Radio star flux density expressions for accurate antenna gain measurements

This paper reports on measurements and analysis to resolve discrepancies in Earth station G/T measurements when using radio stars as calibration sources. The radio star flux expressions for Omega, Orion, and Virgo have been investigated to supplement the results previously reported by Ekelman and Abler (see IEEE Antennas and Propagation Society International Symposium Digest, vol.1, p.172-5, 1996), which considered Cassiopeia, Taurus, and Cygnus. Recognizing the need for accurate sources to measure antenna G/T and gain from locations in the southern hemisphere, the data for Omega, Orion and Virgo were collected (with Cassiopeia-used as the reference) and analyzed to determine accurate flux density expressions to determine antenna gain. In addition, an independent method for measuring the antenna gain was used to confirm that the gains found based on matching Cassiopeia results are correct.