An improved radio-frequency probe for the measurement of electron densities in the ionosphere

This paper describes a radio frequency technique for measuring ionospheric electron densities. Extensive use is made of linear integrated circuits and their application is discussed in some detail. Two alternative forms of the instrument are described, one measuring electron number densities from 102 to 106 cm¿3 in four linear ranges, the other covering the same variation in two overlapping logarithmic response ranges.