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Personal Locator Beacons

Taking the search out of search and rescue

Personal Locator Beacons

Over the river and through the woods
to grandmother’s house I go,
with my PLB securely with me,
if I fall overboard she will know.

Actually my husband bought me a (Personal Locator Beacon) PLB for our anniversary – he says he doesn’t want to lose me after ten great years together.  (Isn’t that romantic?) So I thought I’d share with you what I’ve learned about this amazing little life saving device…the lifeline you take with you wherever you go.

As of July 1, 2003, it became legal to purchase a 406 MHz PLB in the U.S., a lifesaving device that's been available elsewhere in the world for many years. Personal Locator Beacons (PLBs) are smaller versions of EPIRBs (Emergency Position Indication Radio Beacons).  A little bigger than a Blackberry and weighing 10 to 13 ounces, they can be carried by anyone going anywhere they may need rescue – boaters, fishermen, hikers, skiers, campers, outdoor adventurers, even pilots flying over remote regions.  It's really not about survival any more. It's about swift recovery.

There are three types of beacons used to transmit distress signals, EPIRBs (for maritime use), ELTs (for aviation use), and PLBs (previously used mainly for land-based applications but now applicable to water-based usage as well). Unlike EPIRBs which are registered to a vessel and transmit that vessel’s information, PLBs are registered to the owner and stay with the owner wherever he or she goes.  This makes them ideal for adventurers who go into remote areas, individuals who sail on other people’s boats, delivery boat skippers who need to bring all their own safety gear with them, and just about everybody else.  (Okay, not for grandma living in the Florida retirement community.)

Like the new generations of EPIRBs, PLBs transmit primarily on the 406 MHz system to locate the vicinity of the person in distress and have a built-in, low-power 121.5 MHz beacon that allows rescuers to home in on the signal once they are within range. In the two decades since the global 406 MHz satellite system was launched and EPIRBs became available, more than 14,000 people have been rescued, one-third of them in the US. Chances are PLBs will increase that number dramatically.

Some PLBs have GPS units integrated into the distress signal, which pinpoints your location to within a 100-yard zone, about the size of a football field. With time always the critical element in a search and rescue operation (SAR), this could mean the difference between life and death.

The cost of a PLB is about $600 without GPS and up to $1,000 for units with built-in GPS. They are waterproof and they float. In most units, the signal transmits for 24 continuous hours (EPIRBs emit a continuous signal for 48 hours). Battery life is 5 years. Replacement batteries are expensive, and just like dive watches, some manufacturers require PLBs to be returned to the manufacturer for battery replacement so the unit can be properly resealed to ensure that it remains waterproof.

But how does it work?

PLBs can be detected from anywhere in the world by the global satellites known as COSPAS-SARSAT.  This is a search and rescue (SAR) system that uses United States and Russian satellites to detect and locate emergency beacons that may be indicating distress. In the United States , the program is operated and funded by NOAA, the USCG, the USAF, and NASA.

These satellites, along with a network of ground stations and the U.S. Mission Control Center (MCC) in Suitland , Maryland , are part of the SAR system, whose mission is to relay distress signals to the global community.

When a beacon is activated, it transmits a digital 406-MHz signal to the constellation of satellites. The signal, with its digitally encoded unique identifier, is then relayed to a ground station which processes the signal and computes an accurate location for the beacon.  Depending on where the signal is coming from on earth, the beacon activation can be detected within a few minutes but it can take up to 45 minutes to calculate a position.  PLBs with GPS greatly reduce this time frame but still need to acquire satellites when switched on.  That is why some users interface their PLBs with an onboard GPS system just before they take on a dangerous mission so the unit can send reasonably accurate GPS coordinates as soon as it is activated if need be…no need to acquire satellite signals for the first transmission.

Once the ground station has calculated a position, it transmits the alert to the NOAA U.S. Mission Control Center . The US MCC combines this information with other satellite receptions (from other ground stations and MCCs), determines who is in distress based on the registration information decoded from the signal and generates an alert message. This alert is then transmitted to the appropriate Rescue Coordination Center (RCC) based on the beacon's geographic location and/or identification, which begins the actual SAR operation.

In the United States , these rescue centers are operated by the U.S. Coast Guard for incidents at sea, and by the U.S. Air Force Rescue Coordination Center at Langley AFB in Virginia for incidents on land. When a PLB is properly registered, as required by law, the RCC telephones the beacon's owner and/or emergency contact. If the RCC cannot determine that the signal is a false alert, it dispatches SAR teams - using planes, helicopters, and search parties - to locate the individual in distress and bring him or her to safety.

PLB registration and false alerts

In the United States, all beacons (including PLBs) must be registered with NOAA’s SARSAT Office by law. The registration includes critical information such as the owner’s name, address, telephone number and the PLB’s unique identification number. This allows the RCC to call you as the owner and your designated emergency contact to determine if a real SAR event is unfolding or if the beacon has been falsely activated. If the RCC cannot determine that the signal is false, they dispatch an SAR team.

