to 80 meters through air and 20 meters through packed snow, depending on various factors such as the snow conditions and depth. Short-range portable detectors are used, transmitting via a directional antenna at (Europe) or and receiving at twice the frequency. The detector works by transmitting at one frequency on a 20% duty cycle and listening for a harmonic reflection at double the frequency. The signal from the detector can also weakly be reflected from other electronic devices, such as cameras and cell phones, as well as metallic objects. However, even if this effect has allowed the rescue of several buried people who were not carrying a reflector, the search range of those others devices is much shorter and not reliable enough. Rescue applications Avalanche rescue More than 700 rescue groups worldwide, predominantly in ski resorts, used the technology. The professional rescue teams use RECCO detectors as an electronic search method in addition to the avalanche transceiver to find victims in an avalanche. RECCO equipment is included in textbooks on rescue, and a RECCO reflector is included among measures recommended by the International Commission for Alpine Rescue. According to the company, people totally buried by an avalanche were located using the technology in fifteen incidents during 2005–15. A case report of a live rescue of a buried off-piste skier using RECCO equipment that occurred in Spain in 2015 has been published in the Journal of Wilderness and Environmental Medicine. The authors commented that the technology was poorly studied compared with some other avalanche safety methods. Outdoor rescue The RECCO SAR helicopter detector is designed for a large-scale search by professional rescue teams for missing persons in open terrain. The missing person must be equipped with a RECCO rescue reflector to be located by the detector signal. The SAR detector can search from a height of 100 meters and covering a search area of approximately 100 meters wide. The principle of locating a victim is the same as for the handheld detector with the detector sending a radar signal echoed back by the reflector. If receiving a returned signal, the rescuer can locate the lost individual. Other applications The RECCO technology has also been applied to tracking some amphibian species, especially tropical frogs. The system allows researchers to track small frogs in their natural habitat. During 2000‒2004 RECCO equipment was tested for tracking ground beetles. References External links Recco AB Website