> I was thinking of building an 80m four square using
> 30' to 40' of Rohn 25G (freestanding) with the balance of
> the lenght made up of tubing.
When the diameter of an antenna changes, stuff happens.
When the diameter at the feedpoint is thin and the outer ends large,
bandwidth increases and the antenna has a nice current distribution. Thin
feedpoints and thick open ends are good.
When the antenna is uniform cross section, stuff still works OK but current
distribution and bandwidth is less. This works too.
When the antenna is thick at the feedpoint, and thin at the open end(s),
the antenna looks a lot shorter than it is physically. This is the worse
possible shape for an antenna.
I'd put a wire cage around the tubing, or the antenna will look too short
and have poor current distribution.
73 Tom
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