Introduction: Disclaimers and Caveats

This review is a work in progress . . . and might forever remain so, given the open-ended nature of beacon testing, and the periodic updates of software versions.

In particular, the quality is admittedly fair to poor for the pictures and especially videos. (Simultaneously searching, skiing, and videoing is as difficult as it appears!) And I have received from various readers additional suggestions for additional tests, some of which have been very revealing.

Also, for personal disclaimers, I have no background whatsoever in electrical engineering (rather, I’m an economics consultant, specializes in the application of financial economics to litigation disputes, regulatory enforcement, and public policy decisions), so please don’t ask me about the why/how behind the inner workings of all these beacons! And although I appreciate the price discounts extended to me as an AIARE-qualified course instructor and NSP avalanche course instructor, I am neither sponsored nor employed by any company in the ski, mountaineering, or outdoor industries, so as the saying goes (originally from the Cold War, but perhaps more evocative now of NFL off-field scandal), I ain’t got no dog in this fight.

Introduction: Background and Overview

The many reviews I have seen so far on the Ortovox S1 (mainly pre-production versions, given its initial announcement almost four years before regular production units have just now become available) focus mainly on:
- its graphical representation on beacon distance and direction; and,
- its ability to show the distance and direction to multiple beacons.

The former is indeed truly unique. The latter, however, was introduced into regular production a little over a full year earlier (Fall 2006) by Barryvox in the Pulse. Since the S1 and Pulse have similar capabilities, and since no reviews had yet compared/contrasted the two units’ performance, hence I decided to write this review.

Somewhat similarly, the Pieps DSP back in 2003 pioneered the ability to separate beacon signals and then flag/mark/mask a found beacon so as to not confuse the search for other victims. Unlike the S1 and Pulse, the DSP locks onto the strongest signal, then does not display distance/direction to other beacons unlike the first beacon is marked. The user can get away from the lock (and also unmark any previously found beacons) by selecting the scan feature and then moving closer to another signal, but the DSP lacks the capability found on the S1 and Pulse to select among different beacons and display each beacon’s distance and direction.

Nevertheless, since the DSP has similar if not identical capabilities, I included it in the test.

Also, by no means do I wish to imply by this extensive review that these are the only three beacons worthy of consideration; rather, my main motivation is that the S1 reviews so far have been lacking in any sort of comparison with its direct competitor (i.e., the Pulse).

For other beacons, my slightly out-of-date (though much more up to date than the TAR version from last year) comparison tables are available here:
http://www.avalanche-center.org/Education/resources/Beacon-Summary- 2007-09-01.pdf

And of course, the most comprehensive and constantly revised set of reviews is hosted here:
http://www.beaconreviews.com

Another source of reviews, although far less comprehensive, is available here:
http://pistehors.com/backcountry/wiki/Gear/Avalanche-Transceivers

The testing fleet:

(Many thanks to my fellow patroller Bob for lending me his beacons to supplement my own for the test!)

Out of the Box: Ergonomics

I weighed all beacons (including harness and batteries - three AAA for all of them) on a digital postal scale. The DSP wins the Dynafit Weight Consciousness Award at 10.4 ounces, but with the Pulse 11.6 and S1 at 12.8 (the second-heaviest beacon on the market, despite its sleek & slim appearance), no beacon is in contention for the Marker Duke Heavyweight Championship – more like quibbling among the differences between the Dynafit Comfort and Vertical ST.

Harnesses are largely a matter of personal preference, and all three use the tethered-pouch design. Nevertheless, I have never heard anyone (who has used many other tethered-pouch designs) rave enthusiastically about the DSP harness, I have heard many users complain about it, and personally it’s my least favorite in this group . . . but still, it’s adequate.

Both the Pulse and DSP integrate the On-Off and Search-Transmit function into the same switch, and both can be manipulated relatively easily with one hand. The S1 seems difficult (if not impossible) to switch into Search with only one hand (unless the lid’s corner is pressed against something else), but the flip-phone style has a certain intuitive feel to it these days.

Some internet posters have complained that the Pulse turns On before the switch is slid all the way – and hence *locked* – into the On position, so a user thinking the beacon was all set to go might then have the beacon turn itself to Off without the user realizing this. Although I have been able to replicate this behavior, such a delicate and precise touch is necessary, and the locking tactile feedback is so obvious, that I doubt this could ever happen in the field.

By contrast, if just a few errant drops of water fall onto the top edge of the beacon where the switch is located, and then freeze, the Pulse will be locked into Transmit, and at least a minute of warming is necessary before the beacon can be switched into Off or Search. This occurred to me in the field and I have replicated it numerous times at home: I would have lost a significant amount of search time before I was able to turn the Pulse away from Transmit. (I notified the U.S. distributor about this, and was informed that the information would be relayed to Barryvox, but never heard anything back from anyone about this potentially significant flaw. Temperatures that day were in the low 20s, and some additional culprits may have been my practice that day of stowing my skins inside my wind shirt for the descent, as well as some snow from a "little" tree well incident, but still, this is a potentially serious flaw.)

Out of the Box: User Interface

The DSP has three buttons whose functions are generally constant. (For the beacon’s first several years, the Option button on the regular/non-Advanced DSP was merely vestigial from the Advanced and hence entirely dysfunctional; only with the software upgrade in Fall 2006 and the addition of a frequency tester did the Option button gain any functionality.) The buttons have been rearranged and relabeled for the Fall 2007 version so that their placement better reflects their importance. The DSP’s display is similar to the typical modern multi-antenna beacon, with the addition of a few small symbols that display additional information. The LCD display seems to be unaffected by polarized sunglasses.

The Pulse on either side of its housing was two “soft-key” buttons, whose functions are entirely dependent on the context. The full-text (in the choice of several languages) display provides text on the left and/or right side of the screen to identify what function will be performed by what key. The combination of:
- two soft keys;
- a full-text display;
- a large array of main and ancillary functions; and,
- an extensive setup menu; equals...
... a vast range of functionality, but also potential complexity and confusion.
The LCD display can be a bit hard to read with polarized sunglasses.

The S1 has two buttons, which in the parlance of the user’s manual:
“Button 2" = mark/demarking/confirmation
“Button 3" = menu/rejection
(“Button 1" is the On-Off switch, even though it’s located on the case’s hinge, away from the other buttons.)
I found myself thinking of them as:
- top button = enter
- bottom button = tab
Like the Pulse, the S1 has:
- a display capable of displaying large amounts of varied information;
- a large array of main and ancillary functions; and,
- an extensive setup menu.
Also, like the Pulse, the LCD display can be a bit hard to read with polarized sunglasses.
Unlike the Pulse, the S1 communicates all of this using symbols, not text.
I somewhat inadvertently ran a test of the S1's screen in very cold weather (when using it to measure the temperature for some "test" camping): down to minus 9 degrees F, it still displayed clearly, although old images were slower to fade away than in more moderate temperatures.

Out of the Box: User Friendliness and Documentation

User friendliness depends largely on the user. Nevertheless, for all three beacons (like all beacons I’ve tested), my first action is to conduct a search without reading a word of the user manual. With all three beacons, I could successfully conduct a straightforward single-victim search. But with all three beacons, I needed to read the user manual before understanding all the functions, especially so with the Pulse and S1.

