Phase and amplitude scintillations in the 10 to 40 GHz band

Simultaneous measurements of phase and amplitude variability were made on a 64 km slant path using five radio frequencies: 9.55, 19.1, 22.2, 25.4, and 33.3 GHz. The three middle frequencies were chosen for their relation to water vapor absorption. The amplitude data show occasional fades in excess of 20 dB superimposed on ubiquitous smaller scintillations of several decibels. The latter generally increased with radio frequency and the fluctuations at the different frequencies were only moderately correlated (e.g., < 0.7). Neither phase nor amplitude variability show effects on the molecular resonance of water vapor.