Wild Snow Beacon Reviews — Mammut Barryvox Pulse

WildSnow Beacon Reviews Intro and Index

Firmware v3.2 Update for Fall 2011
A v3.2 firmware update will be available for the Pulse as of November 2011. Rather than attempt to integrate all this into what is already a very long and complicated review, the new v3.2 features are posted in a comment, and then in November 2011 an entirely new review will be published for the v3.2 Pulse (omitting all of the historical notes about exactly which features were introduces in which versions).

REVIEW UPDATED DECEMBER 31, 2009
(Mammut Barryvox Pulse: Firmware 3.0 Update)

Barryvox Pulse is an amazing technological tour de force and now with a “Basic” user profile option under the 3.0 firmware to harness those capabilities in a more idiot-proof manner for the user who is, well, I’ll let you the dear reader complete that sentence as you wish!

The Pulse in its “Advanced” user profile continues to offer a high degree of customization. Both user profiles have a host of various improvements sprinkled throughout their various functions, as summarized here. Also, for the institutional user, Barryvox offers some interesting options you can check out here.

Interface and Controls

To switch Barryvox Pulse to Transmit mode, depress and then slide the three-position switch on the top edge of the beacon so that it is flush with the housing. How to tell at a glance the beacon is transmitting? Look for the three-position switch to be the flush with the housing and look for the blinking light.

To switch over to Search, depress and then slide (which is possible with one reasonably dexterous hand) that same switch even further (i.e., so that it protrudes from the other end of the housing). To revert to Transmit, bump the end of the switch. The Pulse will also revert to Transmit within a programmable length of time if it detects no large movements of the unit.

New with version 3.0 firmware, upon switching back into Transmit, the Pulse will hold off while counting down from 5, and then emit a warning signal once it starts transmitting again.

Take care to avoid letting any water drip into, and then freeze, the switch at the top edge of the beacon. My Pulse once froze so firmly that back at the trailhead at the end of our tour I was unable to switch over into either Search or Off until after a minute or so of bare-hand warming. I have also replicated this with a few drops of water and a short amount of time in a home freezer. (By contrast, the assertion that the Pulse can be turned into Transmit without truly being locked into Transmit is misleading: This requires a delicate action to achieve such a fine balancing point, plus the feel of the switch when locked into Transmit is so unmistakable that anyone who mistakes this small no-man’s-land for being locked into Transmit is probably so otherwise incompetent as to be incapable of using the Pulse in a search anyway.)

Previously I had written that the search interface could be interpreted as either elegant or potentially confusing: a full-text LCD screen flanked by two soft keys that perform many (many) different functions depending on the context and user programming. For those who viewed it as potentially confusing, the 3.0 firmware’s “Basic” user profile is configured such that the two soft keys always perform identical functions (so don’t worry if you get your left and right mixed up), and so that all programming options are locked out.

Upon start-up the Pulse has an optional group check mode in which the search range is radically shortened. Furthermore, and new for the 3.0 firmware, like the DSP and S1, the Pulse will report an error for a transmitting beacon whose frequency has drifted out of spec. (And during an actual search, upon initial analog signal acquisition, the Pulse will alert you to a drifted signal so as to shorten your search strip width in order to not go past the burial without picking up the digital signal.)

How It Works: Initial Signal Acquisition > Secondary Search Phase > Pinpointing

In the “Advanced” profile, initial signal acquisition is via analog acoustics only, although almost immediately full digital processing kicks in. With the 3.0 firmware, upon initial signal acquisition, the Pulse emits a distinct warning tone to get your attention. The Pulse combines analog acoustics with an LCD distance readout and a single LCD 360-degree rotating arrow. Within 3m (as measured by the distance readout), the Pulse can be programmed to switch over its acoustics to a digitized tone and/or to stop displaying its rotating arrow. (In other words, with two different options each for two different aspects of pinpointing, the Pulse has four distinctly different patterns of pinpointing behavior.) Note that Barryvox recommends keeping the default of losing the rotating arrow within three meters for pinpointing. Previously, the rotating arrow was replaced by a static cross: with the 3.0 firmware, the cross’s size is proportional to the distance readout (i.e., somewhat similar to the S1’s descending circle graphic).

Under the “Basic” profile, the sound is always digital throughout the entire search, and the directional indicators shut down at 3m.

