Active Antenna Array for Radio Astronomy

Abstract

The design of an effective wide-band active antenna element and an antenna array consisting of 30 such elements is described. The calculation and experiment have shown the upper operating frequency of the active element to be not less than 60 MHz, the dynamic range is 90 dB, the contribution of the amplifier intrinsic noise to the galactic background temperature is about 10 %. The cost of a short (3 m) and thin dipole with a built-in amplifier and metalware is below 45 euro. The active dipole has been tested on a 30-element antenna array which has a configuration coinciding with the subarray of the UTR-2 radio telescope employing 8.6-m long and 1.8-m dia. passive dipoles. The 3C461 ionospheric scintillation spectra observed in the experiments have shown close sensitivity and noise-immunity for both antennas that proves prospects in using this short and cheap active dipole in a giant low-frequency radio telescope of new generation.