Testing the performance of avalanche transceivers

Avalanche rescue beacons are electronic transmitter–receiver devices designed to locate avalanche victims in avalanche debris. They have become standard equipment for the winter backcountry traveler. With the appearance of digital beacons or transceivers and the growing variety of beacons, the need arose for independent testing of this type of rescue equipment. Although there is a European standard for manufacturing beacons, there are substantial differences not only in how performance is defined between different brands, but also in how performance is best measured. Testing the performance is crucial, but not straightforward. There is no standard test procedure. Therefore, test designs are proposed to comprehensively measure search time and range. They should ensure reproducibility of performance results and were applied in two large field tests in Switzerland. A method recently proposed to define the width of search strip based on maximum range measurements in co-axial antenna orientation was verified by these tests and can be recommended. Results show that the maximal range of different beacons varies between about 25 and 100 m. Differences in search times were significant as well, but these were relatively small compared with the total time for recovery of a buried victim. Theoretical considerations of the relation between search time and range were also confirmed.