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Thread: Lost hiker in the Pemi

  1. #31
    Senior Member Trail Boss's Avatar
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    Disclaimer: I don't own a PLB nor SEND device.

    Quote Originally Posted by Hill Junkie View Post
    ....In theory, PLB's should be more reliable in rugged tree covered terrain due to longer wavelength (406MHz) and much higher transmit powers than tracker devices such as SPOT ...
    You're comparing the operating frequency of one device to another. So what's the frequency used by the SPOT?

    ...Kate Matrosova was carrying a SPOT beacon when she ran into trouble.
    According to the Bloomberg article "Trader in the Wild", Matrosova had an ACR Resqlink.
    https://www.bloomberg.com/graphics/2...r-in-the-wild/
    (Plus DougPaul's reply)

    ... Hard to say if more reliable coordinates could have saved her.
    Agreed; it would be hard to say.
    <speculation>
    She activated the emergency signal after retreating from Adams. With no means to survive the brutal conditions, she would've been exposed during the several hours it took the first rescue team to arrive in the col. Even with reliable coordinates it might have been too late to save her life.
    </speculation>

    ... PLB's are designed for one purpose only, SOS when you need it, and don't carry recurring subscription fees. Ships and planes have used this distress network for many years. Established reliability.
    Agreed; PLBs have established a history of reliability over the many years they've been available. Of course, one shouldn't lump all PLB hardware together. All that can be said is that all PLBs use the COSPAS-SARSAT system and it works well. How each model of PLB hardware fares is a separate discussion.

    SEND devices (like SPOT and inReach) can transmit a "breadcrumb" track of your movements. This can also be useful to searchers in the event you are disabled and cannot activate the emergency button. The breadcrumb trail leads to your last known position. A SEND can also transmit messages (an inReach can also receive them) and this is handy for informing others of status (such as if you're delayed by weather or minor injury). Of course, all of this comes at the cost of a subscription fee. Like you said, PLBs have no subscription fee. Their operating costs are limited to battery replacement (every 5 years or so).
    Last edited by Trail Boss; 05-06-2017 at 02:17 PM.

  2. #32
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    Quote Originally Posted by Trail Boss View Post
    Disclaimer: I don't own a PLB nor SEND device.

    You're comparing the operating frequency of one device to another. So what's the frequency used by the SPOT?
    It was on the internet, it must be true! We all get burned sometimes.

    Spot uses the GlobalStar network, which uses an uplink frequency of 1.6GHz. A distress signal would transmit at this frequency. The downlink use 2.5GHz, which is used in two-way communication, like sat phones. Not much is published about Spot transmit power. One reference I can't independently back up says 0.4W. InReach publishes 1.6W peak power and also operates near 1.6GHz. The ACR beacon transmits at 5W. Attenuation by vegetation is a complex subject. The type of trees and what angle the signal must pass through the trees produce considerable variations. Some pine trees can have big impact on 1.6GHz with little impact on 406MHz. Other tree types have small impact at both frequencies. One cannot simply compare transmit power and say higher is better either, without considering the whole link budget. The sensitivity of the receiver in space is an important part of this. What primarily sold me on going with a PLB vs SPOT was this. PLBs use a system that was developed for emergency rescue, while SEND devices use networks that were developed with other motivations. When your phone drops a call, it is a nuisance. If your distress signal doesn't get out, you might die. Saving many hundreds in subscription fees over time helped sway me towards PLB too Certainly pros and cons to each. Either are way better than relying solely on a cell phone. I sometimes carry both when I know I'll have cell signal most of the time.

  3. #33
    Senior Member Becca M's Avatar
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    The trails in the Pemi on the East Side of Franconia Ridge (Franconia Brook/Lincoln Brook) are not maintained for "winter" travel, right? - it is not surprising people get lost in there if that's where he got lost.

    No bridges/minimal maintenance..... these rescues cost FAR more that a bit more maintenance would.
    Yay for winter!!!!!

  4. #34
    Senior Member Trail Boss's Avatar
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    @Hill Junkie
    I agree the subject of attenuation is best summarized as "It's complicated."

    I believe all consumer satellite communications, including GPS, operate in the L band.


    Purely anecdotal but a friend switched from a SPOT Connect to a Delorme inReach SE and reports better performance. Outgoing messages are dispatched faster and more reliably. Both products operate in the same frequency neighborhood so how they go about doing it seems to make a difference (i.e. implementation and execution is important).

