THE RADIO ASTRONOMIC METHOD FOR MEASURING THE EFFICIENCY OF ULTRA-HIGH FREQUENCY RECEIVING SYSTEMS

Abstract

It is known that the working ability of a receiving system is best characterized by its effectiveness – the ratio between its effective space of the antenna to the noise tempera-ture of the system. With appearance of big antennas and high sensitivity receiving systems, the requirements set to measuring thеse parameters of antennas, such as noise tempera-ture, dissipation coefficient, effective space are increased. The Earth methods for investigating the parameters of high effective ultra-high fre-quency receiving systems turn out to be insufficient, and in some cases, impossible. Re-quirements to the parameters of today’s antennas constantly grow. The development of antenna techniques is not possible without adequate improvement and development of new methods for measuring antennas. The increase of geometrical sizes of the antenna is conditioned by the necessity of increasing the resolving power and effective space of antenna, which leads to the devel-opment of new methods for researching antenna characteristics. Such are the radio as-tronomy methods which are used largely nowadays. For measuring the parameters of big antennas, more than 10 cosmic sample sources, which satisfy the requirements to the measurement of antenna parameters with mirror aperture up to 80 m, have been selected. From those sample sources, for measuring the effectiveness in the Northern hemisphere of the earth in most cases Cassiopeia – A is used as the most powerful and non-setting etalon source. We have developed and experimentally researched the radio astronomy measure-ment method of effectiveness for UHF receiving systems which simplifies the measure-ment procedure compared to the existing methods, does not require calibration of the re-ceiving system which is important for decreasing the measurement error.