Equatorial radio scintillations of ATS-6 beacons-phase. I Huancayo 1974-75

The temporal variations of the amplitude fluctuations of the radio beam signals on 41, 140, and 360 MHz transmitted from the ATS-6 satellite and received in Huancayo, Peru, during the first phase of the ATS-6 program are described. Fluctuations at 360 MHz were observed only during the nighttime hours, while the 140 MHz signals began after sunset, reached maximum before midnight and decreased to almost zero after sunrise. The 41 MHz signals were minimum around sunrise and sunset and had maxima around midday and premidnight hours. The mean and median curves for the daily variation in scintillation index are plotted and shown. Nighttime scintillations were most prevalent during the December solstice while daytime scintillations were most frequent during the equinoxes. The frequency variations of scintillations are examined; the exponent of the frequency dependence of scintillations depends on the magnitude of scintillation.