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Re: Stupid Question(From a different guy)
-----Original Message-----
From: Tesla List <tesla-at-pupman-dot-com>
To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
Date: Thursday, May 06, 1999 10:19 AM
Subject: Stupid Question(From a different guy)
>Original Poster: ARSONIST01-at-aol-dot-com
>
>OK i know this sounds stupid..
> But how do you measure your spark length? i can't imagine one going
>up to the Coil w/ a tape measure and letting sparks fly at him :Þ (unless
you
>are suicidal or just plain stupid).
> Another question is what exactly does that Faraday cage do? how does
>it work? and most importanly, if its a valuable thing to have.. how do u
>build one really really fast and cheaply w/ a low budget?
>Thanks
>-Alan the Psycho
>
>
Measuring spark length: Put a calibrated grid in the background and estimate
visually. Or, more sophisticated, take photos and from known distances you
can calculate the size of the spark (the general process is called
photogrammetry, btw).
other way. Put a grounded electrode to take the spark hit, then measure the
distance from coil to electrode with a tape measure when power is off.
A Faraday cage is essentially a shielded box. The idea is that inside a
conductive enclosure, electromagnetic radiation stays there, and likewise,
EM radiation can't get through. The max hole size is determined by the
wavelength of the EM radiation in question. The perimeter of a hole has to
less than about a half wavelength for effective shielding. And, most
important, there can't be any conductor penetrating the hole (like a wire, a
screw, your finger, etc.) or it will carry the signal through the hole (even
on the outside of coax, for instance)
As to cheap and easy construction.. For the low freqs you encounter in TC
work, chicken wire would work pretty well
>