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.