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Re: [TowerTalk] Measuring Common Mode Choke with Anritsu VNA

To: "towertalk@contesting.com" <towertalk@contesting.com>, "jim@audiosystemsgroup.com" <jim@audiosystemsgroup.com>
Subject: Re: [TowerTalk] Measuring Common Mode Choke with Anritsu VNA
From: Máximo EA1DDO_HK1H <ea1ddo@hotmail.com>
Date: Tue, 2 Jan 2018 10:10:00 +0000
List-post: <mailto:towertalk@contesting.com>
Hi Jim,


One more question. regarding the voltage divider (from your slides) to measure 
chokes.

Should I calibrate the VNA with that voltage divider connected?


Thank you very much


73, Maximo

________________________________
De: TowerTalk <towertalk-bounces@contesting.com> en nombre de Jim Brown 
<jim@audiosystemsgroup.com>
Enviado: martes, 2 de enero de 2018 2:40
Para: towertalk@contesting.com
Asunto: Re: [TowerTalk] Measuring Common Mode Choke with Anritsu VNA

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.

Avery,

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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