Abstract: A method and apparatus for calibrating a vector network analyzer for use with a test system using a mathematical model of, for example, a slotted line. Voltage and displacement data sampled along the slotted line, used with the mathematical model, creates a plurality of equations which may be solved to generate a reflection coefficient which may be used as an impedance standard of known accuracy and used to calibrate a VNA thereby, without actual use of precision impedance standards.