What are the AIS frequencies or VHF channels?

AIS transponders and receivers use two VHF radio frequencies: 161.975 MHz (AIS1, or channel 87B) and 162.025 MHz (AIS2, or channel 88B). The USCG has asked the Federal Communications Commission to authorize any US vessel to operate AIS on these two channels under its existing ship station license.

What is the frequency used in AIS?

AIS transceivers use two different frequencies, VHF maritime channels 87B (161.975 MHz) and 88B (162.025 MHz), and use 9.6 kbit/s Gaussian minimum shift keying (GMSK) modulation over 25 kHz channels using the high-level data link control (HDLC) packet protocol.

Does AIS use VHF antenna?

VHF antennas can work on AIS, yet the frequency of 162 MHz they will be operating at, is at the high end of the operable bandwidth of the antenna, where performance is not ideal. Many of the AIS transmit/receive units are also coming with splitters now, to utilize the same antenna as your VHF radio.

What is AIS on a VHF radio?

The Automatic Identification System is a digital VHF radio-based transponder system that can prevent collisions, and can protect your boat from being run down by a huge, fast moving ship. It's like digital radar with precise position information.

Do I need VHF with AIS?

For AIS Transmit and Receive, you need two pieces, a VHF Radio with DSC built-in plus an AIS Transponder.

VHF vs UHF - What's the difference

What antenna do I need for AIS?

Antenna type: The type of VHF antenna you use with your AIS system can also have a big impact on AIS range. Most VHF antennas are optimally tuned around 155-156 MHz but AIS uses frequencies around 162 MHz. In some cases, a good VHF antenna might be substantially less tuned at even close adjacent frequencies.

How do I get an AIS signal?

To receive all AIS transmissions a receiver must monitor both channels simultaneously, so the receiver must in effect be two receivers in one box. If two separate and different transmissions arrive at the receiver at the same time but on different channels both transmissions will be received and output by the receiver.

What are the 2 types of AIS?

Types and classes of AIS

There are two classes of shipborne AIS – Class A and Class B. In addition, there are different types of AIS used for shore stations (AIS Base Stations), AIS aids to navigation (AIS AtoN), AIS on search and rescue aircraft and the AIS search and rescue transmitter (AIS- SART).

What is AIS VHF antenna?

AIS aerials/ antennas and AIS:

AIS (Automatic Identification System) is transmitted on two channels at the top of the Marine VHF band. Regular marine band VHF aerials are tuned to around the centre of the band at 156.8 MHz (channel 16) and AIS aerials at 162 MHz (the AIS frequency).

What is an AIS number?

The AIS number is the unique six-digit number assigned to each inmate incarcerated by the ADOC and represents the quickest way to find a particular inmate.

What is the maximum range of AIS?

The AIS signals have a horizontal range of about 40 nautical miles (74 km), meaning that AIS traffic information is only available around coastal zones or in a ship-to-ship zone. AIS communication takes place using two VHF frequencies, 161.975 MHz and 162.025 MHz, using a bandwidth of 25 kHz.

Why do some boats have 2 VHF antennas?

The advantages of the dual antenna

Not only does the installation of a second antenna give better readability to the AIS signal, but it can also serve as an emergency antenna for VHF. Just allow enough length behind the unit to disconnect the antenna from the AIS and connect it to the VHF.

Do I need a separate AIS antenna?

If you decide to get a splitter, you must use one designed for AIS. If you have a transponder you must use a splitter designed specifically for use with AIS transponders. However, your VHF antenna may not be well tuned at AIS frequencies which will lead to poor transmit performance.

What are the marine VHF frequencies?

It uses FM channels in the very high frequency (VHF) radio band in the frequency range between 156 and 174 MHz, inclusive, designated by the International Telecommunication Union as the VHF maritime mobile band.

What is the difference between Class A and Class B AIS?

Class A AIS transponders are required to have a DSC (156.525 MHz) receiver, external GPS, heading, and rate of turn indicator, and can also transmit and receive safety-related text messages. Class B AIS transponders operate using Carrier-Sense TDMA (CSTDMA) broadcast mode and transmit at a power level of 2 watts.

What are the 3 types of AIS information transmitted by vessel?

Types of AIS equipment.

For a shipboard fitting there are three types of AIS equipment, Class A, Class B and receive only. Class A is intended for vessels where the fit is mandatory. Class A transmits more information, more frequently and at higher power than Class B.

How do AIS work?

AIS works via a combination of GPS, VHF radio, and an AIS transponder. The transponder broadcasts a ship's information, such as speed and heading (information gathered by GPS, of course), the ship's name, port of origin, size and draft, and more, over VHF frequencies 161.975 megahertz and 162.025 MHz.

What is an AIS receiver?

Operating in the VHF maritime band, the AIS (Automatic Identification System) system enables the wireless exchange of navigation status between vessels and shore-side traffic monitoring centers.

How do you connect an AIS to a chartplotter?

What is an AIS base station?

AIS base stations are non-shipborne stations which can relay information from AtoN and vessels. AIS AtoN which can be a physical aid to navigation or a virtual aid which broadcasts information.

What is the frequency of AIS Channel 1 which was allocated by ITU in the VHF band?

The frequencies of 161.965 MHz and 162.025 MHz are known as AIS 1 and AIS 2 and are used exclusively for AIS. Each country determines their own individual channel allocations, based on the ITU guidelines. The band is extensively used by ship, coastal, limited coastal and port operations stations world-wide.

Why do ships turn off AIS?

A ship's crew may turn off its AIS broadcast for a variety of legitimate reasons, but this behavior may indicate that a vessel is hiding its location and identity to conceal illegal activities like fishing in no-take protected areas or entering another country's waters without authorization.

How do I know if my AIS is transmitting?

If you get green across the board then the unit itself is transmitting. Note if you don't get a check for TX position reports then check to see you have a valid GPS signal. The unit will not transmit unless it has a valid GPS position.

Is AIS satellite based?

Automatic Identification System (AIS) is an automatic tracking system used for identifying and locating vessels by electronically exchanging data with other nearby ships, AIS base stations, and satellites. Satellite AIS (S-AIS) is the term used to describe when satellites are used to detect AIS signatures.

Can I connect my GPS to the AIS?

Our very popular AMEC CAMINO-101 Class B AIS transponder can now either use its internal GPS system coupled with the AMEC external antenna or it now supports using an external GPS device connected through the inbound NMEA port.