What is the range AIS covers?
Normally, vessels with an AIS receiver connected to an external antenna placed on 15 meters above sea level, will receive AIS information within a range of 15-20 nautical miles. Base stations at a higher elevation, may extend the range up to 40-60 nm, even behind remote mountains, depending on elevation, antenna type, obstacles around antenna and weather conditions. The most important factor for better reception is the elevation of the base station antenna. The higher, the better. We have seen vessels 200 nm away, with a small portable antenna placed on an island mountain on 700 meters altitude! Our base stations cover fully a range of 40 miles and periodically receive information from some more distant vessels.
