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Re: [TowerTalk] snow static, Quad v. Yagi

To: <jimjarvis@comcast.net>, <towertalk@contesting.com>
Subject: Re: [TowerTalk] snow static, Quad v. Yagi
From: "Tom Rauch" <w8ji@contesting.com>
Reply-to: Tom Rauch <w8ji@contesting.com>
Date: Tue, 31 Aug 2004 21:25:05 -0400
List-post: <mailto:towertalk@contesting.com>
> Because the quad avoids the corona problems of the yagi
and lpda at high power and high altitudes, it is not
unreasonable to think that that same attribute of the closed
loop would also reduce snow and rain induced static at lower
power levels.   Let me append a question mark to that...I'd
be interested in thoughts.>>

That's right. Whats good for corona on transmitting is often
good for receiving.

> I don't buy the "radome" effect notion, though.  I'm not
made of aluminum, but I can build up a lot

Take your hand and grap a spark plug wire. Now tough that
same wire with a non-metalic chunk of fiberglass several
inches or more long. Which passes the most charge through to
your shoes and the ground?

<<of charge walking across a carpet in New Mexico, and have
an ESD event spanning close to an inch.  (> 1 mile above sea
level).   Eventually, any charge buildup on the structure
due to moving snow or rain particles will have to be drained
off.  >>

Why would it last until it hit the upper antenna, and then
in 1% more distance vanish? Is that suddenly diminishing
charge idea reasonable? I don't think so.

Also we are stuck with the problem that rain, snow, and dust
sound the same. None actually have to be incontact with the
antenna to have the noise, and the particle contact rate
does not track the amount of noise or the pitch of noise.

>> Which brings me to a corollary question...has anyone had
first-hand comparison abilities between plummer's delight
monobanders, and an array with floating elements, like a
kt34a, for example?   I'd be interested in the snow/rain
static answer if so.

All of my grounded element Yagis were every bit as bad as
insulated element Yagis, but every antenna also has driven
elements that are grounded.  Why would it make any
dofference if the director or reflector was excited with
noise, when the element with dorect coupling to the feedline
is always grounded?

The only thing that can possibly make a difference is if a
blunt edge was the target rater than a point that protrudes
outward a larger distance. Same thing that makes a quad less
likely to have corona while transmitting works OK in this
case.

Say hi to Yagisan.

73 Tom


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