[Antennaware] Radial mats under dipole

Guy Olinger, K2AV olinger at bellsouth.net
Sun Jun 13 20:17:28 EDT 2004

One interesting thing that shows up if you model it, assuming the vee
feedpoint is directly over the center of the radials, and assuming the
radials are in good condition...

If you ground the feedline shield to the radial mat, this will
function as a current choke on the coax.

This is due to the vertical physical length (slightly over 1/8 wave)
of the feedline which takes a low impedance at ground and transforms
it upward, making the half of the doublet connected to the shield a
far more attractive current path than the outside of the shield.

This choking effect would be at maximum at height of 40-45 meters, but
is still fairly effective at 23.

----- Original Message ----- 
From: "Terry Conboy" <n6ry at arrl.net>
To: <antennaware at contesting.com>
Sent: Sunday, June 13, 2004 5:19 PM
Subject: Re: [Antennaware] Radial mats under dipole

> At 03:36 AM 2004-06-13, David Gould wrote:
> >The question is what to do with the buried radials - should the
> >radials be attached anywhere or left independent?
> Just leave them independent.  Depending on your ground conductivity,
> may improve the gain of the inverted vee by a few tenths of a dB.
> your inverted vee is a balanced antenna, there shouldn't be any need
> connect the radials to anything (assuming you use a current balun at
> feedpoint to reduce common mode feedine current).
> The radials could be used for lightning ground on the coax coming
from the
> inverted vee.
> 73, Terry N6RY


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