VNA Reference Resistance

Changing VNA Reference resistance

Reference impedance 50 ohms

Reference impedance 50 ohms. Circle slightly right.

Reference impedance 52 ohms

Reference impedance 52 ohms. Circle centered to 1.0

You can iterate VNA reference resistance until the circle centered to 1.0. In this case 52 ohms provides 1.0 which means the transmission line impedance is 52 ohms.