[TowerTalk] Measuring Common Mode Choke with Anritsu VNA

Jim Brown jim at audiosystemsgroup.com
Mon Jan 1 21:40:15 EST 2018

On 1/1/2018 6:10 PM, Avery Davis wrote:
> I apologize for not being more clear, but the point of the
> exercise is not to measure the complete complex impedance to within 10%,
> although you are right that a simple S11 reflection measurement has a
> limited impedance range depending on the instrument, but to  assess the
> suitability for use in a certain frequency range, and the S11
> measurement on a Smith chart will clearly demonstrate resonance effects
> and the effective frequency range.


Somehow I failed to clearly make the point that measurement errors 
associated with measuring high Z chokes with S11 is NOT a relatively 
small error, like 10%. It can be a VERY LARGE error, like 50-70% in 
resonant frequency. Which FAILS to allow assessment of suitability for 
use in a given frequency range.

73, Jim

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