The DSP’s user manual is the most brief of out the three beacons, but then again the DSP is the least complex out of all three beacons. Still though, only pieps.com - and not the user manual - provides directions for how to display the software version and also cautions against turning the DSP to On within close proximity to another beacon (which will generate an error message because of the start-up self-test). The Pulse has the most complete manual, which is a necessity for such a complex beacon. I found only a few very small typos (in the Fall 2006 version, which still appears to be current judging by the pdf available online).

The S1 manual is generally fine (and completely separates out the English and German sections, unlike some other Ortovox manuals), although I found three errors/omissions. (One passage has an incorrect reference to Button 1 instead of Button 2; the time to switch out of analog mode is listed as five seconds instead of the actual two seconds; and, the manual never mentions that analog mode can be entered by simultaneously pressing Buttons 1 and 2 for two seconds, which I tried - and verified - on a hunch.) Ortovox USA also includes a one-page supplement to the manual to highlight key aspects.

Out of the Box: Non-Search Functions

The DSP pioneered the integration of functions not directly related to avalanche rescue into an avalanche beacon, so if you really want to have a compass (with apparently some sort of capability to set and then follow a bearing), thermometer, and altimeter in your avalanche beacon, you can pay another $85 for the “Advanced” version. As you can tell by the tone of my prior sentence, I’m not a big fan of this concept, although from my understanding of the user’s manual, the DSP can’t accidentally be switched into such functions while in Search. Note though that entering these functions also switches the beacon out of Transmit (i.e., the beacon is therefore On, but in neither Search nor Transmit). Holding down the Option button for three seconds switches the DSP back to Transmit, which will also occur automatically after two minutes.

The Pulse has a compass for its internal calculations during Search, not for navigation. Replacing the batteries prompts a message to calibrate this internal compass by rotating the beacon.

The S1 has a compass (apparently with no way to set declination or bearing), thermometer, and clinometer (using the lid angle). These functions are entered from the setup menu, so essentially no risk of accidentally entering them during a search. I've used the S1 a few times for measure the temperature for some winter-time "test" camping: the temperature seemed very accurate when measured against a nearby weather station, but was very slow to update when coming inside (e.g., after about an hour inside a 53-degree room, the S1 still thought the temperature was 32 degrees).

Electronics Issues: Interference

Rescue of a European avalanche fatality in December 2000 was hampered by interference from a cell phone:
http://pistehors.com/news/ski/comments/pisteur-killed-at-pra-loop/
http://pistehors.com/news/ski/comments/digital-avalanche-transceivers-affected-by-mobile-phones/
Since then, warnings of possible interference from other electronic devices have been widely circulated, but I have found such warnings to be overblown for most beacons. (Although given the dubious need to multi-task in an avalanche rescue, such warnings are still merited to be on the safe side.) Specifically, last year I tested all the avalanche beacons on the market with:

– FRS/GMRS 1.8-watt two-way radio
- GPS receiver with SiRFIII chipset
- digital camera
- CDMA cell phone (e.g., Verizon)

(I haven’t been able to test with a GSM phone, since CDMA reception is so clearly superior where I live that I don’t know anyone with GSM.)

Approaching a searching beacon with a device that was on but not actively doing anything, I could not cause any noticeable interference. Transmitting with an FRS/GMRS radio or CDMA cell phone caused noticeable interference in ARVA and Ortovox beacons, but not others.

I repeated the tests with the S1, Pulse, and DSP. Only the S1 showed signs of interference: transmitting on the FRS/GMRS radio caused both the location and distance indicator to jump around along with “ghost” victims:

Calling on the CDMA phone caused “ghost” victims to appear at far distances, from 35 to 100m, and then shifted the S1 into its mode for when more than 3-4 beacons are detected:

I have not yet tested the S1 for electrical interference in the field caused by more distant yet more powerful sources of interference, but other sources of consumer electronics also seem to cause problems for the S1 that have no impact on the DSP or Pulse. For example, I was testing another issue with the S1 in my parents’ house, and when I first started searching, a couple ghosts appeared. A WiFi network was broadcasting from only several meters away from me, so I wonder if this was the source of the interference? (The house is otherwise decidedly low-tech.)

The S1 is also susceptible to interference when in acoustical-only analog mode. I accidentally discovered this when I was trying to navigate through the menu system to check the remaining battery life, and instead found myself listening to either a radio station or phone conservation: too garbled to understand the words, but definitely a person’s near-continuous speech and at a comfortable volume for listening, which was still clearly audible even when I turned on a target beacon at a distance of only several cm. (This was indoors, yet at the time no use of a radio, television, or phone of any kind.) I then checked with a Barryvox Opto 3000, Barryvox Pulse, Ortovox M2, and Ortovox F1: the same sound could be heard - but just barely - in the middle (and only in the middle) of the F1's sensitivity range, yet was entirely absent on the other beacons.

I also tested two different iPods against the three reviewed beacons and also a Barryvox Opto 3000, Ortovox M2, and Ortovox F1. Placing a playing Nano right up against any beacon caused interference, some only slight, some significant. I then placed the Nano in my shirt pocket, and held the beacon slightly extended from my body. The resulting interference on each beacon was very sensitive to slight changes in the distance from my body. The conclusion from this test is very clear: the S1 is once again the most susceptible beacon to interference, but most importantly, if you are touring with an avalanche beacon, DO NOT LISTEN TO AN IPOD NANO!
I am very serious about this. The potential for an iPod to throw off a beacon search is very dangerous.

Electronics Issues: Battery Life

The official battery life specifications for all beacons are fairly similar, but some users have commented on the DSP’s perceived propensity to use up batteries more quickly than other beacons (e.g., http://www.skinet.com/skinet/photos/article/0,26964,1650983-5,00.html).

What I had noticed previously about my DSP (based mainly on search testing, as opposed to in-the-field use) has been, on a more anecdotal level:

- The remaining life percentage on the display had sometimes been lower than for other beacons (i.e., when swapping batteries among units).
- The display sometimes shows a dramatic drop over a relatively short period.
- The rebound effect is often quite strong (e.g., a noticeable drop during testing, only to then return almost to where it started off, with almost no net loss).

In an attempt to quantify this, I set up one target beacon, with the three test beacons on search using fresh batteries all from the same package. After three hours of continuous searching (with occasional checks to ensure they really were all searching), I put the S1 into menu mode and saw that its battery level read 75 percent, and turned the Pulse Off then On to read its battery level at 60 percent. The DSP when switched back into Transmit continuously displays its battery level, which at first bounced back and forth between 83 and 88 percent, then 84 and 89 percent.
I then removed all the batteries and tested them in a Barryvox Opto 3000, which lead to results of 61 percent for the S1, 70 percent for the Pulse, and 74 percent for the DSP. These disparities were similar to those from a prior 90-minute test I ran (which I decided afterward had been insufficiently long, plus might have been flawed since even though all batteries read 100 percent, two of the three sets might have been used for transmission earlier and hence weren’t really fresh), in which the Pulse was slightly more pessimistic than its Barryvox cousin (i.e., from 65 percent on its own reading to 70 on the O3k), while the S1 and DSP were similarly more optimistic than the O3k (i.e., dropping from 84 percent to 70 percent and from 92 percent to 79 percent, respectively).

