Re: Plane wave antenna making

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

Original poster: "Charles T. Pike by way of Terry Fritz <teslalist-at-qwest-dot-net>" <ctpike-at-rcn-dot-com>

Hi Terry,

I don't think you can assume that the voltage falls off linearly with
distance.  Take a look at this paper:
www.ce-mag-dot-com/archive/01/11/mrstatic.html

Charlie

Tesla list wrote:
 >
 > 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