[TowerTalk] Fwd: Fwd: OCFD

[Hans Hammarquist]

 Thank you, Rick,

I want to remember 700uF to be the answer, but how do you explain "to free space"? Even if I am a physicist I can't really explain it. You might say that the Earth has a charge that generate an electric field around it, a field that could deflect electric charged particles approaching the earth. Now I am getting too theoretical. Let's stop here.

The point is that the dipole has a capacitance, popularly called "end effect" that detune the dipole to a lower frequency. The thicker the wire the lower the frequency. The strange part to me is that it doesn't matter how thin the wire is, there is always an end effect that lower the frequency from the "ideal" dipole.

Hans - N2JFS

 

 

-----Original Message-----
From: Richard (Rick) Karlquist <richard at karlquist.com>
To: HansLG <HansLG at aol.com>; towertalk <towertalk at contesting.com>
Sent: Sun, 26 Mar 2017 16:43
Subject: Re: [TowerTalk] Fwd: OCFD



On 3/26/2017 10:17 AM, Hans Hammarquist via TowerTalk wrote:
> Hi Jim,
>
> Everything has a capacitance to somewhere. Even Mother Earth has a
> capacitance. You can select what reference point you like, Moon, Sun, Pluto. I
> never really grasped it myself when I took my classes in physics.
>

It is simple problem in electromagnetics to calculate the isotropic 
capacitance of the earth to free space, because of the spherical 
symmetry.  The answer is about 700 uF.

Rick N6RK