Topband: Covered /bare antennn wire

[Bruce]

Tom,

Thank you for your research and information. You have me convinced

My much lower BOG Beverage has a better signal to noise than my taller 
Beverages in storm events. This aligns to your research.

73
Bruce-K1FZ

----- Original Message ----- 
From: "Tom W8JI" <w8ji at w8ji.com>
To: "Bruce" <k1fz at myfairpoint.net>; <topband at contesting.com>
Sent: Thursday, November 15, 2012 12:25 PM
Subject: Re: Topband: Covered /bare antennn wire


>> As you have said it is difficult to get a A-B test unless instant 
>> switching or direct observation is available.
>
> The purpose of my test was to see if p-static was caused by individual 
> charged particles as they hit the wire, or some other mechanism like 
> corona discharge into the charged air or charged cloud of particles.
>
> My thought was if it was charged particles each making noise, the pitch or 
> frequency distribution would be at the rate of particle contact, and that 
> insulation should mute the effect by slowing rise time of charge transfer 
> from particles to the wire.
>
> Clearly the noise was all from corona at sharp points.
>
> This also agrees with the effects people with multiple antennas see, or 
> even two-way antenna on tall buildings or towers. The highest and most 
> protruding antenna has the first and worse noise. Grounded elements, 
> fiberglass housings, and other tricks make no difference at all. The only 
> thing that matters is streamers from the exact point of corona leakage.
>
> We saw this when a repeater moved from side mount on a tower to a building 
> roof peak. The fiberglass Station Master was swapped for a grounded folded 
> dipole antenna, and both were equally useless in bad weather. The only 
> thing that improved p-static noise was using an antenna well below the 
> height of other sticks on the roof, but that didn't work out because of 
> severe pattern nulls. We could raise the antenna and watch the noise 
> increase, and at the same time actually hear the same sizzling 
> acoustically through our ears and see it at night from antenna tips.
>
> Everyone with stacked monoband identical Yagis sees this on the top 
> antenna. The top antenna is always terrible in inclement weather, even 
> though the same precipitation strikes all antennas equally and the 
> antennas are all on the same tower.
>
> This all, since it all always agrees, clearly means the noise has nothing 
> to do with static drain or insulated or bare conductors. It is all about 
> where the highest voltage gradient to space around the antenna is, and how 
> easy that point can "leak" (generate corona).
>
>
>> I was hoping for a test something like, side by side identical wires, one 
>> insulated, and one un-insulated with voltage measuring devices at the 
>> ends.
>> Also separated enough not to get Beverage coupling, and using real stormy 
>> weather measuring.
>>
>> Over the insulation breakdown voltage, one would expect them to be equal 
>> anyway.
>
> Leakage current to earth was identical in my spray tests. It has nothing 
> to do with insulation breakdown. It is more like the effect of a charged 
> plastic comb. The charge obviously distributed right through the 
> insulation. I suppose if the insulation was really thick the charge 
> migration would be pretty slow, but charging of the wire is not what makes 
> the noise we are concerned with. The noise comes from corona.
>
> I've had insulated wire Beverages and bare wire Beverages since the 1960's 
> or 1970's, often at the same time as mixtures of wire. Neither is any 
> quieter for me for local storm static.
>
> My bare wire Beverages here are dead quiet even while Yagi's are useless 
> in foul weather, unless the Beverage points at the towers or are near tall 
> trees.
>
> 73 Tom
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