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Re: Test results



Quoting Charlie Plyler <cplyler-at-i-america-dot-net>: 

> We are almost ready for testing using a Tesla coil to generate
> ELF pulses and I beleive this may get interesting. Time will 
> tell. 

Quoting "Christopher V. Wezyk" <wezman-at-acpub.duke.edu>: 

 > How would you go about designing a coil in the ELF range.  It  
 > seems to me that it would require extremely large values for   
 > the primary cap and coil.  

Back to C.P.

> I was wondering when someone was going to ask that question. 
> You are absolutely correct. It would indeed be beyond known 
> capabilities to construct a Tesla coil with a resonant 
> frequency in the ELF range.

> However, you can take for instance a 100khz coil, fire it up 
> and rectify the high voltage then discharge the HV DC to ground
> or a ground array at specified low frequency pulses and 
> possibly excite a traveling wave at the frequency you desire.

> There is currently some research in this area on the possible 
> ways to rectify the high voltage. I am presently leaning 
> towards a method of charging an elevated sphere with a type of
> field emission. The method does look very promising.

Charlie, all:

I have just been a-messing around. Just a few days ago Richard
Hull was discussing electrostatics and Tesla coils. He remarked
that actual experiments provide support to the idea that Tesla
coil outputs have many DC qualities. This one was all but too
easy to set up and run:

I took a simple 6 inch coil system with a foil wrapped funnel
taped to the side of the toroid. The funnel had the "pointed" end
facing away, and the tip of the funnel was rounded or "blunted"
with a small rubber ball under the foil wrap. The coil was then
tuned as a transmitter (no breakout or spark issues from the
discharger).

About twenty inches from the rounded "point" of the conical
projection, I suspended a spherical terminal 4 inches in diameter
from nylon monofiliment fishing line. A lead wire was taken from
the sphere and routed on insulators towards my system ground. All
measurements/distances were approximate, as I was changing things
constantly, but this should give an idea of the basic arrange-
ment.

The coil was fired at very low power, >1kva, and the suspended
sphere terminal distance to the toroid was adjusted until blue
corona just illuminated the space between the two. By changing
the distance between the lead wire from the elevated spherical
terminal and my system ground, thereby drawing sparks to ground,
I was able to verify the sphere was being charged by the coil. 

My next step was to build an insulated counterpoise above the
ground by stacking some large toroids on a plastic milk crate. 
I connected the counterpoise (a high voltage capacitance of small
value) to the lead wire from the sphere and discharged the
counterpoise to ground periodically with a shunt on an insulated
handle.

For all appearances, this system was acting as if the spherical
"pickup" terminal and the insulated counterpoise above the ground 
were being charged with DC from the coil. The more capacitance
added to the counterpoise, the bigger and brighter the sparks I
was able to draw to the system ground. The longer I allowed the
counterpoise to charge, the bigger and brighter the sparks I was
able to draw to the ground.

There is a lot of additional experiments I have not yet
undertaken with this rather simple apparatus. I will look into
this more in the coming days.

Richard Quick


... If all else fails... Throw another megavolt across it!
___ Blue Wave/QWK v2.12