Caution Pieps DSP Transceiver..........

[Hacksaw]

At ISSW I got to see the Pieps DSP avalanche rescue transciver. I also got to see a presentation about the Pieps DSP at the CAIC's CSAW meeting.

I personally haven't gotten to use this transceiver much. Most folks in Colorado go with Trackers or Ortovox transceivers. So, when I was teaching for the CAIC I didn't see many Pieps DSP transceivers. Last seaon a student did show up with one, he couldn't get it to "flag," the first found transceiver in a multiple buried transceiver exercise. At the time, I couldn't take a lot of time to figure out the problem. I told myself that I should read the Pieps manual and get some hands on time with one.

Any way, I recently pulled up the Pieps DSP manual download from the Pieps website www.pieps.com

Reading it I was distressed to read on page 9 of the manual:

"IMPORTANT: In case of multiple burials involving older analogue devices, faults may at worst occur which impair the efficiency of the digital signal separation. In such cases, you may find for a short time that more signals are displayed than actually exist."

This past weekend at Loveland Ski Area, I got off the top of Lift #2 and found two NSP friends (both VERY experienced with beacons)doing some beqacon practice. One of them had a new Pieps DSP. The buried beacons where older analog beacons. The patroller with the Pieps DSP was having lots of difficulty in trying to find the buried transcivers. So, here was firsthand evidence of the Pieps DSP's problems with mulitiple buried analogue transceivers. A shiver went up my spine......

On page 11 of the Pieps DSP manual it also says:

"IMPORTANT: When OLD BEACON MODE is selected, the count of persons buried in the desaster will no longer function properly and the MARK function, too, can only be used to a limited extent or possibly not at all (several trials required)! Use the SCAN function to return to normal SEARCH mode and the beacon will again offer the full range of services."

This whole statement scares the shit out of me.

Great, in the middle of an accident where I might or might not have buried analog transceivers; I can't depend upon my Pieps DSP transceiver working properly?

I don't really know what to tell folks about this. I think it would be VERY wise to ALWAYS ask your backcountry ski partners what kind of transceiver they have. Obviously, having a Pieps DSP transceiver with a lot of older anaolog transceivers is not ideal. In the old days we used to have problems about which transceiver worked with which transceiver because of different frequencys. It seems to me that there is a new issue of compatablity starting to happen here.

Halsted

[marshalolson]

ah-ha. i saw a NSP'er wndering around like a fool w/ his beacon. now it makes sense. very interesting. thanks hacksaw.

ps. nice to (very briefly) meet you. i was hanging with brett and mir at the rat on sunday.

[pechelman]

holy crap.

any idea what the peips upgrade does and if it will help this issue at all?

I bought one last season and noticed you could send it back it for a new software flash and a new case.

looks like Ill be getting in touch with them here shortly

[mc_roon]

i have a pieps DSP, but have never had any issues because everyone that I tour with either has a tracker or a DSP. But, this news does scare me a lot. I guess that it just didnt pick up as a warning sign when i read the manual because it was a non-issue at the time.

holy crap.

any idea what the peips upgrade does and if it will help this issue at all?

I bought one last season and noticed you could send it back it for a new software flash and a new case.

looks like Ill be getting in touch with them here shortly

if I bought mine in december, do i have the upgraded software?

[pechelman]

probably not
not sure how to check honestly

I guess thats another reason to give peips a call.
let me know if you happen to get to them first and what you find out
ill do the same

heres a link to the form from REIs website
http://a1072.g.akamai.net/f/1072/206...dia/661462.pdf

edit
and heres the contact info for liberty mountain who handles the upgrades
http://www.libertymtn.com/contact.html

[~mikey b]

folks have been dealing with the "ghost beacon" problem with DSP and older analog beacons for a couple of years - nothing new - the 1st software upgrade was supposed to deal with that adaquately, but I did not use ours that were upgraded last season at all to find out

[Tri-Ungulate]

I've had the DSP since it came out. The "ghosting" was initially irritating, but didn't really detract overall, as it could be easily dealt with with practice - practice being the operative term here as it is with all beacons. Got the software upgrade and it improved things quite a bit, though occasionally I will still get short episodes of ghosting - that I'm used to and can deal with. I use the older analog beacons as transmitters for practice, including an F1 and an F2.

As for problems with "flagging", I had that too with the initial firmware - but ended up doing work-arounds that I got used to. It was most problematic with 2 beacons in very close proximity. This too, is improved in the firmware upgrade. The DSP isn't perfect, but no beacon is - yet. Regular practice with different scenarios, just as with any beacon, gets one used to the peccadillos of each different unit.

