Re: A Question on tuning....

[FutureT-at-aol-dot-com (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

In a message dated 7/19/00 6:53:39 PM Pacific Daylight Time, tesla-at-pupman-dot-com 
writes:

> 
>    Mkay, am I the only one having problems tuning?  I've made my
>  mental notes and noticed general trends to tuning, but I've found
>  very little in the way of "if you do this, do that" to tuning.  IE,
>  add capacitance, less primary turns, that kind of thing.  I have
>  burned up lots of 2" diameter secondaries playing with tuning to
>  see what it does, but all I've got is notes and speculations.
>  
>    Maybe some of the upper echelon can shed some light (and maybe a
>  webpage?) devoted to this little issue.
>  

Shad,

Tuning a TC is usually pretty straightforward.  Tuning generally refers
to tapping the primary so that the primary tank frequency matches
the secondary resonant frequency, and so that max spark output
is obtained.  If you tune outward, this lowers the tank frequency
(this is needed for instance when you add a toroid, or increase the
toroid size).  Tuning inward raises the tank freq.  Generally tuning
slightly inward will give more but shorter streamers from the toroid, and
tuning outward slightly will give fewer but longer streamers.  Of course
if the coil is not designed correctly, it might be impossible to get 
enough range on the primary tap position to tune the coil at all.  In
this case, more primary turns may be needed, or a smaller secondary,
or a larger capacitor, etc.  The various TC programs that are available
are useful for designing the coil so that it is tunable (within a tunable
range).  It may be best to loosen the coupling somewhat during the
tuning process to prevent burning up your secondaries, then you can
lower the secondary again after the coil is tuned for max output.  It
is possible too that you are simply overcoupled too much despite
having a good tune point.  But if your secondaries are burning up
near the top, then the coil is not tuned right and needs to be tapped
outwards on the (flat or coned) primary.  

Cheers,
John Freau