[time-nuts] DIY VNA design

Dr. David Kirkby (Kirkby Microwave Ltd) drkirkby at kirkbymicrowave.co.uk
Sun Aug 21 18:59:06 EDT 2016

On 21 Aug 2016 03:19, "Attila Kinali" <attila at kinali.ch> wrote:
> Moin,
> I stumbled over a new open hardware/source VNA design:
> Unlike other designs out there, this one is very well done and has very
> little room for improvement, without increasing the price considerably.

I am not convinced that this is time-nuts related,  although I am sure many
time-nuts either have a VNA or would like one. Such a project needs its own

That said, I don't know why the author is using directional couplers.  A
bridge is much wider bandwidth.  It is more lossy though.

The software is I believe the tricky part. The VNWA software is very
sophisticated, with a lot of useful features like it can design matching
networks,   The software in the PNA-X is very sophisticated too, but in
different ways.

I don't know what the author uses, but Qt seems like best choice to me,
which can be be built on OSX, Linux and Windows.

For many measurements power levelling is not required, so that bit could be
dispensed with.

The author seems of the opinion that a lot of the hardware imperfections
can be corrected in software. Thak is true, but the the residual errors
that remain are a function of the quality of the hardware.

Anyway,  it is an interesting project,  but personally if I were going to
go to the effort of building a 2-port VNA, I would build one with 4


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