slinky/steel as conductor/skin effect Re: Flat Coils (II)

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>


> (NB:
> Someone may be thinking:
> Steel.  Inductive Losses.
> Turns out with the RF flowing mostly on the surface, losses
> are not real dependent on conductor materials.  And these
> are _expedient_, rather than optimized....)
>
>
>

Even though the current is in the surface, it's still passing through steel,
a not too hot conductor.  Interestingly, skin effect is what sets the upper
limit on waveguides.  Eventually, the layer is so thin, that even with very
good conductors (silver), the loss is too high.  I suspect it will be a
while before someone builds a tesla coil at 90 GHz.

There is precedent for spark excited (disruptive) RF generators at
millimeter waves (to keep this tesla coil related).  Somewhere around 1895,
Bose made the first reported millimeter wave experiments in Calcutta using a
spark excited resonator, at around 60 GHz.