Why not improve the existing 121.5 MHz beacons?
The idea of improving the existing 121.5 MHz beacons was addressed in the 1980s. Improving the frequency stability, encoding identification information[3], and increasing the power of the beacons could improve the effectiveness. By 1985 the Cospas-Sarsat program had reached a critical juncture; either continue forward with the superior 406 MHz system which was already operational, or change the focus to the 121.5 MHz system. It was decided to continue forward with the 406 MHz system for the following reasons: • any improvements to the 121.
The idea of improving the existing 121.5 MHz beacons was addressed in the 1980s. Improving the frequency stability, encoding identification information, and increasing the power of the beacons could improve the effectiveness. By 1985 the Cospas-Sarsat program had reached a critical juncture; either continue forward with the superior 406 MHz system which was already operational, or change the focus to the 121.5 MHz system. It was decided to continue forward with the 406 MHz system for the following reasons: • any improvements to the 121.5 MHz system would still be available only at a regional level, as the space segment would have to be modified to provide global coverage; • modifying the space segment was not desirable from a program perspective as international agreements, spacecraft design, and the ground segment would all have to change; • some States had already begun the use of 406 MHz beacons, and it was felt that a market would develop which would lower the cost; and • no experi
