Satellite Beacons Observations from 1964 to 1970

From October 1964 to May 1969 the 40 MHz, 41 MHz, and 360 MHz signals of the satellite Explo- 0 0 rer 22, were recorded at Lindau (51,650 N; 10,125 E). The Faraday effect recordings at 40 MHz and 41 MHz and Dispersive-Doppler-effect recordings at 40 MHz and 360 MHz were used to calculate the ionospheric electron content up to 1000 km. The mean electron content for 1 hour periods over a period 0 of three months as obtained at 51.