[TowerTalk] Ground radials/elevated radials

[W7TMT]

Tom,

1) In your opinion where is the cutoff between "elevated
radials" and a "ground plane" system. How high off the
ground does the system need to be before it becomes a GP
rather than an "elevated radial" system?

and

2) How does the efficiency of 50-60 on-the-ground radials
compare to a reasonable number of radials (insert your
number of radials required here) that are installed under
the feedpoint of a vertical when the feedpoint is let's say
a 1/4 wave off the ground. W4RNL has some pretty interesting
models on his site (http://www.cebik.com/gp.html) showing
rather impressive low angle radiation patterns for the
elevated GP but that article doesn't address the efficiency
issue you're addressing in this thread when the "elevated
radials" are relatively close to the earth. Further, if it
was practical to install a vertical either on the ground
with an excellent radial system as you've described or
elevated a 1/4 wave with the appropriate number of redials
which would you choose?

73 
Patrick 
W7TMT

-----Original Message-----
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of Tom
Rauch
Sent: Friday, October 22, 2004 21:15 PM
To: Paul Playford; 'Yo3ctk'; towertalk at contesting.com
Subject: Re: [TowerTalk] Ground radials/elevated radials

Big snip...

Let's just not imply the efficiency of four radials 1/25th
of a wavelength above ground is near 90%, like it is with
25-50 wires laying on or in the dirt.

Another big snip...

73 Tom