  5. #35
    Senior Member iAmKrzys's Avatar
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    While I am a big fan of gps and satellite tracking devices, I must say that the most cost-effective solution to "I don't know where I am" problem is a phone app that can download maps for off-line use, and OpenStreetMap has many if not most trails marked in the area. This would likely not prevent a mishap like falling into a stream but otherwise could make the situation less complicated.

  6. #36
    Senior Member DougPaul's Avatar
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    Quote Originally Posted by iAmKrzys View Post
    While I am a big fan of gps and satellite tracking devices, I must say that the most cost-effective solution to "I don't know where I am" problem is a phone app that can download maps for off-line use, and OpenStreetMap has many if not most trails marked in the area. This would likely not prevent a mishap like falling into a stream but otherwise could make the situation less complicated.
    Cellphone GPS chipsets are optimized for low power consumption which may come at the cost of reduced performance, particularly in less than optimal conditions (poor skyview, multipath, etc).

    A friend and I compared the GPS tracks from his iphone 4s and my Garmin 60CSx: the iphone track had significant excursions from our (known) route, the 60CSx did not. (The walk was under trees, but terrain was not a problem.) Also a phone GPS drains a battery that may be needed for communication.

    The trail coverage of OSM is spotty--good in some places, not so good in others.

    Doug

  7. #37
    Senior Member DougPaul's Avatar
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    Quote Originally Posted by Trail Boss View Post
    Agreed; it would be hard to say.
    <speculation>
    She activated the emergency signal after retreating from Adams. With no means to survive the brutal conditions, she would've been exposed during the several hours it took the first rescue team to arrive in the col. Even with reliable coordinates it might have been too late to save her life.
    </speculation>
    The party that found her required about 5 hours to reach her from the trailhead. If we add 2-3 hours from the initial distress call to leaving the trailhead, it would be 7-8 hours. Given the conditions, there is a significant probability that she would not have survived that long.


    Agreed; PLBs have established a history of reliability over the many years they've been available. Of course, one shouldn't lump all PLB hardware together. All that can be said is that all PLBs use the COSPAS-SARSAT system and it works well. How each model of PLB hardware fares is a separate discussion.
    The COSPAS-SARSAT system was established in 1988 to handle distress calls from ELTs (aircraft) and EPIRBs (boats). PLBs were first allowed in the early 2000s (2003 in the USA) so much of the experience is pre-PLB. PLBs are designed to be easy for humans to carry while the others are carried by machines. I don't have time to check right now, but it is possible that the ELTs and EPIRBs broadcast a stronger signal than a PLB and can contain a much longer-lasting battery.
    https://en.wikipedia.org/wiki/Intern...rsat_Programme
    https://en.wikipedia.org/wiki/Emerge...beacon_station

    (Note: it appears that EPIRB can also have a more general meaning--ELTs and PLBs are specific types of EPIRB.)

    Doug

  8. #38
    Senior Member Hillwalker's Avatar
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    I find this thread very interesting, informative and it raises a question from my hiking past. When we hiked the Long Range Traverse in Newfoundland a couple of years ago, the authorities required us to carry an device they said was to locate us in the event we "got lost". It consisted of a plastic tube about 8 inches long and one inch in diameter with about an 8 inch long thin wire coming out of one end. We just stuffed it in one of our packs and forgot about it until we finished our hike, then returned it to the park office. What do you suppose it was? I highly recommend this hike to anyone who wants some experience crossing pathless terrain far from civilization. It is also a really great boat ride across the Great Eastern Pond to get to the trail-head.

  9. #39
    Senior Member iAmKrzys's Avatar
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    Quote Originally Posted by DougPaul View Post
    The trail coverage of OSM is spotty--good in some places, not so good in others.
    We don't know (at least from the press articles posted so far) where exactly the hiker was found, but here is OSM link for the general area:
    http://www.openstreetmap.org/#map=13....6319&layers=C

    I don't dispute that OSM coverage is spotty in some places but I think it is getting better every day.

  10. #40
    Moderator bikehikeskifish's Avatar
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    Quote Originally Posted by iAmKrzys View Post
    I don't dispute that OSM coverage is spotty in some places but I think it is getting better every day.
    It has both of the Owl's Head bushwhacks labeled and drawn on the map.

    Tim
    Bike, Hike, Ski, Sleep. Eat, Fish, Repeat.

