Emergency Position Indicating Radio Beacon (EPIRB)

Types of EPIRBs Emergency Position Indicating Radio Beacons (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 described below:

Class A

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.

Class B

121.5/243 MHZ. Manually activated version of Class A.  No longer recommended.

Class C

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.

Class S

121.5/243 MHZ. Similar to Class B, except it floats, or is an integral part of a survival craft.  No longer recommended.

Category I

406/121.5 MHZ. Float-free, automatically activated EPIRB. Detectable by satellite anywhere in the world. Recognized by GMDSS.

Category II

406/121.5 MHZ. Similar to Category I, except is manually activated. Some models are also water activated.

Inmarsat E

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 devices.

121.5/243 MHz EPIRBs

These are the most common and least expensive type of EPIRB, designed to be detected by over flying 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 occur)
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 sold,
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 by 2008.

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 installed properly.

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.

The COSPAS-SARSAT System

COSPAS-SARSAT is an international satellite-based search and rescue system established by the U.S., Russia, Canada and France to locate emergency radio beacons transmitting on the frequencies 121.5, 243 and 406 MHZ.

COSPAS

Space System for Search of Distress Vessels (a Russian acronym)

SARSAT

Search and Rescue Satellite-Aided Tracking

Inmarsat E EPIRB

Inmarsat E EPIRBs transmit a distress signal to Inmarsat geostationary satellites which includes a registered identity similar to that of the 406 MHz EPIRB and a location derived from a GPS navigational satellite receiver inside the EPIRB. Inmarsat EPIRBs may be detected anywhere in the world between 70 degrees North latitude and 70 degrees South latitude.

Since geostationary satellites are used, alerts are transmitted nearly instantly to a rescue coordination center associated with the Inmarsat coast earth station receiving the alert. Alerts received over the Inmarsat Atlantic Ocean Regions are routed to the Coast Guard Atlantic Area command center in New York, and alerts received over the Inmarsat Pacific Ocean Region are routed to the Coast Guard Pacific Area command center in San Francisco.

Testing EPIRBs

The Coast Guard urges those owning EPIRBs to periodically examine them for water tightness, battery expiration date and signal presence. FCC rules allow Class A, B, and S EPIRBs to be turned on briefly (for three audio sweeps, or one second only) during the first five minutes of each hour. Signal presence can be detected by an FM radio tuned to 99.5 MHz, or an AM radio tuned to any vacant frequency and located close to an EPIRB.  406 MHz EPIRBs can be tested through its self-test function, which is an integral part of the device.  406 MHz EPIRBs can also be tested inside a container designed to prevent its reception by the satellite.  Testing a 406 MHz EPIRB by allowing it to radiate outside such a container is illegal.

Battery Replacement

406 MHz EPIRBs use a special type of lithium battery designed for long-term low-power consumption operation. Batteries must be replaced by the date indicated on the EPIRB label using the model specified by the manufacturer. It should be replaced by a dealer approved by the manufacturer. If the replacement battery is not the proper type, the EPIRB will not operate for the duration specified in a distress.

Registration of 406 MHz EPIRBs

Proper registration of your 406 MHz satellite emergency position-indicating radio beacon (EPIRB) is intended to save your life, and is mandated by Federal Communications Commission regulations. The Coast Guard is enforcing this FCC registration rule.

Your life may be saved as a result of registered emergency information. This information can be very helpful in confirming that a distress situation exists, and in arranging appropriate rescue efforts. Also, GOES, a geostationary National Oceanic & Atmospheric Administration weather satellite system can pick up and relay an EPIRB distress alert to the Coast Guard well before the international COSPAS-SARSAT satellite can provide location information. If the EPIRB is properly registered, the Coast Guard will be able to use the registration information to immediately begin action on the case.

If the EPIRB is unregistered, a distress alert may take as much as two hours longer to reach the Coast Guard over the international satellite system. If an unregistered EPIRB transmission is abbreviated for any reason, the satellite will be unable to determine the EPIRB's location, and the Coast Guard will be unable to respond to the distress alert. Unregistered EPIRBs have needlessly cost the lives of several mariners since the satellite system became operational.

What happens to your registration form?

The registration sheet you fill out and send in is entered into the U.S. 406 Beacon Registration Database maintained by NOAA/NESDIS. If your EPIRB is activated, your registration information will be sent automatically to the appropriate USCG SAR Rescue Coordination Center (RCC) for response.

One of the first things the RCC watch standers do is attempt to contact the owner/operator at the phone number listed in the database to determine if the vessel is underway (thus ruling out the possibility of a false alarm due to accidental activation or EPIRB malfunction), the intended route of the vessel if underway, the number of people on board, etc., from a family member. If there is no answer at this number, or no information, the other numbers listed in the database will be called to attempt to get the information described above needed to assist the RCC in responding appropriately to the EPIRB alert.

When RCC personnel contact the emergency phone numbers you provide, they will have all the information you have provided on the registration form. You should let these contacts know as much about your intended voyage as possible (i.e., intended route, stops, area you normally sail/fish/recreate, duration of trip, number of people going, etc.).  The more information these contacts have, the better prepared our SAR personnel will be to react. The contacts can ask the RCC personnel contacting them to be kept informed of any developments, if they so desire.

Registration regulations

You may be fined for false activation of an unregistered EPIRB. The U.S. Coast Guard routinely refers cases involving the non-distress activation of an EPIRB (e.g., as a hoax, through gross negligence, carelessness or improper storage and handling) to the Federal Communications Commission. The FCC will prosecute cases based upon evidence provided by the Coast Guard, and will issue warning letters or notices of apparent liability for fines up to $10,000.

However, the Coast Guard has suspended forwarding non-distress activations of properly registered 406 MHz EPIRBs to the FCC, unless activation was due to hoax or gross negligence, since these search and rescue cases are less costly to prosecute.

If you purchase a new or a used 406 MHz EPIRB, you MUST register it with NOAA. If you change your boat, your address, or your primary phone number, you MUST re-register your EPIRB with NOAA. If you sell your EPIRB, make sure the purchaser re-registers the EPIRB, or you may be called by the Coast Guard if it later becomes activated.

An FCC ship station license is no longer required to purchase or carry an EPIRB.

How to register

Download or request 406 MHz EPIRB registration forms from, and mail or fax completed forms to:

                                    SARSAT Beacon Registration
                                    E/SP3, Room 3320, FB-4
                                    NOAA
                                    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 (above).

There is no charge for this service. IT MAY SAVE YOUR LIFE.

For more information see the NOAA SARSAT Homepage.