[BC] More on lightning

[Mario Hieb]

Actually, lightning IS an alternating current, but it isn't periodic.

In the time domain it is approximately a pulse of nearly infinite amplitude 
and nearly infinitesimal pulse width. Mathematically, it's called the Dirac 
Delta function.

In the frequency domain, it has near-unity amplitude and near- infinite 
bandwidth. Mathematically, it's the Fourier Transform of the Dirac Delta 
function.

Probably more information than you care to know.

Mario





At 05:16 PM 5/12/2005, you wrote:
>                   /|   (Top loading radials not shown)
>                  / |
>                 /  |
>                /   |
>               /    |
>      50 ohm Feed   |
>  ==================!======= Ground ===
>
> >Second, remember that lightning is an ALTERNATING current.
>
>*** No it isn't; it is a wideband pulse that contains frequencies well up into
>the GHz region, but most energy is concentrated into the DC-17KHz region, thus
>that's why 'growlers' can be heard at VLF. See appropriate books.

----------------------------------------------------------------------------------------------------------------------------
Mario Hieb, P.E.
Consulting Engineer