On Fri, 11 Oct 2019 at 21:21, Mat Breton <ab8vj@...> wrote:
Here is an interesting video from W0QE where he shows the effect just a
fraction of an inch (a few thousands in fact) dimensional calibration error
makes in your measurements due to the delay error:
#90: Building VNA Calibration Loads - Revisited:
Others of his videos dealing with cal loads:
#78: Building VNA Calibration Loads:
You gave two identical links. I looked at only the first.
I don¡¯t follow his logic. I think however he has failed to set up his 8753
properly for the calibration kit with the result he is fooling himself. If
he has set up the 8753 properly, he certainly doesn¡¯t say so.
He uses an HP 85033D calibration kit. Attached is a photograph of what the
Smith Chart should look like if he calibrated with his 85033D kit and
measured his 85033D kit. The short should *not* be a dot, but an arc that
starts at the 9 o¡¯clock position on the Smith Chart and ends at about the
11 o¡¯clock position. On a NanoVNA at 1.5 GHz you would an arc half that
length
I got this photograph after setting up my 8753ES properly to use the HP
85033D kit he has. I calibrated with my 85052B kit, which has exactly the
same coefficients as his kit, then measured the short.
--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...
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
Kingdom