SAR teams respond to falsely or inadvertently activated beacons all the time. The manpower and dollar costs of responding to false alerts are extremely high and are a significant burden to SAR resources. To avoid false alerts, NOAA encourages that all beacon owners learn to properly operate and test their beacons and to follow the manufacturer's recommendations carefully. Most units contain a microprocessor that checks for normal function and emits a beep or a flash to confirm that the unit will operate properly. Read the instructions for testing your unit through to the end before beginning the procedure. Sometimes the most important information appears at the very end - like how to turn it off!

It takes some effort to accidentally activate a PLB, but it can happen. If you mistakenly activate your PLB, you have about 50 seconds to turn off the beacon before the distress signal goes out. Promptly shut off the beacon and contact the state search and rescue authority, which can be the state police or an officially designated agency such as the U.S. Coast Guard.  Make sure you call them to cancel the alert or you may be held liable for SAR costs. 

Despite the many advantages to PLBs, they should be used as an auxiliary to a mobile phone whenever possible. Most SAR authorities actually prefer users try their cell phones first and call 911 in a distress situation. Why? Because any time you are able to speak directly to a 911 operator the better. A 911 operator can assess the situation almost immediately, determining the extent of the distress, if any injuries have occurred, how many people are involved, what the weather conditions are like, etc. This information is then used by the operator to dispatch the appropriate emergency response. In the case of a PLB, SAR forces are alerted to a potential distress, often without direct communication with the individual and without any clue about the nature of distress. Usually, the RCC reaches your emergency contact (assuming your PLB is properly registered), who hopefully knows where you are and what you are doing there.

Chain of rescue equipment deployment
1)  VHF radio:  Best means by which to alert as many vessels and authorities in your area as possible, provide as much detail as possible, and keep them informed as the situation progresses
2)   Cell phone: Though reception can be spotty, it provides one on one communication which always provides more details about the situation than a passive signal
3)  DSC:  Emergency alert system transmits your position to every vessel within listening distance
4)   PLB: Transmits a global signal which activates an SAR mission for an individual
5)   EPIRB:  Transmits a global signal which activates an SAR mission for a vessel

Registering with NOAA

To register your PLB, go to follow the simple instructions to register it online.  Registration is free and easy.  You will need the unique number assigned to your PLB as well as manufacturer, model number, and serial number.  You will also need to provide multiple phone numbers for two contacts who can be called if your PLB sends a signal.  If you would rather mail in the form, you can download a pdf here.

You must register your PLB and affix the proof of registration to the unit.
My PLB actually came with a NOAA form with a sticker containing all the information about the unit and a pre-addressed stamped envelope.  I chose to do it online just to see how it works.  I got an immediate acknowledgement of the registration by return email.  The sticker, which you are required to affix to your unit, is delivered in the mail within a few days.

By the way, registration is only good for two years.  NOAA sends an email or fax reminder before the expiration date.  If you buy a previously owned PLB, you must re-register it immediately even if the previous registration has not expired.  It’s for your own good, so don’t delay.

NOAA will accept registration for a PLB by non-U.S. resident provided it is a U.S. legal PLB with a U.S. country code. However, NOAA recommends registering your PLB with the country in which you are most likely to use it. This can be a problem with a U.S PLB since the U.S. has proprietary requirements for PLBs that may not conform to other country's requirements. Check with the manufacturer to see if the U.S. PLB can be modified. The US will not register a PLB with a non-US country code. (By the way, the same applies to VHF radios. Different countries use different frequencies for emergency and working channels.)

Use and Testing of your PLB

The AquaFix with cover open showing the controls. Learning the proper sequences for testing and emergency operation is critical.
It is important to read all of the instructions in your manual and become totally familiar with your PLB's operation before testing its functionality. The manuals may have instructions that are different for multiple units. You do not want to set off an SAR operation by mistake. So read to the end before pressing buttons. On the other hand, it is critical to make sure the unit is working properly before relying on it to save your life.

The ACR unit I have requires the operator to be outside, to place the antenna at exactly the right angle (it clicks into place), to make sure the area where the GPS transmitter resides is unobstructed (even by water), and to hold two buttons down simultaneously for 1-5 seconds to activate the alert; the test sequence requires pressing one button at a time for a different length of time than an actual activation. That cuts down on false alarms, but unless you know how to activate it, it won't do any good. I must say, the sequence of beeps and lights that tells you it is working properly is not easy to follow. I really had to concentrate (and I am not blond)!

One last word

One of the PLBs available in the US was taken off the market last year when the units were found to function less than adequately. When the ACR unit was tested it performed flawlessly. It pays to do your homework before buying.

P.S. I am going to get my husband a defibrillator for his next birthday.  I don’t want to lose him either!

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