What is the range for AIS receivers?
Since AIS uses the same VHF frequencies as marine VHF, it has similar radio reception capabilities which is basically line of sight. This means that the higher your VHF antenna is mounted, the greater the reception area will be. Reception from Class A vessels that are 20 or even 30 miles away on open water is not uncommon. Class B transponders use lower power for transmissions, therefore you can expect Class B vessels to be acquired when they are 5 to 10 miles away. Note that AIS has a major advantage over radar since it can see ships within radio reception range that are behind large objects, such as other ships or points of land.
