[Elecraft] Thinking out loud again...

[k6se@juno.com]

I wrote:

"Critical frequency is defined as the *highest* frequency at which a
signal beamed straight up will still be refracted straight down by the
ionosphere.  Signals beamed straight up which are at a
higher-than-crticial-frequency will penetrate the ionosphere."
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Ron, AC7AC wrote:

"That's a new one on me, Earl, since "refraction" is bending, not
reflection. The less refraction, the further away the signal returns to
earth."
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Note that the word I used above is 'refracted', *not* 'reflected'.  At or
below the critical frequency, a signal beamed straight up is capable of
being 'bent' 180 degrees by the F2 layer.

Maps of the Earth were produced (it used to be by the NBS, I believe -
maybe still is) showing the monthly/hourly predicted critical frequencies
as well as the predicted MUFs.

73, de Earl, K6SE