[Antennas] RE: no radial vertical antennas

Tue, 16 Apr 2002 20:07:12 -0700

A true no radial vertical antenna is very
simply realized by using 1/2 wavelength
of tubing insulated from the ground, and
feeding it at the bottom with an L/C matching
network.  How do I know that no radials
are necessary?  Well, I A/B'ed such an
antenna with and without radials; and
also compared it to a 1/4 wave vertical
with 32 radials on 20 meters.  There is no
difference.   Note that these were measurements
made on real antennas, not simulations.
A report on this work is on my web site
at: http://www.n6rk.com/ground.pdf 

Note:  the "radialess" 1/2 wl vertical
does take advantage of the feedline as
a counterpoise.  I don't claim it would
work with a battery operated transmitter
at the matching network and no counterpoise
at all.  There is no problem with RF
on the feedline.

Rick N6RK

> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of David Kelley
> Sent: Tuesday, April 16, 2002 11:41 AM
> To: [email protected]
> Subject: [Antennas] RE: no radial vertical antennas
> 
> 
> I would just like to add that it IS possible to build a highly
> efficient vertical antenna without radials.  All you do is turn
> a dipole antenna 90 degrees from horizontal to vertical.  A
> vertical dipole radiates vertical polarization, but it needs no
> radials.
> 
> The primary practical disadvantage of the vertical dipole is
> that it is necessary to run the feedline away from the
> antenna at right angles.  An alternative is to move the
> feedline from the center closer to the bottom end while
> keeping the total vertical length equal to 1/2 wavelength.
>
> 
> 73,
> Dave

Rick Karlquist    N6RK
[email protected]
www.n6rk.com
www.karlquist.com 

> 