[cj001f]

folks have been dealing with the "ghost beacon" problem with DSP and older analog beacons for a couple of years

Yup. Nothing new here. There've been problems with other beacons and older frequency drifted beacons as well. Nothing new under the sun except hype.

[Toby]

I remember reading some (impartial) stuff about the causes last year. AFAIK it's not a Pieps problem, it's the problem of the old beacons' transmission characteristics. But it's still a problem. The FAQ on the Pieps site kinda mentions stuff about it. From what I remember it's because some old beacons might experience a transmission frequency shift over time. Receiving beacons (regardless of model) might then have trouble finding the transmitting beacons if the transmission isn't in a certain frequency range. Newer beacons receiving ranges are optimised in the acceptable frequency range to tradeoff between bandwidth of reception (more likely to receive faulty beacons' signals) and range of reception (greater search range).

<edit>Here it is: link</edit>

<edit2>I guess it's not that impartial since it's from BCA</edit2>

<edit3>Actually, now that I've read it instead of just googling it it's pretty questionable marketing for Trackers. The furthest I'd go is it has stuff that's "based on science" in it.</edit3>

[Toby]

OK. Here are some rebuttals (also PDFs):

First, second

[SV-Stormchaser]

Hal - I was the aforementioned student in your class with the Pieps (BTW - thanks for getting us home alive during the worst slide cycle of the season, Rutschblock 0.5! ). I solved the ghosting problem by refusing to tour with poor commoners and their vastly inferior analog beacons.

Signed,
The dude who stole a Pieps off Ebay from some guy from FL who clearly had no idea what it was supposed to retail for.

[Hacksaw]

Hal - I was the aforementioned student in your class with the Pieps (BTW - thanks for getting us home alive during the worst slide cycle of the season, Rutschblock 0.5! ). I solved the ghosting problem by refusing to tour with poor commoners and their vastly inferior analog beacons.

Signed,
The dude who stole a Pieps off Ebay from some guy from FL who clearly had no idea what it was supposed to retail for.

Oh that was a truely "fun day," wasn't it....?

Any way, besides not touring with the "analog commoners," have you found any other way to get the Pieps DSP to work with several analog transceivers? Have you done the software update?

[pechelman]

I sent an email to the folks today referencing this thread and encouraging them to respond here. If I dont hear anything by tomorrow Ill go ahead and call them.

[cj001f]

have you found any other way to get the Pieps DSP to work with several analog transceivers?

Uh, by doing beacon searches the same way you do with an analog beacon? You remember, before all the new fangled technology? The DSP still functions as a perfectly good beacon when the "gheewiz" isn't working.

As for not touring with 'analog commoners' - shouldn't they be the ones not willing to tour with you?

[The Suit]

Any way, besides not touring with the "analog commoners," have you found any other way to get the Pieps DSP to work with several analog transceivers? Have you done the software update?

I use a Pieps DSP, and I've practiced finding multiple analog transceivers quite a bit. I don't really pay any attention to the "number buried" icons, nor do I try to use the "mark" function. I find the first buried transceiver, dig it up and turn it off, then find the second one. I find the Pieps easier to use than a Tracker, but that may just be familiarity. I've never felt that I was at a disadvantage relative to people using other beacon types.

[pechelman]

right now the only thing that has me slightly concerned are those papers toby posted up, specifically the last one where the experimenters were unable to determine the receiving bandwidth of the pieps.

Granted someone shouldnt ever be using a beacon that transmits at 423kHz, but you never know how a beacon will react to an unplanned fall or to impacts should you ever get caught in an avy...especially for the older analog beacons.

and toby those are great papers. got anymore?
is there some library I can browse?
really interesting reads.

[SV-Stormchaser]

Oh that was a truely "fun day," wasn't it....?

Any way, besides not touring with the "analog commoners," have you found any other way to get the Pieps DSP to work with several analog transceivers? Have you done the software update?

Fun indeed, but it certainly crystallized the concepts of "red light" conditions, shooting cracks and whumpfing sounds in my mind.

Sarcasm aside, I did actually tour with multiple analog partners last season and found the problem to sort of be a crapshoot. I think it really has to do with the relative positions of the beacons and how strongly the DSP is sniffing out the other. If the beacons were 60m apart, then I think you'd be hosed. I found my best bet was to flag the first and then move decisively and very quickly in the direction that I guessed the next one would be. I don't think that's necessarily a bad idea since in a real life situation an observer would have had some idea of the relative positions of the buried people, assuming good travel techniques were being used. I never really found the DSP to get confused once I was hot on the trail of the next beacon.

