Which device is better suited for an emergency? Personal Locator Beacon (PLB) versus smartphone and EPIRB

While our last post explained how an Emergency Position-Indicating Radio Beacon (EPIRB) works, this post is about PLBs (Personal Locator Beacons), small, portable devices designed to trigger rescue operations for people in remote or dangerous situations. Why are PLBs better suited for emergencies than smartphones, and how do they compare to an EBIRB?

A radio beacon to mark the emergency position (also known as an emergency position-indicating radio beacon station, or, for short, an EPIRB), is part of every long-distance sailor’s emergency equipment today. safety equipment is part of every long-distance sailor’s basic equipment.

Put simply, the devices, which are also known in German as “Funkbake zur Kennzeichnung der Seenotposition” (or, for short, “Notfunkbake”), are initially nothing more than a radio station for the mobile phone service, the transmissions of which are designed to facilitate the search and rescue work of boats at sea.

As a rule, small radio transmitters are used for EPIRBs, for example as a radio station for rescue equipment, with the help of which satellites or search and rescue forces can locate and rescue aircraft, ships or pleasure craft in distress. However, if you are on different boats at sea, a PLB that is tied to a person is often useful.

These small, portable devices, known as personal locator beacons, are often useful for outdoor activities such as hiking, mountaineering, skiing or camping in areas without mobile phone coverage, for pilots and air sports enthusiasts as an additional safety feature, or for people working in remote locations (expeditions, scientific work or construction projects).

EPIRBs are larger and heavier than PLBs and are assigned to a specific

A personal locator beacon (PLB) works in a similar way to the EPIRB system already described, but there are also some differences. For example, the (larger and heavier) EPIRBs have a standardized transmission power and are designed to operate over long distances to send precise signals in the open sea – optimized for detection by satellites and aircraft. They will operate for at least 48 hours of continuous transmission after activation.

PLBs also offer global coverage, but they do not transmit as long as EPIRBs and they may also have a slightly lower transmission power than EPIRBs. They are designed for shorter distances, which can be a disadvantage for maritime operations in remote waters (however, modern PLBs can have the same high transmission power as EPIRBs, so it is worth comparing). What both systems have in common is that they each have an electronic transmitter that alerts rescue services to a life-threatening situation involving the owner.

A PLB is initially a small portable device that, when activated, transmits a distress signal that can be received by a global satellite system. This then forwards the message to ground receivers and the corresponding rescue coordination center (RCCS). These RCCs then send a search and rescue team (SAR) to help the person in distress (see the article about EPIRBs).

PLBs are now often used in man-over-board (MOB) equipment such as life jackets, but also in various water sports.

The much smaller, more manageable PLB locator devices are a relatively new addition to the rescue options for water sports enthusiasts and those who engage in activities away from civilization. PLBs are now often used in man-overboard (MOB) equipment such as life jackets, but also in water sports such as kitesurfing or windsurfing.

There are different types and models of PLB emergency beacons, from very simple to very advanced. The simpler PLBs only have a 406 MHz transmitter, and these are usually the cheaper versions. Models with a 406 MHz transmitter plus a 121.5 MHz homing transmitter are a bit more expensive, but can send the rescuers to the respective location faster and with greater accuracy.

However, all newer PLBs now have an internal GPS receiver (COSPAS-SARSAT satellite system, which is operated worldwide and is independent of mobile communications. This signal contains a unique identification number (Hex-ID) that is registered to the respective user (unlike EPIRBs, whose code is assigned to a specific vessel).

PLBs are independent of mobile phone networks – one of the advantages of PLBs over smartphones

The independence from mobile networks is also the biggest advantage of PLBs over smartphones: smartphones depend on mobile or Wi-Fi networks, which are often not available in remote areas – an emergency call with a cell phone is often not possible here.

One exception is modern Apple devices such as the iPhone (from iPhone 14) and the Apple Watch Ultra models, which have a satellite emergency call function. This enables users to make an emergency call and alert rescue services even without cell phone reception. According to Apple, this feature is free for two years when activated on a qualifying device and represents a significant advance, providing an additional safety option, especially in remote areas.

