A17.6.2 ITU-R P.452-16

Similarly to Recommendation ITU-R P.452-14, Recommendation ITU-R P.452-16 is implemented in SEAMCAT for clear-air portion of propagation over flat (zero-height) land-only terrain profiles with clutter at the Tx and Rx sides. No coastal or sea radio-climatic zones are accounted for. The major difference between the two versions of Recommendation lies in the definition of diffraction model. Recommendation ITU-R P.452-14 uses the Deygout diffraction model that can be a discontinuous function of the receiver antenna heights. The diffraction loss in Recommendation ITU-R P.452-16 is calculated by the combination of a method based on the Bullington construction and spherical-Earth diffraction (“delta-Bullington” model) that does not have an inherent discontinuity of the Deygout model. Additionally, Recommendation ITU-R P.676-11 (Annex 1) has been implemented for gaseous absorption calculations.