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Re: [TowerTalk] replacement guys (was ...and C31XR)

To: "StellarCAT" <RXDesign@ssvecnet.com>,"tower" <towertalk@contesting.com>
Subject: Re: [TowerTalk] replacement guys (was ...and C31XR)
From: "Tom Rauch" <w8ji@contesting.com>
Reply-to: Tom Rauch <w8ji@contesting.com>
Date: Wed, 21 Sep 2005 17:33:59 -0400
List-post: <mailto:towertalk@contesting.com>
Which is it??

Intentionally cut them to be non-resonant....

> I would however respectfully disagree with your
assessment -
> about being dead wrong. The point is that if guys are cut
to be
> non-resonant and they are by nature further away from the
antennas
> and in the wrong plane than the amount of coupling is
insignificant.

or...

> Sent: Wednesday, September 21, 2005 9:30 AM
> > As for interaction - there is a treatise on the net by a
> gentlemen that I have forgotten his name -
> > very well done overall on tower installations... he said
> in essence: for a dipole to add gain one
> > has to CAREFULLY place another length of conducting
> material in the plane, at the right distance,
> > and have the right length to JUST have a little gain...


The second one sounds like we have to plan to create a
problem.

Gain is one thing. It takes a significant percentage of
antenna current in the guy to affect gain. As far as gain is
concerned, in many cases that idea the guylines have a minor
effect is probably correct.

Nulls are another story. Very small amounts of unwanted
current can affect null areas of patterns.

The fact is a standard guyline group without sectionalizing
insulators, even though not resonant and even if  attached
2/10th of a wave below a Yagi antenna, can significantly
affect pattern nulls. It takes very little current to mess
up antenna nulls in an antenna with deep null areas.

If I had a TA33jr and ragchewed over a 1000 mile path on 20
meters, never had a dipole mounted on the tower or shunt fed
the tower,  I probably wouldn't worry much about breaking up
guylines.

It just isn't accurate to say a conductor outside the plane
of the elements, even if non-resonant, won't affect pattern.
It can affect pattern, especially when the conductor is long
in terms of wavelength and the antenna has deep null areas.

73 Tom

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