Conclusions:
- My prior anecdotal inferences are contradicted by my own testing, as the DSP was actually the most miserly of the three beacons.
- Even if the DSP is less miserly than other beacons not tested here (which unfortunately I couldn’t include, since I didn’t have enough fresh batteries from the same package), at somewhere between 74 percent (going by the O3k readout) to 83 to 89 percent (going by its own readout) of battery power after three hours of continuous searching, the reports of excessive battery drainage to do not appear to be merited.
(And many thanks to the DSP users who criticized my earlier uncritical repetition of those other reports - such feedback is what makes posting reviews here so valuable.)

Electronics Issues: Tilt Angle and Processing Speed

As a general guideline, any avalanche beacon should be kept level and not moved very abruptly. I have deliberately violated the latter guideline to win a ski patrol beacon competition with a Tracker DTS, and the Pieps DSP seems to be relatively tolerant of violations of either guidelines.

By contrast, the Pulse will chastise you to “Hold device horizontally!” if you tilt too far away from level and “STOP” (displayed within a traffic-style octagon) combined with “Stand Still!” if it needs to sit and think a bit. (I switched the Pulse into German in the hope that any of this might be translated into a chilling “Achtung!” but no such luck.) This is somewhat disarming the first time it appears (e.g., “my beacon is telling me to do stuff?”), but after some familiarity sets in, the messages become not much more than a mildly annoying and very brief interruption. (Still though, I greatly enjoyed the reaction of the lead instructor at a course I was teaching at when he started talking back to his Pulse: “Stand still, who are you telling me to stand still!?!”)

Similar to the Pulse, the S1 displays a little angle symbol when it’s tilted. (I received this message incessantly at first when I opened the clam shell only to the angle that I was accustomed to on my flip-phone instead of almost all the way flat.) Also similar to the Pulse, the S1 holds up a warning hand (within a traffic-style octagon) when it needs to sit and think a bit. (The manual also refers to a “pivot” directional signal, but I have yet to receive that.) The user manual refers to “a few seconds” for the halt command but on a few occasions the warning hand has stayed up for a few MINUTES. After being dismayed by this long time, I resolved the situation only by turning the S1 back to Transmit and then back against to Search. This might have occurred only when I switched the S1 to Search almost immediately after turning it to On, but I have not yet encountered this problem enough times to document it sufficiently.

Single Burial - Primary Search Phase, i.e., Initial Acquisition

After some more less rigorous initial range trials, I conducted more comprehensive range tests on bare ground (sigh...), with temps in the high 30sF, in a small suburban park (i.e., two baseball/softball fields, four tennis courts, basketball court, playground paraphernalia, but all packed together fairly closely), bordered on three sides by residences and a fourth by a National Guard Armory that mainly just stores parked construction equipment (although I suppose a secret CIA detention center in the basement can’t be ruled out these days, but then again, waterboarding shouldn’t create much electrical interference).

My main focus was the reviewed beacons but I also included two Barryvox Opto 3000 beacons, a 2001 Ortovox M2, and a 1995 Ortovox F1 Focus.

My protocol was to turn the beacon to On, switch to Search, then walk in a straight line (as defined by a 300-foot fiberglass measuring tape) with the beacon slightly extended and motionless (relative to my body) until I first picked up a definitive beacon signal. After recording the distance, I switched the beacon back to Transmit, walked well outside of the range, and switched to Search for a second trial. I then repeated this for a third trial.

I conducted 134 trials total, split almost evenly between optimal and worst-case alignment/coupling, with a nearly full round of trials searching for an Ortovox M2 and a less-complete round with a Barryvox Opto 3000 target.

Combined with a similar range test earlier this fall (before I had the S1), along with a similar test last year, my definitive conclusions are:
- Beacon range tests take a really, really (really) long time.
- Beacon range tests quickly become horribly tedious.
- Beacon range tests are very frustrating when trying to decide what constitutes an initial signal acquisition, especially for an acoustical signal, and if anything I probably erred on the generous side.
- Beacon range tests can be confounding when results vary so much from trial to trial, even setting aside the variation in acoustical signals that can probably be attributed to passing vehicles, shouting children, etc.
- Beacon range tests at different places/times can produce a wide range of results based on not entirely obvious factors; scroll down at the following link to test #5:
http://www.beaconreviews.com/transceivers/TestDetails.htm
Therefore, relative results are what matter most, although numerical results do help to establish a safe search strip width.

And speaking of search strip width, although I report results for alignment in both optimal (i.e., transmitting antenna of target beacon pointing toward search beacon) and worst-case (i.e., transmitting antenna perpendicular to search beacon), the latter matters more, since such a minimum initial acquisition range should determine the movement pattern of the primary search phase. My understanding is that beacon companies are moving toward reporting only this minimum figure.

Note that I neither test nor report an alignment with the antennas of *both* the target and search beacon perpendicular to the imaginary line connecting the two beacons, since that just doesn’t seem to simulate any real-world situation likely to be encountered. Also, while I’m dismissing such a beacon range test, I’ll add a “test” I was subjected to in which a user on search has each skier on transmit come one at a time out of range and then stop when the searcher picks up a signal: this does not test the transmit range of different beacons, but rather just illustrates how range is affected by flux lines and the random alignment of burials (mimicked here by different harness designs and user positions).

With all those caveats aside, the DSP had the longest range at about 56m optimal and 44m worst-alignment. (I've seen other tests that report identical optimal vs. worst results for the DSP, but in both this round of testing, and two prior rounds, and other tests for other purposes, my DSP has always picked up a signal earlier in optimal alignment.) The S1 edged out the DSP in optimal alignment at 58m, although getting back to all the previous caveats, the S1 and DSP can be considered tied for optimal-alignment range. By contrast, the S1 dropped off considerably more in worst-alignment to 37m, although this still surpasses any other beacon for full distance and directional indicators in worst-case alignment. (Out of curiosity, I also tried the S1 in acoustic-only mode to see if it offered any range boost: it didn’t, perhaps in part because even when it acquired a signal, the background static was far more distracting than in the other beacons’ acoustic-only modes.)

The Pulse provided digital distance and direction indicators at around 52m in optimal alignment, so not much worse than the DSP and S1. Counting the initial acoustical signal that sometimes kicks in noticeably before the full digital distance and directional indicators boosts the Pulse to pretty much tie the DSP and S1 in optimal alignment searches, although comparing acoustical sound vs. digital readout constitutes somewhat of an apples-and-oranges comparison.

But far more importantly, the Pulse falls off noticeably in a worst-alignment search, down to about 21m. (I've seen other tests to report far better results for worst-alignment, and I recorded much better results in Fall 2006, but both of my Pulse units have shown short range in worst-alignment searches this season, whether in this round of testing, another comprehensive round earlier this season, and in tests for other purposes.)

