Rudy Severns wrote:
> I've made these kinds of matrix measurements several times since I got my
> hands on a VNA. It's not too hard and actually a lot of fun. I've found
> that if I've been careful, the reciprocal measurements are usually within 1%
> or better. This holds true even when the values themselves are really
> strange, as they can be when there's a parasitic radiator coupling into the
> array.
>
> Usually I do the measurements using only impedance measurements which is
> very straight forward but occasionally I'll use the transmission mode and a
> current transformer to do a direct measurement of coupling. Both ways seem
> to work fine as long as I pay attention to the details.
>
which VNA are you using?
I've been using Tom's version sold by TenTec.. I've been pretty happy
with it (especially now that there's CocoaVNA for the mac), although I
don't have any strong interferers, either, so the "wide open" receiver
isn't an issue.
I suspect that almost any of the new crop of analyzers/VNAs would give
good (symmetric) results on matrix measurements. It's trying to do it
with the older MFJ-259 or Autek units that would be challenging,
because of the dynamic range issues, I suspect.
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