locked Re: Interference with touchpad #FT8


Jim Brown
 

On 6/21/2022 7:59 AM, Eugene Morgan wrote:
I know this can be a deeper subject and not exactly about WSJT-X but the
various studies done seem to suggest that you use a 43 mix for HF baluns and 31 mix for HF chokes
See Balun Design's Web Site
See Palmar Engineering Web Site
Neither of these understand how chokes work. When I measured a Balun Designs product several years ago, it didn't look ANYTHING like their online data sheet.

Palomar sells the wrong mix parts.

See G3TXQ references
Steve (SK) was a very good lab tech, but he failed to understand that the very wide manufacturing tolerances of ferrite materials make the higher Q NiZn materials #43 and #52 unsuitable for HF chokes. I suspect that he measured only one or two parts of a given part number; I measured nearly 200 of one part, more than 100 of another, and more than 50 of a third. My take those tolerances into account. Steve's do not,
and when I bought 40 of the #52 cores he recommended, measured them all, chose cores at the limits of those I had measured, his recommendations didn't match.

Note that I have worked ONLY on common mode chokes.

73, Jim K9YC

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