Radio Beacon

A Beacon is a portable electronic device that is used to transmit distress message, which are picked up by the satellite and transmitted to the LUT's for processing to locate the exact position of accidents. The transmitted frequency can be any one of the following:

1. 121.5 MHz
2. 243 MHz
3. 406 MHz

Beacons operating at 406 MHz and 121.5 MHz are compatible with the Cospas-Sarsat system, however, the operational capabilities of the system are different for these two types of beacons. Sarsat satellites (but not Cospas or GEOSAR satellites) are also capable of relaying 243 MHz beacon transmissions. 243 MHz beacons have similar characteristics to 121.5 MHz beacons. The Cospas-Sarsat Secretariat maintains a list of Cospas-Sarsat type approved 406 MHz beacons, manufacturers of type approved beacons, and beacon test laboratories recognized by Cospas-Sarsat.

The frequency stable 406 MHz beacons have a unique identification code and are capable of transmitting for at least 24 hours. For the system to operate effectively, these beacons should be registered in a database to enable identification of the user and provision of contact details. Some of these beacons may also have a VHF (Very High Frequency) or SART (Search and Rescue Radar Transponder) transmitter built-in to assist with final homing by SAR units.

Types of Beacons

The beacons can be broadly divided into three categories.

1. PLB (Personal Locator Beacon):

A 406 MHz Personal Locator Beacon (PLB) could be the only link between yourself and civilization in a life-threatening emergency. Modern space technology allows you to access this link. A 406 MHz PLB is a battery-powered emergency transmitter which, when activated, sends a coded signal. A signal received by the COSPAS-SARSAT Satellite System from a PLB is considered to be an indication of serious distress and search and rescue authorities in India will react to the alert in the appropriate manner.

Every 406 MHz PLB authorized for use in India contains a unique coded signal. This feature, combined with procedures for storing personal data about beacon owners in a central registry, can provide important information to search and rescue authorities.

2. Emergency Position Indicating Radio Beacon(EPIRB):

These beacons are carried on ships and can float free under distress condition under sea. The two popular version of these EPIRB are the auto-release, float free and own manually thrown in the sea under distress conditions. The auto-release beacons are released from their holding at a depth of 2-3 meters automatically and float to the surface in case of distress condition caused by sinking and would start transmitting the signals while resting it its positive buoyancy position.

3. Emergency Locator Transmitter (ELT):

The ELT become a vital component of United States General Aviation aircraft in the early 1970's under congressional mandate. The COSPAS-SARSAT satellite system was developed to monitor the ELT transmissions. The system was designed to alert the ground stations in the event of an ELT signal and provide location information.

Different types of ELTs are now being used, but all transmitters include stable frequency source modulators, radio frequency amplifiers and batteries. An omni-directional antenna, crash activation sensors, on/off/reset switch, cables and mounting hardware are standard equipments. During operations, the batteries will last between 24 to 48 hours at minus 20 degree Fahrenheit or lower.

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