406 MHz BEACONS
Locator Beacons were authorized for nationwide use
July 1, 2003
There are three types of beacons used to transmit distress
EPIRBs (for maritime use), ELTs (for aviation use), and PLBs
(used for land-based applications).
SEA 406 MHz EPIRB
This EPIRB has a high intensity xenon strobe
light aid final location even in poor visibility.
Types of EPIRBs
Emergency position indicating radiobeacons (EPIRBs), devices which cost from
$200 to about $1500, are designed to save your life if you get into trouble by
alerting rescue authorities and indicating your location. EPIRB types are
121.5/243 MHZ. Float-free, automatically-activating, detectable by aircraft and
satellite. Coverage is limited. An alert from this device to a rescue
coordination center may be delayed 4 - 6 or more hours. No longer recommended.
121.5/243 MHZ. Manually activated version of Class A. No longer recommended.
VHF ch15/16. Manually activated, operates on maritime channels only. Not
detectable by satellite. These devices have been phased out by the FCC and are
no longer recognized.
121.5/243 MHZ. Similar to Class B, except it floats, or is an integral part of a
survival craft. No longer recommended.
406/121.5 MHZ. Float-free, automatically activated EPIRB. Detectable by
satellite anywhere in the world. Recognized by GMDSS.
406/121.5 MHZ. Similar to Category I, except is manually activated. Some
models are also water activated.
1646 MHZ. Float-free, automatically activated EPIRB. Detectable by Inmarsat
geostationary satellite. Recognized by GMDSS. Currently not sold in the U.S.;
however, the Federal Communications Commission is considering recognizing these
121.5/243 MHz EPIRBs
These are the most common and least expensive type of EPIRB, designed to be
overflying commercial or military aircraft. Satellites were designed to detect
these EPIRBs, but are limited for the following reasons:
1.Satellite detection range is limited for these EPIRBs (satellites must be
within line of sight of both the EPIRB and a ground terminal for detection to
2.Frequency congestion in the band used by these devices cause a high satellite
false alert rate (99.8%); consequently, confirmation is required before search
and rescue forces can be deployed,
3.EPIRBs manufactured before October 1989 may have design or construction
problems (e.g. some models will leak and cease operating when immersed in
water), or may not be detectable by satellite. Such EPIRBs may no longer be
4.Because of location ambiguities and frequency congestion in this band, two or
more satellite passes are necessary to determine if the signal is from an EPIRB
and to determine the location of the EPIRB, delaying rescue by an average of 4
to 6 hours. In some cases, a rescue can be delayed as long as 12 hours.
5.COSPAS-SARSAT is expected to cease detecting alerts on 121.5 MHz, perhaps
One November 3, 2000, the National Oceanic and Atmospheric Administration (NOAA)
announced that satellite processing 121.5/243 MHz emergency beacons will be
terminated on February 1, 2009. Class A and B EPIRBs must be phased out by that
date. The U.S. Coast Guard no longer recommends these EPIRBs be purchased. See
the U.S. Coast Guard Media Advisory on this subject.
Class C EPIRBs
These are manually activated devices intended for pleasure craft which do not
venture far offshore and for vessels on the Great Lakes. They transmit a short
burst on VHF-FM channel 16 (156.8 MHz) and a longer homing signal on channel 15
(156.75 MHz). Their usefulness depended upon a coast station or another vessel
guarding channel 16 and recognizing the brief, recurring tone as an EPIRB. Class
C EPIRBs were not recognized outside of the United States, and were no longer
recognized in the U.S. after 1999.
406 MHz EPIRBs
The 406 MHz EPIRB was designed to operate with satellites. The signal frequency
(406 MHz) has been designated internationally for use only for distress. Other
communications and interference, such as on 121.5 MHz, is not allowed on this
frequency. Its signal allows a satellite local user terminal to accurately
locate the EPIRB (much more accurately -- 2 to 5 km vice 25 km -- than 121.5/243
MHz devices), and identify the vessel (the signal is encoded with the vessel's
identity) anywhere in the world (there is no range limitation). These devices
are detectable not only by COSPAS-SARSAT satellites which are polar orbiting,
but also by geostationary GOES weather satellites. EPIRBs detected by the
GEOSTAR system, consisting of GOES and other geostationary satellites, send
rescue authorities an instant alert, but without location information unless the
EPIRB is equipped with an integral GPS receiver. EPIRBs detected by
COSPAS-SARSAT (e.g. TIROS N) satellites provide rescue authorities location of
distress, but location and sometimes alerting may be delayed as much as an hour
or two. These EPIRBs also include a 121.5 MHz homing signal, allowing aircraft
and rescue craft to quickly find the vessel in distress. These are the only type
of EPIRB which must be certified by Coast Guard approved independent
laboratories before they can be sold in the United States.
