Many electronic devices can affect avalanche transceivers.
And metal, even in food wrappers, can affect a transmitting beacon. This page contains advice based on informal
testing and the manufactures' instructions. Read your
user manual for specific advice.
When searching, your consumer electronics (e.g., phones, cameras, music
players, headed gloves, etc) need to be further away from
your transceiver than when transmitting. (These devices haven't been shown to interfere with a beacon's
transmissions.) Here are some examples of official recommendations:
The Tracker DTS manual says at least 15 cm (6 inches), the
Tracker2 says 30 cm (12 inches), and the Tracker3
says at least 40cm (16 inches) when searching and at
least one inch when transmitting.
Most Ortovox manuals recommend at least 30 cm (12 inches) from other electronics. The
Ortovox 3+ owner's
manual increased that to 50 cm (20 inches).
Mammut says at least 50 cm (20 inches).
My informal testing leads me to feel
that the recommendation of 30 cm (12 inches) is a reasonable
minimum. To be even safer, turn the devices off
(which is what most manufactures suggest), but since this might be overlooked during the inevitable
panic of a real rescue, it best to turn them off even when transmitting. And it is preferable to turn off your electronics when transmitting
so you don't forget to turn them off when searching. If you need to keep them turned on, always keep
them at least a foot from your beacon.
By contrast, metal layers can partially block a beaconís transmission.
We confirmed that something as seemingly innocuous as a few Gu gel packs (which contain metal sandwiched
in between plastic layers) can drastically shorten a beaconís transmission range. Don't keep any
suspected metallic layers in a clothing pocket that might overlap your transceiver.
Remember that a cell phone that is not being used still transmits
a signal to the cell service periodically even when not placing a call. Even in "airplane" mode the
power conversion can cause interference.
MP3 music players can wreak havoc during a search. (I've seen
a tiny no-name MP3 player that was in the front pocket of a
searcher confound his transceiver.) And don't forget that
GoPro strapped to your chest. In our informal
testing, 30 to 50cm (12 to 20 inches) seems necessary if you want to "be a hero."
In search mode, irregular readings and decreased range can
also be caused by other sources of electrical interference,
such as power lines, lightning, and electrical generating equipment.
Ironically, chairlifts also generate background "noise"
that can affect the searching transceiver.
The Petzl Tikka XP2 headlamp cautions, "Warning,
when your lamp is lit and in close proximity to an avalanche
beacon in receive (find) mode, it can interfere with the
operation of the beacon. In case of interference (indicated
by static noise from the beacon [you won't hear static
on a digital beacon]), move the beacon away from the
lamp until the noise stops, or switch off the lamp."
Diamond's heated gloves warn, "Electronically
heated gloves interfere with avalanche beacon reception. Turn
gloves off while searching. If you are buried with gloves turned
on, the search beacon will see interference when it is within
a 1/2 meter radius of the gloves." Although heated
gloves aren't commonly used by backcountry skiers, they are
becoming quite popular with snowmobilers. Turning off
your gloves is one more thing you'll need to remember should calamity
Magnets can be a culprit, too:
Some transceivers use a magnetic switch (even though the switch might appear to be
mechanical). It is possible,
although not easy, to switch between Off, Send, and Search
with an external magnet. The transceiver will return to
its previous mode when the magnet is removed. This is another
reason to avoid jackets with magnetic closures.
Some transceivers use a magnetic compass while searching
It is especially important that you keep magnetic items away
from these transceivers while searching. Be especially wary
of magnetic closures on jackets.
The Black Diamond Magnetron carabiners include a warning
saying that the carabiners should be kept 50cm (20 inches)
from avalanche transceivers.
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