Alternatively, under the “Advanced” profile, the Pulse can be switched over into an “Analog” backup mode, whose exact behavior depends on user programming. I put “Analog” in quotes because with a 180-degree rotating arrow and no spikes/nulls in the pinpointing phase, the Pulse is still using all three of its antennas and digital processing: the difference is that the signal separation and hence marking/masking is turned off, as well as the forward/backwards capability of the rotating arrow. Combined with full sensitivity control and even a multiple-burial indicator, even if the Pulse had only this backup mode and not its regular mode, its design would be an impressive technological accomplishment. The Pulse can also be switched into a pure analog mode that shuts down the display entirely and receives on only one antenna.

If the preceding paragraph is completely overwhelming to you, then rest assured that you need never use “Analog” mode or ever be concerned about it.

How It Works: Multiple Burials

The Pulse automatically locks onto the strongest signal, but displays a list of other victims. When a beacon is found, the user can then mark/mask it, and the Pulse will automatically switch the search to the next-strongest signal. Under the “Advanced” profile, the user can scroll through the list and choose a different order of searching. By contrast, under the “Basic” profile the order of searching cannot be overridden by the user, and neither can a previously found beacon be unmarked/unmasked by the user. (The benefit is that the “Basic” user does not have to worry about an inadvertent key press switching to a different beacon or unmarking/unmasking a previously found beacon.) Also under the “Advanced” profile, the user can switch into backup mode, which (as noted earlier) displays only a symbol for the presence of a multiple burial, with no marking/masking.

Under the “Advanced” profile, a heart symbol next to a victim indicates a fellow Pulse unit that is detecting minute vibrations from the victim, hence the model name. (A “Basic” user will transmit vitals data, but will not receive it.) The goal behind this feature is to aid in triage decisions, i.e., shift rescue priorities to victims who are likely to still be alive. However, if a multiple burial occurs in a party with a mix of Pulse and other beacons, a searcher with a Pulse can give preference — or not! — to victims who are known to have a Pulse, setting up some interesting ethical decisions.

But wait, as is often the case with the Pulse, there’s even more! A victim’s beacon will display how long the victim was buried (i.e., no large movements) and for what portion of the burial time the victim was most likely still alive (i.e., minute vibrations). Barryvox claims this information can be important for the medical team and was based on input from International Commission for Alpine Rescue. But if you disagree, the “Advanced” user profile offers you the option of just turning it all off. (And for the “Basic” user profile, the vitals data is transmitted only, not received.)

How Well It Works: Initial Signal Acquisition > Secondary Search Phase > Pinpointing

I’ve recorded some very confusing range test results for the Pulse over the last three years. But I’ll cut to the chase and report here only the latest results, for my Fall 2006 Pulse units upgraded to the 2.6/2.7 firmware in Fall 2008 and then to 3.0 in Fall 2009, combined with rotating the beacon throughout a 90-degree arc during a worst-case coupling test. (In prior years I kept the search beacon aligned with my direction of travel.) And the results are . . . just fine, thanks, sometimes even rivaling (and in some trials besting) the range-champ DSP for full directional indicators. (So ignore any older test results you see from me, whether published on-line or by the American Avalanche Association.)

The initial acoustics though usually add almost essentially nothing noticeable to the range. I suspect that the typical searcher–focusing on visual cues on the snow surface and digital indicators on the screen-– would not even catch the faint acoustical signal that in my latest tests becomes audible only a meter or so before digital processing commences.

But wait, even for range results, there’s more! Under the “Advanced” user profile, you can go into “Analog” backup mode, then max out the sensitivity (which is possible only if the “Manual” option is selected for “Analog” from the menu) so that the display shuts off (as does all but one receiving antenna). Now the Pulse rivals and sometimes exceeds *any* beacon on the market, directional or otherwise. I even had one Pulse acquisition at 112 meters (with optimal alignment of both target and searching beacons). That’s an entire football field, plus both end zones, and another eight feet. (And the actual acquisition range might have even longer, but I had run out of room at my testing site!) But if switching the Pulse over to Search then into “Analog” backup mode and finally maxing out the sensitivity so that the display shuts off all sounds complicated and potentially confusing in a panic-prone lift-or-death rescue situation . . . well, it might be.

