> The only hard data I've ever seen that suggests the
> ionosphere itself
> may contribute to "one-way propagation" is the extensive
> work of John
> Wang at the FCC in the 1970s in validating North American
> signal
> strength predictions in the AM broadcast band for
> frequency allocation
> issues.
It's a shame with all the common claims of one way prop
there is only one set of hard data.
I hope my reply will make people realize there are several
very common things that can make us think there is one way
propagation.
Quite honestly I find very few cases (if any) where that
effect seems to be true other than the effective radiated
power of the other station and his noise level.
For example a certain EA3 has very good ERP but very high
noise. Someone not knowing that might hear his booming
signal and conclude when he doesn't reply heard it is just
one way prop.
When I hear the same DX stations I always seem to get the
same reports back in proportion to how they are here. If
they are weaker than normal here, I am weaker than normal
there. This is the rule, and the exceptions are really so
rare I don't notice them. I actually can't even find them
when I look for them intentionally, as Bob and I have done
for many years and thousands of exchanges.
While not finding something doesn't mean it doesn't exist,
we also tend to leap to giant conclusions. I can remember
when after one contest someone offered a theory that all
signals were ducted and the angle was always high. If I'm
not mistaken that was based on a dipole on the edge of a
cliff overlooking the North Atlantic (maybe 100-200 feet
above the water?), and it resulted in what amounted to a
rule. When I compare a near perfect 318 foot high dipole to
a near perfect 200 foot vertical in blind A B tests
(thousands of tests), the vertical by a large margin wins at
sunrise, sunset, and every time between. Not always, but
almost always. If the vertical was even three dB less signal
that would change substantially.
It really takes a great deal of data and time and thought to
find something new. My intention is to make people think a
bit before they leap.
My bet is while there are abnormal things that happen, it is
pretty rare. Spotlight propagation is often used as an
excuse for poor local receiving conditions, and one way
propagation is often used to excuse a DX stations high noise
level or a transmitting stations lack of ERP or choices in
transmitting antennas. We shouldn't write theories based on
feelings, unless we are in the mental health profession.
73 Tom
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