One often sees experts online insisting that s11 reflection impedance measurements of common mode chokes is inaccurate, and the ONLY way is s21 series measurement.
This one is built upside down so the connections are visible.
In this experiment using the SDR-KITS VNWA testboard (above), a series of measurements are made of an inductor, and the test setup.
The nanoVNA-H (modified) was calibrated using the test board and its associated OSL components. The test board is used without any additional attenuators, it is directly connected to the nanoVNA-H using 200mm RG174 fly leads.
s11 reflection measurement
Above is the s11 reflection measurement. It is quick, and most tools directly display R and X vs frequency (though some of the new age tools display X as pF or µH equivalents). This is nanoVNA MOD v3 (a derivative of nanovnasharp).
Ok, so we have 4856-j852Ω. Continue reading nanoVNA-H – a ferrite cored test inductor impedance measurement – s21 series vs s11 reflection