Re: Electrical Properties of Aluminum and Network Analzyer was : RE: Brass

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

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

Not as flawed as you might think:
1) Aluminum is substantially cheaper and lighter than copper. If you're
looking to optimize spark length/dollar, it's worth understanding aluminum's
properties.
2) Yes, the material properties are in the tables for both Cu and Al.
However, I haven't seen much handbook data or actual theoretical treatment
for RF properties of actual oxide layers, at any power level. At the worst,
the network analyzer will confirm that you can use the handbook numbers and
extrapolate, at best, you'll learn something new.
3) Sort of in the same vein, if you find an effect at the milliwatt power
levels of the network analyzer then you know there will be effects (possibly
different) at the high power level. By the way, there ARE high power network
analyzers around.


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Sunday, April 20, 2003 8:02 PM
Subject: Re: Electrical Properties of Aluminum and Network Analzyer was :
RE: Brass


 > Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>"
<dhmccauley-at-spacecatlighting-dot-com>
 >
 >
 > Terry,
 >
 > That test is severely flawed:
 > First, we already know that for the same cross-sectional area, aluminum
has
 > a higher resisitivity per unit length than copper.  No need to use
 > a network analyzer for this.
 > Secondly, a network analyzer is not going to tell you squat about how an
 > oxidized coil performs under high rf current conditions like those
occurring
 > in a
 > tesla coil.  You really need to make the measurements somehow at the rated
 > power levels you are going to operate at for the data to be meaningful.
 >
 > The Captain
 >
 >
 >
 >  > We have RF effects forcing the current to the outside and resistive
 > effects
 >  > forcing current in....  Exactly where the current goes and what the
loss
 >  > is, is an interesting problem I am sure ;-))  In a few days I am
getting
 >  > some high power RF coils that are aluminum heavy plated with silver.
They
 >  > work well since the currents travel in the thin silver layer.  What
will
 > be
 >  > fun to see is what happens if the plating gets a crack.  We "think" it
 > will
 >  > incinerate.  But have to see for sure.  Stay tuned...
 >  >
 >  > I or Gary Lau may be able to get two coils that are exactly the same
 >  > dimension but one is copper and the other aluminum and test the
resistance
 >  > on a fancy HP machine.  Soaking or boiling the aluminum one in salt
water
 >  > will certainly oxidize it well.  I'll ask the guys that know how to run
 > the
 >  > HP network analyzer beast to see if that is "easy" to do.
 >  >
 >  > Cheers,
 >  >
 >  >          Terry
 >  >
 >  >
 >  >
 >  >
 >  >
 >
 >