Field notes · real products
The hardware behind the signal
AIS is a system, not a single box. A transponder needs identity, position, power and an antenna; a receiver only listens; a plotter turns messages into something readable. These are named products that fit those roles, with the caveat beside the recommendation.
Photo: Belov Sergey / Unsplash · source · Unsplash License
How we choose
Specification fit before sales copy
We have not bench-tested every item here, so we do not publish invented rankings or pretend one installation suits every boat. We name the exact model, explain the role it fills and call out the decision that can make it wrong for you.
As an Amazon Associate, MarineActivity earns from qualifying purchases. Amazon is the seller; we do not set prices, hold stock or fulfil orders. Prices and availability can change.
Start with the job
Which AIS hardware do you need?
Most bad AIS purchases answer the wrong question. Pick the job first; each card links to the guide that explains the trade-offs and, where available, a named example below.
- 01
I want to see the ships around me
A receive-only AIS unit decodes nearby traffic for a plotter or app. It does not make your boat visible.
- 02
I want other vessels to see me
Only a transponder transmits. Class B/SO (5 W) or Class B/CS (2 W) for most small craft; it needs a registered MMSI.
- 03
I want to hear and be heard further
Antenna height and cable loss decide range more than transmit power. One antenna can serve radio and AIS through an active splitter.
- 04
I want to be found after going overboard
An AIS MOB beacon alerts your own boat and vessels nearby; a 406 MHz PLB alerts the rescue services. They do different jobs.
01 · AIS systems
AIS systems
Receive nearby traffic or transmit your own vessel identity.
em-trak
Transmit + receive · 5 W SOTDMA
B951 AIS transceiver
A compact Class B unit with 5 W SOTDMA, internal GPS, NMEA 0183 and NMEA 2000.
This is the kind of equipment that makes a leisure or light-commercial vessel visible to nearby AIS receivers.
Check: Requires correct MMSI programming and a suitable VHF antenna or active splitter.
Check price & availability for em-trak B951 Class B AIS transceiver on Amazon
AIS transponders explained: Class A, Class B/SO, Class B/CS and receive-only
02 · VHF & DSC
VHF & DSC
Fixed and handheld marine radios for routine and distress calling.
Icom
Fixed mount · GPS + DSC
M330G VHF/DSC radio
A compact fixed VHF with an external GPS antenna and Class D DSC capability.
DSC and AIS use the same MMSI identity, so correct registration matters across both systems.
Check: DSC distress functions require a registered MMSI and a complete installation.
Check price & availability for Icom M330G fixed-mount VHF/DSC radio on AmazonUniden
Handheld · floating · IPX8
Atlantis 275 handheld VHF
A 6 W floating handheld with weather alerts and US, Canadian and international marine channels.
A handheld is useful as a cockpit radio or independent backup when the fixed set loses power.
Check price & availability for Uniden Atlantis 275 floating handheld VHF on Amazon
Marine VHF radios: fixed vs handheld, DSC and AIS integration
04 · Antennas
Antennas
The VHF hardware that determines practical AIS and radio range.
Shakespeare
8 ft · 6 dB gain
5101 VHF antenna
A widely used eight-foot fibreglass marine VHF antenna for powerboat installations.
AIS is VHF line-of-sight, so antenna placement and height often matter more than another watt of transmit power.
Check: An eight-foot antenna is not appropriate for every hull or sailing rig.
Check price & availability for Shakespeare 5101 eight-foot VHF antenna on Amazon
AIS antennas and splitters: height, cable loss and sharing a VHF antenna
05 · Distress & recovery
Distress & recovery
Satellite and local-alert beacons for very different emergencies.
ACR
406 MHz PLB · GPS/Galileo
ResQLink 400 PLB
A compact registered personal beacon that alerts the satellite search-and-rescue system.
A PLB reaches a rescue network; it is not an AIS target and does not replace a local man-overboard alert.
Check: Registration is essential. Check the beacon coding and rules for the country where it will be used.
Check price & availability for ACR ResQLink 400 personal locator beacon on AmazonOcean Signal
AIS MOB + DSC · local alert
rescueME MOB1
A lifejacket-mounted beacon that sends an AIS man-overboard target and compatible DSC alert nearby.
Its reserved 972 identity is why an AIS MOB alert looks different from an ordinary vessel on a plotter.
Check: Regional Class M rules are changing. Verify legal use and compatibility where you sail before buying.
Check price & availability for Ocean Signal rescueME MOB1 AIS man-overboard beacon on Amazon
06 · Reference
Reference
A serious desk reference for navigation, rules and seamanship.
John Rousmaniere
Hardcover · fourth edition
Annapolis Book of Seamanship
John Rousmaniere’s illustrated reference to sailing, navigation, weather, safety and boat systems.
AIS is an aid to awareness, never a replacement for seamanship, the collision regulations or a proper watch.
Check: Fourth-edition hardcover: ISBN 9781451650198, published by Simon & Schuster. Other formats have different ISBNs.
Check price & availability for The Annapolis Book of Seamanship, fourth edition on Amazon
Before you order
Marine electronics are an installation decision
Confirm voltage, connectors, network standard, antenna plan, chart region and required approvals. AIS and DSC equipment also depend on a correctly registered MMSI. When the installation affects distress calling or collision awareness, use a qualified marine electronics installer.
A product link is not navigational advice. Keep an effective watch and use the required charts, lights, sound signals and collision-avoidance equipment for your vessel and waters.
AIS transponders explainedMarine VHF radios explainedAntennas and splittersDistress beacons comparedHow MMSI identity worksSee it on the live mapFull affiliate disclosure