This review of avalanche transceivers was written by Jonathan Shefftz. It has been republished on BeaconReviews.com.

I tried the Pulse’s other search modes to see if anything else might help. Backup mode did not help (nor is it intended to, but I was curious). If anything, Backup mode was a bit better in optimal alignment yet even shorter for full-digital acquisition in worse alignment. (Note that the user manual confuses these potentially confusing options even more by sometimes referring to Backup mode as “Analog” mode despite full digital distance readout and directional indicators -- the acoustics are indeed analog, with sensitivity control, although regular Search mode can be set to analog acoustics, albeit sans sensitivity control. See “Optional Search Modes/Functions” section of this review for how the different Backup mode options.)

I then shut down the LCD display, which also shuts down all but one antenna. This significantly boosted worse-alignment range to 33m, but unfortunately this mode offers no sensitivity control or any other controls, although a skilled user can switch quickly back into the more complete Backup mode and then regular Search mode. Even more dramatically, this boosted optimal-alignment range to about 81m, surpassed only by the M2 at 82m (although its LCD display doesn’t kick in until about half that range). Then again, I might have been too conservative in recording the Pulse’s one-antenna range: on my final trial I went even further out of range than before, and discovered that . . . I was still in range? Unfortunately my testing configuration meant that to go any further I would have needed to hop a fence into a neighboring residential driveway, but at 112 meters (i.e., an entire American football field, plus both end zones, along with another three feet for good measure), I could hear an exceedingly faint yet distinctly rhythmical beeping/chirping that definitely had the same cadence as when the signal became stronger closer in.

Somewhat more simply, when I slowly but steadily pivoted the Pulse back and forth (but kept it in the same horizontal plane), I was able to boost the worst-alignment range by about 8m. This is what the Pulse user manual advises, although I had been keeping all beacons steady for comparability purposes. (By contrast, the S1 manual says *not* to “rotate” the beacon, although this seems to be a prohibition on moving the beacon out of the horizontal plane; the DSP manual makes no mention of the issue.)

To boil all this down to a few sentences:
- The DSP and S1 both have excellent range, with the DSP winning out overall on the basis of its worst-alignment scenario results, although other test results might differ from my own.
- The Pulse in regular Search mode has excellent range if it is exactly aligned with the target beacon, but drops off precipitously if the target beacon is in the worst possible alignment. A skilled user can boost this range significantly with the Pulse’s alternative search modes, though manipulating the two soft keys to switch back and forth could cause confusion. Any user should definitely pivot the beacon back and forth while searching, or else the range could become drastically shortened.

In even more detail, the spreadsheet image is copied below for complete results; some notes:
- Initially recorded in feet, then reduced by five percent for estimated slack in my fiberglass measuring tape, converted to meters, then rounded.
- Blank cells are that way only because I didn’t want to spend any more hours on this.
- The Pulse averages on the bottom two lines are not the averages of the previously computed averages in prior rows, but instead are the averages of the individual cells (since I ran more trials for the M2 than for the O3k).

Single Burial - Secondary Search Phase

I started about 40m from a target beacon whose antenna was in direct alignment with me, turned each beacon to search, and cross-country skied straight to the target beacon.

In such a single-burial search, the DSP behaves essentially like what is now considered a “traditional” design, even though of course it was a major breakthrough when first pioneered by Backcountry Access with its Tracker DTS. The DSP displays one or two of five possible LDC directional indicators along with a distance readout, which is by necessity using signal strength as a proxy for distance. Note that such a design is unable to distinguish between a beacon that is ahead or behind the searcher: if the distance indicators increase instead of decrease, the user needs to make a 180-degree change of direction. During the entire secondary search phase of this test, the DSP’s center arrow stayed on, and none of the other four arrows came on.

The Pulse puts a twist on the traditional design by taking advantage of its full LCD screen to create a rotating 360-degree arrow, thereby distinguishing between ahead and behind. In practice, the arrow can sometimes become confused between ahead and behind: my experience with other tests has been that it can start off pointing in the wrong direction, but then after several steps, the arrow corrects to perform a 180-degree rotation, which the user must then also execute. During the entire secondary search phase of this test, the arrow pointed straight ahead, deviating only a couple degrees in each direction.

The S1 takes an entirely new approach, displaying a victim symbol with distance indicator somewhere on a cross-hairs screen, with a small portion of the bottom of the screen symbolizing victims buried behind the searcher. During the entire secondary search phase of this test, the victim was often not perfectly aligned with the center of the screen, though the deviation was relatively small. Note that my field tests were conducted in a residential neighborhood of six houses, and my home office WiFi network is especially close to the target beacon.

Here’s the maximum extent to which the S1 was off-center, toward the beginning of the secondary phase:

Here’s a video showing the more typically lesser extent of the off-center skew.

The forward/behind feature on both the Pulse and the S1 is very consistent when the user is moving steadily toward the target. The two beacons sometimes get the forward/behind direction wrong at the very beginning of the search, but quickly correct themselves once the user starts moving. But the two beacons will flip the direction in mid-search if the user is stationary but tilts the beacon, even within the acceptable range of what the beacon will tolerate before warning the user. The S1 is especially susceptible to this effect. (At first we thought the flip was caused by turning on my ski patrol radio, but then we realized I was moving my torso slightly as a moved my hand to turn the rotate the switch.) After some puzzling over this with a fellow patroller and avalanche instructor, who is also an electrical engineer, we agreed that this is probably caused a slight change in the orientation of the flux line when the beacon is tilted, which leads a decrease in signal strength. The beacon then thinks the user is moving away from the beacon, and hence flips the forward/behind indicator.

Single Burial - Pinpoint Phase

The goal of the pinpoint search phase should be to minimize the probing area, not to substitute endless beacon searching for careful probing. That caveat aside, all of these beacons have three antennas and therefore eliminate spikes and nulls during the pinpoint phase, a major advantage in accuracy. (The Ortovox D3 and X1/Patroller also have a third antenna that becomes active at 2m, therefore eliminating spikes and nulls approximately within that distance in my testing, although spikes and nulls are possible just *outside* that distance and have been very easy to replicate in my testing.)

The DSP shuts down its directional arrows at 2m and then displays only a distance readout down to 0.1m, although often the DSP won’t go below a readout of 0.3m. The reason for this programmed behavior is that the flux lines are so densely packed together at this point that the directional indicators can be misleading.

The Pulse displays directional indicators down to at least 3m. Within 3m, the default is for the directional indicators to disappear, although the user can program them to stay on until 0.3m. (Personally, I find the distance indicators to be helpful within 3m with a triple-antenna beacon, although I follow them less rigorously than in the secondary phase.) The user can also choose to have digital, analog, or no acoustics within 3m. The Pulse’s distance readout goes down to 0.0m, although it often stops at 0.2m.

Like the other beacons, the S1 changes its display for the pinpoint phase, though once again, its display is totally different from any other beacons: at 3m the S1 displays a descending circle graphic with distance readout. This size of the circle is also representative of the distance. If the user is getting closer, a little arrow in each corner of the screen points inward; if the user is getting further away, the four arrows point outward. The distance readout goes down to 0.10m, although I found that it dropped from 0.60m to 0.10m over the span of only about 0.12m.

