The cheapest way to get AIS
on your yacht

AIS stands for Automatic Identification system and was originally designed as an anti collision system for commercial shipping.
It detects any commercial ships within a 400+ square Mile area surrounding your position and warns you of their presence.
It tells you their current GPS position, speed and course, so you can take action to avoid a possible collision. The data are updated Automatically every few seconds.
Every yacht can have access to this information....

Q. Can I still use my radio as before, after the installation of the filter?

Yes, there will be no difference in comms or scanning channels.

Q. Can I transmit or scan while using the radio for AIS?

No, you can only do one thing at the time, just like before, you can not transmit while scanning or v.v.

Q. Why is AIS data only transmitted on Ch 87 and 88?

Because these were spare channels prior to 2004 and were not designated for any specific purpose.

Q. Can I receive AIS data even though I don't have a boat?

Yes, everybody can receive AIS data, as long as your VHF antenna is located near the coast or harbour. The higher you are above sea level, the bigger your reception range is.

Q. What is AIS, Automatic Identification System?

AIS is the digital transmission of data derived from GPS and shipboard sensors, via VHF radio operating according to digital communication protocols that give a voiceless exchange of navigation information between vessels and shore-side receivers. This information is continually transmitted in real-time and received by all AIS-equipped ships and shore stations in VHF range.

Q. Do all ships transmit AIS data?

For vessels on international voyages AIS is mandatory from vessels over 300GT . For vessels on national voyages it is mandatory from 500GT. and for all passenger ships.

Q. What kind of information is transmitted over AIS?

Vessels name, call sign, MMSI number, IMO number, position, course over ground, speed over ground, true heading, rate of turn, length, beam, draught, type of vessel, navigational status, destination and estimated time of arrival

Q. How will the Automatic Identification System help to increase safety?

The AIS corroborates and provides identification and position of vessels not always possible through voice radio communication or radar alone and creates an awareness of vessels in the maritime domain. The full benefits of AIS are only achieved when it is fully integrated and displayed on other shipboard navigation systems (e.g. Electronic Charts Data and Information System (ECDIS), ECS, Radar, Automatic Radar Plotting Aide (ARPA), Tracking Devices etc. Most commercial vessels comply with this.

Q. How much does Automatic Identification System transponders cost?

An approved AIS can range in price between $2500 and $5000, not including installation cost which will vary considerably depending on the level of integration of the AIS with other shipboard systems; e.g. radar, speed log, rate of turn indicator, navigation positioning system, ECDIS, etc.

Q. When did AIS regulations become effective?

AIS Regulations became effective November 21, 2003. All vessels required to have an AIS as denoted in 33 CFR § 164.46(a), must have a USCG 'type-approved' and 'properly installed' AIS on the vessel no later than December 31, 2004.

Q. Can the system receive the AIS information further than 10 nautical miles?

When the VHF antenna is set at the height of 15 meters above the sea level, the farthest receivable distance is around 20 nautical miles.

Q. How can I find a ship on Google Earth ?

For AIS Tracking you need Google Earth version 4 or higher.

Q. Can I connect my old GPS to the AIS?

The GPS connected to the AIS must fulfill the IMO performance standard. It means that the output from the GPS must be in WGS 84 and that there is no dead reckoning of the position.

Q. Under what circumstances is it allowed to switch off the AIS?

Where the master believes it is necessary for the safety of the crew and/or the vessel and/or the cargo. Eg Repairs, suspected pirate areas etc

Q. What are the differences between AIS Class A transponders and AIS Class B transponders?

Class B is intended to be a simpler, less expensive version for the use on non-SOLAS vessels. Class B is intended primarily for recreational crafts.

Q. How is GPS and chart datum collected?

AIS co-ordinates are in WGS-84, the co-ordinate system used by GPS.

Q. How is the AIS data limited to safety information?

ITU-R recommendation M.1371-1 limits AIS transmission on AIS designated channels (87 and 88) to maritime safety related messages.

Q. What does an IC look like?

A typical 16 pin IC or Integrated Circuit looks like this:


Their size is approx. 18mm long, 7mm wide and 4mm thick.

For DIY, You will get detailed, step by step, filter installation instructions.

Below is a random circuit board with a number of mounted IC's