  11. #41
    Senior Member Trail Boss's Avatar
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    Quote Originally Posted by DougPaul View Post
    ...A friend and I compared the GPS tracks from his iphone 4s and my Garmin 60CSx: the iphone track had significant excursions from our (known) route, the 60CSx did not. (The walk was under trees, but terrain was not a problem.) Also a phone GPS drains a battery that may be needed for communication...
    Just like different models of PLB, different models of phones can vary in GPS performance. Case in point:

    I have a Garmin Rino 530HCx. It's the same vintage as the Garmin GPSMAP 60CSx (circa 2007). I performed extensive testing in a local forest (~30-40' canopy of mature maples), comparing four GPS apps on my late-model phone. My Garmin served as the "gold standard".

    Here's what the phone did. This is eight laps around a ~2 kilometer circuit. Two laps for each of the four apps.




    The Garmin recorded all 8 laps. Here's what the "gold standard" did:



    Subsequent field tests in the Adirondacks demonstrated the phone's track deviated from the "true path" about as often as the 530 HCx. However, the deviations were well within the range of GPS accuracy. I've found it to be more than adequate for general navigation and trip statistics. My friend used a Garmin 76CS for years and recently switched to using Gaia with his iPhone 5s. He reports the same level of satisfactory performance as with the old 76cs.

    As for loss of GPS fix, yes, it can happen, but re-acquisition is fast. In practice, it hasn't proven to be a problem. Honestly, I've only noticed it once and that was during my last hiking trip (the first time in dozens of trips). It appeared as a straight-line segment in my track, running for several meters. For general trail-walking in the mountains, it works fine.


    Quote Originally Posted by iAmKrzys View Post
    ...the most cost-effective solution to "I don't know where I am" problem is a phone app that can download maps for off-line use...
    +1
    Phones are so ubiquitous that it's disheartening to hear when someone gets "lost" with one. Sure, they ought to have a map, compass, skillz, etc but all they'll probably have is their phone. A navigation app, an offline map, and an hour learning how to use it, will at least tell you which way to get back on the trail and out to the road.


    Quote Originally Posted by iAmKrzys View Post
    ... I don't dispute that OSM coverage is spotty in some places but I think it is getting better every day.
    Gets better even faster if more people get involved.

    To all those who know the area forwards and backwards, I suggest you get a free OpenStreetMap account and share your knowledge. FWIW, for the past year I've been enhancing OSM's data for the Adirondack High Peaks region. I post my changes in ADKhighpeaks.com so others in the community (who have even greater familiarity with area) can give me feedback. I also hope it inspires others to contribute.

    It's important to know that OSM serves as the source for other maps. Maps you may be using, but aren't aware they are created from OSM data.
    Suunto Movescount
    GAIA GPS
    Thunder Forest Outdoors (in Caltopo)
    Waymarked Hiking Trails
    BRouter (a routing engine that works with OSM data)
    etc

    If you don't have the time or inclination to do mapping, please consider just uploading your (clean) GPS tracks to OSM. When a map editor selects an area to work on, she can optionally request to download all publically-available GPS tracks (for the area). Seeing umpteen, closely-spaced tracks snaking up a mountain is the best resource for drawing a trail to within meters of its true location.


    PS
    @iAmKrzys
    Haha! Just found your moniker in OpenStreetMap! You're definitely no stranger to OSM!
    Last edited by Trail Boss; 05-07-2017 at 12:52 PM.

  12. #42
    Senior Member DougPaul's Avatar
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    Quote Originally Posted by Hillwalker View Post
    I find this thread very interesting, informative and it raises a question from my hiking past. When we hiked the Long Range Traverse in Newfoundland a couple of years ago, the authorities required us to carry an device they said was to locate us in the event we "got lost". It consisted of a plastic tube about 8 inches long and one inch in diameter with about an 8 inch long thin wire coming out of one end. We just stuffed it in one of our packs and forgot about it until we finished our hike, then returned it to the park office. What do you suppose it was?
    A wild guess is that it might have been a transmitter normally used for tracking wildlife. (Did you hold any wild parties? )

    If so, it would likely have been a low power transmitter that could be located by radio direction finding (RDF). (More sophisticated trackers transmit GPS locations and need not be RDFed.)