Go dog go! -

Doh! -

My pinpoint phase accuracy test was inspired by an avalanche beacon review in the New York Times last year - as a native North Easterner, I feel obliged to take seriously everything the NYT writes, even on subjects where its editors probably know absolutely nothing. The NYT review commented on the large “box size” of one model, so I devised a test to attempt to replicate such results, as shown below:

The Pulse has an exceedingly small box size, close to zero, as its distance readout usually doesn’t “minimize” out until its almost immediately adjacent to the target beacon. (In my prior testing, only the ARVA A.D.vanced had a smaller box size, at effectively zero.) The box sizes for the DSP and S1 were larger, but still so small that the differences among the units are unlikely to have any impact in a real search (for an actual person).

Single Burial - The Tricky Perpendicular Search

Imagine an avalanche path or deposition zone that is twice the width of a beacon's range in worst-alignment coupling. The victim is buried at the extreme edge of the beacon's range, with the transmitting antenna pointing toward the center of the slide path. The searcher enters the slide path with the beacon pointing toward the center. This is a worst-coupling scenario, and with the target beacon at a 90-degree angle to the searcher.

I attempted to replicate this scenario by approaching a target beacon that was pointed toward me, but with my beacon at a 90-degree angle to the target. The DSP's furthest-off-center directional indicator is at about a 45-degree angle, which is similar to other directional beacons other than the Pulse and S1. The DSP's results were roughly split between the following three outcomes:
- The correct furthest-off-center directional indicator would appear, and once I started following it, the DSP led me in a direct path to the target.
- The correct and incorrect (i.e., essentially backwards) indicators would trade back and forth, but the correct indicator would win out if I hesitated a bit.
- The incorrect indicator would appear, and following it would cause the distance readout to increase rapidly, which should be an obvious indicator for a DSP searcher to turn around.

The Pulse suffered from its short range in a worst-alignment coupling, but its 360-degree rotating arrow pointed very accurately and consistently to the target beacon (i.e., off at a 90-degree angle).

The S1 performed very poorly. The two times I started with the beacon pointed to my right, the beacon led me to the right and almost all the way off a large open field onto Mass state highway 63 before losing the signal entirely. Yes, the distance readout was increasing (albeit slowly), which is in indication that something is amiss, but the display kept showing ahead, not behind. When I started with the beacon pointed to my left, the S1 led me to the left and almost all the way off the large open field into a snow fence before finally correcting and then taking me on a long route that went around and behind the target before eventually leading me to it. After three such searches with the S1, I gave up on this test (even though my fellow patroller was amused to watch me wander all over the field).

Multiple Burial: Testing Protocol

I set up three target beacons as shown in this picture:

 . . . and in this diagram:

First I conducted the tests with a target group of one Barryvox Pulse and two Barryvox Opto 3000 beacons. I then repeated the tests with a target group of one Ortovox F1 and two Ortovox M2 beacons.

(Note that I did *not* ever use a Pieps DSP a target beacon. Starting in Fall of 2006, the DSP has a “Smart Transmitter” that will shift its transmission in an attempt to keep in from overlapping with other nearby beacons:
http://www.beaconreviews.com/transceivers/PiepsUpgrade.htm#Smart_Transmitter
Unfortunately, this seems to have the potential to confuse beacons that are trying to flag a DSP, as they might identify a shifting DSP as an additional beacon – I have not yet tried to confirm this beyond some initial testing that apparently showed some difficulties with the Pulse separating the signal from a DSP.)

Why “only” three beacons? I’ve tested the Pulse previously with eight beacons, and the Pulse was able to display separate directional indicators and distance readouts for all of them (although not instantaneously). The DSP displays symbols for three beacons, and then has a separate symbol if additional beacons beyond those three are detected. The S1 displays separate symbols for “3-4" [sic] beacons, and then if detects more it will display a separate graphic with “4+” which is the clue to the user to either go back to the default search mode or instead narrow the search strip width to only 5m. I suspect the vagueness of “3-4" means that if the S1 detects more signals than it has comfort in separating, then it will display that separate graphic and choice, and that four signals is right on the edge of its comfort zone.

Given all that, I decided that three beacons would be a reasonable way of testing the beacons within their respective comfort zones for multiple burials.

Anyway, sounds like a nice controlled test, right? Wrong! Why? Read this:
http://www.backcountryaccess.com/english/research/documents/SignalOverlapPaper_001.pdf

In [very] quick summary, because of ever-shifting signal overlap, each test was actually different, as each test beacon was facing a different set of signals with respect to their timing with one another. So for example, my first search with the S1 was a complete disaster, at it send me in all sorts of directions as the three little victims jumped around the screen. By contrast, on one Pulse test, I had all three signals separated/identified before I reached the first beacon, but on another test, the Pulse didn’t identify the third until I had already flagged the first two.

Running dozens - maybe even hundreds - of tests would therefore be necessary to reach any quantitative conclusions, but based on several test of each set of target beacons, and based on my prior tests of the DSP and Pulse, some preliminary assessments are feasible.

This review of avalanche transceivers was written by Jonathan Shefftz. It has been republished on BeaconReviews.com.

Multiple Burial: DSP

A multiple-burial search with the DSP starts off almost identically to a single search: the only difference is that more than one burial symbol appears. The DSP locks onto the strongest signal, with no distractions other than additional burial symbols at the bottom of the screen. (That is, unlike some other two-antenna beacons, the directional indicators and distance readouts will *not* jump back and forth between multiple victims’ signals.) Once at the first burial, the user presses the flag button, a box appears around the first burial symbol, and then the DSP displays the directional indicator and distance readout for the next beacon.

Sounds simple, right? Well, when the flagging works as intended, it is. When the flagging doesn’t, it isn’t, and instead becomes a frustrating and perhaps dangerous waste of time. Furthermore, the symbol count is sometimes wrong (usually overcounting rather than undercounting). How often do these problems occur? Definitely more frequently with older analog beacons (with a continuous carrier signal), which are supposed to cause the beacon symbol to blink, although even this attempt to deal with the inconsistent performance is also inconsistent. Otherwise, I have not yet attempted to quantify this, and moreover, it’s something of a moving target, though fortunately it’s moving in the right direction: each successive software update seems to have helped (my beacon is from Fall 2006 and already on its third software version) and older analog beacons are only going to become less popular over time.
Here’s another take on the issue:
http://www.beaconreviews.com/transceivers/MultipleBurials.htm#Pieps_DSP

Were a user to have trouble flagging a found beacon, the best protocol would probably be to press the Scan button, get a rough idea of how far away the other beacons are, then head out in some variation of the Three Circle method:
http://www.beaconreviews.com/transceivers/MultipleBurials.htm#Generic_Multiple_Burial_Search_Techniques

Here’s a rough video of a DSP search, and although it’s not quite real time (my camera records in 30-second spurts, and I didn’t always restart it immediately), you can tell that the flagging is slowing me down. Still though, the delay in getting the mark button to work in these searches is far less than the delay that would have been caused by getting my own brain to work in sorting through three beacon signal in close proximity to each other (watch the video).

