[Antennas] VHF "Folded Dipole" question

[Robert Lay - W9DMK]

On Sun, 2 Nov 2003 13:58:45 -0700
 "John Burch" <occupant@rushmore.com> wrote:
> Assuming a folded dipole, commercially manufactured 
> for use in the 150 MHz region is operated at the design 
> frequency, what would be the characteristic impedance 
> of the antenna?
> 
> If one end of the dipole was grounded for lightning 
> protection to the boom on which it's mounted (thus 
> a DC resistance of zero), would that impact the 
> impedance significantly?
> 
> Thanks very much for the help.
> 
> John

Dear John,

It's clear to me that you should be thinking in terms of a folded,
ground plane vertical. It will have one end grounded (earthed to the
boom) and can have almost any electrical length you want. Since you
were going to be dealing with a much higher feed impedance
(characteristic of folded dipoles), you won't mind the strange
impedance that you will get with, say, a 5/8 wavelength. The GREAT
advantage is that, voila', it will be NON-directional.

73 de W9DMK (Bob Lay in Dahlgren, VA)
http://www.qsl.net/w9dmk