The Maritime Safety Committee
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Statutory Documents - IMO Publications and Documents - Circulars - Maritime Safety Committee - MSC/Circular.863 Recommendation on Prevention of Harmful Interference to 406 MHZ EPIRBS Operating with the COSPAS-SARSAT System (Adopted on 22 May 1998) - The Maritime Safety Committee

The Maritime Safety Committee

  1 The Maritime Safety Committee, at its sixty-ninth session (11 to 20 May 1998), being concerned with the harmful interference to 406 MHz EPIRBs operating with the COSPAS-SARSAT system, noted the information provided by COSPAS-SARSAT on the 406 MHz interference sources. Accordingly, the Committee approved the following recommendations which would assist Member Governments to prevent harmful interference to 406 MHz EPIRBs.

  2 The COSPAS-SARSAT search and rescue satellite system is a multi-national system using low earth orbiting and geostationary satellites and ground receiving stations to locate 406 MHz emergency position indicating radio beacons (EPIRBs) activated in distress situations. The system has contributed to saving over 7,000 lives since it became operational in 1982.

  3 The 406 MHz EPIRBs are very important parts of international search and rescue. They are mandatorily carried on ships under the International Convention for the Safety of Life at Sea (SOLAS) as part of the Global Maritime Distress and Safety System. Additionally, carriage of EPIRBs on small vessels is mandated by various national Administrations. The life-saving mission of these beacons must not be interfered with.

  4 Transmissions from ground based emitters cause harmful interference to distress signals from 406 MHz satellite EPIRBs. A major cause of harmful interference is due to unwanted emissions from radars and other wideband transmitters operating within 30 MHz of the 406-406.1 MHz allocated bandwidth for satellite EPIRBs.

  5 ITU regulations prohibit interference in the 406 to 406.1 MHz band; however the maximum permitted emission limits for the bands within 30 MHz of the 406 distress band are not adequately defined to comply with the harmful interference limits described in ITU Recommendation SM. 1051.

  6 Member Governments are invited to bring the problem described above to the attention of their radio spectrum management authorities and request them to assure that new equipment designs will not interfere with the COSPAS-SARSAT system; and also to notify owners of existing equipment operating within 30 MHz of 406 MHz of the potential for interfering with the COSPAS-SARSAT system.

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