ITU-R P.619-4 PDF

This Recommendation provides methods for predicting signal propagation losses for interfering signals between stations in space and stations on (or near to) the surface of the Earth in the overall frequency range of 100 MHz to 100 GHz, except for a few exceptions restricted to lower frequencies which will be specified where they are described. Prediction methods for some of the loss mechanisms are reliable over narrower frequency ranges, and some of the loss mechanisms are not significant at certain frequency ranges. This Recommendation provides methods to predict the propagation losses not exceeded for 0.001%-50% of the time. Guidance is given for single entry as well as multiple entry propagation losses in analyses that determine interfering signals, where correlations of temporal variability and location variability may be influential.