    Doug

  13. #43
    Senior Member Trail Boss's Avatar
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    Quote Originally Posted by bikehikeskifish View Post
    It has both of the Owl's Head bushwhacks labeled and drawn on the map.
    It's a fairly recent addition (or modification): http://www.openstreetmap.org/way/419689873
    It's part of a larger set of changes ("Changeset") that also includes the Black Pond bushwhack: http://www.openstreetmap.org/changes....5864&layers=C

    This is where VFTT, the pre-eminent online hiking community for the Whites, may want to collectively ask itself if "bushwhack routes" belong on public maps. I think they should not, but then I'm seeing the topic through the lens of an Adirondack preservationist (don't promote unofficial routes). I'm not steeped in the local customs of the Whites. Maybe the Brutus and Black Pond bushwhacks are so well-known, and so well-trodden, that they transcend the classic definition of a bushwhack and are effectively trails.
    Last edited by Trail Boss; 05-07-2017 at 12:05 PM. Reason: Added clarification.

  14. #44
    Senior Member DougPaul's Avatar
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    Quote Originally Posted by Trail Boss View Post
    Subsequent field tests in the Adirondacks demonstrated the phone's track deviated from the "true path" about as often as the 530 HCx. However, the deviations were well within the range of GPS accuracy. I've found it to be more than adequate for general navigation and trip statistics. My friend used a Garmin 76CS for years and recently switched to using Gaia with his iPhone 5s. He reports the same level of satisfactory performance as with the old 76cs.
    I have a 60CS and a 60CSx (analogous to the 76CS and 76CSx). The 60CSx is significantly better. (It was the first of Garmin's "high sensitivity" GPSes--the primary difference was ~200K correlators increased from less than a few hundred. (Don't recall the exact numbers, but they are on that order.)) One of the advantages is fast satellite acquisition and re-acquisition, particularly in degraded skyview situations.

    As for loss of GPS fix, yes, it can happen, but re-acquisition is fast. In practice, it hasn't proven to be a problem. Honestly, I've only noticed it once and that was during my last hiking trip (the first time in dozens of trips). It appeared as a straight-line segment in my track, running for several meters. For general trail-walking in the mountains, it works fine.
    For general hiking navigation, exact accuracy isn't important (we're not surveying...), just that it gets you close (say 10--100 meters depending on the situation). Maps often have position errors that are greater than typical GPS position errors.

    Phones are so ubiquitous that it's disheartening to hear when someone gets "lost" with one. Sure, they ought to have a map, compass, skillz, etc but all they'll probably have is their phone. A navigation app, an offline map, and an hour learning how to use it, will at least tell you which way to get back on the trail and out to the road.
    Most phone GPS apps are road oriented. One has to plan ahead by installing a topo app and downloading the appropriate maps. And if you look at it from an ex post facto viewpoint (ie look only at those who have needed rescue due to being lost), I suspect that many have not done the preparation. However if one prepares properly, a phone GPS should be adequate in most situations. And if one does manage to reach 911, the GPS coordinates can be interpreted on the other end.

    Re OSM:
    Unfortunately the OSM website does not have a mode in which it plots hiking trails on USGS topos. (Yes, the biking mode has contours, but they are spaced too far apart for hiking and the political boundaries are lost.) A while ago I looked for OSM trails plotted on USGS topos but didn't find any that covered the NE--a quick look at some of your references suggests that the situation may have improved. I have been downloading trail tracks from OSM and converting them into GPX files for plotting on topos with my GPS software to make my own maps... (very easy to do once you work out the details including writing a few simple programs)

    Doug

  15. #45
    Senior Member Trail Boss's Avatar
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    Quote Originally Posted by DougPaul View Post
    ... Unfortunately the OSM website does not have a mode in which it plots hiking trails on USGS topos.
    The OSM website is rudimentary by design. It doesn't even show all the details the OSM database actually contains (guideposts, fords, cols, and much more). For what you want, you can use something like Caltopo, or any of the better navigation apps, that can overlay maps. For example, using Alpinequest (Android app), I can create whatever "layer cake" I want and then download it for offline use. Here's TF Outdoors (derived from OSM) + Strava Bike Heat Map + Caltopo's Slope Shading






    ...I have been downloading trail tracks from OSM and converting them into GPX files for plotting on topos with my GPS software to make my own maps...
    Check out Waymarked Hiking Trails (link above). You can select any trail (designated as a route), see its length and elevation profile, and download it as a GPX file. If the map-editor did his job right, that trail is based on several GPS tracks and more "true" than a single one. Less work for you!

    Example: Boot Spur Trail
    Last edited by Trail Boss; 05-07-2017 at 01:11 PM.

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