Hi Paul,
I made S21 measurements using a test jig quite similar to Steve's. His
measurement technique seemed quite good. The (major) shortcoming of his
work is that he measured only chokes on only a few cores, failing to
understand the contribution of production tolerances to reproducible
designs.
A limitation on the precision of my data is that my fixture had to allow
measurement of many hundreds of chokes on many cores, not a few.
73, Jim K9YC
On 12/25/2022 12:02 AM, Paul Christensen wrote:
Jim (K9YC),
When making Rs measurements are you using the S11 or S21 method? Steve,
G3TXQ was an advocate of S21 while Owen, VK2OMD claims S11 results in better
accuracy with high Rs values.
I've been using S21 with G3TXQ's VNA adapter on a PC board. It's shown at
the bottom of the page in the link below:
http://www.karinya.net/g3txq/chokes/
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