The Reflection Coefficient of the Night-time Ionospheric F Region

Abstract

Night-time records of Fa reflections at normal incidence have been made at three frequencies, 2�28, 3�84, and 5�8 Mcls, using a swept-gain technique. The reflection coefficient of the F region has been measured from these records. The reflection coefficient is appreciably lees than unity at all frequencies for a large part of the recording period. Resolved trace measurements show the absorption to occur in the deviative region. There is some suggestion of the reflection coefficient, measured at 2�28 and 3; 84 Mcls, depending on season, monthly K" sum, and true height of reflection. The reflection coefficient measured at 5�8 Mcls appears to be independent of these parameters. There is 8 suggestion that the reflection coefficient is related directly to i.E, for K indices=5, and inversely to the operating frequency.