In this article, we discuss what EPIRBs are, the various types including PLBs and their role in Search and Rescue. Digital 406 MHz Epirb distress beacons save lives.

What is an EPIRB?

EPIRBs stand for Emergency Position-Indicating Radio Beacons and are used in emergency situations to assist Search and Rescue parties locate people who may be in some sort of distress or danger. These tracking transmitters also known as distress beacons or emergency beacons are commonly used to aid in the detection and location of distressed boats out at sea.

EPIRBs do not really allow "communication" as it is essentially an emergency beacon designed only to be used to request emergency response in the case of severe accident when no other form of communication can be made. ERIRBs do not require a network service and will always transmit a beep in any location.

Other Types of Emergency Beacons

There are two other types of beacons and these are: ELTs which stand for Emergency Locator Transmitters which is used when aircraft is in distress and PLBs which stand for Personal Locator Beacons and is used for personal use, where someone in distress is away from normal emergency services.


ELT’s (Emergency Locator Transmitters) are generally reserved for aviation use, and are permanently fitted in aircraft.


For land use, which of course includes 4WD touring, AMSA, (the Australian Maritime Safety Authority, who are responsible for detection and search and rescue in our 52.8 million square kilometre region of world responsibility), recommend the use of a PLB (Personal Locator Beacon). They are smaller and more lightweight than an EPIRB, and are thus easily carried on your person, in a backpack or in the vehicle. EPIRB’s are essentially designed as maritime distress beacons, because they have inbuilt flotation, and an inbuilt strobe light. Generally, an EPIRB will be a larger unit than a PLB.

How much?

A new 406 MHz PLB without GPS capability will set you back in the region of $400. A new 406 MHz PLB with inbuilt GPS capability will set you back in the region of $600. But when you look at the fact that a GPS capable unit reduces the search radius to about 100 metres, it’s got to be the way to go. When you really need to be rescued, every second counts, so the smaller the search area, the quicker you should be found.


A PLB is not a substitute for a 406 Mhz Marine EPIRB. Where Australian & International Law require a 406 Mhz EPIRB to be carried, this product does not meet these requirements.

How do EPIRBs Work?

EBIRBs as well as ELTs and PLBs interface with Cospas-Sarsat, the international satellite system for Search and Rescue. When activated, these beacons send out a distress signal that, when detected by non-geostationary satellites, can be located by triangulation similar to the way GPS satellites let GPS Units know where their position is.

Beacons that transmit in the 406 Mhz frequency, transmit digital signals and this signal can be uniquely identified almost instantly (via GEOSAR) and a GPS position can be encoded into the signal, therefore providing both instantaneous identification and position. This signal can then be homed in by Search and Rescue aircraft, boats and/or ground search parties who can come to the aid of the distressed boat, aircraft or person.

What is the HexID or UIN?

The HexID or Unique Identity Number (UIN) is the unique code programmed into each 406 MHz distress beacon and transmitted when the beacon is activated. When registering a distress beacon, this code must be included on the registration form as it is the only code that links the individual distress beacon to the registration database. Without the HexID the beacon cannot be registered.

The HexID is 15 characters long and is made up of hexadecimal numbers (0-9) and letters (A-F). The code can be found on the label of all 406 MHz distress beacons.

Important Note on EPIRBs

The internationally owned satellites that monitored the 121.5 MHz distress beacons have now been switched off and therefore, it is absolutely crucial that you upgrade to a digital 406 MHz distress beacon immediately - if you have not done so already.

406 MHz distress beacons save lives. The Australian Maritime Safety Authority (AMSA) that coordinates all aviation and maritime search and rescue across Australia’s 53 million square kilometre search and rescue region, no longer has the ability to detect an analogue 121.5 MHz distress beacon via satellite.

406 MHz beacons must be registered with AMSA. Registration is free and can be done on-line at the AMSA web site. When upgrading to a 406 MHz distress beacon it is essential that old analogue models are appropriately disabled and disposed of responsibly so that they do not trigger false alarms. More advice about distress beacons is available from the AMSA web site: www.amsa.gov.au/beacons or by calling 1800 406 406.


Use of a 121.5 beacon is now illegal.

Register Your 406 MHz Beacon!

