International comparison of thermal noise-temperature measurements at 2, 4, and 12 GHz

We discuss an international comparison of thermal noise-power measurements (GTRF-92-2), which has recently been completed under the auspices of the Co nsultative Committee for Electricity and Magnetism (CCEM). The noise temper atures of two solid-state sources with GPC-7 connectors were measured at 2, 4, and 12 GHz at the national laboratories in France, Germany, the United K ingdom, and the United States. Good agreement was found among the results f rom the different laboratories, with all results agreeing within the expand ed uncertainties, which ranged from approximately 0.5% to 2.9%. The compari son was performed in accordance with the guidelines recently adopted by the Bureau International des Poids et Mesures (BIPM).