Mammut/Barryvox Pulse v3.2- Avalanche Beacon Review

WildSnow Beacon Reviews Intro and Index

The Pulse Barryvox (Mammut’s official somewhat backwards nomenclature) avalanche beacon has been an amazing technological tour de force ever since it original introduction. Yet its optional “Basic” user profile harnesses most of its 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! Meanwhile, successive firmware upgrades have added even more functionality to the “Advanced” user profile along with a high degree of customization.

Note that this review applies to the v3.2 firmware Pulse. Older Pulse units can be upgraded to v3.2 firmware for a small fee. If interested in the historical differences of prior firmware, see this older review. (The main point of this new review is not that the 3.2 firmware really mandates an entirely new review, but just that all the upgrades have accumulated so many new features that the old review with all the historical differences has become quite the mess!)

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.

The 3.2 Pulse is the first and only beacon to be fully compatible with the use of [non-rechargeable] lithium batteries. Li batteries are a must for my GPS during winter, as their longer life relative to alkaline batteries is even more pronounced in cold temperatures. By contrast, beacons already last for hundreds of hours on alkaline batteries (although replacing them well before that is a sensible caution), yet for long expeditions, especially in cold conditions such as Alaska, the ability to take Li batteries (both for longer life and interchangeability with other three-AAA devices like a headlamp & Spot) is a nice plus.

And of course the light-is-right in me I can’t resist noting the half-ounce weight savings per set of three AAA lithium batteries. Also, Li batteries can’t leak battery acid, which with alkaline batteries can lead to corroded contacts. Just remember though that Li use in any other beacon (including a pre-3.2 Pulse) is an EXTREMELY BAD IDEA (as the battery meter will go straight from 100% to dead, with little or no warning).

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. Upon switching back into Transmit (whether manually or via auto-revert), the Pulse will hold off while counting down from 5, and then emit a warning signal once it starts to transmit again. This is to alert the user in case of an unintentional switch to Transmit, and if the beacon is switched back into Search during this five-second countdown, all the search details will be restored (i.e., as opposed to starting the search anew).

Alternatively, if during that five-second countdown you press either of the two buttons, then the Pulse will go into “Rescue Send” mode. This mode essentially means the Pulse will be On but in neither Transmit nor Search mode. If the Pulse detects a lack of large movements during four minutes, it will go back into Transmit. The goal is to allow diggers and bystanders to avoid beeping away in Search yet have a way of going into Transmit if buried in a secondary avalanche.

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 to 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.)

The Pulse’s full-text LCD is flanked by two soft keys that perform many (many) different functions depending on the context and user programming. The “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. 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 > Final Search Phase

In the “Advanced” profile, initial signal acquisition is via analog acoustics only, although almost immediately full digital processing kicks in. Upon initial signal acquisition, the Pulse emits a distinct warning tone to grab your attention. The Pulse combines true analog acoustics with an LCD distance readout and a single LCD 360-degree rotating arrow. The Pulse is the only beacon (with the sole exception of Barryvox’s own yet discontinued Opto 3000) that allows the user to hear the true analog signal (which can be useful in multiple burials) while simultaneously receiving digitally processed directional information.

Within 3 meters (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. Note that Barryvox recommends keeping the default of losing the rotating arrow within three meters for the final search phase. In lieu of the rotating arrow, two different graphical options are available: a cross whose size is proportional to the distance readout or the static “Airport” graphic. (So that means six distinctly different patterns of behavior are available for the final search phase, i.e., two different acoustics options independently combined with three different display options.)

Under the “Basic” profile, the sound is always digital throughout the entire search. But the digitized acoustics will change tone not only in response to signal strength but also in response to flux line alignment. In other words, essentially an acoustical signal that you’re heading in the right direction. For the final search phase, the “Basic” profile shuts down the directional indicators at 3m and displays the dynamic cross graphic.

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 multiple 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 for significantly enhanced range.

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

Pulse automatically locks onto the strongest signal yet still 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 beacon can give preference — or not! — to victims who are known to have a Pulse beacon, i.e., buried victims are no longer anonymous.

