Just the title attracted me to this, ID'ing core material. I have nanovna
and other stuff, Keep it up! Retired from plants with kilobuck equipment
and just MFJ and bottom feeded test equipment.
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On Mon, Jul 13, 2020 at 11:12 PM Graeme Jury <gvjury@...> wrote:
Hello Group,
Yes I know that this has been pretty fully dealt with before and I have
read all the posts but I still can't get a consistently good result.
The method that I used was to tightly wrap a single turn of 24 swg wire
around the core (or 1 turn looped through the balun core) and soldered with
minimum lead length to an sma female connector and run an S11 R/w & X/w. I
tested on a range of type 43 cores and the FT50-43 and BN43-202 matched
well plus the X = R crossover came out where I expected but the others came
out widely different and seemed to give results more like I would expect
from type 61 material.
I also experimented with an FT240-43 core and could not get the X and R
lines to crossover with 1 turn at all so I tried 2 turns and got a
crossover at around 80 MHz and 3 turns at about 25 MHz (going from memory
here as I didn't screenshot this) so I am missing something entirely I
think. I will look into Jeff Anderson's work
and see if there is a better approach that I can make but it means that I
will need to come to grips with matlab which I have not done up til now so
there will be a time delay until I get some results.
Naturally I am hoping that someone will come up with "Hey Graeme, you
didn't do this" as I am feeling that there is more that I have not done
like maybe a low inductance copper tape around the core or something.
73, Graeme ZL2APV
