RECCO
Encyclopedia
The RECCO system is an electronic method of finding a person or persons buried in snow as a result of an avalanche
.
, in 1973.
Magnus collaborated with researchers at the Royal Institute of Technology
in Stockholm
, at first studying all the existing technologies. Although transceivers
were most effective, their disadvantages such as high cost, the need to turn them on and off, and their need for batteries, made him decide that some sort of passive reflector carried by the skier would be a simple and practical solution.
In 1975, the developer of the Skadi avalanche transceiver, John Lawton
, proposed that a reflector could be put on a lift ticket
. During the winter of 1978/9 Magnus, in conjunction with the Royal Institute of Technology, Stockholm
, painstakingly conducted an experiment. All winter, radio waves were sent into the snow, and by varying the frequencies every few hours an optimum frequency for penetration of the snowpack was arrived at.
Magnus formed RECCO AB in 1980 and soon created a first prototype, which was heavy and cumbersome, but it worked.
Nearly 30 years later (2009) the RECCO system now utilizes a small hand-held detector which can easily be carried by one rescuer, on foot or in a helicopter. These detectors are now standard equipment with more than 600 ski resorts, mountain rescue teams, and parks worldwide.
The reflector consists of a small, flat capsule, about 1/2" by 2" by 1/16" thick, which contains a pair of foil aerials, joined by a diode
. The size of the aerials makes the unit a tuned circuit resonating at one specific frequency. The reflector is passive meaning it has no batteries and it never has to be switched on. RECCO recommends users be equipped with two reflectors placed on opposite sides of the body. Many garment manufacturers now place one in one jacket sleeve and one in the opposing side trouser leg. Many snowboard and ski boot manufacturers place one in each boot.
The detector sends out a highly directional signal on that frequency from an aerial projecting from the front of the unit, and if the signal ‘hits’ a reflector it is bounced back. And, due to the diode the returned signal is doubled in frequency - harmonic radar. Thus the detector tells the operator that it is pointing at a reflector, and not just a piece of metal the right 'length'.
The returned signal is translated into an audio tone whose volume is proportional to the returned signal, and by means of a volume control a trained rescue operator can literally go straight to the buried reflector once a signal is detected.
RECCO's newest detector - 9th generation released in 2009 - also includes an avalanche rescue beacon receiver. The R9 detector allows a single rescuer to perform both the search for RECCO reflectors and 457 kHz avalanche beacons at the same time.
The RECCO signal easily passes through air, dry snow and ice. Liquid water absorbs the signal, so in spring time when the snow is wet—liquid water present—the range is decreased. Rescuers need to make slight adjustments to their search tactics search in wet snow conditions.
The time to search with the RECCO detector is about the same as the search time with a transceiver so large areas can be searched very quickly.
The system was originally developed for use at ski resorts where it is already recognized to be extremely valuable for ski-resort-based rescue teams and ski patrols. However, its value is not confined only to ski resorts. Even in the backcountry RECCO has demonstrated its capability to find buried victims quickly.
Time is the enemy of all buried avalanche victims, and devices and technologies that can significantly reduce search times can make a difference for buried victims. Transceivers, RECCO, and dogs are all much faster than probe lines.
Avalanche
An avalanche is a sudden rapid flow of snow down a slope, occurring when either natural triggers or human activity causes a critical escalating transition from the slow equilibrium evolution of the snow pack. Typically occurring in mountainous terrain, an avalanche can mix air and water with the...
.
History
The RECCO system was developed in response to an avalanche tragedy that involved the inventor, Magnus Granhed, in Åre, SwedenSweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
, in 1973.
Magnus collaborated with researchers at the Royal Institute of Technology
Royal Institute of Technology
The Royal Institute of Technology is a university in Stockholm, Sweden. KTH was founded in 1827 as Sweden's first polytechnic and is one of Scandinavia's largest institutions of higher education in technology. KTH accounts for one-third of Sweden’s technical research and engineering education...
in Stockholm
Stockholm
Stockholm is the capital and the largest city of Sweden and constitutes the most populated urban area in Scandinavia. Stockholm is the most populous city in Sweden, with a population of 851,155 in the municipality , 1.37 million in the urban area , and around 2.1 million in the metropolitan area...
, at first studying all the existing technologies. Although transceivers
Avalanche transceiver
Avalanche transceivers are a class of radio transceivers specialized to the purpose of finding people or equipment buried under snow. They are variously called Trackers, Pieps, or Arva's in a reference to some of the popular brands, "avalanche beacons" or "avalanche transceivers" - with many...
were most effective, their disadvantages such as high cost, the need to turn them on and off, and their need for batteries, made him decide that some sort of passive reflector carried by the skier would be a simple and practical solution.
