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Secondary frequency: I got it (fwd)





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From:  RWB355-at-aol-dot-com [SMTP:RWB355-at-aol-dot-com]
Sent:  Wednesday, August 19, 1998 10:58 AM
To:  fwd
Subject:  Secondary frequency: I got it (fwd)

Hi to all,

 I want to thank all for you for your help.Okay, so I got shot down in flames,
 guys. 
He (BTW "He" is Mike Hammer) was RIGHT and I was WRONG!!

I used (as some of you assumed correctly) the 1/4 wave theory. After thinking
 about this I now can understand why a Tesla  (secondary) is not just a piece
 of wire (as in  "antenna") but rather a "lumped system". So 1/4 wave theory
 wonīt work. I (ahem, cough, cough) do have an excuse though. I built my last
 Tesla 15 years ago (I was 14) and at the time 1/4 wave was still the "hit."
 You never stop learning!!

After digging some of the new math (Medhurst & Wheeler) I can understand now
 that different diameters DO change capacitance and inductance and one cannot
 use the wire length alone.
The reason I placed the question, was because I am presently writing a new TC
 prog and if I take the time, why not do it right ?! 

After sifting through everbodyīs results and programming the new stuff I found
 Bart Andersons calcs where closest to mine (using the new math). The coils
 were unloaded (no top cap), so perhaps this is why some of you got different
 results then Bart and I did. Perhaps it is also because I didnīt take "K" for
 the Medhurst formula from a table, but rather calculated the value. This
 should be a little more exact.

My "NEW" calcs turned out:

Coil A: 6": (783 turns) (40.75mH) (7.44pf)  FRes=289.2Khz
Coil B: 3": (1571.5 turns) (24.71mH) (8.2pf) FRes=356.3Khz

Now I do have a last question: Does anyone out there have a formula with which
 one could calc the aprox. spark length. I know itīs difficult and I just want
 to give the coiler using my prog an estimation of the spark length possible.
 Iīve heard of the theory 500W are aprox 12" sparks. I donīt think this is all
 to accurate as I have buit tcīs with more input and less sparks and less input
 and more sparks. One should be able to calc the spark length using the
 capacitance and inductance of the secondary (given input power) though. Any
 ideas ?



Thanks,
Safe  and happy coiling to all,

Reinhard