Tropospheric diffraction phenomena of radio signals from the beacon satellite Explorer 22

Abstract

The amplitude of radio signals from the beacon satellite Explorer 22 has been recorded since November 1964 for the purpose of obtaining the ionospheric electron content from the Faraday effect. On a considerable number of occasions when the satellite was at low elevation angles, sudden increases in signal amplitude were observed. From detailed investigations we conclude that these enhancements are the result of diffraction of the radio waves by structures within the troposphere. These effects were observed on 20 MHz, 40 MHz, 41 MHz and 136 MHz.