Another disadvantage of geostationary satellite systems is that in many areas—even where a large amount of open sky is present—the line-of-sight between the phone and the satellite is broken by obstacles such as steep hills and forest. The user will need to find an area with line-of-sight before using the phone. This is not the case with LEO services: even if the signal is blocked by an obstacle, one can wait a few minutes until another satellite passes overhead, but a moving LEO satellite may drop a call when line of sight is lost.