Feature
History
Bios
Events
Orgs
Gear
Photos
Forum
Quotes
Reads
Links
Home
This feature article was snagged from WHAT THEY
ARE AND HOW THEY WORK: An
avalanche beacon (or transceiver) is, or used to be, a simple
radio transmitter and receiver - sending or receiving a
beeping signal on a standard frequency of 475 megahertz. When
someone wearing a transmitting beacon is buried by an
avalanche, their transmitter continues to emit "beeping"
signals which can be picked up by a searcher/rescuer who has
another beacon set to receive the signals. These signals
become stronger as the rescuer gets closer to the buried unit,
allowing the rescuer to zero in gradually on its location and
find the buried wearer. THE
EVOLUTION OF BEACON DESIGN Avalanche
beacons have evolved and improved over the years, with each
innovation designed to make them easier to use. This is
important because they are actually quite difficult to learn
to use, requiring a fair bit of training and a great deal of
practice in order to quickly find a buried beacon. Until
recently, the most important design change was the addition of
colored lights to the unit, indicating visually the change in
volume of the signal as the searcher got closer. Since changes
in volume can be hard to detect, this visual reinforcement
proved quite helpful. More
recent innovations include adding a second antenna and
digitizing the signal with a micro processor in the unit.
Backcountry Access introduced the digital technology with the
"Tracker". Unlike the traditional "analog" transceiver, the
Tracker's micro processor, in combination with two antennas,
allows it to analyze the incoming signal for the user,
calculating both direction and strength of signal. It then
displays the signal as a numerical readout indicating distance
from the target and "points", by means of an array of lights,
in the direction the searcher needs to turn. The searcher no
longer uses her ears to listen for a change in volume, she
just reads the numbers on the screen and walks in whichever
direction makes them grow smaller, turning right or left as
indicated by the lights. The unit does the work that used to
be done by the user's ears, eyes and brain. BEACON
MANUFACTURERS AND THEIR DESIGNS Various
beacon manufacturers have responded to the challenge of the
new digital technology in different ways. Ortovox
has kept the "analog" technology - direct signal to the user
with no intervening processor, single antenna - while
digitizing the display to make it easier to use. The signal is
displayed on a small screen as a numerical display giving
distance to the target, and volume is also indicated by a bar
that fills more completely as the signal gets stronger. A
light also echoes the indication of closer range. The Ortovox
strategy is to display information in several ways, since
individuals differ in the ways they process information most
effectively. The analog technology doesn't indicate direction
as effectively as the digital units, but the Ortovox unit does
indicate direction in a "yes/no" sort of way by having an
arrow that fills in when the receiving unit is aligned with
the radio waves coming from the transmitting unit. Barryvox
has embraced the dual antenna, digital design. However,
recognizing the diversity of peoples' perceptive styles as
well as the reluctance of experienced beacon users to abandon
acquired skills and habits to learn new ones, they have
attempted to provide a choice between direct signal (analog)
modes where the signal is processed by the users' own ears and
brain, and the directional ability of the digitized signal.
CHOOSING
THE RIGHT UNIT Here are
some pros and cons of the new digital, dual antenna design:
CONS:
Reduced range: The addition of the
processor seems to have reduced the range of usable reception
significantly. (The Barryvox so far is worse than the Tracker
in this regard). This could be a distinct disadvantage in a
large search area, or when the rescuers didn't see the burial.
It's hard to say how important this is - in other words, how
much range does one actually need in practice? Less
effective with multiple burials: If more than two
people are beneath the snow, the task of separating and
identifying the different signals becomes much more difficult
with a digital readout than with an audible signal. Our ears
are pretty good at differentiating between the relative
strength of several signals and picking out the loudest, and
the digital unit doesn't allow the user to do this. With
training, a digital readout user can learn to differentiate
and identify a single signal out of several, but it is not as
easy as with an audible signal. PROS:
The
digital unit is simply much easier to learn and to use,
especially with a single burial. One guide tells a story of
giving his 9 and 11 year old niece and nephew two simple
instructions: keep the light in the middle, and make the
numbers get smaller - and they found a buried beacon in 90
seconds! Since survival rates of buried victims decrease
dramatically and exponentially after 10 to 15 minutes of
burial time, and skiers and other winter fun-hogs hate to take
time away from the good stuff to practice beacon searches,
this is an important difference for the recreational user.
THE
UPSHOT: Many
professional users highly trained in the use of avalanche
beacons, such as guides, ski patrollers and other avalanche
professionals, may be more likely to prefer an analog beacon.
But for the recreational user, who doesn't care to invest a
lot of time learning to use a traditional beacon, or who has
received only minimal instruction, the digital, dual antenna
technology is a better choice. Comments?
views@mountainwoman.com
.
Click here for the previous articles
 |
About womenclimbing.com | Advertising Info | Contact Us designed by Heidi Haas | powered by TNR Webworks |