Abstract: A method of automatically determining the reliability of any LOS radio link given certain parameters. Specifically, this method allows a communications network operator to specify and determine the path reliability (PR) for each backbone and extension link in a communications network for a given operating frequency, path length and climatic factor. For each link, the fade margin required (RFM) for a desired path reliability (PRD) is calculated. Then, the actual fade margin of the selected link is calculated using known radio parameters. Preferably, these known radio parameters are stored in a database to facilitate access to this information. Then, the corresponding value of the actual path reliability for the link is calculated using modifications of known statistical models which take into account climatic and geographic factors.