If the preceding paragraph is completely overwhelming to you (hmm, did I write that before?), then rest assured that you need never go through this procedure. (And indeed, in the “Basic” profile, you can’t.) But for a professional rescuer searching a large debris field with an unknown number of victims, this can be a highly valuable feature.

Once the signal is acquired, the Pulse works best if you keep moving. Why? The answer is in how the 360-degree rotating arrow behaves. Although I am no electrical engineer, I did spent lots of time puzzling over the ahead-versus-behind detection of both the Pulse and S1 with a fellow avalanche instructor who is also an electrical engineer. He concluded that the only way these beacons are able to detect ahead versus behind is the way you do with your own sense: whether the signal is becoming stronger or weaker. Keep moving and all is well. Stand still, and then any small drop-off in the signal strength (often caused by tilting the beacon slightly) will cause the Pulse or S1 to direct you (incorrectly) to turn around. So if in doubt, move!

Two situations in particular cause the ahead/behind function to become confused. First is the tricky perpendicular search, where initial signal acquisition occurs with the searching beacon pointing at a 90-degree angle to the target, and with the target pointing straight at the searcher. Any “traditional” directional beacon has a furthest-off-center directional indicator at about a 45-degree angle. What then happens is that either:
– The correct furthest-off-center directional indicator appears, and once the searcher starts following it, the beacon will lead the searcher in a direct path to the target.
– The correct and incorrect (i.e., essentially backwards) indicators trade back and forth, but the correct indicator wins out the searcher hesitates a bit.
– The incorrect indicator appears, and following causes the distance readout to increase rapidly, which should be an obvious indicator for a searcher to turn around.

Okay, so that’s with a “traditional” directional beacon. What happens with the Pulse? For my latest testing with the 3.0 firmware, out of 10 trials, the Pulse performed perfectly seven times, pointing straight at the target (i.e., 90 degrees to the housing’s long axis). On the other three trials, the Pulse pointed in the incorrect direction. Of those three trials, twice the arrow flipped around (i.e., pointing to the correction direction), yet one time the arrow kept leading me in the correct direction until I went out of range.

With additional trials, the exact proportions might shift, but I suspect the overall conclusion will stand: the 3.0 Pulse will usually perform flawlessly in this test, but will sometimes behave in a manner that might cause confusion (and hence searching delays).

The other confusing behind/ahead situation is during a multiple burial, when once the first beacon is marked/masked, the next beacon might be behind or ahead of the searcher. During many multiple beacon searches, after the behind/ahead function performed flawlessly for the first beacon, I suffered from some turnarounds for the second beacon when I faithfully followed the rotating arrow’s behind/ahead distinction.

So even though the Pulse does have a behind/ahead function, remember to think for yourself, i.e., pay attention to whether the distance readout is getting smaller or larger. And once again, keep moving.

Oh, but don’t move too dramatically: the Pulse will chastise you to “Hold device horizontally!” if you tilt too far away from level.

For pinpointing, I like being able to keep rotating arrow on past the 3.0m mark, but if you don’t (and Barryvox advises against doing so), well, program it as you wish if you’re using the “Advanced” user profile. Ditto for retaining analog acoustics or switching to a digitized tone that increases in intensity. Under either profile, once the rotating arrow disappears, the cross graphic now increases or decreases in size in proportion to the distance indicator. This seems inspired by the Ortovox S1, and although I didn’t find it quite as helpful as the S1’s descending/ascending circle-with-arrows graphic, the 3.0 firmware’s dynamic cross is definitely a helpful improvement upon the previous firmware’s static cross. And as before, however you program it, the “box size” is very small.

How Well It Works: Multiple Burials

In my testing, I have found the Pulse (and S1) to be more reliable in both victim count and marking/masking than other beacons I’ve tested. With numerous victims (I’ve tested up to eight, and then I ran out of beacons), the Pulse is more likely to display “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. Firmware upgrades are supposed to have reduced the frequency of these interruptions, and my experience has confirmed this, although it is difficult to quantify. (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 to tell me to stand still?”)

The Pulse (as well as the S1) essentially substitutes model-specific familiarity for more general beacon searching skills. In other words, hand a Pulse with no prior explanation to a user highly skilled in resolving multiple-burial searches on a beacon that has no special features, and the user (especially with no prior cell phone usage) might be confused with manipulating the soft keys correctly. By contrast, a user familiar with the Pulse can usually solve multiple-burial searches as if with x-ray vision. The analogy that comes to mind is the difference between a driver in an entirely unfamiliar city yet skilled with the latest vehicle GPS system versus a driver with a good map and a general sense of a city’s layout trying to navigate through an unfamiliar neighborhood.