Multiple Burial: Pulse

The Pulse automatically displays the directional indicator and distance readout for the strongest signal, but simultaneously shows a list of how many other beacons are detected. The user can use the soft keys to scroll through the list to see the directional indicators and distance readouts for the other beacons. Once a beacon is flagged, the Pulse switches to the next beacon, although once again, the user can make a different choice.

Both in this test and previously, the flagging has always works immediately for me. Detecting additional beacons can sometimes take awhile though, but eventually the Pulse gets it right. I haven’t yet quantified the average time, and as my graduate school professor Robert Reich said about his height and Shaquille O'Neal’s, in some contexts the average isn’t very meaningful, but my experience so far has been that the delay in detecting additional signals hasn’t been significant enough to hamper a real-world search.

Here’s the start of a multi-burial search (watch the video).

And here’s an even rougher video of a complete multi search - the only hesitation during flagging is because with the camera in my right hand, I have to reposition my left hand a bit to press the right-hand soft key. (If it was in my right hand, or if I had both hands free, I wouldn’t even need to stop really.)

Multiple Burial: S1

The S1 simultaneously displays all the victim symbols and distance indicators on the same screen. One victim symbol is displayed larger than any of the others, but the user can head for another victim symbol if so desired. Once the first victim symbol is flagged, that victim symbol turns into a flag symbol, and the next-closest victim symbol becomes larger.

The flagging has always worked flawlessly for me so far. And the victim symbols have been reasonably quick to appear.

So what’s not to like? I wish the screen were a bit bigger - all those little victim symbols can get kind of jumbled together. But that’s a problem only if the searcher is trying to do something other than concentrate on the larger-sized victim symbol. In other words, if the searcher is simultaneously trying to keep track of the relative location of three different victims, the searcher might become hopelessly confused as the small symbols’ positions shift about relative to the larger victim symbol. But if the searcher is just trying to locate the larger victim symbol, and just kind of noticing in the background how many other symbols appear, the display seems to work very well.

Here’s yet another roughly shot video - this one often shows my skis better than it shows the beacon display, but you can see how quickly I moved from beacon to beacon, with barely any pause at all for flagging:

Optional Search Modes/Functions: DSP

The DSP’s only optional search mode is the Scan feature, which shows (successively) the number of beacons within a radius of 5, 20, and then 50 meters.

The beacon count in Scan mode suffers from the same reliability problems (i.e., sometimes biased upwards) as the beacon count in regular Search mode. But given the inconsistency of the DSP’s flagging feature, the Scan mode could be very helpful for a user in a multiple-burial search who has located the first beacon, is able to neither turn off the found beacon quickly nor use the flag feature successfully, and hence needs to get some idea where the other beacon is located before using the Three Circle Method or some other search methodology.

Optional Search Modes/Functions: Pulse

Depending on programming, the Pulse has two different versions of its Backup mode, which is entered by pressing both soft keys simultaneously in Search mode and then:

- In the more simple of the two alternatives, the Pulse confirms that the user really wants to switch into Backup mode, and then displays a distance readout, 180-degree rotating arrow (i.e., will always point forward, never backward), and symbol for the presence of a multi-victim burial. Pressing either soft key reverts back to regular Search mode.

- In the more complex of the two alternatives, the Pulse skips the confirmation and then provides a distance readout, 180-degree rotating arrow, symbol for the presence of a multiple-victim burial, and analog acoustical tone with sensitivity control. Pressing both soft keys simultaneously again reverts back to regular Search mode. Alternatively, by adjusting the sensitivity control past its maximum level, the user can shut down the display entirely and use only one antenna.

Note that both the manual and even display complicate all this by referring to the first Backup mode as "Analog" even though everything but the sound entails multiple-antenna digital processing.

This review of avalanche transceivers was written by Jonathan Shefftz. It has been republished on BeaconReviews.com.

Optional Search Modes/Functions: S1

The S1 offers two alternative Search modes:

- Acoustical-only analog mode, with sensitivity control, which is entered automatically if the battery power drops below 25 percent, or entered optionally at any point via the menu, or by simultaneously pressing both membrane-style buttons.

- A 5m search-strip width, which can be entered by confirming the presented option when the S1 has trouble separating more than 3-4 signals (and hence displays the Three Circle graphic), or entered at any point via the menu.

Other Topics: Companion Beacon Check

Each of these three beacons tests itself when first turned to On. The DSP should be kept at a distance of a few or several meters from other beacons during its self-test or else it will report an erroneous [sic] error given its ability to receive its own transmission:
http://www.beaconreviews.com/transceivers/SelfTests.htm
The S1 exhibits the same behavior, implying the same highly sophisticated test of its own transmission. No such issue with the Pulse apparently.

The DSP can check the frequency drift of other beacons:
http://www.beaconreviews.com/transceivers/Frequency.htm#Pieps_Frequency_Tester
My results thus far are posted here:
http://www.avalanche-center.org/phpBB2/viewtopic.php?p=602
As you can see, given how many beacons I have detected as out of spec, this can be a valuable feature.

The Pulse has a group check mode that facilitates checking companions’ beacons - basically it just shortens the receive range drastically to facilitate testing several beacons in relatively close proximity.

The S1 has a group check mode similar to the Pulse’s, but at the same time it checks the transmitting beacon’s transmission frequency, transmission period, and period length, then if necessary displays a warning sign and notes specifically which type of fault has occurred. I have not yet had the chance to use the S1 to test any suspect beacons, so this information is all from the user manual.

Other Topics: Auto Revert to Send

In case a searcher is caught in a secondary avalanche, all three beacons can be easily switched back into Transmit: the sliding switch on both the DSP and Pulse can be pushed back in, and the S1's lid can be closed.

In addition, both the Pulse and S1 can be programmed to revert from Search to Transmit if after a certain time period the beacon neither is moved nor has any buttons pressed. The selectable time periods on the Pulse are 4 or 8 minutes, and on the S1 are 0.5, 1.0, 1.5, or 2.0 minutes. (The S1's menu screen displays the periods in seconds, but I reexpressed them here in minutes for comparability purposes.)

Other Topics: Software Updates

All three beacons have software that can be updated, although only Pieps has any established procedure for this. I purchased my DSP in Fall 2006, and two upgrades later, it is now on 5.0 software version. My Pulse was also purchased in Fall 2006, and display software 2.0, hardware 3.0, and due for check-up in November 2009. My S1 arrived in late December 2007 and displays 1.1.2261.

Other Topics: Customization

The DSP does not offer any customization.

The Pulse allows the user to customize:
- language (eight options);
- behavior in Backup mode;
- audio behavior during the pinpoint phase;
- directional indicators (or lack thereof) during the pinpoint phase;
- auto-revert behavior for Search to Transmit;
- transmission of “Vital” data (see next section under “Ability to Lead a Search”);
- owner ID, displayed upon start-up (which I use to display a message from my wife imploring me to be safe); and,
- W-Link region (see next section under “Ability to Lead a Search”).
The user can reset the Pulse to all the default settings in one action. I’ve also heard - though I have not verified - that an organized group (e.g., guide service, SAR team) can customize a batch of beacons via a computer link to a certain collection of settings and then lock out any further customization by any individual user.

