[Elecraft] my KPA1500 and 160M

[Jim Brown]

On 9/2/2020 9:02 PM, Adrian wrote:
> A dielectric is defined as an insulator . A ferrite core is not a 
> dielectric (insulator),  This is the false fact in your theory.
You have massive gaps in your understanding of how common mode chokes 
work and the properties of ferrite materials. The best technical data 
refererence I know of Fair-Rite's catalog, which is online and can be 
downloaded as a pdf.

https://ebiz.fair-rite.com/newfair/pdf/Fair-Rite_Catalog_17th_Edition.pdf

The fundamental properties of ferrite materials vary widely depending on 
their chemical composition, commonly called "the mix," and each mix is 
tailored to a specific range of applications. A table summarizing those 
properties begins on page 4 in the print version, page 6 of the pdf. The 
resistivity of the materials listed varies over 7 orders of magnitude, 
from 50 ohm-cm to 10 exp9 ohm-cm.

My tutorial on how common mode chokes work is here.
k9yc.com/RFI-Ham.pdf
The concepts were added to the ARRL Handbook around 2011. Designs for 
practical transmitting chokes are here.
http://k9yc.com/2018Cookbook.pdf

Note that these are not "baluns," a word that describes at least ten 
very different physical things, but rather common mode chokes. Their 
sole function is to minimize common mode current. They do not do 
impedance matching. That function is provided by very different things 
best called tranformer baluns, and they come in multiple forms.

Extensive research I published in a peer reviewed AES paper in 2003 
found manufacturer's literature from the '50s/'60s indicating that they 
understood how common mode chokes work, and after I published my work to 
the ham community, an engineering manager from the CIA passed along to 
me an unclassified engineering report from the US Army in the '70s that 
was in agreement with all of the fundamental concepts I had published 
and had developed a family of designs for field use. The only thing they 
missed was the property of dimensional resonance, which I learned about 
in classic reference a colleague found in the U of Chicago engineering 
library. That reference, by E. C. Snelling, is cited in several of my 
publications.

73, Jim K9YC