In this paper, we show a propagation model that combines the modified two-ray with a ray tracing (RT) technique based on uniform theory of diffraction (UTD) techniques, as well as refractive effects of the standard atmosphere. The proposed model of a Modified Two Ray model, in a canonical scenario, is compared with a Standard Parabolic Equation (SPE) model, implemented by the authors. The proposed model pretends to improve the results obtained in the design of point to point links in mountainous terrain, typical of andean countries.