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Re: Question regarding synchronous gap driven coils

In a message dated 97-01-31 00:51:47 EST, you write:

<< 
 Hi everyone
 
 I address this post mostly to those of you who run synchronous rotary
 gaps but will certainly appreciate responses from anyone.
 
 Here is a quick description of my latest creation although the question
 also applies to my previous smaller TCs.
 
 Secondary:240 turns #14 ga wire on a 14" x 30" skeleton acrylic frame
 
 Primary:6 turns 3/8" copper tubing spaced 3/8" apart solenoid wound on 
 18" diameter acrylic skeleton frame tapped at 5 turns
 
 Neon:15kv -at- 120ma
 
 Toroid:8" x 18" mounted 2" above top turn of secondary
 
 Primary top turn is even with lowest turn of sec giving k=.25(about)
 
 Rotary synchronous break -at- 1800rpm giving 1 break per half cycle of the
 mains at about peak of the sine wave
 
 Discharge length over 60" point to point limited by room dimensions
 
 Although the discharges maximize at the fifth turn tap, a variation of
 +/- 1/2 turn has very little effect on the discharge length although
 changing to the sixth of fourth turn has more effect. The connecting
 wires between the gap, cap and primary are from 6" to 12" max.
 
 In reading various posts it appears that those of you running static
 gaps and non-synchronous gaps obtain very definite peaking when tuning
 the primary. My question is: do those running synchronous gaps see the
 same sharp tuning or do you see the much broader peaks which I
 encounter. Also is it possible that the broader tuning is due to the
 fairly large diameter primaries and secondaries which I use or is it due
 to the synchronous gap.
 
 Skip
  >>
Skip,

I see the same thing on both of my coils.  The 6" uses a nonsynchronus gap
and the 3" uses a static gap.  Both made with high Q materials and relatively
short primary interconnects.  If the best tune seems to be at say turn 13, I
can definitely tell the differnence between turn 14 or turn 12, but not
between 12.5 or 13.5.  I think these coils, when running actually have quite
a low Q due to the discharges loading the secondary. 

Ed Sonderman