Hi,
Xbee-Pro SX has a 65 miles range in line of sight with a high gain antenna according to its datasheet.
Does this mean that transceivers should be located high enough for a clear line of sight? Let’s say, both located at a height of 150 meters according to equation:
LOS(Km)= 3.572sqrt(h(m)*4/3)
where h is the height of both antennas