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#### elton

##### New Member
8) The formular for resonance f = 1/(2pi*sqrt(L*C)) does not tell the specific values of L and C. There are an infinite set of values that give the desired frequency (big L, little C, or big C, little L, etc.) Articles on oscillators sometimes say something like "for 40 meters" use a coil with a certain reactance. Where does one learn to derive the desired reactance value for a particular frequency?

Hi elton,

At those frequencies thats coils of less than
thirty turns, just fiddle about til it goes right.

Its not infinite in practise, cos there is
capacitance between the turns, so there would be
a maximum resonance frequency to any coil.

There are calculations based on DIA and TURNS
and probably the CORE (SLUG) which will give the
henries. These are usually approximate because
lots of things can influence the result.

Maybe someone could post them, i generally just
guess then fiddle about. If it involves oscillators
and tuning, then my guess is you'll end up fiddling
about to get it right anyway.

Best of luck with it,
John

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