atmospheric unpredictability, resulting in a higher fade margin during the planning phase. At lower frequencies of 7 GHz, the FM is kept at about 35-40 dB. Outage Calculation ( Pw) Once the received power and fade margin have been calculated, the next step is to calculate the outage. To calculate the outage (based on ITU-R 530), the following inputs are required: Fade margin (FM) Frequency of operation f (GHz) Hop length d (km) Geoclimatic factor K pL factor Magnitude of path inclination EP From the calculations above, the FM can be calculated. The frequency (in GHz) and hop lengths are known inputs. However, the pL factor needs to be found from the ITU-R Recommendations and the geoclimatic factor calculated. pL factor This is the percentage of time that the average refractivity gradient in the lowest 100 m of the atmosphere is less than 100 N units/km. Geoclimatic Factor This is dependent upon the location of site, i.e. latitude and longitude, pL factor and antenna heights. The following are the empirical relations. For overland links (TX and RX antenna heights < 700 m AMSL) (3.34) For overland links (TX and RX antenna heights > 700 m AMSL) (3.35) For links over medium sized water bodies, coastal areas, lakes, etc. (3.36) For links over large bodies of water or coastal areas besides such bodies of water (3.37) Microwave Link Planning where the coefficients of latitude su are given by CLat = 0, 53°Nor°S 60° Nor°S CLat = 0.7, 60° Nor°S and the longitude coefficients CLon are given by CLon=0.3, Longitudes of Europe and Africa CLon==-0.3, Longitudes of North and South America CLon=0, All other longitudes The month that has the highest value of pL is selected from the four seasonally representative months of February, May, August and November for which maps are shown. However, for latitudes greater than 60° N and S, only the maps of May and August must be used. Magnitude of Path Inclination If the antenna heights he and h1 metres above sea level or some other reference heights are known, the magnitude of path inclina