I don't envy the engineers and programmers working the bugs out of that system. What a mess. I forgot to send my beacon off for the software upgrade over the summer. I need to call them and find out if they could do it in short order while I'm traveling over the holidays.

[Toby]

right now the only thing that has me slightly concerned are those papers toby posted up, specifically the last one where the experimenters were unable to determine the receiving bandwidth of the pieps.

I'm not worried. They're using lies, damn lies and statistics. E.g. Pieps could've equally published a scare paper about range (since they've optimised for range) and had tables where at 50m in certain environmental conditions, other beacons failed to receive a signal at all - shock, horror! Basically the BCA guys tailored their experiments to suit their product.

The figure 1 discussion (signal drift and whether the Pieps would pick it up) is addressed in another paper. Notice the signal only drifts outside the standard detectable range (457KHz +- 100Hz) as temperature descreases below -5°C. If you wear your beacon low down on your layers (I wear mine above my base layer) it'll never get that low unless you've been dead a long while.

The figure 2 discussion they said the Pieps still detected a signal but with ghosting therefore they discounted it (marketing ). AFAIK from reading the Pieps manual the new firmware (v2.8 which I've got) now indicates if ghosting is occurring and in that case you just use it old-school style like cj001f mentioned - ignore the "Mark" and "No. of Victims" features.

and toby those are great papers. got anymore?
is there some library I can browse?
really interesting reads.

Nope. That was from googling. After I read the first one in more detail I recognised the marketing-speak so searched for counterarguments.

[pechelman]

I guess i should have paid more attention to who wrote those papers.
Thanks.

[Tri-Ungulate]

Any way, besides not touring with the "analog commoners," have you found any other way to get the Pieps DSP to work with several analog transceivers? Have you done the software update?

I have no problem touring with partners using analog transceivers, so long as they remain compatible, which they can. I mentioned above, I practice with old units, including an F2 bought when the F2 was the latest-and-greatest. Perhaps, freakishly, my older tranceivers havent' drifted too much over the years, but if your old transceiver is starting to drift, I might suggest you consider updating. I mean, who's still out there realistically expecting their Ramers to be useful?

Like cj sez, even if the gadgetry of the DSP somehow gets confused (which it can, even after the firmware upgrade, though not as often), you're still stuck with a perfectly functional unit which can be still be used so long as one understands the underlying concepts. That's what I meant by "work-arounds" and "dealing with" the peccadillos of an admittedly imperfect design (again, there is no perfect design - yet).

The key is understanding the limitations of the technology and getting it work for you to the extent that it can (which isn't always as good as we'd like, but hey), but not to become a slave to the technology.

What's the point of drills with a mix of transceivers? What's the point of the trailhead beacon check? You know better than anyone, Hacksaw.

[Hugh Jardon]

"I guess i should have paid more attention to who wrote those papers.
Thanks."

I talked in length with some BCA guys a while back and thier beacon has always been designed to pick up signals that may not be chirping at 457KHZ. This has been an unspoken feature for some time. I think it's good. How often is beacon compatability really checked? Not often is my guess...They are way ahead in their understanding of the condition of backcountry skiers beacons in North America in my opinion.

[nesta]

I find the first buried transceiver, dig it up and turn it off, then find the second one.

ummm, that might be OK for practicing occasionally, but is not the generally accepted way to do it that I've seen. What if you are the only one left on the surface, with 3 of your buddies buried at various depths, and the first one you locate is buried 1.5m deep- are you going to spend precious time digging him up to find out the other two or even one of the other two were more shallowly buried? You must be able to find multiple beacons without turning them off one at a time.

[cj001f]

You must be able to find multiple beacons without turning them off one at a time.

Uhhh.... isn't the Pieps DSP the only beacon with that capability? Their aren't any (11/6/6) other beacons with that capability.

[~mikey b]

humans have the capability to overcome the limitations of their gear, though, right, Carl? You can do it with any beacon. 3 circle method is a good way to start.

[Arty50]

Tri-Ungulate has pretty much said it best. I'm very comfortable with my DSP and it's really easy to deal with ghosting when it occurs.

Frankly, the range is what seals the deal for me. I'm able to pick up a signal 10-20m before people with Trackers. So while they're still on a coarse search, I'm tapped into a flux line and headed in.