Re: errors of "error" models

Dr. David Kirkby from Kirkby Microwave Ltd <drkirkby@...>

On Fri, 27 Sep 2019 at 12:33, yza <yzaVNA@...> wrote:

17 : From A Common User's Point Of View


Allow us, please, for the sake of completeness of
an appropriate preparation of a presentation for the
Estimation of the -sine qua non- Core of the Measurement
Uncertainty that Exists in *A N Y * VNA System, regardless
of what it really is, a VNA or a NanoVNA,

Maybe if you wrote a document on this, including adequate references, much
like a scientific paper, we could follow you. But you have made endless
posts, at least one of which has incomplete definitions of the equations,
it is almost impossible for anyone to follow you.

I am sure what you have is interesting, and some will be able to follow you
- perhaps not myself as my mathematics is not very good. But the way the
information is presented makes it impossible to follow.

One of things that is important is the phase difference between the offset
male and offset short standards. This will obviously be 180 degrees at low
frequency, but will depart from this as frequency is increased. I have seen
calibration kits assembled from inappropriate parts where the phases
difference drops to zero at one frequency. It’s obviously impossible to
calibrate then. But if one standard has a phase able of 0 degrees, and the
other 10 degrees, the calibration will be poor.

The whole issue is far from simple, but the way you are presenting the
information makes it difficult for anybody to follow you.


Dr. David Kirkby,
Kirkby Microwave Ltd,
Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United

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