Could someone tell me the length of top loading wires (4 wires planned)
needed to add to the top of a base insulated 90 foot Rohn 25g tower to
maximize the radiation resistance on 160 meters. I understand there is a
point of diminishing returns on the top loading lengths. The 4 wire
angles will be around 45 degrees or as close as possible. If I knew how
to model ,or even had a modeling program, I would attempt this already
relatively simple task to many.
From 50+ years of practical experience, I am ‘guessing’ maybe 28 feet long
each?
Ideally it would be where the antenna has the current maximized near the
center of the vertical section, lower as you fold the hat wires down.
Centering current is going to be with the hat wires way out around 60ft or
so if you use four thin wires sloped down at 45 degrees, and any radiation
resistance improvement would probably be so minor as to be unnoticeable over
just making it self resonant. That thick 90 foot radiator with a hat on
the top makes current almost uniform.
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