Performance of a 3.3-mm Radiometer

The performance of a 3.3-mm radiometer, operational in the Space Radio Systems Facility of the Aerospace Corporation since December, 1963, is described, and a criterion for judging the long-integration-time performance of the radiometer is discussed. This criterion is applied to a study of radiometer output noise; from the results, it is inferred that the output noise spectral distribution is flat from a few ten-thousandths of a hertz to a few hertz.