An avalanche beacon is a device used to find people lost in avalanches. The sensor has modes of receiving and transmitting signals. A transmitter with a certain frequency generates radio signals that are received by a receiver operating with it at the same frequency.
Principle of operation
The device has had the same pattern of operation for many years – if turned on as a transmitter, it creates a pulsating signal with a frequency of 457 kHz, which is received by another beacon operating as a receiver.
In modern versions of the sensor, the incoming signal is displayed on a digital display in the form of information for rescuers about where to look for victims, at what depth under the snow they can be, after which a sound is heard.
Each sensor is switched on as soon as the group enters the route. It is best to do this before you fasten your skis and boards – in the cabin of the cable car or at home. When starting, be sure to check the status of the device.
When a person gets into an avalanche, the beeper continues to send a signal, and other sensors in its coverage area are put into search mode to detect this signal. Time is of the essence when searching for snow-covered areas, so you need to understand how your own beeper works and practice using it regularly.
Varieties of beepers
All avalanche sensors are arranged according to the same scheme, and their principle of operation is the same. The only difference is how the received signals are played back. There are two types of sensors in total.
The principle of operation is to convert the radio signal as it approaches the object. Most analog versions lack a display that shows direction and distance to help you navigate.
Only a sound indicator helps out, which is not always convenient due to certain weather conditions. Indication of a line of LEDs allows you to identify the correct movement to the target.
This type of beeper has a built-in processor, as well as several antennas. The work of the antennas is to capture the radio signal, and the processor translates the signal into sound, and then displays it on the screen. This determines the direction of the transmitting beacon and the distance to it. The closer the transmitting signal to the beeper, the stronger the signal on the receiving transceiver.
With all the advantages of digital beepers, they also have disadvantages. One of the main ones is exposure to electromagnetic radiation from outside. Electromagnetic radiation distorts, interferes with receiving and processing the signal.
Sometimes it is better to use digital and analog in pairs, since digital is quickly and efficiently aimed at long-medium distances, but near the target (about 3 m) it loses aiming accuracy, and analog, on the contrary, works very well near due to the maxima-minimum technique.
According to the new standards, modern avalanche sensors have all the necessary technical characteristics in order to quickly and quickly find a person caught in an avalanche, thereby facilitating the work of rescuers.
Operating time and batteries
The duration of the beepers is as follows:
- Modern sensors work on signal transmission up to 400 hours, depending on the model. This means that during a ten-day trip to the mountains, the avalanche beacon can be turned on at the beginning of the first day of skiing, and its operation will be enough for all 10 days of operation in the active transmission mode of the radio signal.
- It is recommended to use only alkaline/alkaline batteries to power avalanche transceivers. The use of saline is not recommended.
- It is customary to change batteries when the remaining charge is 30% – this is due to the loss of capacity in batteries in the cold.
- Changing the battery charge from 100% to 5% does not change the signal strength and range of the sensor – it emits the correct signal and correctly processes the received one.
Frequencies and Compatibility
The avalanche transceivers currently on the market are compatible with each other as well as with older dual-frequency models. The frequency of modern sensors is 457 kHz.
Until 1996, two-frequency transceiver models were used – at 2.275 kHz and at 457 kHz. They were canceled because they could only work at short distances, plus ceramic resonators were used, which caused the devices to lose their frequency over time.
The main source of information when searching. But remember that the numbers displayed on the display show the distance to the victim along the line of electromagnetic field strength. This often results in the distance on the display being much greater (sometimes 2-2.5 times) than the actual distance to the target.
The high sensitivity of antenna devices, digital processing and powerful amplifiers guarantee signal reception and transmission at a distance of up to 80 m (up to 5 m in snow).
The distance of the gadget most often means the maximum length at which the beeper works. In practice, it has been proven that at such a distance the signal is not always good and may be distorted.
