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I'd like to find SWR given F, R and X outputs from my AA-600. Can somebody give me an equation or online resource? Thanks!

On Wed, Dec 28, 2022 at 09:31 AM, Bob Martin wrote:

I'd like to find SWR given F, R and X outputs from my AA-600. Can somebody give me an equation or online resource? Thanks!

First you have to compute the complex reflection coefficient Gamma in the form a +/-jb

Gamma = (Zl-Zo)/(Zl+Zo)? where Zo is 50+j0? and Zl = R +/- jX

Then you convert gamma from the? rectangular a +/- jb? form to? P@angle polar form.

Then VSWR = (1+P)/(1-P)

It is all described in the attached document with an example...


Roger

Hi Roger,

Have you found an online source for RigExpert’s documentation of how they explicitly compute these parameters in their analyzers?I’ve been searching for that documentation.

HNY,

Frank
K4FMH

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Frank M. Howell, PhD
Ridgeland, MS
frankmhowell (at) hotmail.com
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On Wed, Dec 28, 2022 at 10:13 AM, K4FMH wrote:

Hi Roger,

Have you found an online source for RigExpert’s documentation of how they explicitly compute these parameters in their analyzers? I’ve been searching for that documentation.

I don't think there is such a document available from RigExpert.? Most of their Analyzers are one port Vector network analyzers that use a bridge and a down convertor like the AA-55 Zoom drawing below.? The digitized analog signals are are used to calculate the S11 reflection coefficient.? From their R, X, VSWR are all pretty standard computations as detailed in the document I posted early.? The tools like cable stub, impedance etc. is where they have their own versions developed from VNA theory.? The AntScope 2 software is available as Open Source so if you dig into the code you might find how some of their algorithms work.?





Roger

Yes, I’ve already seen this…I can certainly depve into the (open) source code for Antscope 2.

Frank

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Frank M. Howell, PhD
Ridgeland, MS
frankmhowell (at) hotmail.com
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