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Re: Topband: corona noise

To: Tom W8JI <w8ji@w8ji.com>
Subject: Re: Topband: corona noise
From: Jon Zaimes AA1K <jz73@verizon.net>
Date: Sat, 17 Nov 2012 07:07:54 -0500
List-post: <topband@contesting.com">mailto:topband@contesting.com>
Tom,

What is "a lot taller"?

Would an aluminum or steel (or combination) mast extension with pointed tip, extending say 10-20 feet above the top beam -- let's say one for 20m -- help to reduce corona discharge noise in the top beam?
73/Jon AA1K

On 11/16/2012 6:58 PM, Tom W8JI wrote:
Hi would a static discharge wick mounted on the lightning rod be helpful? They seem to work well for aircraft AM radios.
<<

Anything a lot taller than the antenna being used and close to the antenna can help reduce corona from the antenna itself, because it is a better "leak point". This is why lower antennas are quieter than higher antennas during storms.
Static wicks would work especially great if our stations were in the 
air hundreds or thousands of feet above earth, with no earth contact. 
They would make the earth-isolated station assume the potential of the 
air or clouds around the station. Any corona (charge equalization) 
between the aircraft and air around the aircraft would come from the 
wicks, and not the antenna.
The problem with having wicks work for terrestrial applications is 
getting the great big earth, which is larger than most aircraft, to 
assume the potential of the clouds or air around the antenna. The 
antenna has a path to earth, so the charge just keeps coming back.
Lightning equalizes things between the sky and earth temporarily. 
Listen to an antenna during a storm, and watch out the window. When 
lightning flashes close by, the noise goes away.  I'm not sure that is 
a safe way to operate though.   :-)
73 Tom
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