This page explains the test criteria that was used to test the avalanche transceivers. I have worked hard to keep the tests as scientifically
accurate and unbiased as possible.
Range Testing
The range chart summarizes the results of multiple test sessions over several years.
In a recent session, I tested a whopping 69 transceivers that included 22 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. These tests do show a digital transceiver's ability to filter out
background noise and did not effect the range test results materially.)
The tape measure was non-metallic.
 There 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 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 rather unfair to compare the analog distances (which required total silence) to the digital distances (where
the background 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 chart.
My typical multiple burial test involved 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 rates (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.
My multiple burial testing has been limited to two transmitters.
To test if a transceiver can ignore spikes, the transmitting beacon 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 X1, 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 sometimes as
provided by the manufacture). Certainly lighter, smaller, transceivers are preferable.
Range Tests Sessions
 Session #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 tested.
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.
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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.
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.)
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