Topband: corona noise

Jon Zaimes AA1K jz73 at verizon.net
Sat Nov 17 07:07:54 EST 2012


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
> _______________________________________________
> Topband reflector - topband at contesting.com
>



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