I think the F2 layer and NVIS are not "compatible". NVIS usually
utilizes the "D" layer, IIRC.
Quoting David Jordan <firstname.lastname@example.org>:
> Hi Folks,
> Now that the F2 layer is producing some good refraction I've got a
> question about the NVIS Jamaica antenna.
> A few years ago I built this Jamaica antenna, basically four 1/2
> wave wires or two full way dipoles fed in phase and spaced 1/2 wave
> It was a cold day in winter when the antenna went up. I cut the
> wires to 70ft ea. and spaced the dipoles at 70ft. Used 600 ohm open
> wire for the phase line and drop to the coupler. It was easy to
> match on 40m. The wires are 18ft AGL.
> The antenna works as claimed when NVIS is supported by the F2 layer.
> Much better than a dipole at 50ft for stations within a few hundred
> miles. I've always wondered if it would be worth the effort to go
> back and prune the wires...
> The question is would performance of the antenna improve noticeably
> by pruning the elements to resonance on 40m?
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