Another advantage of a PLB over a modern cell phone is the long battery life: batteries in a PLB often last five to seven years in standby mode and can operate for 24 hours or more when activated. Furthermore, PLBs have been specially developed and tested for emergency situations. The devices are not particularly affected by weather (especially extreme temperatures), moisture or shocks.

In addition, PLBs are very easy to use: there are no complex apps or menus to select – simple activation, usually at the push of a button, is all that is needed. Thanks to satellite reception and GPS positioning, exact coordinates can be delivered to the rescuers in the shortest possible time – smartphones, on the other hand, can only provide relatively inaccurate or no location data at all, especially with weak reception.

Finally, PLBs do not require subscriptions or mobile phone contracts; after registration (to a person or by MMSI), no further fees are incurred. PLBs are particularly interesting for water sports enthusiasts (surfers, kiters, dinghy sailors, SUP, paddlers or rowers) because, in addition to being waterproof, they also have a certain buoyancy, so they cannot sink, and in most cases have practical holding clips.

If you are thinking of buying a PLB, there are a few things you should look out for

If you are thinking of buying a PLB, you should make sure that the device is small and compact, that it can withstand strong impacts without triggering, and that it is easy to use in an emergency. Other considerations are that you should be able to attach the device securely and easily.

One of the most compact PLBs currently available on the market is the Ocean Signal RescueMe PLB1, which measures just 77 x 51 x 32.5 mm and weighs just 116 g. This emergency beacon offers three options for transmitting your location and drawing attention to yourself in an emergency: in addition to the 406 MHz signal (satellite), there is a homing signal on 121.5 kHz and a high-intensity LED flashlight.

The Ocean Signal RescueMe PLB1 is simply attached to a life jacket or belt; the antenna is pulled out when needed. The advantage of the device is that it can be operated with just one hand in an emergency. A cover protects the activation button and prevents accidental triggering.

The battery life is estimated by the manufacturer at seven years, the device is said to be waterproof up to 15 m, and the operating temperature is specified as ranging from -20° C to +55°C.

What should be considered regarding the transmission power?

We asked Steve Moore, Product Manager at Ocean Signal Ltd, about the facts (and differences) between PLBs and EPIRBs.

“Transmitter power is important for range, but it also has to be limited so that an EPIRB or PLB can transmit for the prescribed time,” says Steve Moore. An EPIRB must transmit for 48 hours and a PLB must be able to transmit for 24 hours after activation. The different frequencies transmitted by EPIRBs and PLBs serve completely different purposes and therefore also differ in output power.

“The primary transmission for an EPIRB and PLB is the 406 MHz Cospas-Sarsat satellite signal. The data transmitted on this frequency includes the beacon identity and GNSS position information and is received by instruments on board satellites in geostationary and low Earth orbits. Atmospheric and sea conditions have only a minimal effect on this transmission,” says Steve Moore.

The 121.5 MHz frequency, on the other hand, is merely ‘a target signal that guides search and rescue services within the local search area’. Directional receivers are generally mounted on rescue vehicles (helicopters and lifeboats) for this purpose. Although this signal is affected by atmospheric and sea conditions, it is used locally together with visible and infrared strobe lights to definitively locate an accident victim.

The Ocean Signal EPIRB3 and PLB3 also contain DSC and AIS transmitters that would transmit signals in the VHF frequency band (commonly referred to as the line of sight range), which could be received by any vessel within range that was equipped with a DSC radio or AIS receiver, adds the Ocean Signal product manager.

By the way: programming is included in the price of approx. €400 for this device (MMSI number). Other PLB providers include Garmin, Onwa and McMurdo. The devices are available from all major water sports equipment suppliers and online retailers.

For PLBs – as with EPIRBs – the owner should familiarize themselves with how the device works.

As with the EPIRBs described above, the user should familiarize themselves with the functioning of the device before starting their trip or excursion, because this is not a toy – even an accidental activation inevitably triggers a rescue chain. Every user should therefore know the importance of a PLB, the basics of how it works and how to activate it.

This includes, for example, that if a PLB is triggered accidentally, not only must it be switched off again immediately, but (if possible) the appropriate rescue center must also be informed immediately that it is not an emergency.

The following table illustrates a direct comparison between PLBs and EPIRBs: