This page explains the test criteria that were used to test the avalanche transceivers.
I have worked hard to keep the tests as scientifically accurate and unbiased as possible.
The range chart summarizes the
results of multiple test sessions over several years. In a recent session, I tested
a whopping 105 transceivers that included 32 different makes and models. All of the test
sessions follow the same basic criteria:
There were not any overhead or buried utility lines. (We listened with an analog
transceiver for background signals. Occasionally, a faint radio station was heard
in the background. The small background noise
does show a transceivers' ability to filter out the notice and did not effect the range
test results materially.)
The tape measure was non-metallic.
were no metal poles or wires nearby.
All transceivers had new batteries (the same make and model purchased at the
In the case of digital transceivers, the distance recorded was the point where
the testers agreed the transceiver had locked on to the signal. That means the transceiver
was consistently displaying both the distance and direction indicator (an occasional
missed beep was acceptable). Note that some transceivers, specifically the
Ortovox Patroller and
the Tracker2, display the
distance to the transmitter before they display a direction indicator. As with the
other digital transceivers, the distance that was recorded was when the direction
indicator was displayed.
In the case of analog transceivers, the distance was the point where the sound
was "faint but undeniable." This required a very quiet background—you
would never hear the faint signal over the sound of moving skis (or even while walking
on snow). This makes it a bit unfair to compare the analog distances (which required
total silence) to the digital distances (where the
ambient noise was immaterial).
Due to the subjectivity of when the signal was "faint but undeniable,"
differences of less than 5 meters are insignificant.
The distances displayed on the screen of the digital receivers is an estimate
of distance to the transmitter following the
flux line rather than a straight line between the transmitter and receiver.
Most digital beacons display a distance that is greater than the actual distance.
In all cases the actual measured distance, rather than the distance displayed by
the digital beacon, was recorded and is displayed in the
My typical multiple burial test involved placing
two transceivers placed approximately five meters apart. The searching transceiver was
then changed to search mode (sometimes within the receiver's range where it would immediately
pick up a single and sometimes from a distance where no signal was received). This process
was repeated using two transmitting beacons of the same brand (without signal overlap),
using two transmitting beacons with different cadences (periodic signal overlap), and
using two beacons using the DSP's Smart
Transmitter (different brands, without signal overlap).
The "suppress" functions were used to see if the searching beacon would
consistently suppress the victim's beacon and if the searching beacon would direct the
searcher to the next victim.
Most of my multiple burial testing has been limited to two transmitters, although
in the fall of 2010 I did numerous tests of the
Ortovox 3+ with three transmitters.
To test if a transceiver can ignore spikes, the transmitting
beacon (not a Tracker2 because its antennas are not inline with its housing, and not
the Ortovox 3+ or S1+ due to their
was placed two and three meters above the ground on a non-metallic pole (this is easier
than digging a three-meter hole). Tape measures were run from the base of the pole in
opposite directions on the ground. The receiving beacon was then moved very slowly along
the ground, in a straight line, to search for the strongest signal(s).
This test was repeated on numerous sessions, using different transmitting beacons,
at different "depths." The orientation of the two transceivers plays a large
role in the location of the spikes, but the results were very consistent based on the
number of antennas (the exceptions being the
Ortovox Patroller, and
Ortovox D3 which are
three-antenna transceivers but which did not
accurately eliminate spikes).
The weights listed in the comparison table are the actual
weights including the harness and batteries (if you choose to display "additional
details" in the comparison table, the weight with batteries but without the harness
is also displayed). The volume of the transceivers was calculated based on the length,
width, and depth (usually the actual measurement, but occasionally as provided by the
possible, the dimensions listed in the comparison table
are the actual sizes as measured with calipers. Small protrusions that are less than
approximately 5% (such as the triangular Search switch on this ARVA Link) are not included.
The volumes in the comparison are calculated as "height x width x depth"
and ignore irregularities in shape.
Major Range Tests Sessions
#1 took place on January 15, 2004. The air temperature was approximately 18F
(-8C). The ground was covered with approximately 6" of snow. The
transmitting transceiver was an Ortovox M2 placed on top of the snow. Five beacons
Session #2 took place on January 17, 2006. The outside temperature was approximately
25F (-4C). The ground was covered with approximately 3 meters
of snow. The transmitting transceiver was a Pieps DSP placed on top of snow. Seven
beacons were tested.
Session #3 took place on January 18, 2006. The conditions were similar to Session
#2. Four beacons were tested.
Session #4 took place on February 27, 2006. The outside temperature was approximately
50F (10C). Three beacons were tested.
Session #5 took place on October 24, 2006. The outside temperature was approximately
65F (18C). The test was done in a city with some background
noise (a faint music radio could be heard). The surface was a lawn. The transmitting
transceiver was an ARVA Evolution+. The six transceivers tested had an average increase
in range of 50%! Whether the increase was due to the transmitting beacon (an ARVA
Evolution+), the temperature or other environmental conditions, these values were
not averaged into the test results. Six beacons were tested.
Session #6 took place on November 12, 2006 in a remote area in the mountains. The
air temperature was approximately 26F. The ground was covered with approximately
two feet of snow. The transmitting beacon was a Tracker DTS placed on top of the
snow. Ten trained rescuers tested 53 transceivers at this mother-of-all-tests.
Session #7 took place on December 5, 2006. During range testing, the outside
temperature was between 23F and 26F. The ground was frozen
dirt with approximately 2 inches of snow. For performance and spike testing, the
temperature was approximately 33F and the ground was covered with two
feet of snow. The transmitting beacon was an Ortovox M2. Nine beacons were tested.
Session #8 took place on December 27, 2007. The outside temperature was approximately
22F. The ground was covered with approximately 12 inches of snow. The
transmitting beacon was a Tracker DTS that was inline (so the transmitting antenna
was at an angle) with the receiving beacons. Eight beacons were tested.
Session #9 also took place on December 27, 2007, but at a different location.
The outside temperature was approximately 15F. The ground was covered
with approximately three feet of snow. The transmitting beacon was a Pieps DSP with
v5.0 software. Nine beacons were tested.
Session #10 took place on November 19, 2008. The outside temperature was approximately
24F. The ground was covered with approximately two feet of snow. Ten
transceivers were tested using two different transmitters.
Session #11 also took place on November 19, 2008. This test measured the ability
of nine transceivers to transmit a signal. The
outside temperature was approximately 29F. The ground was covered with
two feet of snow. The receiving beacons were a Pieps DSP and an ARVA Advanced.
Session #12 took place on January 24, 2010. The outside temperature was approximately
14F. The ground was covered with approximately four feet of snow. Fifteen
transceivers were tested using two different transmitters.
Session #13 took place on January 26, 2010. This session included exhaustive
testing of spike handling, at both one and two meters,
using 11 different avalanche transceiver models.
Session #14 took place on October 15, 2010. This outside temperature was approximately
70F (warm). The ground was dry grass in a large city park. There was
minimal background noise and no visible power lines. Eight beacons were tested (include
three Ortovox 3+ transceivers).
An Ortovox multiple transmitting test station was used to simulate multiple burials.
Session #15 took place on December 14, 2012 in a large
city park. We could hear a faint radio station when using an
analog transceiver. The range of 34 transceivers (20
different models) were tested. This was the largest sample
size I've ever had in one test session.
Many variables influence how close a transceiver must be before it detects a signal.
The signal is strongest when the antennas of both transceivers are aligned. The ranges
published on BeaconReviews.com are when the transceivers were physically aligned. (In
many tests I also recorded the antennas in worst case, i.e., perpendicular, orientation,
but I have not published that data.)