OK, thanks Jim.
This has been a very educational thread.
I read your document once but I need to go back and take more time and study
it.
There is far too much information in it to be comprehended in a single
reading.
73
Rick, DJ0IP
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Jim Brown
Sent: Wednesday, April 24, 2013 8:24 AM
To: tentec@contesting.com
Subject: Re: [TenTec] Built in SWR meter bannans
On 4/23/2013 10:27 PM, Rick - DJ0IP / NJ0IP wrote:
> OK, I got the point on too little common mode impedance causing the
> damage, but there is nothing wrong with using Teflon covered wire, is
there?
Dielectric constant will be different, which changes the capacitance, which
changes the shape of the Z curve. THHN yields a particularly nice Z curve.
I haven't looked at Teflon, which might be fine too, or maybe not.
Fundamental truths.
1) The heat is produced in the WIRE, NOT THE CORE. It is the WIRE that gets
hot.
2) Heat is produced by common mode current in the resistance of the parallel
resonant circuit. P is I squared R, and P becomes smaller twice as fast as R
becomes larger (because I is squared in the equation).
3) Chokes fail because R is too small. Period. R depends on the core
material and the physical details of the winding.
73, Jim K9YC
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