Embodiments herein use a real-time system to conduct a line of sight (LOS) survey between radio sites. The system includes a drone controlled by a UAV LOS System (ULS) server to gather information regarding the LOS path between the radio sites. In one embodiment, the ULS server instructs the UAV to travel a LOS path between a first location and a second location, and determine a Fresnel radius at one or more defined locations along the LOS path between the first location and the second location. The ULS server determines a Fresnel zone between the first location and second location based in part on the determined Fresnel radius for each of the defined locations along the LOS path. The ULS server evaluates the Fresnel zone to determine if the LOS path can support a LOS wireless communication link.