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Re: Fine Tuning a Spark Gap



Hi Bill,

> Original Poster: "Wysock, William C." <Wysock-at-courier8.aero-dot-org> 
> 
> 
> To Mike, D.C., All.
> 
> I have to agree with Mike's statement below.  If one has an aluminum
> conductor in a (Tesla coil) tank circuit, that is of sufficient surface 
> area,
> I see little (if any) degredation in the performance of the circuit.  People
> have been using aluminum rectangular strip for flat spriral primary
> inductances, for many years, with very good success.  Moreover, if
> aluminum is so poor a conductor at radio frequencies, then how come
> all the commercial capacitor manufactures use this material in their
> extended foil construction?  The high end polypropylene capacitors
> using this foil exhibit very low ESR and ESL numbers, and very high
> Q's.
> 
> Of course, the conductivity of aluminum is not as good as copper.
> In coil designs where every precious joule of input energy must be
> conserved (at any cost,) then clearly, copper is the superior choice.
> 
> Granted, you wouldn't want to use aluminum wire for a secondary
> inductance, but where a primary inductance is concerned (typically
> say less then 100-150 feet in length and a strip width of say, 2",)  I
> know of a number of very effective and efficient coils that have been
> built, using this material.  One common trick has been to use 4 to 5
> strips of equal width, and sandwich them together, then wind the
> flat spiral.  Using this method, each individual strip had a thckness
> of around 0.020 to 0.030"; therefore a composit thickness of 0.100" to
> 0.150".
> 
> Bill Wysock.

Have you thought about insulating each strip before making the 
sandwich? The conductor would be even more effective though it might 
not be worth the trouble perhaps. Sort of a strip litz. I also agree 
with Mike for reasons I outlined in a couple of other posts.

Malcolm
<snip>