What range will I receive AIS information from?
The range at which you can receive AIS information depends on several factors, primarily the height of both your AIS antenna and the transmitting antenna, as well as environmental conditions. AIS operates on VHF (Very High Frequency), meaning its range is largely determined by line-of-sight communication.
Typically, AIS information can be received within the following ranges:
- Coastal and Ship-to-Ship Communication: Between 10 to 40 nautical miles, depending on the height and quality of the antennas. For example, if both antennas are mounted at a higher position (e.g., on tall masts), the range increases.
- Base Stations with High Antennas: AIS base stations with antennas mounted on tall structures, such as cliffs or towers, can extend the range significantly, sometimes up to 50 nautical miles or more.
- Satellite AIS: Some AIS transceivers or services utilise satellites to receive AIS signals from vessels over long distances. In this case, range is virtually unlimited, but this capability depends on the specific product or service being used.
Factors that influence AIS reception range include:
- Antenna Height: The higher the antenna, the greater the line-of-sight distance, resulting in better range.
- Antenna Quality: Using a high-quality VHF antenna optimised for AIS frequencies (around 162 MHz) can improve performance.
- Obstructions: Physical barriers such as mountains, buildings, or even large ships can block AIS signals and reduce range.
- Weather Conditions: Certain weather conditions, like heavy rain or fog, may slightly reduce AIS signal strength, although VHF signals are generally robust in most conditions.
For optimal performance, ensure your AIS receiver or transceiver is paired with a properly installed and positioned antenna. If you’re aiming to achieve maximum range, consider elevating the antenna and using high-quality equipment.
To get the best range with our AIS Receivers and Transmitters, pair them with one of the dedicated Comar Systems AIS VHF Antennas.
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