SUMMARY
The methodology to properly calculate the heights of the antennas above the surface of the Earth in a line-of-sight (LOS) microwave link from its radio profile is presented. The effect of the Earth's atmosphere on RF signals, the effective Earth radius factor for Mexico and the analysis of the first Fresnel zone are described. With the proper position of the antennas ensuring clearance of the first Fresnel zone the proper reception of transmitted beams arriving from different paths to the antenna at the other end, all in phase with the direct beam in LOS is achieved.