The ABCs of the PLB (Personal Locator Beacon)

December 23, 2016
Bryan HanselA PLB provides a lifeline to civilization, but is for emergency uses only.

The worst has happened. You are severely injured. Or profoundly lost. Or dangerously exposed to the elements. You cannot get out of the backcountry on your own. And now you are going to die. Your only hope is that help comes and finds you.

Fortunately, you have a personal locator beacon, or PLB. You activate it, sending out a signal that indicates you are in mortal danger and need immediate assistance. This initiates a search-and-rescue response that may well save your life.

Before you buy, however, it’s important to understand the differences between true PLBs, which have a single life-saving function, and satellite trackers and messengers, which are designed primarily for communication rather than emergencies.

PLBs are designed to do one thing: send out an alert when your life is in peril. Once activated, a PLB transmits a high-powered (usually 5-watt) signal to the COSPAS-SARSAT network, a collection of military satellites that provides global coverage. In the United States, the National Oceanic and Atmospheric Administration (NOAA) and the Air Force Rescue Coordination Center (AFRCC), which initiates search-and-rescue operations, monitor this network.

PLB owners are required to register their devices with NOAA, which then assigns you a 15-character Unique Identifying Number (UIN). Once a PLB is triggered, it transmits a personalized signal that allows AFRCC to identify you and your location, to reach out to your designated emergency contact, and to alert the local search-and-rescue agency, if appropriate.

PLBs are considered the gold standard in reliability, accuracy, and the likelihood of effectively initiating a search and rescue. The size, weight, and cost of PLBs has dropped dramatically since they were first introduced to the public about a decade ago. Several of today’s models—such as the ACR ResQLink (4.6 ounces) and McMurdo FastFind 220 (8 ounces)—are smaller than a cell phone and cost less than $300. No subscription fee is required for a PLB once you have purchased and registered it.

It’s important to note that PLBs are intended only for life-threatening situations after all other options, including cell phone calls, have been exhausted. You can be fined by for misusing a PLB.

These satellite devices share some of the functionality of PLBs, including an emergency SOS feature, but are fundamentally different in important ways. Two varieties of satellite messengers are currently available: the SPOT GEN3 and DeLorme’s InReach.

Satellite messengers are designed primarily as communication tools that allow you to send text messages. SPOT (4 ounces; $169) transmits simple, preprogrammed “I’m OK”-type missives that are one-way only; you can’t receive messages. InReach (7 ounces; $300 to $370) gives you the ability to both send and receive custom messages. Both also function as tracking devices, allowing you to map your location in real time for others to view.

After purchasing a satellite messenger, you must pay a subscription fee for it to work. For SPOT, that’s $150 per year. For InReach, options range from $144 to $600-plus annually, with the lower end limiting the number of messages you can send and receive.

Both SPOT and InReach include SOS functionality, allowing you to send an alert if you are in danger, but their half-watt signal is much weaker than that of a PLB. What’s more, the signal is routed through a private, for-profit satellite network and response center (Globalstar for SPOT, Iridium for InReach) and generally isn’t as reliable as that of a PLB.

It’s up to you. If backcountry communication and tracking is what you’re after, a satellite messenger is the way to go. If your life is your priority, go for a PLB.

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Matt Heid

Equipped blogger Matt Heid is AMC's gear guru: He loves gear and he loves using it in the field. While researching several guidebooks, including AMC's Best Backpacking in New England, he has hiked thousands of miles across New England, California, and Alaska, among other wilderness destinations. He also cycles, climbs, and surfs.