borne radiation detectors between Alaska and Macquarie Island as
well as Iceland and the Syowa, the Japanese base in Antarctica.  We found
good correlations in electron bombardment between the two hemispheres with
large substorm events but weaker events and pulsating patches did not
always show up in both hemispheres, suggesting motions of the field-line
regimes.


I am not familiar with 1.8 MHz RF penetrating the ionosphere and being
ducted in the magnetosphere.  It was my impression that regular
observations of that frequency range required satellite detectors above
the ionosphere.  Again, in terms of simple explanations, that sort of
thing seems to be a bit far-fetched but that may just be my ignorance.  In
other words, I am looking for explanations that involve regions where I
well know the 1.8 MHz RF travels, below the 200-250 km region without any
great attenuation.

I agree that more observations are needed and we may have an opportunity
with the upcoming A61AJ operation.  If the SSW/SSE paths are for real,
then there should be successful QSOs with the aid of terminator guidance.
I seriously doubt it and have said so, giving my reasons, albeit quite
conventional.  If the A61AJ experiment works, you and others should put
together your ideas for the rest of us to look at.

That's about all that comes to mind at this early hour. As I said, my
views are very conventional; I've read my share of articles and
dissertations on things like "Long delayed echos" and have no stomach for
getting into that type of discussion.  It seems endless, no-productive and
ends up with everyone unsatisfied.  Maybe that's the way we should go but
count me out.

73,

Bob, NM7M


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