RE: 2x9 secondary

["Dale Hall" <Dale.Hall-at-trw-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Sundog,
Good show, BTW I assume your "mood" improved as the sparks grew ?

FYI, RE: ground DC resistance measurement

While low DC resistance is a good assurance, it is the 
Inductive reactance of that path
at the coils resonant frequency ~200kHz 
and the Spark frequency content ~1Mhz to 30Mhz
that determines its true effectiveness.

That is to say a high frequency ground is important objective.

It is nearly impossible to establish a good HF ground with any reasonable
length of round wire due to its inductance (reactance) per unit length.

A first order approach is to use wide copper strap (the wider the better -
reduces L/ft)
approaching counterpoise proportions.

This brings me to my advocation and effectiveness of using a "Counterpoise".

Essentially I look at a counterpoise as a large metal (Al or Cu) plate that
serves
as an effective HF ground i.e. return path for all the HF TC & Spark currents 
as well as TC field control.

It should have a large surface area (larger = better)
   At least ~10X your longest discharge: 
   Ex: 10' discharge use ~10x10 = 100sq ft)

It need not be thick, anything over a mil or so, is for practical handling
and hardiness.

It need not be solid, however commonly available galvanized coated steel
  will not be as effective as Cu or Al at high freq, but it is worth a try
if you have some.
  Does anyone know of a mfr/distr of Al mesh ? 

I envision a fully enclosed mesh 
(very large, maybe 3x-5x longest discharge, min, 
  surrounding the TC on all sides, top & bottom) 

so the TC which needs NO earth ground as all the fields are contained. 

A symmetrical toroid over the opposing TC topload 
 connected to the perfect mesh counterpoise is technically appealing.

Independent generator power is desired to avoid the AC power ground situation.

Maybe experiments of this nature could nail down the wavelength influence
issue.

What do you think ?

BTW, Magnifier wants the Sec closely coupled to the Pri & should have lower
L than 3rd coil.
2x works in my DCTC tests though optimum is likely ~>5x. 

Idea is for Pri/Sec "driver" to optimize its high current delivery
capability at a reasonable HV.
3rd coil magnifier LC load is in series resonance with the surroundings
equivalent C 
 (sparking through C's dynamic dielectric reflecting as a dynamic parallel
to series Rdc) 
which represents a low Z at resonance (XL, Xc cancel) to the driver so
a high peak current is the desired drive characteristic requiring a lower L.

Regards, Dale

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Friday, September 15, 2000 7:05 AM
To: tesla-at-pupman-dot-com
Subject: 2x9 secondary
Original poster: "sundog" <sundog-at-timeship-dot-net> 

    Hi all,

 Got bored (and in a *very* bad mood) this afternoon, so I set up a
2" secondary on my testbed to relax myself.  Today, I finally set a
mark of achievement for myself, though I don't know if I can repeat
it (I'll certainly try!)
...snip...    I must have hit the
sweet spot dead on, 'cause there was very little flashover, and
great big 20-24" streamers comin' off the thing.  

...snip...  BTW, I checked my ground (from the 120v line, and I'm
pulling 118v to my ground (and 118v to the other side of the outlet
:), and only ~10-20 ohm from house neutral to my ground.  I'd
suffice it to say it's a good ground :)  
...snip...
  A thought I just had...I've a nearly-identical secondary, so
maybe I'll try a magnifier setup?  Hmmm....The freq. of both coils
together would drop down really far.  

  Caio!  Sundog