At 04:00 PM 8/11/98 -0400, w8ji.tom wrote:
...
>The "real" optimum angle may be quite different than the measured or
>modeled optimum angle and varies from day to day and moment to moment and
>can not be measured or modeled with antennas at one height. After many
>suggestions wave angle can be measured near earth, I'm glad to see others
>recognize the serious flaw in that thinking.
>
>Models of wave behavior in complex and esoteric things like dirt or
>ionosphere need validation or they are just guesses.
Just 2 comments:
First, of course the predictions are just that, and have only statistical
validity. They probably won't describe the actual situation if you could
measure it at any given time, which is why they use the monthly average SSN
as their key parameter.
Second, in the case of IONCAP and VOACAP, the predictions are *very*
validated, through a network of observers and observations that go back
through at least 3 complete solar cycles. The VOACAP suite also includes
ICEPAC, which also produces the probability that a given path will be open,
at a given frequency and time of day, for a given solar flux. That's a
pretty useful number for band planning in contests.
73, Pete Smith N4ZR
In wild, wonderful, fairly rare WEST Virginia
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