Personal Locator Beacons (PLBs):
Survival in the Palm of Your Hand

isits to wild places can yield deeply meaningful rewards. These adventures also entail risks that can occasionally prove life threatening—even for the most experienced outdoors people.

That's where Personal Locator Beacons (PLBs) come in. Now available for use in the United States, this remarkable technology provides a powerful safety net for wilderness travelers.

About the size of a TV remote control, a PLB can send a distress signal to satellites, which in turn alert Search and Rescue (SAR) of your location. PLBs transmit a Unique Identification Number (UIN). When SAR receives your transmission, they index a UIN database to learn your personal info. A standard PLB takes an average of 45 minutes to alert SAR of your position. For GPS-enabled PLBs, however, it takes an average of just 5 minutes. There is no subscription fee for a PLB. The satellite network and Search and Rescue teams are already in place and at your service should you face grave danger. A PLB runs on a specialized long-lasting lithium battery designed to transmit for 24 hours in very cold temperatures.

A PLB is a portable transmitter (about the size of a TV remote control) capable of sending out a personalized emergency distress signal to a network of orbiting satellites. These satellites can then relay your information to search and rescue teams anywhere in the world.

PLBs have rugged, waterproof plastic housings and are powered by special long-lasting lithium batteries. The models sold by REI weigh approximately one pound and have external antennas that stow away compactly when not in use.

While PLBs became available for use in the U.S. on July 1, 2003, this powerful technology has been around for decades.

If you have saltwater boating experience, you may be familiar with Emergency Position Indicating Radio Beacons (EPIRBS). These devices, designed exclusively for marine environments, have been in use for over 20 years and saved nearly 15,000 lives.

PLBs are the land-based equivalents of EPIRBS and utilize the same satellite networks. So why has the Federal Communications Commission (FCC) only recently approved PLBs for use in the United States?

Previously, no unified organization for land-based rescues has existed. While the U.S. Coast Guard serves as the point of contact for marine rescues, different states have long handled terrestrial rescues through a variety of organizations.

To overcome this issue, the FCC, NOAA and the U.S. Air Force recently teamed up and designated the Air Force Rescue Coordination Center (AFRCC) as the single point of contact for land-based rescues. The AFRCC in turn has established connections and software compatibility with search and rescue groups in each state.

A PLB communicates with a network of Russian, Canadian, American and French satellites know as COSPAS-SARSAT (SARSAT is an acronym for "Search And Rescue Satellite Aided Tracking").

After receiving your transmission, theses satellites "fix" on your location using a Doppler Shift method and relay your information to the AFRCC where search and rescue procedures begin. If you use a GPS-compatible PLB, you can deliver your GPS coordinates very quickly without having to wait for the satellites to determine your position.

When you buy a PLB, you must register it with NOAA. When you do so, they will link your essential personal information to a 15-character alpha-numeric code known as a Unique Identifying Number (UIN). When activated, the PLB transmits your UIN to the COSPAS-SARSAT satellites via electronic bursts.

While the electronic bursts provide Search and Rescue with your location, the UIN tells them personal information such as your name, address, phone number and any medical conditions you may have.

When activated, a PLB sends two signals: 406 MHz (which carries the UIN and GPS data to the satellites) and 121.5 MHz, a homing frequency.

If you use a PLB without a GPS, the 406 MHz signal from the satellite will get rescuers to within 2 miles of your position. Then Search and Rescue will use a tracking device to home in on the 121.5 MHz frequency. With this type of PLB in the continental U.S., it takes an average of approximately 45 minutes to alert Search and Rescue of your position.

If you use a PLB with a GPS interface, the 406 Mhz signal will guide rescuers to an area less than 100 meters from your position. At the same time, they will employ a tracking device to home in on the 121.5 MHz frequency put out by the PLB. When using a GPS-compatible PLB in the continental U.S, it takes only 5 minutes to alert Search and Rescue of your position!

Keep in mind that it's always a good idea to have a visual and/or audible distress signal such as a signal mirror, whistle, or a strobe light to help catch Search and Rescue's attention when they get close.

A PLB comes equipped with a long-lasting lithium battery. This battery has an 11-year life span and remains dormant until you flip the switch to activate the PLB.

By COSPAS-SARSAT regulations:

• A class 1 heavy-duty battery must be able to transmit at -40° F (-40° C) for 24 hours.
• A class 2 battery must be able to transmit at -20° F (-28.9° C) for 24 hours.

Since cold temperatures will shorten a battery's operating time, the situations above represent worst-case scenarios. For example, at a temperature of 70° F, these batteries will operate for approximately twice as long as they will at very cold temperatures.

Larger than PLBs, EPIRBS are designed to automatically right themselves, float and transmit in an upright position. These features are essential in a marine environment, as they allow you to tread water while waiting for rescue.

PLBs are smaller devices that are waterproof and do float, but they're not specifically designed to transmit in water.

Both types of beacons signal the same satellites and give them the same information. Both can be used in a land or marine environment, if needed. However, as a general rule choose a PLB for land travel and an EPIRB when venturing into marine environments.

You will not have to pay any recurring fees in order to use a PLB. The satellite and Search and Rescue networks are already in place, ready to serve you should you encounter grave danger in the outdoors. Keep in mind, however, that rescues generally come with significant price tags.