AIT2500 – Class B+ 5W AIS Transponder

If you want to stop transmitting your position, you can either fit a physical silent switch on the AIS transponder or you can stop the AIS transmission through the ProAIS2 software.

You can stop the AIS transmission of our iAISTX & AIT5000 with their built-in web interface. Easy to stop the AIS transmission with your smartphone.

The AIS transponder can be configured with the free PC/Mac software called ProAIS2. The ProAIS2 software can be downloaded free of charge directly from our website. The functionality of the proAIS2 software is the same on Windows or Mac.

Installation of the proAIS2 software, also installs the USB drivers and we recommend not plugging the transponders USB cable in to the PC/Mac until after you have installed proAIS2. Once the installation is complete, plug the USB cable in to the computer to complete the USB driver installation. The transponder receives enough power from the USB connection to power the processor and ancillory circuitry required to configure the transponder, however the GPS will not get a fix, the NMEA interfaces will not be working and the transponder will not transmit while on USB power.

Digital Yacht are not the only company that supply proAIS2 with transponders, but to our knowledge, we are the only company to produce a video showing how to configure and diagnose Class B transponders with it. So we hope that not only Digital Yacht users but owners of other brands will benefit from this video.

Please note that the MMSI number cannot be changed once the product has been configured. To change the MMSI number, you must reset the product and for that, please contact us.

To find out how to use the proAIS2 software to configure an AIS transponder, please watch the video below: https://www.youtube.com/watch?v=FTiMynP8KDs

If the AIS transponder doesn’t have a built-in VHF splitter (i.e. AIT5000), there are 2 options: either install a dedicated VHF antenna for AIS or install an antenna splitter so that the main VHF antenna is used for both VHF radio and AIS.

For those who want to use their existing VHF antenna, then we recommend the use of a certified zero loss VHF antenna splitter such as our SPL1500 and SPL2000. Please do not use a non-zero loss certified VHF antenna splitter. They are inexpensive, but they can destroy your AIS transponder.

For those who want to install a VHF antenna dedicated to AIS, then we recommend a VHF antenna tuned to AIS frequencies. The AIS transmission and reception works on 2 dedicated channels which use the frequencies 161.975 and 162.025 MHz (channel 87B and 88B). VHF frequencies in the maritime environment use frequencies from 156.0 to 162.025 MHz and most VHF antennas are designed to provide maximum gain on channel 16 (156.8 MHz). You can now find antennas on the market dedicated to AIS frequencies such as the HA156 antenna.

These antennas, dedicated to AIS frequencies, offer maximum gain at 162 MHz (which is the centre between the 2 AIS frequencies 161.975 and 162.025 MHz). So if you install a VHF antenna instead of a VHF antenna splitter for your AIS receiver or transponder, then choose an AIS frequency VHF antenna to compensate for the loss due to the installation of the antenna lower down than the main VHF antenna at the top of the mast. The graph below shows how a dedicated AIS frequency antenna (162 MHz) provides a better VSWR and therefore a better transmission and reception.

There are 3 types of AIS transponders: Class A, Class B and Class B+ :

• Class B AIS Transponder is for recreational craft installation and is a simplified, lower powered 2W transceiver which is normally a black box and uses a connected chart plotter to display local AIS targets. It transmits every 30 seconds regardless of vessel speed and can’t transmit additional data like destination port.
• Class B+ AIS Transponder (also called Class B SOTDMA or Class B 5W ) is a new standard that utilises SOTDMA format transmissions which offer a 5W power output (2.5 x more powerful than a regular Class B), a guaranteed time slot for transmission in busy traffic areas and faster update rates depending upon the speed of the vessel. It’s ideal for ocean sailors requiring the best possible performance and future proof satellite tracking applications, fast power boats and smaller non-mandated commercial vessels.
• Class A AIS Transponder must have a dedicated (and type approved) display to show the location of nearby AIS targets and transmits at 12.5W. Data is sent at up to every 2 seconds depending upon the vessel speed and the display also allows for data to be inputted to the transmission such as vessel destination. A Class A device is normally used on commercial vessels as its Type Approved to IMO specifications.

To help you choose the AIS transponder that best suits your needs, the following guidelines may be useful:

• Receive AIS targets on a chartplotter
  If you only want to receive AIS targets on a chartplotter, you can choose between the AIT2500, AIT6000, or iAISTX Plus. These units feature NMEA interfaces for connection to a chartplotter. If you have an older chartplotter, ensure that it is AIS-compatible. In that case, you will need either the AIT2500 or the AIT6000, as these are the only AIS transponders that support the legacy NMEA 0183 interface.

• Receive AIS targets on software or mobile applications
  If you wish to receive AIS targets exclusively on navigation software or mobile applications, we recommend the iAISTX. This AIS transponder is equipped with an external GPS antenna and a built-in Wi-Fi server, allowing it to transmit AIS and GPS data wirelessly to tablets and smartphones.

• Receive AIS targets on both a chartplotter and software/applications
  To receive AIS targets simultaneously on a chartplotter and navigation software or mobile applications, we recommend the AIT6000 (Class B+). The AIT6000 is our most comprehensive AIS transponder, featuring a certified zero-loss VHF antenna splitter, an NMEA multiplexer, an external GPS antenna, and an integrated Wi-Fi server.

• AIS for rental boats
  If you are looking for a portable AIS receiver or transponder that can be easily transported and used on rental boats, the Nomad2 is the ideal solution. It is the only portable AIS transponder with a built-in GPS, USB power supply, and a portable VHF antenna.

An AIS which sends and receives data is known as a transceiver (or often called a transponder). There are also simple devices called AIS receivers which pick up transmissions and decode for displaying on a compatible chart plotter or PC based navigation system – or even an iPad or tablet.

AIS transponders will allow you to receive data from vessels close to you, but will also allow you to continuously transmit your vessel’s identity, position, speed and heading, as well as other relevant information, to all other AIS-equipped vessels within your range.

To transmit its position, an AIS transponder must have its own GPS antenna. All our AIS transponders are supplied with a GPS antenna or have a built-in GPS antenna.

This is a very valid question. After spending several hours installing a transponder, it is understandably important to confirm that it is operating correctly. The proAIS2 configuration software allows you to verify that the GPS position is valid, monitor the reception of AIS signals from other vessels, and confirm that there are no errors or alarms. However, for those new to AIS, there is often a lingering uncertainty about whether your own vessel is being seen by others.

The most reliable way to test a Class B+ AIS transponder is to ask another vessel in your marina that is equipped with AIS to confirm that they are receiving your transmissions. When your vessel is stationary, the transponder transmits approximately every three minutes. Once your speed over ground (SOG) exceeds 2 knots, the transmission rate increases to every 30 seconds. For this reason, it is important to allow sufficient time for your signal to be detected. Additionally, upon initial reception, other vessels will see only your dynamic data—position, speed, course, and MMSI number. It may take up to six minutes for your static data (vessel name, call sign, vessel type, dimensions, etc.) to be received. This behavior is normal and reflects how the AIS system manages data transmission bandwidth.

Another increasingly common method of verifying AIS operation is to check one of the online “live” AIS tracking websites. Among the free services available, MarineTraffic.com is one of the most widely used.

It is important, however, to understand the limitations of these online platforms and not to assume that your vessel will always be visible on them. The accuracy and availability of these services depend entirely on their network of AIS receiving stations, which are often operated by volunteers and enthusiasts. Coverage can be excellent in some areas, but gaps in reception do exist.