Sapelo

Originally Posted by Offshore

Originally Posted by iAmKrzys

While we are awaiting more information about this tragic accident, there is already one lesson that can be learned from this story: people who think that a helicopter will arrive half an hour after activating distress call from their PLB should rid themselves of this delusion, and the sooner the better.


Even if a helicopter arrives it is not certain that they will be able to pick up the caller - I highly recommend this winter rescue story on Rosalie Peak in Colorado: http://www.summitpost.org/rescue-on-...19-2011/701157

I do most of my hiking alone and I often go off trail, so I started thinking about getting a PLB about two years ago as I was descending on Boott Spur trail quite late in the day, it started raining, rocks became pretty slippery and I arrived at the ladder. I looked down and thought to myself that if I fell from the top and became disabled my family wouldn't even know where to look for me. Eventually I decided to get a Spot last summer ahead of a week-long backpacking trip in Kings Canyon National Park in California. My choice was driven primarily by tracking mode as 1) I wanted my family to know approximately where I was, 2) I wanted to transmit my location in case I got badly hurt and wouldn't be able to to activate a distress signal, and 3) it would give me an opportunity to test the device accuracy in a variety of conditions myself without relying on manufacturer's marketing hype.

So how accurate is my Spot? It surely matters given the reports that Kate's location transmitted by her PLB were all over the map (which is what I mean by reported "1 mile radius" in this terrain.) Maybe the rescuers could reach her on Sunday if they were certain where she was? Well, after using my Spot for over half a year, I think it is mostly fine i.e. within 50 feet of traces recorded with my Garmin eTrex 30, but there were times where it was so far off that it became a subject of jokes among my family like one time I "hiked" 6.3 miles in 10 minutes or there was a sudden 0.6 mile "side-jump" from the trail. See example below: first is the original screen shot from Spot web site and then comparison to my Garmin traces (in red):

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I tried to get Spot support to investigate these problems with fixes but it wasn't going too well and I pretty much gave up after exchanging a couple of e-mails with them without much progress. I also think there are other issues such as the fact that the transmissions sometimes don't go through for quite some time and the unit will automatically shut off 1 hour after it stops detecting motion, so if you get disabled your last location may never make it through. Despite all of its limitations I think I will renew my subscription when the time comes as I don't see other viable alternatives for me.

Bottom line is that I think I am still very much on my own when hiking solo and my chances of survival are maybe only slightly higher if I found myself in a life-threatening situation.

This post raises a lot of excellent points. Carrying any type of personal locater is not a panacea - the crisis is not over with a press of the SOS button. Its also important to know your equipment capabilities and limitations - especially with safety gear.

I also do a lot of solo hikes and picked up a SPOT Gen 3 at the beginning of last season. I'm experienced with GPS technology - I use handheld and survey-grade GPS units recreationally and professionally and find the occasional wildly erroneous points show up in $100 Garmin to the $10K Trimbles (admittedly much less with the higher end units). There is a lot that goes into getting an accurate GPS point - some you can control and a some that you simply can't. Things you can control include starting with a decent GPS receiver, orienting the antenna properly, and minding the sky cover. Other things out out one's control included topography blocking line of sight to satellites and GPS satellite constellation status (geometry of the array at a particular time, number of working satellites overhead).

Looking at your images, it looks like your SPOT is actually doing pretty well. I do think your second image could easily be misinterpreted, though. What's important in that image is where the SPOT points fall on the Garmin track, not the SPOT track itself. Ignore the yellow line and look at the actual points. A comparison of the tracks to each other is not meaningful due to the difference in resolution - the SPOT tracking interval was 10 minutes and the Garmin was much less. It looks like there are about 15 points in the SPOT track and maybe two or three are way off. That's about an 87% or better agreement, so its not all that bad. It's similar to what I've been seeing in hilly terrain over the last year when comparing my SPOT Gen 3 to my Garmin GPSmap 60csx. The goal is to have good data when you need to press the SOS button.

I try to do this in a couple of ways. First, I pay attention to how the SPOT is attached to my pack since I've found that the SPOT antenna to be more directional than my handheld Garmin. I usually clip the SPOT to the carry handle and tuck the SPOT in the top pocket of the pack, taking care to orient the antenna surface up and not to put anything between the SPOT and the pack material. When I've just clipped it to my pack, I found it winds up upside down or hanging off to the side and the data quality is pretty bad. The second thing I did was to buy the enhanced tracking for $50/year and set my tracking to 2.5 or 5 minute intervals to get a higher resolution track log. I also set up the SPOT shared web page to display my track. I make the page private and give the login info to my emergency contact at home. That provides a track to augment the single point that gets transmitted with an SOS in the event of an emergency. I also like having a higher resolution when I download the points from the SPOT website.

Getting out of the SPOT-specific weeds here, the takeaway is the importance of understanding i) the use, capabilities, and limitations of one's gear; and ii) that no gear can replace common sense.