The Moon as Source for G/T Measurements

For large-aperture antennas, it is customary to utilize radio stars in order to determine the receiving gain to temperature ratio. In the case of small-aperture antennas, which not only have reduced gain but usually higher system noise temperature as well, the y factors obtained from the radio star measurements are so small that the measurement error is intolerable. The moon, on the other hand, provides a power flux density higher by at least one order of magnitude compared to the strongest radio star, and the resulting y factors are usable. G/T ratios determined from moon measurements agree well with expected values.