[Update: As of the Fall 2011, the more expensive "Advanced" version has been discontinued, and a significantly less expensive "Tour" version has been introduced, which is essentially a single-button DSP. Also, firmware version 8.2 is now available, although the only new feature is searching for the new off-frequency TX600 transmit-only beacon (for dogs & gear).]
The Pieps DSP avalanche beacon combines a relatively simple user interface with a marking/masking feature for multiple burials. According to my tests it has the longest reliable range of any beacon with full directional indicators.
Interface and Controls
To switch the DSP to Transmit, depress and then slide the three-position switch on the front face of the beacon so that it’s flush with the housing. How to tell at a glance if the beacon is transmitting? With the latest harness design (new as of Fall 2008), look for a light flashing through the pouch’s mesh material.
To switch to Search, depress and then slide (realistically a two-handed maneuver) that same switch even farther, so that it protrudes from the other end of the housing. To revert to Transmit, bump the end of the switch.The search interface is relatively simple: two-digit LCD numerical display, five LCD directional indicators, and three buttons (arrayed vertically since Fall 2007, and with a triangular layout prior to that). One of the buttons plays no role whatsoever in searching: instead, it can check the frequency drift of other beacons, and on the DSP Advanced (which is otherwise identical to the DSP) it accesses navigational functions.
The firmware can be upgraded: latest version is 6.2 (as of Fall 2008). Keeping track of exactly what has changed with each version is confusing since the summaries from Pieps include changes that were already incorporated in prior firmware versions, and the only on-line summary is in German.
The DSP runs a sophisticated self-test upon start-up. Just be sure to keep the DSP away from another beacon during start-up, or else when it attempts to receive its own signal the amplification from an immediately adjacent antenna can cause the DSP to report an error. (The DSP will still function normally after this happens, but the error message, with the explanation available only at the Pieps website, not in the user manual, would be somewhat disconcerting if you don’t know the cause. This is also unlikely to occur in the field anyway, unless two users are huddled up against one another while powering on the DSP, and is something I’ve experienced only during testing when I’ve been holding multiple beacons, as opposed to turning on my beacon in the morning for an actual tour.)
How It Works: Initial Signal Acquisition > Secondary Search Phase > Pinpointing
Initial signal acquisition is via a combination of sound, one or two of five directional indicators, and distance readout.
The directional indicators disappear at 2.0 meters, and the distance readout goes down to a minimum of 0.1 meter. (Distance shown is not necessarily the actual distance to the victim, as is the case with all beacons.)
How It Works: Multiple Burials
The display shows between one and greater-than-three victim symbols. The DSP directional indicators and distance readout are displayed exclusively for the beacon with the strongest signal. Once that beacon is found, pressing a button marks/masks that beacon, and then the DSP focuses exclusively on the next-strongest signal.
Alternatively, the scan button shows the number of beacons within 5, 20, and 50 meters. The scan button also erases any previous markings/maskings.
How Well It Works: Initial Signal Acquisition > Secondary Search Phase > Pinpointing
DSP has the longest reliable fully directional range of any beacon on the market. What do I mean by reliable? I have run some range tests in which other beacons essentially matched the DSP when the beacons were positioned relative to each other (coupling) for the best signal. But in the opposite case the DSP has a very small range drop-off compared to other brands.
The third antenna eliminates all spikes and nulls in the pinpointing phase and the box size is small.
How Well It Works: Multiple Burials
DSP’s marking/masking has improved significantly over its many firmware versions, and now works reasonably well. The victim count is now generally reliable when searching from most modern beacons, although still not as reliable as its S1 and Pulse competition.
In detail: When searching for modern beacons, undercounting by the DSP is extremely rare, but some ghosting is typical. Moreover, while all three signal separation beacons – i.e., DSP, S1, Pulse -– have more trouble with Ortovox F1 beacons because of their continuous carrier signal that is always on in between pulses, the DSP has considerably more difficulty with F1 beacons as compared to the S1 and Pulse.
The DSP is supposed to display a symbol for such a beacon to indicate possible lack of confidence in the information DSP displays. Nonetheless, often when searching for an F1 I just end up with three regular victim symbols instead of one “old beacon” symbol.
Pieps says the Scan feature provides a more accurate count, although I have still experienced some F1-induced ghosts in Scan mode. Even when searching for multiple modern beacons, I have experienced slowdowns and frustrations when attempting to mark/mask a found beacon.
Then again, the DSP search function has far fewer potential distractions and complications than the Pulse and S1, so as is often the case, it’s a matter of trade-offs and personal preference. Also, see our Pulse and S1 reviews for their range issues when searching for a second beacon after focusing in on the second beacon, a problem that seems to be a byproduct of their outstanding marking/masking reliability. By contrast, the DSP exhibits none of this problem.
Overall: To What Kind of Person Does This Beacon Appeal?
The DSP has wide appeal. For example, it is ski mountaineer Andrew McLean’s beacon of choice. For a single-burial search, it functions in a simple straightforward matter, and the marking/masking feature has improved significantly over the years. The range at which full directional indicators function is impressively reliable.
By contrast, in my opinion the DSP Advanced version is at best a pointless waste of additional dollars. I like to keep my barometric altimeter on my wristwatch, my compass on my sighting-mirror magnetic unit, and my thermometer in my snowpit kit. Constantly taking out my avalanche beacon to reference navigational functions has no appeal to me, and even strikes me as potentially dangerous (e.g., if a slide were to hit as the beacon were dangling about outside its harness).
Overall: What Thoughts Go Through My Mind If a Partner Has This Beacon
“I hope my partner has upgraded to a relatively recent software version.”
“I know my beacon has no potentially dangerous frequency drift, because my partner was able to check it at the trailhead.”
“My partner will pick up my signal from a long ways away, regardless of how he holds his beacon, and with full directional indicators.”
“My partner had better be prepared to deal with possible slowdowns, frustrations, and ghosting during a multiple-burial scenario, and be familiar with the scan feature to help resolve them.”
A victim’s DSP (or Pieps Freeride) transmission can also be turned off by the Pieps iProbe, which is essentially a probe with a miniature search beacon in its tip. The iProbe can detect the signal from any beacon, and works the same way regardless of what beacon the searcher has, or even if the searcher has any beacon at all (though the “turn off” feature only works with a current Pieps beacon). More, for a guided party equipped entirely with the DSP (or Pieps Freeride), a guide with an iProbe could reliably turn off any located victim’s transmission so that the signal would now effectively be marked/masked for all other searchers too. (This feature is somewhat spooky to demonstrate: turn a DSP or Freeride to transmit, set up a bunch of people standing nearby with their beacons on search, press the mark/mask feature on the iProbe, then watch as all the other searchers’ beacons go silent.) If the iProbe is moved away from the target beacon, then the beacon will begin to transmit again.
(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.)