This part of 61788 describes measurement of the surface resistance of superconductors at microwave frequencies by the standard two-resonator method. The object of measurementis the temperature dependence of Rs at the resonant frequency.The applicable measurement range of surface resistances for this method is as follows:– Frequency: 8 GHz < f < 30 GHz– Measurement resolution: 0,01 mÙ at 10 GHzThe surface resistance data at the measured frequency, and that scaled to 10 GHz, assumingthe f 2 rule for comparison, are reported.