On Wed, 25 Sep 2019 at 15:53, <erik@...> wrote:
Using a not too good BNC Tee I performed a T-Check
Attached the measurement (.s2p) and the excel file (.xlsx) in which the
T-Check is calculated.
Next to the T-Check calculation the excel also calculates the
abs(Zin-Zout)/Z0 (the percentage absolute distance of the two impedances as
another estimate of error)
The frequency is denoted in MHz
Do ignore anything above say 500MHz
The T-Check suggests the error quickly increases to substantial levels but
the abs(Zin-Zout)/Z0 suggests there is a very systematic error in my
measurement where the absolute distance of the two rotating impedances
grows very linear with frequency.
What do you connect on the the third port of the T? Most people connect 50
ohm loads, but personally I am skeptical of the logic of that, as it means
both ports see a constant 25 ohms.
BNC calibration kits are as rare as rocking horse dung, so I doubt that the
calibration kit is working correctly.
What am I doing wrong?
Dave.
--
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
