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Re: some ?'s about a odd TC setup

In a message dated 5/28/2000 1:34:58 AM Mountain Daylight Time, 
tesla-at-pupman-dot-com writes:

>  I have a few questions about my current "practice coil",mainly questions
>  about my layout.
>   My coil uses a 555 circuit to drive a ignition coil,the coil output is
>  connected to a bank of 25 1N4007 rectifiers.The spark gap is two caridge
>  bolts spaced at about .125"and the tank cap is a MMC type cap(1 strings of
>  10 -at- .056uf/cap).The secondary resonator is 14" long 3" Dia. and wound with
>  22Awg wire,there is no topload.The primary resonator is 5 turns of 9Awg 
wire
>  spaced a 3/8" appart in a helix config.
>   Now here is the part that I have questions about.I had no where to put a
>  ground so I had very poor arcs(1/4" and problems with the sec. arcing to 
the
>  pri.)So I tried connecting another resonator to the bottom of the sec.
>  resonator(16" long/1.5" Dia. w/22Awg wire)This improved the arc output to
>  about a inch.
>  I then decided to place a coffee can on top of the second resonator and 
this
>  made the arcs about 1 1/2" long.
>   My first question is: why does doing this increase the arc length,my 
second
>  question is could this be considered a"uneven vertical bipolar coil"(that 
is
>  realy out of tune)
>  
>  TIA,
>  Kevin Dalpe
>  
Kevin,
    It sounds to me like you have more primary capacitance or inductance than 
 you need to be well tuned,.  As you add either to your secondary, your 
results improve.  Now as you noticed, you get better output as you add L or C 
to the secondary.  You can achieve the same thing by REDUCING either the L or 
C in your primary circuit(remember that the primary LC must equal secondary 
LC to be in tune)  Since you only have 5 or so primary turns, it might become 
increasingly difficult to get it well tuned and with 22g wire on the 
secondary, you will see very sharp tuning as it is, compared to using 24g.  
In other words, you go from max spark to wimpy very quickly as your tap point 
is moved away from the ideal spot, so you probably need to add a good topload 
and reduce the primary capacitance rather than the inductance.  This could be 
done by adding another cap in series and seeing how it affects the tuning(and 
repeating this process a few times until you get the best result).   You 
might get it crudely tuned this way and fine tune it with the tap on the 
primary coil.  
   As far as grounding your secondary, I don't know how your 555 circuit 
would like it, but I just attached my secondary coil to the negative side of 
the car battery I used for powering mine.  Smaller coils don't seem to need 
to be grounded as much as larger AC driven ones.   
Hope this helps,
Mike