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

To: topband@contesting.com
Subject: Re: Topband: Voltage at top of vertical and scaling?
From: Jeff Blaine <KeepWalking188@ac0c.com>
Date: Tue, 16 Apr 2019 19:42:09 -0500
List-post: <mailto:topband@contesting.com>
I used a W1W relay at the top of mine for years without incident.

73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com

On 4/16/19 7:22 PM, Jim Miller wrote:
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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