Precision Measurement of Antenna System Noise Using Radio Stars

This paper reviews the National Bureau of Standards (NBS) preision noise measurements program for antenna systems which have been made using Cassiopeia A and the moon. The Earth Terminal Measurement System (ETMS) was developed by NBS to make measurements of figure of merit (G/T), and the noise equivalent flux (NEF). The accuracy of the noise measurements are, typically, between 5 and 15 percent for systems with antenna gains between 51 and 65 dB and frequencies between 1 and 10 GHz. Key words¿antenna gain; antenna half-power beamwidth; atmospheric loss; Cassiopeia A; earth terminal measurement system; figure of merit; moon; noise equivalent flux; noise measurement; radio stars; satellite communication.