Beepers, in which the antenna is as powerful as possible, are able to pick up sensor signals at much greater distances. However, the receive range values may vary depending on the location of the transmitting transceiver’s antenna when it is under snow.
Many modern models allow you to consistently mark and quickly determine the direction and location of the victim. This is a handy and informative feature that may not be accurate.
Since the direction is indicated by arrows that show the orientation of the device in relation to closed lines of electromagnetic field strength, the device may not understand whether you are moving towards or away from the victim.
Sound indication is the most accurate, but uninformative parameter. The sound appears first, even before the arrows and numbers appear on the display, and the closer to the target, the louder the sound and the higher the tone.
Other parameters that avalanche beacons have:
- Radius of action – distance (50-80 m), which implies the optimal orientation of the device and signal strength. Long-range beepers detect the signal of the victim at a great distance, but this depends on how the sensors are positioned relative to each other.
- Work in the temperature range. Here it is advisable to talk about indicators from -20 to +45 degrees.
- Smart Antenna. The sensor “understands” its position in the avalanche and automatically switches to the most efficient antenna for transmission. With a vertical, the most unfavorable position for finding the victim, the device is the transmitter of the farthest signal.
- Pieps and BCA technologies similarly, they allow you to find a person who has fallen under an avalanche, using the potential of all antennas.
- Angle clinometer – a function intended for lifeguards, instructors and guides. It allows you to objectively, in numbers, understand the angle of the slope.
The best beeper models
We bring to your attention the following five models.
Pieps DSP PRO
The first three-antenna sensor. The new model has proven itself among professional users. Convenient case, ergonomic design, it is comfortable to work with the device even in thick gloves.
According to the test results, it is one of the best in all parameters, technical characteristics and functionality. Its weight is 200 g, the radius of operation is 60 meters, the duration of operation from one set of batteries in transmission mode is 400 hours. Price – 18,500 rubles.
More details about this model are described in the following video:
Pieps DSP Sport
It has a system of three antennas, is able to transmit a signal without the imposition of other signals, the display shows the number of victims in the form of figures. When a signal is detected, arrows show the direction and approximate distance. The price is 6,597 rubles.
Mammut Barryvox Pulse
One of the oldest three-antenna sensors. This is a professional model with the ability to switch to analog mode (for difficult search situations when the processor cannot separate the signals). There is a comfortable case, in general, good ergonomics. According to the test results, it shows good results in all respects.
This is one of the most complex devices with a branched menu and a large number of functions. Weight – 210 g, working radius – 60 meters, working time – 200 hours. Marking function – yes. Price – 26,000 rubles.
Three-antenna avalanche beacon. Shows the direction of the search, the distance, a scrollable list is supported, fixing up to five victims. There is a mode “for a beginner”, the ability to switch to analog mode, marking. Several signals are available. The radius of work is 40 meters, the duration of work is more than 240 hours. Price – 27,290 rubles.
Backcountry Access Tracker 2
The unique design of the device provides fast signal processing, and the speed of the display is able to instantly display data on the location of the victim. Weight – 180 g, there are three antennas, the duration of work in the transmission mode – 200 hours, in the search mode – 50 hours, the radius is 60 meters. Price – 18,000 rubles.
A sensor based on an intelligent position recognition system that automatically switches to the best transmitting antenna. Search range – 40 m, there is a function of automatic switching in case of repeated avalanche and marking, sound notification. Weight – 200 g, time – 250 hours. The case is rubberized, completely protects the sensor from moisture. The direction and distance to the victim is displayed in real time. The price is 23,550 rubles.
How to choose an avalanche transceiver (video tips)
A video is presented to your attention, which tells about the types of avalanche transceivers, their technical characteristics, rules of use, and also gives practical advice on choosing a device:
According to statistics, avalanche sensors significantly increase the chances of rescuing a person buried under an avalanche. The beeper does not reduce the likelihood of falling into an avalanche, it only reduces the severity of the consequences.