>
>
>
> YES. One VERY important caution. Antenna analyzers typically have stray
> input
> capacitance on the order of 10 pF! The equivalent circuit of a ferrite
> choke is
> a parallel equivalent circuit, and for most chokes the capacitance will be
> half
> that value. Thus, the analyzer can introduce considerable error.
Jim, you're talking about the finished choke, right?
Putting -j11,000 ohms (8pF like my MFJ-259 @ 1.8MHz ) in parallel with
30+j50 or whatever my test winding shows is basically irrelevant.
If you try to measure the impedance of a finished choke, or sweep for
resonances like I suggested, there's probably a problem. It's also a
problem to multiply excessively: "oh, I have 30+j50 with 1 turn through this
bead, so if I put 100 turns I'll get 30000+j50000" ;-)
Then that -j30000 shunt capacitance of your winding matters a lot, and your
-j10000 of the analyzer even more ;-)
It's a good point and important.
What do you think about signal generator + 1kOhm-5kOhm resistor + high
impedance high frequency 10x scope probe? That should be able to do OK from
a ham-at-home perspective at measuring the impedance in a voltage divider
setup, don't you think?
73
Dan
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