Avalanche transceiver
An avalanche transceiver ( LVS device ) is an electronic device used to search for avalanche victims . The device can also be used to locate people with an avalanche transceiver turned on and who have been buried by an avalanche in order to be able to free them as quickly as possible. This is important because the chances of survival of a buried person drop dramatically after just 15 minutes.
function
Avalanche search devices have two operating modes: transmit and search mode. Both operating modes cannot be active at the same time. The device is normally in transmission mode and should be worn close to the body. The search mode is activated after an avalanche to search for buried people.
In transmission mode, the device periodically transmits a weak radio signal with a duration of 70 ms at a carrier frequency of 457 kHz at intervals of at least 200 ms , older devices also work on the ELF frequency of 2275 Hz. The devices must have temperatures of −30 ° C to Withstand +70 ° C in operation and for a period of more than 10 hours. The procedure and the necessary requirements are specified by the European Telecommunications Standards Institute (ETSI) in the ETS 300.718 standard.
A safety rule in the area away from the slopes says that you should only move there in a group and that the individual group members should keep a large distance from each other. This is to ensure that not all group members are hit by an avalanche. Group members who have escaped the avalanche then set their avalanche transceivers to reception ( search mode ) and can thus locate the signal of the casualty. Depending on the avalanche transceiver, location and burial depth, the range is 20 to 60 m.
In addition to an avalanche probe and an avalanche shovel, an avalanche search device is part of the standard equipment of ski tourers , freeriders and other winter sports enthusiasts away from the secured ski slopes.
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Technical developments
The aim of the development of avalanche transceivers is to ensure that accident victims can be located more quickly and more accurately. The first devices worked analogously with an antenna, they indicated the distance to the buried subject via the volume of the signal tone. Later, devices with two antennas and a display were brought onto the market, which not only indicated the distance but also the direction (along a field line ).
In 2003, the Pieps DSP, the first digital avalanche transceiver with three antennas, came onto the market. This generation of devices, which is now offered by all well-known manufacturers, works more precisely and faster. It also offers much better possibilities to locate several buried subjects at the same time. Specifically, the current digital three-antenna devices have better localization and greater independence from the coupling position in contrast to the outdated analogue LVSs with single antenna. In addition, some avalanche transceivers offer special functions such as an additional analog mode, an inclinometer or a separate group check function.
Avalanche transceivers can be disturbed by electromagnetic fields .
A search process
Trained use of the avalanche transceiver is decisive for a good and fast search result, which requires regular exercises. An efficient search process also depends on a systematic approach, which is why the search process is divided into different phases. The relevant nomenclature is not uniform and different structures have already been used. The International Commission for Alpine Rescue (ICAR) recommends as of 2009 the procedure in four phases: signal search , coarse search , fine search and point search .
The signal search includes the systematic pacing of the avalanche cone (starting, for example, at the point where the victim disappears under the snow) until receiving a first signal with the avalanche transceiver or another sign from the victim (sighting, acoustic signals, ...). The specific procedure for the signal search depends not only on the number of searchers but also on the characteristics of the avalanche transceiver, in particular its range. The rough search extends from the point of the first signal reception (which is usually marked) to the immediate vicinity of the victim. For the transceiver this point is defined as the point where the amplitude of the signal decreases in all directions for the first time. In this phase, digital and analog avalanche transceivers require different search strategies. Even with the fine search in close range, where work is usually done just above the snow surface, there may be design-related differences between different avalanche transceiver models (analog / digital or two or three antenna devices). The fine search ends according to today's ICAR nomenclature with the transition to the use of the avalanche probe. In the past, the search with the avalanche transceiver in the vicinity was also referred to as pinpoint location, today the search with the probe until the buried subject is found is summarized under this term.
"Multiple burials" are particularly challenging, when several people are buried under the snow, since the signals can overlap, especially if the victims are close together. In this case, special methods such as the three-circle method or the procedure with micro search strips are necessary. Some devices offer their own functions for special search strategies in such cases.
See also
Web links
- Avalanche emergency systems in comparison (field tests) , Swiss Federal Institute for Snow and Avalanche Research, WSL
- Avalanche transceivers 2013/2014 being tested , German Alpine Club , December 6, 2013
- Info page for avalanche transceivers,
Individual evidence
- ↑ Smartphones are useless as avalanche search devices , Die Welt , December 5, 2013
- ^ Radio Equipment and Systems (RES); Avalanche beacons; Transmitter-receiver systems. (PDF) European Telecommunications Standards Institute (ETSI), 1997, accessed June 28, 2014 .
- ^ Gregor Krenn: LVS basic knowledge. (PDF) Retrieved January 27, 2014 .
- ↑ Avalanche transceivers in comparison: Market overview 2017/18. In: Bergzeit Magazin. October 18, 2019, accessed June 30, 2020 .
- ↑ Troubled lifesavers? Electronics and avalanche transceivers do not get along , February 19, 2013, skiinfo.de
- ↑ Electromagnetic Compatibility of Avalanche Beacons ( Memento of the original dated February 2, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , ICAR, English
- ↑ a b International Commission for Alpine Rescue (Ed.): Recommendation REC L 0009 of the Commission for Avalanche Rescue from September 24, 2009 on the terms that describe the search phases in an avalanche rescue . 2009 ( ikar-cisa.org [PDF; accessed December 5, 2010]). Recommendation REC L 0009 of the Commission for Avalanche Rescue of September 24, 2009 on the terms that describe the search phases in an avalanche rescue ( memento of the original of October 29, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ a b Dieter Stopper, Chris Semmel: In a nutshell? In: German Alpine Association , Austrian Alpine Association , Alpine Association South Tyrol , Swiss Alpine Club (publisher): bergundstieg . No. 1 . Innsbruck 2005, p. 54–57 ( bergundstieg.at [PDF; 2.1 MB ; accessed on December 5, 2010]).
- ↑ Chris Semmel, Dieter Stopper: Stress to the power of four . In: German Alpine Association , Austrian Alpine Association , Alpine Association South Tyrol , Swiss Alpine Club (publisher): bergundstieg . No. 1 . Innsbruck 2003, p. 22–26 ( bergundstieg.at [PDF; 175 kB ; accessed on December 5, 2010]).
- ↑ Multiple burials . In: German Alpine Association , Austrian Alpine Association , Alpine Association South Tyrol , Swiss Alpine Club (publisher): bergundstieg . No. 4 . Innsbruck 2004, p. 66–73 ( bergundstieg.at [PDF; 13.3 MB ; accessed on December 5, 2010]).
