Propagation phase noise identified using 40 GHz satellite downlink

Experimental evidence of the existence of propagation phase noise or phase scintillations is reported using a one-way only radio link. The noise has been found to exceed on occasions the downlink 40 GHz beacon phase noise of Italsat in what appear to be conditions of cumulus clouds and high turbulence. Experimental and theoretical values are given for the power spectral density and reference is made to past work and immediate applications to systems.