On Apr 9, 7:05 pm, "Hal Rosser" wrote:
"usmcbrat" wrote in message

newsX8Lj.19131$4O1.19019@trnddc03... Hi All:

Is there an optimum % length for an antenna when the antenna is a simple
straight stick? 1/4 wave... 1/2, 5/8, full wave? Does it differ
depending on wavelength? If size is not a consideration, is a full
wavelength preferable?

I've Googled around a bit but haven't found a good explanation yet.

If you're talking about a vertical whip antenna, you may want to look at a
5/8 wave - but you would need to add a little coil at the bottom to match
impedence to 50-ohms.
I read somewhere that that the pattern of a vertical antenna improves as the
length approaches 5/8-wave.
Picture the pattern like a small balloon full of water sitting on a map -
and as you increase the length of the whip, you press down on the
water-balloon - making its coverage more horizontal - thus covering more
area. Some of the radiation that would have gone up now goes out.
And a dipole with 5/8 wave on each pole would make it more directional as
well.
I don't have references to point you to, just going by memory - which may -
or may not - be intact.

..64 wave is the length that gives the maximum gain for a single
element. But.. Single 5/8 elements really need a lower 5/8 element
to live up to expectations. Also, some may prefer slightly shorter
to minimize radiation at the higher angles.
If you had an EDZ, the best length for maximum broadside gain
is .64 wave per leg/pole.
But like Roy says, there is really no best element length unless
you have a specific purpose for the pattern a particular length
provides. Any gain is one direction is a loss in some other direction.
IE: the EDZ will have more gain broadside than a 1/2 wave dipole,
but less gain in the appx end fire directions. No free lunches.. :/