Calibration of standard horns in X band

For antenna gain measurements by the substitution technique, a precise knowledge of the gain of a standard antenna is required. It is shown that a good (+ or - 0.2 dB) accuracy can be reached by means of a usual two antennas calibration method, on condition of reasonable carefulness. This accuracy can be increased up to values consistently better than + or 0.1 dB only through extrapolation technique, which requires a dedicated (and seldom available) translational set-up. Consequently + or - 0.2 dB can be regarded as a state of the art accuracy for not dedicated, but good quality set-ups.