Quoting Ed Sonderman:

 ES> You asked if I have done any ground current experiments.  
 ES> I am not sure what you are refering to here.  I did try to   
 ES> wind some small coils to measure the current in the main     
 ES> ground wire from the base of the secondary as a means to     
 ES> tune the system but it was not successfull.  

The easiest ground path experiment uses only a fluorescent bulb
or other low pressure gas tube. Fire the coil, then touch one
terminal of the tube to a grounded conductor somewhere in the
system ground path. The ground strap is really a highly excited
RF transmission line. Observations of the energy in the ground
path would appear to show that greater brightness indicates more
energy in the ground path. Often times sparks can be drawn
directly from the tops of the copper ground rods, showing
substantial voltage in this "null voltage" point.

Small coils simply used as inductive pickups are not as efficient
as resonant pickups and detectors. Because the frequency of the 
six inch secondary has been greatly reduced by toriod loading,
any small resonate pickup coil is going to require many many
turns of some very small gauge wire. On the other hand, the next
size up of PVC thin wall drain pipe is eight inches, and a
properly wound coil with this diameter will most likely match
your current system frequency with the use of one of your smaller
toriods. This would give reams of experimental setups using high-
Q resonate coils with matching frequencies. 

 ES> I am still only using two 8.0 foot long copper clad steel    
 ES> ground rods about 3.0 feet apart.  I know you would like me  
 ES> to add at least two more.  It has been raining here all      
 ES> month so the ground is good and wet. 

Good time to pound in more pipe huh? :-)

 ES> I have not tried to raise the secondary up to loosen the
 ES> coupling.  I am going to need to get some plastic spacers    
 ES> made to do this as my original design did not take this need 
 ES> into account.  Can you tell me what the objective is here? 

Higher VSWR, more voltage.

 ES> How do I know when I have the coupling set just right? 

You get bigger sparks.

 ES> Will I get more power out of the coil?  

You should.

 ES> Will I still see the blue corona, only not as intense and    
 ES> without the sparks?

There are most likely several ways to ease the overloading and
still get more power thruput. An expanded ground system would
almost surely help you reduce some of the overloading and
splitting in the secondary. Expanded grounding decreases the
standing energy in the ground path and allows greater loading and
throughput through the secondary coil. However, it is unlikely
that ground improvements alone will totally cure the problem.

Loosening the coupling between the coils will directly relieve
any overloading that remains after ground improvements and toriod
loading have been completed. If the secondary coil is lifted up
high enough the condition will be relieved regardless of other
improvments in the system. 

Toriods can be lifted up higher to eliminate the "shorted turn"
effect that couples in the discharger. Properly positioned, the
toriod is an important tool used to reduce overloads in the
secondary coil by increasing throughput, but larger toriods place 
a greater demand on the system ground.

The end result needs to be elimination of visible corona and
splitting of the secondary. Your throughput energy in the 
system, and the spark, will improve.

 ES> You suggested to experiment with the height of the toroid. 
 ES> I think I have it set now at about 6.0".  What is your       
 ES> experience with this?

The larger the diameter of the discharger, the higher up it
should be.  

 ES> How far above the secondary do you have your 48" discharger? 

About 18 inches seems optimum on my large coil, but there are a
lot of variables.

 ES> What am I trying to accomplish? How do I know when I have    
 ES> found the optimum height? 

With a large toriod the adjustment should be made to reduce or
prevent direct strikes to the primary/strike shield. The spark 
should leave the system sideways. The secondary should not be

Richard Quick

... If all else fails... Throw another megavolt across it!