RE: Yet another first coil question

Subject:  RE: Yet another first coil question
  Date:   Fri, 06 Jun 1997 06:40:00 -0500 (EST)
  From:   Benson_Barry%PAX5-at-mr.nawcad.navy.mil
    To:   tesla-at-pupman-dot-com

Hi Matt, All,
My first coil gave 6" sparks also.  I found empirically
that a flat spiral primary with about 1" spacing between
it's ID and the secondary OD gave good spark.  The
toroid really helps a lot.


From: "tesla"-at-pupman-dot-com-at-PMDF-at-PAXMB1
To: Benson Barry; "tesla"-at-poodle.pupman-dot-com-at-PMDF-at-PAXMB1
Subject: Yet another first coil question
Date: Thursday, June 05, 1997 11:05PM

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Subject:  Yet another first coil question
  Date:   Wed, 4 Jun 1997 16:55:26, -0500
  From:   RSNV02D-at-prodigy-dot-com ( MATT MCARTHUR)
    To:   Tesla-at-pupman-dot-com

Hello all,

 I have been silently watching this list for a month or
so now (except when I argued on how caps work) and
I finally finished my first coil.  I am using a 10KV 23mA
OBIT transformer with a .0061 uF leyden jar cap. My
primary is 7" in diameter, with a total of 10 turns -at-
about 6" tall. The secondary is 3.5" PVC with 486 turns
of .025 enameled wire.  My supposive operating
frequency is around 600KHz.
  I am running two series gaps made out of brass angle
brackets and carriage bolts. My discharge terminal is
pretty cheesy, its a large globe 60 watt light bulb covered
with aluminum foil.
  The only problem I am having is that after I fire it up and
tune the primary at about 7 - 8 turns (depends on the
spark gap spacing) I only get 6 inch sparks at most.  The
sparks sre pretty weak too. The bottom of the secondary
is earth grounded and the discharge was to a spool of chicken
wire that was also grounded.
  The only thing that I can think of that is wrong is primary
secondary coupling. The secondary sits almost all the
way down in the primary.  I just read a post that said
something about raising the secondary to about an inch and
a half above the primary to improve coupling.
  Could someone please help me out here!!!???