Sorry to ask, but is he resetting the calibration each time before
calibrating? Missing that requirement was my problem last time I had a
similar issue.
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On Mon, Feb 6, 2023, 4:05 PM Brian Beezley <k6sti@...> wrote:
I put less emphasis on the 25-ohm measurement after calibrating with 50
ohms because then the load accuracy matters. I think he used a pair of
highly accurate HP loads, but who knows the exact values. Also
disconnecting the cal load and connecting the test load invites SMA issues.
That's why the original data I presented impressed me so. Cal with xxx,
then read xxx without disconnecting anything. Results should be flat to
within the data and algorithm resolution. I wonder if the divide by 16 you
noted in your uncertainty analysis is coming into play.
Brian
