Re: Trying to understand the T-Check outcome of the nanoVNA
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Hi Erik
One note If you are using the NanoVNA-saver and has entered the calibration kit data as a female kit (adding the delay of the Thru adaptor (2 x 62ps) for the short and open, then you only need to subtract the delay of the Thru adaptor for the s21/s12 measurements to have the right phase (0 degree) at both the two SMA male adaptors. Kind regards Kurt -----Oprindelig meddelelse----- Fra: [email protected] <[email protected]> P? vegne af erik@... Sendt: 25. september 2019 16:54 Til: [email protected] Emne: [nanovna-users] Trying to understand the T-Check outcome of the nanoVNA 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. I did calibrate using the Tee without (OSL) and with (T) the outgoing cable connected but maybe that did result into the error. What am I doing wrong? |
Kurt Poulsen