The S1 allows the user to customize:
- sound (high, low, off);
- auto-revert behavior for Search to Transmit; and,
- screen contrast level.

Other Topics: Ability to Lead a Search / Triage

The Pulse has a separate “W-Link” frequency that allows Pulse units to communicate additional information with each other. Europe and North America have different W-Link frequencies, and in Asia use of either frequency is prohibited. (See map in user manual for geographical details.) Pulse units purchased in Europe can be switched by the user to operate on the North American frequency. Pulse units purchased in North America must be modified by a Barryvox service center to operate on the European frequency, but then after this modification, such a unit can then be switched back and forth by the user in the future. Any Pulse unit purchased anywhere can have its W-Link frequency switched off by the user for operation in Asia.

The W-Link frequency was originally expected to be used to transmit flagging between different Pulse units. In other words, if multiple Pulse units were searching in a multiple-victim burial, then once one Pulse unit flags a victim’s signal, then that signal will be flagged on all Pulse searchers. Unfortunately, that feature has not yet made it into the current software.

Currently the W-Link frequency transmits only “Vital”data, which is essentially whether or not the Pulse detects minute movements that would be associated with a victim wearing the Pulse beacon who is stationary yet still alive. A searching Pulse displays a small heart symbol next to a beacon signal that is transmitting positive Vital data, but it shows the same absence of any symbol for either a Pulse transmitting from a dead victim or from a victim using any other model of beacon.

This features raises several interesting triage scenarios and associated moral issues:

- If everyone in the group has a Pulse beacon, then even with potential reliability issues associated with the Vital data transmission (and the range is not specified, nor have I tested it yet), a triage approach would be to search for signals with the heart symbol first, even if they are further away, as the closer Pulse beacons that are not transmitting Vital data are much less likely to be alive (especially by the time of excavation).

- If the group is mixed, then should the rescuers first search for the Pulse burials that are definitely still alive, or the non-Pulse burials whose status is unknown?

- Here’s another twist that I’ve never heard anyone else mention. Several victims are buried. Until now, this has been the one truly egalitarian, color-blind, race-blind, class-blind situation a person could face, i.e., all buried avalanche victims are identical. But what if you have a Pulse, and of the several buried victims, only one has a Pulse? And that one buried Pulse belongs to a spouse, or other loved one, or just in general someone whose personal ties to you are far, far stronger and more meaningful than all the other buried victims. The other signals are much closer to you than the Pulse signal, and you have a difficult climb up a steep, awkward debris field. Even once you pinpoint the signal, your probing reveals a burial depth that is going to take a long, long time, leaving insufficient time to rescue the other victims...

The Pulse also displays a list of the five most recent “burials” (i.e., periods during which the beacon was transmitting but not moving), providing the duration of the burial as well as the duration of the period during which Vital data was detected. I suppose this could be used to . . . reassure your rescued companion that even though it *seemed* like your companion was buried forever it *really* wasn’t all *that* long? Or maybe . . . be introduced as evidence on behalf of your defense in the civil lawsuit to show that even though you botched the rescue search and took forever, your companion was dead from trauma almost immediately so that a non-negligent rescue effort by you would not have made any difference anyway?

The S1 has also been the subject of discussions concerning its potential ability to lead a search, given its unique display for a “map” of the victims’ relative locations. Although a true map would be highly valuable, as a search leader could dispatch multiple searchers to multiple victims, I’m skeptical, for the following reasons:

- Any rescue by multiple searchers for multiple victims is going to be organized chaos at best. From what I’ve heard of Canadian Mountain Guide training exercises, such an assignment within a group of professional rescuers might be possible, but among typical recreationalists, I’m doubtful.
- Any map is going to be inaccurate because of the way flux lines work. Depending on the buried beacons’ orientations, this inaccuracy could be slight or instead so significant that attempts to dispatch different teams to different beacons might only hinder rescue efforts. (See the S1's performance under "Single Burial - The Tricky Perpendicular Search" for an absolute worst-case situation.)

- The S1's screen is too small to sort out the relative positions of beacons for this purpose. To compare the ability to display complex images, the S1's screen measures ~5.3mm diagonally, is monochrome, and uses relatively large text and symbols; by contrast, a Garmin 60Cx measures ~6.6mm diagonally, has a large color palette, and can use very finely drawn images. So on the S1, unless all the beacon symbols are very widely dispersed, doing anything but trying to get the primary beacon symbol on the cross-hairs entails inherently difficult differentiation among a jumble of closely packed symbols. (Now given that beacons are already on the market specifically designed for searching from helicopters, a larger-screen version of the S1's technology without concerns for weight, size, and price, hmm....)

This review of avalanche transceivers was written by Jonathan Shefftz. It has been republished on BeaconReviews.com.

Conclusions

Conclusions: Beacons in the Larger Context of Avalanche Safety

I disagree strongly with the various variations on the line about beacons being nothing but corpse locators: the reality is that many lives have been saved by beacon searches, and those who attempt to explain that away with references to risk homeostasis incorrectly and misleadingly conflate partially offsetting behavior with fully offsetting.

But I do think that beacons receive far more attention than other more important aspects of avalanche safety. I realize that this long review might seem hypocritical after such a statement, but given that I lack daily access to avalanche terrain, it’s the only potentially valuable contribution I can make to avalanche safety (as opposed to, say, posting regular snowpit profiles or avalanche activity observations). And even though I’ve typecast myself into taking on the companion rescue presentation at the avalanche courses I teach, I place higher value on my decision making class exercise presentation.

So instead of reading up on avalanche beacon features, assuming you’ve already had the typical two- or (especially now) three-day introductory beginner course (aka “Level 1 Certification”), set aside the time to --
... take a Level 2 course:
http://www.avtraining-admin.org/courseprov.cfm
http://avtraining.org/Avalanche-Training-Courses/AIARE-Level-2.html
http://www.nsp.org/nsp2002/edu_template.asp?mode=course_schedule
[select “Level II Avalanche” from “Course Type” pull-down menu]

... read Tremper’s book:
http://www.mountaineersbooks.org/productdetails.cfm?PC=472

... browse through the (relatively) comprehensible sections of the new McClung edition:
http://www.mountaineersbooks.org/productdetails.cfm?PC=697

... buy (then heed) the SWAG guidelines:
http://americanavalancheassociation.org/obs.html

... subscribe to TAR:
http://americanavalancheassociation.org/pub_subscribe.html

... contribute to CSAC and read the incidents, comparing/contrasting what the bulletin said and what the victims did:

http://www.avalanche-center.org/Incidents

... every day (even if you don't have any upcoming ski plans) read both your local avalanche bulletin (noticing how weather patterns contribute toward avalanche conditions, even trying to predict each day’s avalanche conditions based on the prior 24 hours’ weather) and some other region’s (UAC is especially educational, given the wide range of conditions there as a Transitional snow climate)
http://www.avalanche-center.org/Bulletins

Conclusions: Signal Separation Beacons vs. Other Types

Another frequently heard bromide is that the best avalanche beacon is the one you own and with which you practice on a regular basis. I disagree - no, I’m not saying you shouldn’t practice, but rather that almost all users will be better off with a directional multiple-antenna beacon. Yes, I do know that once upon a time all we had were the F1, VS 2000, Optifinder, M1/2, 9000, etc. And I’ll believe that certain grizzled vets out there are capable with their old beacons. But as one internet poster insightfully commented, “I don’t trust anyone with an older-style beacon unless he has a gray beard.” Same here - I highly doubt any newcomer to the sport is going to invest enough practice time into mastering the basics of a non-directional single-antenna beacon (whether it’s a hand-me down SOS F1-ND or a brand-new Pieps Freeride), especially when anyone else practicing beacon searches is ready almost immediately to move onto advanced multiple-burial scenarios. I also suspect that many old-beacon veterans who think they are just as fast as they could be with a directional multiple-antenna beacon . . . are not as fast as they think they are.

