As the Fresnel zone is smaller near the transceivers, obstructions near the ends of the link have a greater impact on performance than obstructions near the center of the link. It is therefore vital to obtain the most accurate possible survey data at the two ends of the link. The planner needs to answer the following questions:
To obtain approximate answers, use a map and Google Earth(TM): an example is described in Verifying a Link End Using a Map and Google Earth.
To obtain more reliable answers, visit the site and survey the end of the link: an example is described in Verifying a Link End Using a Survey.