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[TowerTalk] 402-CD vs. EF-240X

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Subject: [TowerTalk] 402-CD vs. EF-240X
From: (Tom Rauch)
Date: Wed, 29 Apr 1998 23:30:24 +0000
To: <>
> Date:          Wed, 29 Apr 1998 13:29:06 -0400

> This comment got me to wondering what the advantages of insulated
> parasitic elements on a beam are.  Tom, of Force 12, whose antennas use
> insulated parasitic elements on yagis once commented that if you
> believed that by removing the insulation and directly grounding the
> elements to the boom, in plumber's delight fashion, would produce a
> quieter antenna, then go ahead and do it.  My question is, why have
> antenna designers decided to insulate anything other than the driven
> element in the first place?  Has anyone actually bothered to test the
> idea that grounding the elements of a yagi produce a "quieter" antenna
> than one with the parasitic elements insulated?

Like Tom, I seriously doubt it makes a bit of difference.

I'm certainly open to any explainations why a dc ground has anything 
to do with RF noise, unless the antenna is actually a noise source 
from element corona and the grounding or ungrounding changes the 

My grounded plummer's delight 5 element 20 meter beam was useless 
during foul weather (it was at 160 feet, the highest antenna on the 
stack), while lower antennas were pretty quiet. After I installed a 
tall 2 meter vertical above the yagi, it quieted right down and the 
vertical was useless. Both were dc grounded.

Now where'd I put my Corona?

73, Tom W8JI

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