[TowerTalk] Example Faraday Cage for Lightning

[Jim Lux]

On 9/28/13 5:09 AM, Larry Loen wrote:
> Jim, what's going on in that first picture and the video "next" to it?

She's the demonstrator, wearing a lab smock.  they do the show half a 
dozen times a day.  The big Van de Graaff (largest in the world, I 
believe), a couple spark gap tesla coils, some vacuum tube tesla coils 
(probably using 817s, I didn't look that closely when I was there), and 
a couple solid state coils (FET drivers) driven with music.

They fire the big Van deGraaff multiple times, and it hits pretty much 
the same place each time, so the demonstrator can put their finger on 
the inside of the bar where the spark hits.

An interesting aspect is that the VDG is remote controlled from inside 
the cage, and the demonstrator is wearing a wireless mic.  An excellent 
demonstration that the cage provides little or no RF shielding.


>
> It looks like a comely young woman, dressed as a magician's assistant,
> is taking the entire "lightning" discharge through her finger.  I
> presume this is some sort of trick?  Why does her finger (presumably,
> carefully placed in the "inside" of the cage) attract most of the bolts
> (N.B. there's a short You Tube video just after the picture in Jim's
> first link)?
>
>
> Larry WO7R
>
>
> On Sat, Sep 28, 2013 at 4:47 AM, Jim Lux <jimlux at earthlink.net
> <mailto:jimlux at earthlink.net>> wrote:
>
>     On 9/28/13 4:33 AM, Jim Lux wrote:
>
>
>           From a "Faraday cage" standpoint, you don't need to have
>         continuous
>         sheet.  A very coarse mesh ( 1 foot spacing) will work as well.  If
>         you've ever seen the cage demos at High Voltage shows (e.g. Boston
>         Museum of Science) the bars on the cage are fairly far apart.
>
>
>     http://www.mos.org/live-__presentations/lightning
>     <http://www.mos.org/live-presentations/lightning>
>
>     or me in a cage
>
>     http://home.earthlink.net/~__jimlux/photos/dcmini15.jpg
>     <http://home.earthlink.net/~jimlux/photos/dcmini15.jpg>
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