IRREGULARITIES IN LOWER IONOSPHERE DEDUCED FROM BEACON SATELLITE OBSERVATIONS

Received field strength measurements of the 20 MHz. transmission from Explorer 22 have been made at London, Ontario, Canada (43°N, 81°W). It was possible to perform such measurements unambiguously only during quiet ionospheric conditions. Most daytime observations showed evidence of the presence of electron density fluctuations whereas night-time observations were nearly always smooth. Interpretation of the results in terms of non-deviative absorption along the ray paths suggests that the irregularities observed are occurring at the 70 km height level and are probably the same as those thought to be responsible for the continuous signal received on high power VHF forward scatter circuits. © 1969.