Ka-band scintillations: Measurements and model predictions

New propagation data from a 30/20-GHz propagation experiment at several U.S. sites, including Fairbanks, AK, and Norman, OK, are presented to examine existing models for scintillations. Beacon measurements were collected at one sample per second continuously and at 20 samples per second for selected intervals. The widely separated measurement frequencies and the wide range of measurement elevation angles of about 8-52 degrees provide a solid set of measurements to test existing models and formulate new ones. It is found that current scintillation prediction models overestimate the magnitude of scintillation. The Karasawa model was modified to fit the Fairbanks data, with this modification valid for the climate zone containing Fairbanks. The model of the radiocommunication sector of the International Telecommunication Union was examined for several sites, and an elevation angle modification was attempted to bring it into agreement with the data sets. Measurements indicate a frequency dependence of f(7/12).