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Beacon Breakthrough

Change to 406 MHz frequency not an easy transition

As of February 1, 2009, emergency beacons will no longer be monitored on the 121.5 MHz frequency.

The Council of COSPAS-SARSAT, the international organization that coordinates the satellite detection of distress signals, announced in October 2000 that it would phase out the use of the lower frequency. After February 1, 2009, only signals transmitted by emergency locator transmitters (ELTs), emergency position indicating radio beacons (EPIRBs) and personal locator beacons (PLBs) operating at the 406 MHz frequency will be tracked by satellite.

After the COSPAS-SARSAT system was developed, the first 15 months were to determine the system's effectiveness. Only nine days after testing began, on September 9, 1982, the system picked up the signal of a downed aircraft.

The decision was made based on recommendations from the International Maritime Organization and the International Civil Aviation Organization. These two United Nations agencies are responsible for regulating the safety of ships at sea and aircraft in international transits and for international standards and plans for maritime and aeronautical search and rescue.

Transport Canada and EMS Technologies, with financial support from the New Search and Rescue Initiatives Fund, have invested $690,700 in a three-phase project to develop a low-cost 406 MHz ELT. The ELT is currently being tested to COSPAS-SARSAT specifications in an approved laboratory, and the goal is to make it available at about the same price as the current 121.5 MHz beacons.

While there is an increase in price, there is also an increase in accuracy. The 406 MHz beacons provide more accurate and reliable alert data to SAR agencies.

The 121.5 MHz beacon has an accuracy of approximately 10 nm, whereas the new beacon has an accuracy of 2 to 4 nm because of its very high signal stability.

This means that searchers will be able to pinpoint a distress signal with better accuracy because the beacon's signal is stronger and more stable, compared to the 121.5 MHz signal.

Not only are the 406 MHz beacons more accurate, but they have a feature that allows the receiving agency to look up the beacon registration and find out who owns it. Each beacon's signal includes a digital identification number so technicians will be able to know who is in distress, and other relevant data, such as, position data, the type of user - whether it be a maritime, radio, serial, aviation or national user - radio call sign and emergency code. This allows technicians to take available details and search a database for more information before launching a search, if necessary.

According to Captain Brian Hoogkamp of the Canadian Mission Control Centre, since 1982, approximately 88 per cent of 121.5 MHz emergency beacon alerts have been false. Use of the new 406 MHz beacons will also help reduce the number of false alerts received by rescue coordination centres, as well as the number of unnecessary search and rescue actions. With the new technology, the number of times the beacon would go off for non-emergency reasons should be diminished.

Though data is not yet compiled for 2002, Capt. Hoogkamp says 406 MHz statistics indicate "a possible better knowledge of 406 handling procedures and fewer interferers being broadcast on the frequency over a period of time."

According to the COSPAS-SARSAT Council, there are currently more than 220,000 of the new 406 MHz beacons operating world-wide.

Since 1982, more than 11,000 people have been rescued world-wide through the COSPAS-SARSAT System.

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