By definition, all satellite phones need to be operated in an open area away from buildings and trees so there is a clear line of sight to the sky. Since the satellites used for IsatPhone Pro service are in a geostationary position near the Equator you may have to direct the antenna in that direction. It follows that signal strength is reduced the farther away you are from the satellites orbit and middle distance obstructions such as mountain ranges are another factor to be considered. As long as you know where the satellites are positioned and your location relative to the satellite you should be able to determine whether or not you will have adequate signal strength to place and receive calls. For example: If you are in the 30o range, you should point the antenna straight up and your signal strength should be quite strong. If you are in the 20o range, you may get 2 bars but the service quality may be better if you pointed the antenna towards the satellite. Refer to the coverage map shown below and in the User Guide.