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RE: Basic questions, Ground Options, RSG benefit

Hi Kamil,

1.) Grounding is often a compromise especially since
    I have a portable coil I take around to varying sites for demo's.

My order of preference for grounding TC: 
 directly over a pond of salt water w/short Cu strap to immersed electrode 
 directly over a pond of salt water w/short Cu strap to immersed electrode
 directly over a pond of other water w/short Cu strap to immersed electrode
 close to pond of salt water w/min length copper strap to immersed electrode
 close to pond of other water w/min length copper strap to immersed
electrode 
 directly over moist soil w/short Cu strap to buried electrode(s)
 close to moist soil w/min length Cu strap to buried electrode(s)
 etc. 

but more practically:
 I use a counterpoise (min ~2x area of topload)

  Idea is to provide the bulk of the Cap plate opposing the topload.
  (rather than the floor, walls, all else that the topload seeks as 2nd
plate)

   i.e. a large Cu sheet/clad providing main source of Sec arc peak current

   Benefit: Sources the highest possible current for beefiest sparks !
   accomplished by providing the min HFreq impedance to HV Sec Cap plates
   which is where we all Spark  (2nd plate typically more subtle)

   It is best placed just above the topload just beyond max strike distance
        (but then problem is routing connection around to Sec base)
      but usually winds up under the Pri case directly on a good ground
      or wired to a good ground via Cu strap.

 If an independent good ground is not available I use:
   a cold water pipe (or other but not gas [don't flirt w/danger])
   the AC safety ground

The counterpoise allows the use of more common external grounds as
the external ground is then for personnel safety
 and not the main part of high freq current path.
i.e. keeps TC ground structure close to people potential even during
Sparking.
 
High frequency peak current is supplied by the counterpoise & topload plate.

Situation of Most Coilers:
If you don't use a counterpoise then the wired gnd paths develop very high
peak voltages responding to the very high peak Sec current strikes.
  That is the problem. 

Whatever else is connected to that ground will experience large transients.
Even short grounds develop kilovolts !! 
Try a 2' dia wire hoop with a 1/8" gap close to operating coil, see arc
jump.
Now try bringing a few feet of your present ground wire to within ~1/8".
 Does a spark jump ? Aha ! now do you "see" the problem ?

So the danger is:
Neutral Gnd, Pipes can cause arc in electronics that are connected down
line.

Large area Cu Strapping lowers effective impedance. 

High peak current Sec Mhz impulses make the largest wires look very poor.
 
Setting up close to good grounds & use of Cu strapping is a good compromise.


2.) Performance of any coil using a static gap(s) is improved with an RSG.

  RSG's allow closer electrode spacing lowering series resistance/impedance
  combined with quick separation decreasing Off time, aka Quench
  while motion provides cooler electrodes for less hot ions to extinguish
  while synchronous timing permits control over charge and discharge times.

Regards, Dale

-----Original Message-----
From: Tesla List [mailto:tesla-at-pupman-dot-com]
Sent: Tuesday, December 21, 1999 10:31 AM
To: tesla-at-pupman-dot-com
Subject: Basic questions.

Original Poster: Kamil Kompa <czlonek-at-polbox-dot-com> 

I want to ask you several basic questions.

1. Whats wrong in making grounding with home water pipe system?
   Is it dangerous? Is coil working worse (shorter sparks) ?
   Is it good enough for small coil ?

2. Why the rotary spark gap is better? In which kind of coils should it
be    used (only high power coils , or every coil will work better)? 

Thanks for your answers.

Kamil Kompa  czlonek-at-polbox-dot-com