Attempting to reconstruct rain maps using data which was obtained from Commercial Wireless Networks (CWN) has been widely studied in the past few years. Such rain maps are created via measurements from a given set of sensors and their ability to sense/detect rain in a given area depends on the specific set-up. In this paper we discuss the different problem, of detecting rain fields, using measurements from a given set of microwave links. By considering the process in which the CWN data is provided, and by exploiting the power law which describes the relation between the microwave signal attenuation and the rain rate per km, we develop an algorithm which generates maps depicting the minimal detectable rain rate. Given a functional description of a cloud profile, we may generate, for any given set of microwave links, a 2-D description (a map) which presents the minimal rain rate which such a set of links may detect. In other words, our algorithm generates maps which present the coverage of a given set of links.