Nine different directional multiple-antenna beacons are currently on the market, not counting the DSP regular vs. DSP Advanced variation, and Ortovox X1 vs. Patroller rebadging. (The Barryvox Opto 3000 has ceased production, so its availability is limited, but meanwhile BCA is preparing the Tracker2 for a Fall 2008 launch, so the total model count seems likely to remain at nine.) These models all have their advantages and disadvantages. Some will appeal to some users and not to others.

If you already own a directional multiple-antenna beacon and are comfortable with it, I don’t see any overwhelming need to buy one of the tested beacons in this review: they have their advantages, but with their enhanced capabilities come greater complexity along with the potential in a panic-inducing rescue situation for pressing the wrong button or being confused by an unfamiliar symbol. So I’m not on any campaign to get my touring partners to buy one of these beacons (although I am trying to get them all Dynafitized). But if you’re intrigued, especially if you want to buy another beacon anyway to have an extra for practice or a spare/loaner, or are buying your fist beacon, then read on . . .

. . . although first, another word (or rather paragraph) of warning: the more feature-packed the beacon, the more mesmerizing the screen, and the greater the danger that a user will look exclusively at the screen and miss any helpful clues on the snow surface, whether a stray piece of equipment or even a protruding limb. Somewhat analogously, I once fell prey to this trap in the navigational realm as we were heading back to the car at the end of a tour. I called up the car waypoint in my GPS, selected the GoTo function, noted the bearing, dialed it in on my magnetic compass with its nifty circle-on-circle alignment method, and then looked through the mirrored sight to find an object to navigate toward in the little sight hole. And the object I found was: yes, my car. That’s right, I had used all that high-tech navigational gear to plot a bearing toward my car that was already visible.

Conclusions: DSP vs. Pulse vs. S1

The DSP pioneered signal separation, and its beacon count accuracy and victim flagging consistency have improved with every new software upgrade. Unfortunately, the DSP’s signal separation in my testing is still not as good as that on the relative newcomers from Barryvox and Ortovox, but it still is very impressive and far beyond any multiple-victim feature on any beacon other than the Pulse or S1. Then again, the advanced features are relatively unobtrusive, and the DSP has the longest range with full directional indicators of any beacon on the market, and by a huge margin in a worst-alignment scenario in my testing. So if you want a beacon that is relatively “traditional” yet has a beacon count and victim flagging that *could* be helpful in a multiple-victim burial, the DSP is a strong choice. Just don’t be lulled into overly high expectations for its signal separation reliability.

The Pulse is a technological tour de force. The extent of its customization is vast. Its capabilities in a multiple-victim burial, especially in an ultimate nightmare incident of more than three or four burials, are especially impressive. Personally, my main reservations at this point in my experience to date are the potential of the switch to freeze into Transmit and short to very short range test results in a worst-alignment scenario. For others, the sheer amount of text I had to devote in this review to explaining its features reveals the complexity that accompanies such a technological tour de force, although a Pulse user can certainly just accept all the default setting and ignore everything else.

The S1 was a radical innovation when it was first announced almost four years ago. Now that it has finally hit the market in regular-size (?) production batches, its display is still highly innovative as well as unique, but its signal separation is merely a competitor to the Pulse instead of any sort of breakthrough. Nevertheless, competition is good, so how does the S1 compare in my opinion to the Pulse? Some aspects are more personal preferences, so I won’t bother with those, i.e., up to the individual user whether the cross-hairs display of multiple beacon symbols is easier to follow than a rotating arrow combined with scrollable list, and ditto for universal symbols versus full language-specific text. (And given that each major alpine nation has one and only one beacon manufacturer, I would try to develop an analogy about how the S1 represents Swiss elegant simplicity while the Pulse represents German orderliness and engineering, but the nationalities of Ortovox and Barryvox are actually switched from such an analogy, so I’ll give up on that.) But for its core functions, the S1 performs as promised, although it kind of shies away from signal separation over a wide area after it detects more than three to four signals, whereas the Pulse keeps trying to separate any number of signals it receives and over any search strip width. My main reservations at this point in my initial preliminary experience are more susceptibility to interference than other beacons, some instances in which the “halt” command symbol wouldn’t go away until I switched into Transmit and then back into Search again, and very poor coping with a tricky 90-degree search angle.

Conclusion: A Final Thought on Beacons

To quote (or at least paraphrase) Marcus Peterson, of Ortovox USA, much of beacon design boils down to how much of your thinking do you want the beacon to do for you. At one extreme, the original avalanche beacons allowed you merely to listen in on the target beacon’s signal. The current Ortovox F1 and SOS F1ND still mainly do just that, with only a few colored LED lights to provide some additional clues as to signal strength.

The beacons tested in this review attempt to do almost all of the thinking for you. When they work as intended, you can do what they tell you to with great success. When they don’t work as intended, suddenly you have to (re)engage your brain and start thinking again for yourself. Not only is this transition difficult, but deciding *when* to overrule the beacon and use your own brain can sometimes be difficult. The beacon says the victim is behind you but the point last seen is definitely below you? That’s easy. The flagging isn’t working right away, so do you keep trying to get it to work or do you use an alternative multiple-burial search strategy? That’s . . . not so easy.

Another illustrative anecdote from the navigational realm. For years I used a GPS only in the backcountry. Then I bought a Garmin 60Cx for its SiRFIII chipset, which always receives a satellite lock, even in the most improbable locations. But it also has a removable memory slot, and has auto-routing capability, allowing me to load city street data for almost all of North America, with plenty of room to spare for topo maps too.

So previously on business trips to unfamiliar locations, I would carefully print out maps and directions beforehand. Now I just show up and enter the address, then the GPS tells me exactly and precisely where to go. Except when it makes a mistake, and suddenly I have to think for myself. Or when I think it’s making a mistake, and suddenly I have to start thinking whether I should start thinking for myself.

These errors don’t add up to much, just a few missed turns here and there, as well as flack from my wife. (Especially since her office has a Trimble GPS that costs several thousand dollars with something like sub-centimeter accuracy.) Or perhaps the occasional destroyed rental car and damaged rail track:
http://www.newsvine.com/_news/2008/01/03/1202051-man-using-gps-drives-in-front-of-train

But errors in avalanche rescue . . .

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