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 same time).
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
Ortovox Patroller and the
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
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 range
Learn how to test your avalanche
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
(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
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
orientation-based transmitting) 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
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 manufacture).
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 were
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
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
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
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
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
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
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.
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.)