(To expand further on the interesting ethical decisions this could prompt, assume that a touring party of four comprises two married couples, one of which has his & hers Pulse beacons. An avalanche fully buries three party members. Mr. Pulse locks onto a signal of only 5 meters yet with no heart symbol, but the burial list shows two more victims, one of whom has the heart symbol, which must therefore be Mrs. Pulse. The husband scrolls up to the symbol for his wife, which shows a much further distance of 40m with the directional arrow pointing the way toward some steep terrain with forestry debris and avalanche chunks.)

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 > Final Search Phase

The Pulse’s initial signal acquisition range is on the upper end of the current triple-antenna models from various competitors in my latest range tests.

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. By contrast, the digital processing kicks in upon initial signal acquisition with a very attention-getting sound.

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, 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!) Now 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. Yet again, advanced functionality if you want it, but ignore it or even lock it out entirely (via the “Basic” profile) if you don’t.

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!

One potentially 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.

In the final search phase, the third antenna eliminates all nulls and spikes. And the box size (i.e.,
the area over which the distance indicators are unable to differentiate the remaining distance to the target) is very small (essentially zero).

Of the various final search phase options as described previously, my personal favorite is the digitized acoustics combined with the cross symbol. The “Airport” static graphic? Well, it’s just a static graphic, so on the one hand, it’s not really doing anything, and isn’t any different than the lack of anything shown by most beacons in the final search phase (other than the distance readout of course). As for the idea it’s trying to convey, I agree with the goal that Barryvox is trying to reach, since when teaching beacon searching skills to my avalanche course students I’ve seen far too many searchers rotate or pivot the beacon in the final search phase (a big no-no) and/or spend far too much time moving both forward and back as well as left and right trying to pin down the location to within a few centimeters.

So the landing strip aspect of the graphic (with some relatively small left<>right elements) is intended to prevent searchers from rotating/pivoting the beacon and from going left and right in addition to back and forth. But sometimes a little bit of left and right will aid significantly in the subsequent probe strike. On the other hand, the searcher is still free to go left and right — as noted earlier, it’s just a static graphic intended to convey a searching strategy in the final search phase, not a limitation upon the beacon’s capabilities. Plus it’s only one of three displays options for the Pulse under the “Advanced” profile, and not even available in the “Basic” profile (although it’s the only display mode for the final search phase on the sibling Element beacon).

How Well It Works: Multiple Burials

In my testing, I have found the Pulse to be very reliable in both victim count and marking/masking. 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, very brief, and infrequent interruption. Firmware upgrades have reduced the frequency of these interruptions over the years since the Pulse’s initial debut.

The Pulse (and many competitors) 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, as is the case with any competing beacon that tries to separate out the different signals in a multiple-victim burial. 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, but outliers do occur.

This becomes a more significant problem when searching for older F1 beacons, which can cause more persistent undercounting or even ghosting. (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 competing models. The Pulse’s true analog acoustics (in combination with full digital processing for direction and distance, a unique feature of the Pulse) can also help in such situations.

In my new “5-25/5-20 Walk-the-Line Test” (as described more fully in my test notes), the Pulse did reasonably well for a beacon that marks/masks so reliably. That is, although the Pulse locked onto the Near Target and then the mark/mask function worked instantly (as it should), the subsequent strides and time needed for the signal of the Far Target to be acquired was typically just around ten seconds or so.

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

The Pulse has perhaps the broadest range of appeal for any beacon. For the keep-it-simple user, the Basic profile is relatively idiot-proof (or at least idiot-resistant?), yet offers lots of functionality. (Remember, this review would be a fraction of its length if it were covering only the Basic profile.) For the user willing to put in some time reading the user manual carefully and some serious practicing, the Advanced profile offers even more functionality. And for the professional willing to read the user manual even more carefully and spent some time exploring all the various options, the Pulse offers yet more.

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.”

Barryvox Pulse Manual

Shop for 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.)