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Re: Topband: Voltage at top of vertical and scaling?

To: HP <pfizenmayer@q.com>
Subject: Re: Topband: Voltage at top of vertical and scaling?
From: Jim Miller <jim@jtmiller.com>
Date: Tue, 16 Apr 2019 20:22:12 -0400
List-post: <mailto:topband@contesting.com>
Thanks all for your help on this. It sounds like my 15Kv relay at 53ft on
the 68ft vertical is safe. It's never hot switched and provides connection
to a 160 "tail" to give me my inverted L there. Best I can do on my limited
size, no tree property.

73

jim ab3cv

On Tue, Apr 16, 2019 at 7:52 PM HP <pfizenmayer@q.com> wrote:

> Just for grins - did a EZNEC free space - perfect ground - with  80 m
> vertical of #12 wire resonant at 3.55 mhz
> then put another #12 quarter wave resonant wire at right angles to the top
> thru 1 megohm -1500 watts in to the vert
> (says its 36.42 + j 0 at source ) says there is 3042 volts at angle -92.56
> deg across the 1 meg resistor .
>
> If go to 10 megs it says 3051 at -93.6 deg and base goes to 36.23 +J 0.02
>
> at 10K  its says 1245 v at -29.7 deg and base goes to 41.62 + J 8.2
>
> FWIW and grins --
>
> Hank K7HP
>
> ----- On Apr 16, 2019, at 6:38 AM, Jim Miller <jim@jtmiller.com> wrote:
>
> Is there any data on what the voltage might be at the top of a full size
> 80m vertical at 1500w input?
>
> Is there some zener like ionization at the top that limits the voltage?
>
> If so is there a way to estimate the voltage at lower points along the
> vertical? I assume the scaling wouldn't be linear since starting at the
> bottom on 36 ohms (sorta) and going to "infinity" at the top would preclude
> that.
>
> Thanks
>
> jim ab3cv
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