Re: Plane wave antenna making

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Terry Fritz" <teslalist-at-qwest-dot-net>

Hi,

There are a lot of ways.  I usually just charge the coil to a known high 
voltage and short it to give a known voltage step.  The voltage is very 
proportional to distance.

Relative distance   Relative voltage
1                       1
2                       1/2
4                       1/4
8                       1/8
16                      1/16

So you can use a smaller voltage close and then back off a known distance 
for a known attenuation.  A lot depends on how accurate one cares to 
be.  At a far calibration distance (~5 feet) and a high calibration voltage 
(50.0kV) it can be extremely accurate.  I prefer using a high voltage 
supply and such as opposed to "figuring it out" on paper (computer) since I 
have the stuff.  It is easier to calibrate it with known high voltages and 
I don't have to worry with ceiling, floor, and other room effects messing 
with the fields.  E-Tesla-6 is pretty good at doing that, but the room has 
to be pretty big without much nearby stuff.

In many cases, I don't care what the voltage is, I just need to know what 
the waveform looks like so I don't worry about calibration.

Cheers,

         Terry




At 10:05 AM 6/2/2003 -0400, you wrote:
>Terry,
>
>How do you calibrate your voltage measurements?
>
>Charlie
>
>Tesla list wrote:
> >
> > Original poster: "Terry Fritz" <teslalist-at-qwest-dot-net>
> >
> > Hi All,
> >
> > I am going to loan my plane antenna to DC for awhile:
> >
> > http://hot-streamer-dot-com/TeslaCoils/MyPapers/planant/waveant3.html
> >
> > The most obnoxious part about making these is the etching of the grid 
> pattern:
> >
> > http://hot-streamer-dot-com/TeslaCoils/MyPapers/planant/Image133.jpg
> >
> > http://hot-streamer-dot-com/TeslaCoils/MyPapers/planant/Image136.jpg
> >
> > So I thought this would be a good time to try it with a solid plane
> > instead.  So I whipped one up:
> >
> > http://hot-streamer-dot-com/temp/030601-01.jpg
> >
> > it seems to work fine:
> >
> > http://hot-streamer-dot-com/temp/030601-02.gif
> >
> > The wave form is still very true without any problems.  I was originally
> > worried about eddy currents and such floating around in a solid plane, but
> > it does not seem to mater.  One "could" put a few simple slits in it too I
> > guess...
> >
> > In this case, I am just driving a toroid with a signal generator and the
> > attenuation is 5000:1 at 5 inches.  Of course, for a real operating coil
> > that distance might be 15 to 20 feet so the attenuation might be more like
> > 100000:1.
> >
> > So if one wants to make one of these and you can't etch the nice pattern
> > easily, just leave it solid.
> >
> > I also fine I hardly ever use the current sensing side for anything.  Just
> > making the simple voltage side probably covers 99% of the uses.  It is also
> > best to use very small leaded resistors and capacitors for the
> > antenna.  Trying to solder those delicate surface mount components to try
> > and squeeze out better performance is a real pain and probably not needed.
> >
> > Cheers,
> >
> >         Terry