Re: Couples Therapy

Hi Antonio,

After three months reading on The List and visiting the most beautiful and
impressive sites you come up with something like k=(b^2-a^2)/(b^2+a^2) ;-).
Thank you Antonio, I thought I was almost done and had to look out for the
black hole (I suspect myself to read a lot on The List to have an excuse not
to go to the garage and finish 'Catweazle 1')

Searching the net I stumbled upon 'Coupling Questions & coil measurements',
august last year on the site
http://w4dfu.ufl.edu/listarchives/1999/August/msg00225.html. (some
mirror???)'Magical K-values', remember Antonio? When I have more time I will
look into this matter. The formula reminds me (probably because of the +/-
bit) of the formula's to calculate the secondary frequencies of a coupled
bandpass filter when k > critical:
Flow = Fres / sqrt (1+k) and
Fhigh = Fres / sqrt (1-k)
and surprise surprise, these are the same as used to calculate 'the
bandwidth' of a TC!

And now your remark about my slightly adjusted statement (to understand it

'Overcoupling is the moment that an inductive loose coupled bandpass filter
stops to increase the signal transfer and the bandpass is widened to form
two peaks in the dB/f graph (when k is increased from 0 to 1). This is on a
distinct point in the dB/f graph:
k < k-critical -> one freq-peak (fo),
k > k-critical -> two freq-peaks.'

> This condition would require explicit resistances in the circuit, and
> result in an extremely lossy Tesla coil.

I don't understand which condition would require explicit resistances in the
Could you explain this to me or could you give me some reference where to

Thanks in advance!

Ruud de Graaf