On 11/10/2017 7:37 PM, Jeff wrote:
I have been poking around using AutoEZ (a front end for EZNEC) where
the guy has cooked up a comprehensive model for the 4-square inclusive
of a hybrid combiner.
You've described a really good process, Jeff. One caution that you're
probably aware of, but just in case -- NEC can get real picky about
segment length in certain situations, and I think that parallel wires is
one of them.
One data point -- when I made the 100 ft vertical section of my 160M Tee
two wires rather than one, spaced by 6-8 inches, the 2:1 SWR bandwidth
approximately doubled. The tuning, of course, moves slightly down in
frequency. You're also quite right to be concerned about twisting. Mine
does twist, and I've been too lazy to do what's needed to fix it. The
method you describe sounds like a good one. The tree guys are coming
around in a month or two to rig one end of that antenna higher (and
re-rig an 80M dipole that I lost in a storm last spring), and I'll take
that opportunity to re-build that vertical section with more spacers.
But I can't use your method of anchoring each vertical wire separately,
because my vertical blows around too much in the wind.
As I'm sure you know and Bill both know, effective bandwidth of the
array is affected both by that effective conductor diameter and the
array spacing. And your model will take that into account.
73, Jim K9YC
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