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>

With high power in waveguides (many kW), you're looking at breakdown
phenomena, and hence, inherently nonlinear. I don't think that inductor that
Terry's contemplating measuring is going to actually breakdown, and hence,
will remain linear, so the low power measurement should be valid.

There are low voltage threshold effects: tunneling, etc. because of the
possible semiconducting nature of the oxide/native metal junction; that
which gives folks running multiple transmitters at the same site fits from
intermods. However testing at a few watts (sufficient to get a few volts
across any spurious junction) should be enough power to get over those.

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Monday, April 21, 2003 6:34 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>
 >
 >
 > ----- Original Message -----
 > From: "Tesla list" <tesla-at-pupman-dot-com>
 > To: <tesla-at-pupman-dot-com>
 > Sent: Monday, April 21, 2003 8:05 PM
 > Subject: Re: Electrical Properties of Aluminum and Network Analzyer was :
 > RE: Brass
 >
 >
 >  > Original poster: "Ed Phillips by way of Terry Fritz
<teslalist-at-qwest-dot-net>"
 > <evp-at-pacbell-dot-net>
 >  >
 >  > Tesla list wrote:
 >  >  >
 >  >  > 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
 >  >
 >  > Guess I disagree with that.  The increase in effective resistance due
 >  > to skin effect is independent of the current; there's no mechanism
which
 >  > could make it any different.
 >  >
 >  >
 >  > Ed
 >
 > Thats where you are wrong Ed.  At high power, things are always much
 > different than at low power.  For example, take a 10 foot piece of
waveguide
 > and hook it up to your
 > network analyzer.  The thing looks like an ideal transmission line.
 > Reflected RF is practically nil.  Now measure it again but at 600 kW peak
 > power.  You cannot imagine the
 > things that start going haywire.
 >
 >