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Re: Natural RF suppression?
Chris,
Tesla List wrote:
> Original Poster: mel wise <mwise44-at-flash-dot-net>
>
> Tesla List wrote:
> >
> > Original Poster: "Barton B. Anderson" <mopar-at-uswest-dot-net>
> >
> > Gary,
> >
> > Tesla List wrote:
> >
> > > Original Poster: Gary Lau 28-Oct-1998 0735 <lau-at-hdecad.ENET.dec-dot-com>
> > >
> > > >Original Poster: "Barton B. Anderson" <mopar-at-uswest-dot-net>=20
> > > >
> > > >Could you elaborate more how you constructed the aluminum standoffs in
> > > >between each copper pipe? I was discussing with someone today an idea
> > > >of using aluminum components in a sparkgap. Not to conduct energy,
but to
> > > >utilize aluminum's RF suppression characteristic to enhance quenching.
> > >
> > > What RF suppression characteristic? Are you saying different metals
> > > favor conduction at different frequencies? I don't think so.
> > >
> > > Gary Lau
> > > Waltham, MA USA
> >
> > I'm saying the conductance changes at RF frequencies for aluminum. I have
> > heard this on this list. I don't know how dramatic the change is. At first
> > thought, I was relating this to the resistive oxidation which aluminum
> > develops, but posts indicated it is at the RF frequencies which aluminum's
> > conductive ability drops, and this tells me that it is not the resistive
> > oxidation, but the actual characteristic of aluminum at high
frequencies. I
> > don't know why, and it may or may not be true, but if it is true, then
could
> > this variable be used somehow.
> > Bart
>
> Heres a question. If aluminum is not a poor RF conductor, then why is it
> usable in a capacitor? I would think that the capacitor would be
> subjected to the same RF the rest of the coil would.
>
> Chris
Of course it would, but could you imagine the cost of a commercial cap using
copper sheeting? The aluminum they use in caps is high quality aluminum
sheeting
and plays a big role in why caps are so expensive. Cost savings is in quantity
sold. Comparing cap manufacturers to the aluminum foil purchased in stores,
the
stores out sale in quantity over cap manufacturers by many magnitudes, and
store
bought foil has no need to be high quality and free of impurities. Cap
manufacturers need the best foil they can get to maintain their specs.
Because of
this and quantity purchased, their cost is high and of course, cap prices
for the
end user are incredible. I wouldn't want to imagine the cost of a cap made of
better material, but I sure wouldn't mind using one.
Bart