The effects of the satellite position on the spatial occurrence of angular scintillations

Phase interferometry, based on longitudinal (north-south) and transverse (east-west) antenna systems, was used to record scintillations in the angle-of-arrival of satellite beacon transmissions at a frequency of 136.410 MHz. It was found that the enhancement region of angular scintillations was equatorwards of the recording stations, and coincided with small angles (denoted as aspect angles) between the ray-path and magnetic field. Ninety per cent of the night-time passes, recorded at the azimuth angles 170–190°, were associated with the occurrence of scintillations; the number of scintillations decreased for satellite passes removed east or west of the plane of the station's meridian. Horizontal extents of scintillations were considerably larger east or west, than directly south of the station. Finally, no transverse angular scintillations were recorded whenever the aspect angle reached its minimum value for each satellite pass; simultaneously longitudinal scintillations were enhanced. It is suggested that the above effects are associated with a specific satellite position in relation to the recording station.