Set = + 1. p u – If both and then increase by 1 and repeat. – p<v hp>hp1, p Set = 1. q v – – If both and then decrease by 1 and repeat. q>u hq>hq–1, q – If = then the sub-path obstruction loss is set to 0. Otherwise the calculation proceeds as follows. p q It is now necessary to find the minimum value of normalized clearance, given by / CF, hz F1, where in self-consistent units: height of ray above profile point; hz: radius of Fresnel zone. F1: The minimum normalized clearance may be written: (107) where: (hz)i = (hr)i (ht)i (108) – (109) (hr)i, the height of the ray above a straight line joining sea level at and at the profile point is u v i-th given by: (hr)i = (hu · · / (110) div+hv dui) duv (ht)i, the height of the terrain above a straight line joining sea level at and at the profile point u v i-th is given by: (ht)i =hi+dui · / 2ae (111) div The minimum value of normalized clearance is used to compute the knife-edge diffraction geometrical parameter for the most significant sub-path obstruction: (112) The sub-path diffraction loss is now obtained from equation (31) or Fig 9. L" For some applications it may be undesirable to include sub-path diffraction enhancements. In this case a value of should be set to zero when it would otherwise be negative. L" ________________
– Set p = u + 1. – If both p<v and hp>hp1, then increase p by 1 and repeat. – Set q = v – 1. – If both q>u and hq>hq–1, then decrease q by 1 and repeat. If p = q then the sub-path obstruction loss is set to 0. Otherwise the calculation proceeds as follows. It is now necessary to find the minimum value of normalized clearance, CF, given by hz / F1, where in self-consistent units: hz: height of ray above profile point; F1: radius of Fresnel zone. The minimum normalized clearance may be written: (107) where: (hz)i = (hr)i – (ht)i (108) (109) (hr)i, the height of the ray above a straight line joining sea level at u and v at the i-th profile point is given by: (hr)i = (hu · div+hv · dui) / duv (110) (ht)i, the height of the terrain above a straight line joining sea level at u and v at the i-th profile point is given by: (ht)i =hi+dui · div / 2ae (111) The minimum value of normalized clearance is used to compute the knife-edge diffraction geometrical parameter for the most significant sub-path obstruction: (112) The sub-path diffraction loss L" is now obtained from equation (31) or Fig 9. For some applications it may be undesirable to include sub-path diffraction enhancements. In this case a value of L" should be set to zero when it would otherwise be negative. ________________
R-REC-P.526-13201309-P!!MSW-E.docx