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Topband: FYI

To: <topband@contesting.com>
Subject: Topband: FYI
From: Tom Rauch" <w8ji@contesting.com (Tom Rauch)
Date: Thu, 16 Jan 2003 18:44:44 -0500
>       Is this another way of saying, MW signals will be attenuated when
> propagating through auroral zones; hence, residual skewed-path signal
> energy, that would ordinarily remain undetected vs a more direct
(non-skewed
> path) path, is what is actually detected under absorptive conditions?

Skewed paths for any *long distance* path certainly are somewhat common. For
example VK3ZL is slightly south of due west for me, nowhere near a polar
path, and his signal waddles around between NW and SW. ZL3REX, direct path
SW... has skewed as much as NW.

JA's and VK's skew as much as south.

LA3XI comes in from the east or southeast all summer long, like clockwork,
with very good signals.

Many times the JA's are SW, and many days the JA signals arrive from
multiple directions.

I can hear K9DX, when he is beaming NW, scattering in from the SW with 1/4
second to 1/2 second delays on the echo. (Between John's TX antenna and my
RX antenna there is probably a 60dB null on the direct path). When K1ZM and
AA1K hear JA's from the NW, I'm hearing em better from the SW. I'd bet if we
did a delay measurement, it would amount to a significant amount between
what gets here and what gets there.

There is more scattering and skewing going on than most of us ever know
about, probably because it isn't a shiny smooth mirror up above. There is
generally a poor correlation between predictions and results. Even our
Handbooks, like ON4UN's book, warn us of that.

One good test of observations not fitting explanations is to look at the
history of discussions. The only nearly 100% agreement you will see is
people with directive antennas who do a lot of listening over long periods
of time all agree not much ever comes in through the magnetic pole areas,
and paths on lower bands are not predictable.

73 Tom


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