A new type of 406 MHz EPIRB, having an integral GPS navigation receiver, became
available in 1998. This EPIRB will send accurate location as well as
identification information to rescue authorities immediately upon activation
through both geostationary (GEOSAR) and polar orbiting satellites. These types
of EPIRB are the best you can buy.
406 MHz emergency locating transmitters (ELTs) for aircraft are currently
available. 406 MHz personnel locating beacons (PLBs) are available in Alaska and
Canada, and will soon be available throughout the U.S.
The Coast Guard recommends you purchase a 406 MHz EPIRB, preferably one with an
integral GPS navigation receiver. A Cat I EPIRB should be purchased if it can be
406 MHz GEOSAR System
The major advantage of the 406 MHz low earth orbit system is the
provision of global Earth coverage using a limited number of polar-orbiting
satellite. Coverage is not continuous, however, and it may take up to a couple
of hours for an EPIRB alert to be received. To overcome this limitation,
COSPAS-SARSAT has 406 MHz EPIRB repeaters aboard three geostationary satellites,
plus one spare: GOES-W, at 135 deg W; GOES-E, at 75 deg W; INSAT-2A, at 74 deg
E; and INSAT-2B (in-orbit spare), at 93.5 deg E. Ground stations capable of
receiving 406 MHz. Except for areas between the United Kingdom and Norway, south
of the east coast of Australia, and the area surrounding the Sea of Okhotsk near
Russia, as well as polar areas, GEOSAR provides continuous global coverage of
distress alerts from 406 MHz EPIRBs.
Note that GEOSAR cannot detect 121.5 MHz alerts, nor can it route unregistered
406 MHz alerts to a rescue authority. GEOSAR cannot calculate the location of
any alert it receives, unless the beacon has an integral GPS receiver.
406 MHz Person Location BEACONS
PLBs are portable units that operate much the
same as EPIRBs or ELTs. These beacons are designed to be carried by an
individual person instead of on a boat or aircraft. Unlike ELTs and some EPIRBs,
they can only be activated manually and operate exclusively on 406 MHz. And like
EPIRBs and ELTs all PLBs also have a built-in, low-power homing beacon that
transmits on 121.5 MHz. This allows rescue forces to home in on a beacon once
the 406 MHz satellite system has gotten them "in the ballpark" (about 2-3
miles). Some newer PLBs also allow GPS units to be integrated into the distress
signal. This GPS-encoded position dramatically improves the location accuracy
down to the 100-meter level…that’s roughly the size of a football field.
Until July 1, 2003 only residents of Alaska can use PLBs. The
Alaska PLB Program was set up to test the capabilities of PLBs and their
potential impact on SAR resources during public usage. Since March of 1995, the
experiment has proven very successful and has helped save nearly 400 lives while
generating only a few false alerts. The success of the Alaska PLB program
undoubtedly paved the way for nationwide usage of these devices.
Federal Agencies have also been using the PLB system for years. These agencies
equip their agents who often work in remote or hostile environments and rely
upon the Cospas-Sarsat system for immediate distress alerting capabilities.
When can I purchase and start using a PLB?
PLBs were authorized for use on July 1, 2003.
Where will the Personal Locator Beacons be sold?
Personal Locator Beacons will be sold in various outdoor supply stores, boating
supply stores, electronics stores, and thru online and catalog distributors.
How much will they cost?
The PLBs will cost approximately $300 - $500 for lower
end models. $1,200 to $1,800 for the higher end models. The higher end models
will be GPS enhanced.
Will there be a penalty for an intentional false alert?
Under federal law, 14USC88, knowingly and willfully transmitting a hoax distress
call is a felony. It is punishable by up to six years in prison, a $250,000
fine, and restitution to the rescue agency for all costs incurred responding to
If you purchase a new or a used 406 MHz EPIRB, ELT or PLB you
MUST register it with NOAA. If you change your boat, your address, or your
primary phone number, you MUST re-register your location beacon with NOAA. If
you sell your beacon, make sure the purchaser re-registers the beacon, or you
may be called by the Coast Guard (EPIRB), Civil Air Patrol (ELT) or local Search
and Rescue team (PLB) if it later becomes activated.
Download or request
406 MHz EPIRB registration
forms from, and mail or fax completed forms to:
SARSAT Beacon Registration
E/SP3, Rm 3320, FB-4
5200 Auth Road
Suitland MD 20746-4304
or call toll free at 1-888-212-SAVE (i.e. 1-888-212-7283) for further
information or a copy of the
registration form. From outside the U.S., call +1 (301) 457-5430 (fax: (301)
568-8649) for further
information. Forms may be requested by phone or fax, or downloaded by computer
There is no charge for this service. IT MAY SAVE YOUR LIFE.
For more information see the NOAA SARSAT