1. A method for operating a network analyzer with at least four measuring points, comprising: implementing a plurality of calibration measurements with calibration standards, using the at least four measuring points, prior to implementing measurements on a device under test, determining, via at least one processor, error matrices based on the results of the calibration measurements, implementing measurements on the device under test using, simultaneously, exactly three measuring points, determining, via the at least one processor, the measured values in each case of a fourth measuring point based on the results of the calibration measurements and the measured values of the three measuring points, wherein the three measuring points, at which measurements are implemented, belong to the set of the at least four measuring points, at which the calibration measurements are implemented; and terminating ports of the device under test using switches that are switched between a low-reflection termination and a supply of a test signal to the port, wherein the switches are long-term stable and substantially frequency independent.