Topband: Effect of current max not at base of vertical.

[Mike Waters]

Guy,

I'm not saying that I understand this 100%, but I certainly do find it
fascinating. I have a question, though.

For quite some time, my understanding has been that by making a bottom-fed
vertical (or inverted-L) longer than 1/4λ --and thereby raising the max
current point-- that we simply move the point of maximum current farther out
on the radials. This makes sense to me, if we consider the thought that the
ground is an image of the antenna, the "missing" portion (for lack of a
better expression).

Other well-respected hams used to say that this condition significantly
added to the requirements for the radial system under such a longer vertical
in such a way that we now need even longer radials. Later, though, one of
these hams seems to have reversed his beliefs 180°. I don't pretend to know
the answer. (And at this point, I'm not sure anyone does. :-)

If I use a 5/16λ or 3/8λ inverted-L, how does this change the requirements
of:

1. ~60 radials stapled to the surface of the earth ?
2. An elevated counterpoise (which would of course require far fewer
radials) ?

Thanks,
Mike
www.w0btu.com

On Fri, Sep 16, 2011 at 11:03 AM, Guy Olinger K2AV <olinger at bellsouth.net>wrote:

> This is an answer to an off reflector conversation, relating to a "too
> long" electrical length over radials reducing performance.  I am writing to
> the  [snip]
>