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Re: Grounding ?'s

In a message dated 97-02-04 01:00:32 EST, you write:

<< 
 Hi all,
 	I am just about done with my first attempt at a coil and I had a
 couple questions.
 	I am wanting to have it done for the science fair that I am
 having for my students this thursday.  My first problem is that the fair
 is in the gym.  I do not think I have the time ro run a good RF ground to
 a stake outside.  Thus my question, I know it has ben said over and over
 not to use the ground on the outlet but is there any other way to run
 one in a gym.  My transformer is really small -6kv -at- 30ma- and the
 circuit in the school gym is pretty substantial any ideas?
 	The other question is I am just about to finish the spark gap ala
 R. Quick.  and was wondering if an industrial wet/dry vac motor would
 work better or worse than a muffin fan motor?  I have both and thought
 that maybe the vacuum motor would increase the quench rate?
 	One last thing, I know there have been meny postings on how to
 build chokes and I was wondering if the I really should have them for
 such a small transformer and if so the building directions one more
 time.
 	I really really apreciate any help offered, and thanks for all
 the help already given in the list.
 
 Adios
 Ronnie Pittman
  >>
Ronnie,

For a small, low powered coil as you describe, you should be able to get good
performance by using a counterpoise instead of a real earth ground.  You need
a metal plate, screen, etc. the larger the better but 4' x 4' should work.
 Place it on the floor spaced up maybe on some quart jars and connect the
bottom of the secondary to it.

I built and use two of the Richard Quick cylindrical gaps.  The small muffin
fans work fine for me.

You might want to place a 3,000 ohm 10 or 20 watt resistor in series with
each leg of the transformer.  I also have 1 mh chokes in series with each
resistor.  I made mine with 1.5" I.D. toroid forms and as much #24 pvc
insulated wire as I could get on them.  You really want about 5mh or more
which means larger toroid forms or much smaller wire.

Ed Sonderman