Pri./Sec. Tuning

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Mike Knowlton" <amdx@xxxxxxxxxxx>

  Hi all,
I have been reading this group for about six weeks now and
see confusing info on pri./sec. tuning. ( to me anyway)
  My understanding is you have a secondary coil with toroid (tophat) that 
is resonant at a fundumental frequency.
  Then you wind a Primary, and wire it with capacitors in parallel, then 
adjust a tap on the primary until the primary is resonant at the same 
frequency as your secondary.
(I understand this is performed with the secondary in place.)
  My confusion is sometimes I see people say tune your primary lower or 
higher. Shouldn't they ring at the same frequency?
  Also as a tuning method, could you lightly couple a scope probe to the 
circuit and drive the primary with a signal generator, then watch for 
double peaks, then adjust the primary inductance (or capacitance) until you 
have a single peak.
                     Just curious,
                                   Mike

P.S. I aquired an 8.5" x 42" clear plastic tube today, I think it's my 
start to building a TC !
 "clear plastic"? How do I find out what type of plastic this is?
It has a 1/4" wall thickness.