406 MHz beacons are smarter and safer because they can also identify their owner. They transmit a unique code, unique that is to your beacon. So if you register your beacon with AMSA, they will know exactly who you are; what make and model of vehicle you are in; its colour and registration number. And they will have contact details for you including your HF callsign (if you have one); your sat phone number (if you have one); mobile telephone number(s); and whether you have UHF capability. (As a 4WD club member, you should at the very least, have good UHF communications).

If you have registered with AMSA, the moment they first detect your emergency signal, they will know from the unique code that the transmission is from your vehicle. They can immediately begin to try to contact you to ascertain firstly; that it is indeed an emergency; secondly, where you are and the nature of the emergency. So if you have HF or sat phone capability, the whole rescue process could be in operation before the satellites have confirmed your position. (They may be able to phone or call in to you, even though you may not have been able to get a call out from your position). This could sometimes spell the difference between life and death.

Please ensure you REGISTER your details with AMSA. It’s a FREE service. Registering your 406 MHz beacon is very easy, and the more information you provide the AMSA - the better they can utilise this information in a coordinated manner should you ever need emergency assistance. There are a number of ways to register your 406 MHz beacon, and this can be done via the AMSA website. Before you can use this web site you must activate your account. Please note that registering a beacon and activating your online account are not the same.

Online Registration

This method is the fastest and easiest way to register your 406 MHz beacon. Once you have created an online account, you will also be able to:
  • update your contact details

  • indicate change of ownership

  • post trip itineraries
To register your beacon online go to: www.beacons.amsa.gov.au

Email Registration

To submit your registration details by email, simply download, complete and save the Beacon Registration Form and email the completed document to: ausbeacon@amsa.gov.au


To submit your registration by fax, simply download, print and complete the Beacon Registration Form and fax to:
Local: 1800 406 329
International: +61 2 9332 6323

Mail registration

To submit your registration by mail, simply download, print and complete the Beacon Registration Form and post it to:

Australian coded beacons:
Beacon Registration Section,
Australian Maritime Safety Authority
GPO Box 2181 Canberra City ACT 2601

Want more info?

More information can be gained from the AMSA Web Site or call 1800 406 406 (office hours) and speak with the AMSA team.

Emergency EBIRB Activation

In an emergency, HF radio or sat phone are far better options than simply activating your beacon. The two-way communication capability of HF or sat phone provides the certainty of knowing that someone is actually coming to assist you. And, you can inform potential rescuers of the exact nature of the problem. However, if all you have is a distress beacon, the first indication you may have that someone is coming to assist you, is when a search aircraft or helicopter over flies you, or a ground party comes over the hill. And of course, they won’t know the nature of your emergency until they actually get to speak to you, probably on your UHF. So your beacon should be considered as a device of last resort to be used in the event that you have no other method of contact, or your other communications processes have either failed, or are ineffectual.

If you are using a sat phone or HF radio in an emergency situation, it’s highly likely that you will also be asked at some stage to activate your distress beacon (if you have one), so that searching aircraft can home in on your exact location.

And remember, in many emergency situations assistance is sometimes sought far too late. Sadly, this has also meant on a few occasions that help has also arrived too late. So assess your situation, make a decision, and act on it. Just don’t leave it too late.

Beacon Hints & Tips

Which Brand of Beacon?

AMSA will tell you that every unit on sale in Australia meets the appropriate standard, and thus will do the job efficiently and effectively. It is simply a matter of your personal preference as to brand, size, shape, features, etc., and of course, price.

Know Your Beacon

Make sure you know exactly how your beacon is activated for maximum effect. Aerial position and the ground location where you activate the unit can be critical to ensure good connectivity with the satellites. And make sure you regularly test the unit, and replace batteries, in accordance with the manufacturers’ recommendations.

Disposal of Old Beacons

When you buy your new beacon, DO NOT THROW YOUR OLD ONE IN THE BIN!! Binned beacons have been known to go off accidentally. It can then be a heck of a job to find the beacon in a garbage dump somewhere to shut it off. Battery World stores will happily accept your old beacon for disposal. Alternatively, most retailers of new beacons will also accept your old one for disposal.

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Created: March 2008
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