The determination of noise temperatures of large paraboloidal antennas

A maser receiving system may have higher noise contributions from the antenna and transmission line than from the amplifier. To develop lower-noise receiving systems, it therefore is important to know the antenna and transmission-line noise temperature as well as the receiver noise temperature. Several techniques for the measurement of absolute antenna noise temperature have been tested at the Jet Propulsion Laboratory (JPL). Experiments have been conducted at 960 and 2388 Mc using an 85-ft paraboloidal reflector with several antenna feed configurations. At 2388 Mc, an antenna noise temperature of
15\deg
K has been attained with an efficient antenna feed.