> why aren't there more sunset enhancements?
If the theory is correct that sunrise enhancements are tied to the tilt
in the ionosphere at sunrise, then one would expect sunset enhancements
to be just as prevalent since there's a tilt then, too. But there is a
difference in the sunrise tilt and sunset tilt - the tilt (i.e., the
electron density gradient) at sunset is not as steep as the gradient at
sunrise because the recombination process at F region altitudes is
slower than the ionization process. To reiterate, all of this is not
proven - it's just the most plausible explanation we have at the moment.
And John K9UWA commented in a personal e-mail that at sunrise the noise
from the east drops off, too. That's just another effect of propagation
on the low bands at sunrise that others have mentioned previously.
Carl K9LA
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