Ionospheric temperatures during the launch of NASA rocket 8.14 on July 2, 1963

In a previous communication [Evans, 1962a] preliminary measurements were reported of ionospheric temperatures deduced from the spectrums of radar signals incoherently scattered from the F region. This early work suffered because of the very weak nature of the signals, which caused the spectrum shapes (and hence the temperatures deduced from them) to be uncertain above about 300-km altitude. Beginning in January 1963, further measurements have been made at approximately weekly intervals for a period of 24 hours at a time. These new observations have benefited from the construction of a 220-foot parabolic antenna which replaces the 84-foot antenna used in the early measurements.