Computer modeling in the MM wave communication link design

We are looking at a rapid increase in the number of communication links and their transmission at higher and higher frequencies to answer the burst of information traffic. As a result of such activity, the problem of quick and qualified estimation of the real atmosphere influence on a link performance (possible attenuation as a first try) is springing up. Let us suppose that the link designer has the following problem: based on economical considerations or any others he must choose the antenna diameter, the transmitter power and the receiver sensitivity for both terminals and thereby determining the link budget where the atmospheric attenuation is included. This can be done using a computer especially when multi-beam antennae are involved. After that he needs the computer code, which permits him to calculate the attenuation probability distribution on the link located at in fixed area with a fixed frequency and elevation angle. Using this distribution one can find how much time in the year the link budget can be exceeded. If the received figure is unacceptable, the budget of the link under consideration must be changed and the calculations repeated. The computer code for the modeling is written in FORTRAN