ACR Electronics 2842, PRO 406, RLB-37 Step TWO HOW the Beacon Works, How your beacon brings help

STEP TWO - HOW THE BEACON WORKS

1.How your beacon brings help

406 MHz beacons are a type of portable emergency equipment that transmits a distress signal to search and rescue (SAR) organizations. The purpose of these beacons is to aid SAR teams in tracking and locating ships or individuals in jeopardy as rapidly as possible.

The 406 MHz frequency is a worldwide dedicated emergency frequency that is detected by a special system of satellites called the Cospas-Sarsat system. This satellite system was established by, and continues to be supported by, its primary benefactors - the USA, Russia, Canada and France. The Cospas- Sarsat system has saved over 24,800 lives - and counting - since its inception. See Appendix G or the Cospas-Sarsat website for more information about the system at www.cospas-sarsat.org.

When a 406 MHz beacon is activated, the digital distress message is sent to Cospas-Sarsat satellites and, in turn, the distress message is relayed to SAR. The distress message contains important information about the beacon and its owner. Additional information about the beacon is accessed by SAR from the beacon registration database. At the same time the 406 MHz signal is activated, a 121.5 MHz signal is turned on. The 121.5 MHz signal is used by SAR to home in on the beacon as they approach it.

The 406 MHz signal is detected by multiple satellites and from that information the location of the beacon can be calculated. This data alone is sufficient for SAR to find persons or ships in distress in a reasonable timeframe. However, as a further enhancement, some beacons have a GPS engine onboard. This feature allows the beacon to acquire current location coordinates from an internal GPS receiver. The coordinates are added to the ID of the unit, which is transmitted with the 406 signal. This enables the SAR authorities to locate the beacon to an accuracy of 110 yards (100 m).

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