In 1975, the developer of the Skadi avalanche transceiver, John Lawton
John Lawton
John Lawton may refer to:* John Lawton , thrice Member of Parliament for Newcastle-under-Lyme* John Lawton Member of Parliament for Newcastle-under-Lyme* John Lawton * John Lawton...
, proposed that a reflector could be put on a lift ticket
Lift ticket
A Lift ticket is an identifier usually attached to a skier's outerwear that indicates they have paid and can ride on the ski lift up a mountain to ski....
. During the winter of 1978/9 Magnus, in conjunction with the Royal Institute of Technology, Stockholm
Stockholm
Stockholm is the capital and the largest city of Sweden and constitutes the most populated urban area in Scandinavia. Stockholm is the most populous city in Sweden, with a population of 851,155 in the municipality , 1.37 million in the urban area , and around 2.1 million in the metropolitan area...
, painstakingly conducted an experiment. All winter, radio waves were sent into the snow, and by varying the frequencies every few hours an optimum frequency for penetration of the snowpack was arrived at.
Magnus formed RECCO AB in 1980 and soon created a first prototype, which was heavy and cumbersome, but it worked.
Nearly 30 years later (2009) the RECCO system now utilizes a small hand-held detector which can easily be carried by one rescuer, on foot or in a helicopter. These detectors are now standard equipment with more than 600 ski resorts, mountain rescue teams, and parks worldwide.
How it works
The RECCO system consists of two parts: a reflector integrated into clothing, boots, helmets, and body protection worn by skiers and riders; and a detector used by organized rescue teams.The reflector consists of a small, flat capsule, about 1/2" by 2" by 1/16" thick, which contains a pair of foil aerials, joined by a diode
Diode
In electronics, a diode is a type of two-terminal electronic component with a nonlinear current–voltage characteristic. A semiconductor diode, the most common type today, is a crystalline piece of semiconductor material connected to two electrical terminals...
. The size of the aerials makes the unit a tuned circuit resonating at one specific frequency. The reflector is passive meaning it has no batteries and it never has to be switched on. RECCO recommends users be equipped with two reflectors placed on opposite sides of the body. Many garment manufacturers now place one in one jacket sleeve and one in the opposing side trouser leg. Many snowboard and ski boot manufacturers place one in each boot.
The detector sends out a highly directional signal on that frequency from an aerial projecting from the front of the unit, and if the signal ‘hits’ a reflector it is bounced back. And, due to the diode the returned signal is doubled in frequency - harmonic radar. Thus the detector tells the operator that it is pointing at a reflector, and not just a piece of metal the right 'length'.
The returned signal is translated into an audio tone whose volume is proportional to the returned signal, and by means of a volume control a trained rescue operator can literally go straight to the buried reflector once a signal is detected.
RECCO's newest detector - 9th generation released in 2009 - also includes an avalanche rescue beacon receiver. The R9 detector allows a single rescuer to perform both the search for RECCO reflectors and 457 kHz avalanche beacons at the same time.
The RECCO signal easily passes through air, dry snow and ice. Liquid water absorbs the signal, so in spring time when the snow is wet—liquid water present—the range is decreased. Rescuers need to make slight adjustments to their search tactics search in wet snow conditions.
Usage
The search with the RECCO detector is very similar to how an avalanche rescue beacon search is performed. The avalanche debris area is searched in 20-m wide corridors. The detector can be used by a rescuer on foot, skis, or from a helicopter who aims the detector toward the snow. Once a signal is heard the operator orients the detector to the strongest signal and follows the tone—along a straight line. When the tone disappears the rescuer is right above the victim. The detector is then aimed downwards at the snow and several rapid crisscross sweeps are done to pinpoint the signal. Unlike an avalanche beacon the RECCO detector is truly directional and accurately pinpoints the location. A probe pole is recommended to determine the burial depth.The time to search with the RECCO detector is about the same as the search time with a transceiver so large areas can be searched very quickly.
Capabilities
The RECCO system is not intended for companion rescue and is not a substitute to transceiver use in the backcountry. The RECCO detector is another tool for organized rescue teams that complements their other search methods including rescue dogs, transceiver, and probe lines.The system was originally developed for use at ski resorts where it is already recognized to be extremely valuable for ski-resort-based rescue teams and ski patrols. However, its value is not confined only to ski resorts. Even in the backcountry RECCO has demonstrated its capability to find buried victims quickly.
Time is the enemy of all buried avalanche victims, and devices and technologies that can significantly reduce search times can make a difference for buried victims. Transceivers, RECCO, and dogs are all much faster than probe lines.