Avalanche transceiver facts for kids
An avalanche transceiver (also called an avalanche beacon) is a special radio device. It helps find people buried under snow after an avalanche. Skiers, especially those exploring off-trail areas, carry these devices.
Before a trip, everyone in a group turns their transceiver to "transmit" mode. This sends out small radio signals. If an avalanche happens and someone gets buried, the others switch their transceivers to "receive" mode. This allows them to listen for the signals from the buried skier's device. It works like a radio compass to guide rescuers. Avalanche beacons use batteries to work. Some ski suits also have a passive RECCO transponder sewn in, which is another type of rescue aid.
The first avalanche transceivers used a frequency of 2.275 kHz. In 1986, a worldwide standard frequency of 457 kHz was chosen. This is still the standard frequency used by most transceivers today.
It's important to remember that an avalanche transceiver doesn't stop avalanches. Instead, it helps rescuers find buried people faster. This quick response greatly increases the chance of saving lives.
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The Story of Avalanche Beacons
In 1968, a scientist named Dr. John Lawton created the first useful avalanche transceiver. He worked at Cornell Aeronautical Laboratory in New York. The first devices were sold in 1971. They were called "Skadi," named after a goddess from old stories.
These early devices used a 2.275 kHz frequency. They turned the radio signal into a sound you could hear. Rescuers would listen for the loudest sound. This helped them find the buried transceiver. They used a special search pattern to cover the area.
In 1986, a group called IKAR set a new standard. They chose 457 kHz as the international frequency. Later, in 1996, ASTM also approved this standard.
By 2007, clear rules were in place for these 457 kHz transceivers. These rules covered things like how accurate the frequency should be. They also set how long batteries should last. For example, a beacon should transmit for 200 hours at 10°C. It should receive for 1 hour at -10°C. They also needed to work in temperatures from -20°C to +45°C.
Once the 457 kHz standard was set, people wanted easier-to-use devices. New digital beacons came out with tiny computers inside. These computers could figure out both the direction and distance to a buried person.
In 1997, the first digital beacon was shown. It was made by Backcountry Access and called "Tracker." The Tracker DTS quickly became very popular. Many outdoor adventurers still use it today.
As of 2021, many companies make digital beacons. These include Ortovox, Arva, Pieps, Mammut, and Backcountry Access. While technology keeps getting better, practicing with your beacon is key. Knowing how to use it well is the most important part of saving lives.
Different Kinds of Beacons
Avalanche beacons come in two main types: digital and analog. Both types follow the same international frequency standard. They differ in how they show you where a buried beacon is. Most beacons sold today are digital. They are easier to use and help find people faster.
Analog Beacons
The first avalanche beacons were analog. They sent out a pulsed signal that you could hear as a tone. The sound got louder as you got closer to the buried beacon. Newer analog beacons also added LED lights. These lights showed how strong the signal was. Some even had earpieces to help you hear the tone better.
Digital Beacons
Digital transceivers are smarter. They measure the signal strength and pattern. Then, they calculate the distance and direction to the buried beacon. To do this, they need at least two antennas. Most modern digital beacons have three antennas.
Digital beacons show you the direction with an arrow on a screen. They also give you sound clues, like different pitches. Simpler digital beacons have arrows that point in a few forward directions. They might show a "U-Turn" if you are going the wrong way. More advanced beacons have a digital compass. This allows for a more exact, free-flowing arrow. Some can even point in a full 360 degrees. Many digital beacons can also switch to an analog mode. This can be useful for experienced rescuers or for better signal range.
W-Link Technology
Some advanced digital beacons have an extra feature called W-Link. This uses a second frequency to send more details to other W-Link beacons. This extra information helps rescuers in several ways:
- It helps sort out many signals when several people are buried.
- It gives a better idea of how many people are buried.
- Rescuers can quickly mark a found person. This tells the beacon to ignore that signal and look for others.
- It helps choose the best person to search for first. Sometimes the closest person is not the easiest to reach.
- It can send and receive extra data, like if the person is moving.
Detecting Signs of Life
Beacons with W-Link send a special code. This helps separate signals from different devices. Some W-Link beacons can even sense tiny movements from a person's heartbeat. They send this information through the W-Link frequency.
This means a rescuer with a W-Link beacon can see if a buried person is still moving. This helps rescuers decide who to focus on first. If everyone in a group has these special beacons, rescuers can quickly find those who are still alive.
What if someone in the group has a beacon without W-Link, or one that doesn't detect movement? The rescuer's W-Link beacon will show two things for each buried person. One shows the beacon is sending a W-Link signal. The other shows if the person is moving. This helps make sure no one who is alive is accidentally missed.
W-Link Frequencies Around the World
The W-Link frequency changes depending on where you are.
- In Region A (most of Europe, Sweden, Norway, Greenland, Iceland), it uses 869.8 MHz.
- In Region B (Canada and the United States), it uses 916-926 MHz.
W-Link frequencies are not allowed in some countries. These include Russia, China, India, Australia, New Zealand, and Japan. If you travel to these places, you might need to turn off W-Link on your beacon. Changing between Region A and B might need help from a special store.
How Rescuers Search
The 457 kHz signal from beacons is very focused. This means rescuers need special ways to find buried beacons. Learning how to search with a beacon is a must-have skill. This applies to casual skiers, mountain climbers, and avalanche experts. Ski guides, ski patrollers, and rescue teams all practice these skills. They do drills and pretend scenarios often. This is a key part of their avalanche safety training.
When only one beacon is buried, rescuers might use different methods. These include the Grid search, induction search, or circle method. These techniques are also changed and used when more than one person is buried.
Learn More
- Emergency locator beacon
- Emergency position-indicating radiobeacon station
- RECCO
 | William Lucy |
 | Charles Hayes |
 | Cleveland Robinson |
