[TowerTalk] Wireman W2DU Current Type Balun

[Jim Brown]

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/