Some examples are given of mechanically and electrically stable attenuation transfer standards, developed or assembled for the international intercomparisons GT-RF 75-A 3 and 78-1 proposed by the radio frequency working group of the CCE. A 4-port directional coupler with matched loads terminating the ports of the side arm and a switchable short interrupting the power flow in the side arm between two coupling sections was constructed for 0.01 dB in waveguide R 140 at 15 GHz. At frequencies of 8 GHz < v < 18 GHz in coaxial systems, switchable transfer standards consisting of commercially-available components incorporating a waveguide directional coupler and two isolators are the most stable and have the best repeatability. For comparing 100 dB at 30 MHz, two transfer standards applying the WBCO principles (using an R 100 rectangular waveguide) were developed, one of them for insertion into and removal from the line, the other fitted with a coaxial switch of optimal repeatability for remaining in line during the measurement.The total uncertainty of these standards is < 0.01 dB at 100 dB.

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