Backcountry Essentials: Why you should be using a two- or three-antenna beacon
WORDS: Erin Smart
Erin Smart is an AMGA certified Ski Mountaineering Guide, and is working towards her IFMGA license. She has been working as a ski guide and an AIARE avalanche instructor for the last five years. She currently lives in Chamonix, France. Find more of her work at ErinSmart.com
The differences in transceiver technology can be measured in minutes, and in an avalanche burial rescue, minutes mean lives. Transceivers use either a one-, two-, or three-antenna technology. Not only is there a difference in ease of use between an analog (one antenna) transceiver and a digital (two or three antenna) transceiver, but both professional and novice users are on average one to three minutes slower when they’re using an analog transceiver rather than a digital one. The “best by” date has passed on the one-antenna transceivers, which were the leading technology over 15 years ago. If you or a friend still uses an analog beacon, it’s time to upgrade.
Comparing two- and three-antenna beacons comes down to the fine search, also known as the grid search. The third antenna turns on when a user comes within approximately two meters of a signal. With that additional antenna, your transceiver analyses the flux lines in order to lead you directly above the victim. This lowers the chance of a false minimum, which is a term for a bad situation—your beacon is leading you astray. A false minimum is more common with deeper burials, and without that third antenna, you may end up probing one to two meters away from the correct spot, delaying your rescue efforts and costing precious time against a clock of 15 minutes, the time when a buried victim’s chance of survival is the highest.
Another advantage that some three-antenna transceivers have is a marking function, also referred to as flagging or masking. This feature is designed for use in the event of multiple burials. Once one signal is found and has a confirmed probe strike, the marking function allows you to “hide” that signal, and go and search for another one. There are techniques to search for multiple transceivers without a marking function, but they take lots of practice, and even then are not as quick and easy as it could be with a marking function.
As with any piece of software, sometimes you might find that your transceiver is not working properly, whether you’re using the marking function or just searching normally. In the event that happens to you, simply reboot. Turn it off and then on again. Yes, just like your computer.
If you’re looking for a new transceiver, pick one with three antennas. It’s an easy choice and most professionals are expected to use a three-antenna transceiver. If you are still using a one-antenna transceiver, upgrade. If you are still using a two-antenna transceiver, consider upgrading. Whatever transceiver you have, go out and practice with it. Bury another transceiver at least the average burial depth, which is 1-1.5 meters down—deeper than you think. Practice multiple burials, and practice with the people you go out with the most. As with any tool, a transceiver in your hand is only as valuable as the training behind it. Take an avalanche course, practice your rescue skills, and know what the avalanche danger is before you head out the door.
|Last week’s backcountry tip: What to think about when skiing in a persistently sketchy snowpack. →|
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