But the Pulse is still not perfect. Why? For the very same reason that your own human ear can have trouble discerning the presence of more than one beacon signal as the different signals can overlap. Eventually, the signals’ different timing will cause them to diverge from another, and the Pulse will correctly identify the number of beacons. In my testing with modern digital beacons as the target, this resolution is usually very fast, usually before I even reach the first beacon. For a dissenting view from a conceptual perspective, you can read this.

This becomes a more significant problem when searching for older F1 beacons, which can cause more persistent ghosting and (more typically) undercounting. (And many F1 beacons -– once the popular beacon world-wide — are still out there in use.) However, when the Pulse is uncertain, it will helpfully (from my perspective at least) display a “+” symbol next to the number of beacons. For example, when searching for three beacons, often I will at first have two victim symbols, with a “+” to indicate that the Pulse is working on determining what it suspects is a third signal. And the relatively rare ghosting incidents are almost always denoted with a “+” instead of an additional victim count. Personally, I like seeing the “+” symbol to indicate possible uncertainty or “working on it . . . ” status as opposed to the “either/or” nature of the victim count on the DSP and S1.

I have also heard the claim that the excellent reliability of the Pulse’s marking/masking function comes with a drawback: namely that the focus on the strongest signal causes the Pulse to effectively reduce its range for other beacons. Here is an interesting account that could be a manifestation of that drawback (scroll to post #9 by “khyber.pass”):

When I ran some tests in Fall 2008 to investigate this issue under the previous firmware, sometimes the Pulse performed perfectly fine but other times it was unable to find a beacon within its typical range, seemingly because it was so focused on the first beacon it had found. This year’s tests with the 3.0 firmware found no such problems, even with repeated trials. (Ditto for the Ortovox S1.) Perhaps something was different this year with my testing protocol, but I suspect Barryvox has largely fixed this pervious problem.

Overall: To What Kind of Person Does This Beacon Appeal?

Previously I’d felt the Pulse’s biggest problem was its being named after a relatively minor (yet still potentially useful) feature (i.e., vitals transmission) and that it should instead be named the Whoah beacon, since that summarized the polar-opposite reactions users are likely to have to it, i.e., either:
– “Whoah, this beacon is amazing!” or,
– “Whoah, what is going on with this beacon??

But if you fall into the latter category, now you can just select the “Basic” user profile upon initial start-up.

Either way, like with any beacon, you should definitely read the Pulse’s user manual before purchasing, and then again once you buy it, and then yet again at the start of any season. If you plan to use the Pulse under the “Advanced” profile, you’ll probably have to read it a few times at each stage. Carefully. Very. By contrast, the “Basic” user profile really is much more idiot-proof, while still retaining the essentials of the Pulse’s advanced capabilities. (Remember, this review would be only a fraction of its length were it covering only the Pulse under its “Basic” profile.)

Overall: What Thoughts Go Through My Mind If a Partner Has This Beacon?

“My partner had better be prepared to second-guess the forward/backward indicator if the distance readout is increasing (instead of decreasing as it should).”

“My partner will be a whiz at solving a close-proximity multiple burial.”

For the Advanced profile:
“My partner better be good as matching up left and right soft key presses with what the screen indicates.”

(Note, the Ortovox S1 shares most of the Pulse’s impressive capabilities, albeit with a radically different user interface. So if you’re potentially interested in the Pulse, you should also look into the S1, and vice versa.)

Manual

Shop for Mammut Barryvox Pulse avalanche beacon.

WildSnow Beacon Reviews Intro and Index

(WildSnow guest blogger Jonathan Shefftz lives with his wife and daughter in Western Massachusetts, where he is a member of the Northfield Mountain and Thunderbolt / Mt Greylock ski patrols. Formerly an NCAA alpine race coach, he has broken free from his prior dependence on mechanized ascension to become far more enamored of self-propelled forms of skiing. He is an AIARE-qualified instructor, NSP avalanche instructor, and contributor to the American Avalanche Association’s The Avalanche Review. When he is not searching out elusive freshies in Southern New England or promoting the NE Rando Race Series, he works as a financial economics consultant.)