Re: Primary Q's and Spark Gaps

You wrote: 
>O.K., here are some real figures based on measurement of my coil.
>Stats : Lp = 11.8uH (including a couple of feet of stray wiring)
>        Cp = 102nF  (extended foil)
>        Static Gap firing voltage = 7.5kV
>Measured Q (using sig gen and scope - i.e. no spark gap) about 50
>        => Rp about 0.22 Ohms
>Measured Q (operational using ping test and decrement calc.) =11.5  
>        => Rtot = 0.95 Ohms
>        => Rgap about 0.73 Ohms!! (accounts for 3/4 of all losses)

I guess this means your Fo ~= 150KHz.  That 0.1uF cap seems a bit large 
for that freq.  Tesla ran the Colorado lab at 80-100KHz with 0.12uF.  
You know what to do now.  Switch to 0.015uF, about 1/10 what you are 
using now and use a rotary gap.  The reactance of the primary 
components will be 80ohms instead of 10ohms.  Your Q should go way up, 
tuning get tighter, and (hopefully) sparks get longer.