The Case for PLBs

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gdurkee
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Re: The Case for PLBs

Post by gdurkee »

Campers: just ran across this thread and thought I'd add to it. It's something I've done quite a bit of research on over the last couple of years and like to think I might be helpful.

First understand that there's some critical differences between a PLB and what SAR nerds are beginning to call SENDs (Satellite Emergency Notification Device -- of course!). The latter include InReach, GeoPro, ShoutNano. PLBs include ELTs (Emergency Locator Transmitter for aircraft; PLB is, of course, Personal Locator Beacon, designed to be carried by a person; and EPERBs Emergency Position Indicating Radio Beacon which are carried on boats).

PLBs do not continuously track you. You activate the emergency button and it sends out a signal to any of a number of orbiting satellites. The signal is then passed to an earth station, the data recorded and sent, in the US, to the Air Force Rescue Coordination Center (AFRCC -- are you guys getting these acronyms down? There's a test later). The AFRCC then analyzes the data they get. They do this by analyzing the doppler shift of passing satellites to the stationary signal from the PLB. From that, they come up with several "solutions" and highlight the most likely based on magic algorhythms. Newer PLBs have a GPS built into them and the coordinates are sent with the signal. AFRCC passes this information on to, first, the state office of emergency services responsible for the area the signal is thought to have been activated in, THEN to the agency responsible for responding -- County Sheriff or NPS. This takes a number of hours.

The bad news is they can be seriously inaccurate. A plot of solutions to each ping can be scattered over miles of terrain. As noted, AFRCC provides a set of coordinates of the likeliest location but they usually don't pass on how that's derived. Most SAR responders aren't aware of the errors inherent in the solutions and don't know to ask questions that could help make a better guess as to the actual location. For various reasons, even if a GPS is part of the data stream, it might not be helpful, in part because the total data that can be sent is limited by the decades old architecture inherent in the system. Finally, many PLBs emit a signal at 121.5 megahertz. The idea is responding SAR can use an RF receiver to home in on that signal as they get close. Unfortunately, many SAR teams don't have that capability.

PLBs can work but because of serious errors inherent in the system, I don't really recommend them.

SENDs, though, are pretty accurate and depend on one of two satellite systems. They can continuously track you but ONLY if you set them up to do so. With permission (password access) the InReach, NanoShout and GeoPro can be activated by an Administrator but, of course, only if the unit is on. I'm not sure even the manufacturer is able to do that independently.

SPOT uses Globalstar satellites; the others use Iridium network. The latter may be a little more reliable and are capable of two way communication (e.g text) where the former (Globalstar) only seems to be able to handle outbound from the signalling device. When a location for any of these gizmos is actually acquired and sent, I'm not aware of any errors in finding the person. The problem is often in being able to both acquire a GPS fix then send when there's a satellite passing within the arc of sky available for the device. GPS and Iridium are two different satellite systems. I've seen no formal tests -- just what users have reported. From that anecdotal information, it appears the Iridium network (high earth orbit) seems more reliable for sending and receiving.

For emergency activation, SPOT goes only to SPOT International Emergency Response Coordination Center (yep, IERC). The other devices can all be configured to go to a call out list of friends or whoever. InReach can be configured to to to IERC for a small fee. Of course, you can also give friends limited web access for tracking or sending messages or location.

Finally, although all these gizmos have gotten a bad rap (rep??) in the press, my experience has been that they've been mostly used responsibly -- a few annoying exceptions but when you're in trouble, it's really great that responding SAR can find you right away. Fewer resources, less danger to responders.

There is a problem where you tell Mom you'll send a "OK" signal when you get into camp at the end of each day. Often, especially with SPOT, that signal doesn't connect and Mom immediately assumes you've been eaten by a borg and calls the NPS who, wrongly I think, might send someone that way. The key is telling mom -- or whoever -- that it's technology and you might go off radar for a few days. Don't worry... .

OK. Blah, blah .... . All things considered -- cost, reliability, two way messaging -- I'd recommend one of the InReach models but SPOT is pretty widely used and also OK. The other SENDs are designed for agency use. And, as above, I'd be really cautious about using a PLB.

Good luck.

George
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maverick
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Re: The Case for PLBs

Post by maverick »

Thanks George for posting that info about the PLB's, especially since quite a few members rely on this device, or have been considering it as an alternative to the SPOT! :thumbsup:
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Re: The Case for PLBs

Post by Jimr »

Interesting George. While not all of these devices are the same, what do you know about the reliability of PLB's that send signal and GPS co-ordinates at 406MHz frequency to COSPAS-SARSAT and simultaneously send out a signal at 121.5 MHz frequency for honing in locally?

Obviously, mine does that or I wouldn't be asking :confused: , so I'm curious if you have any info on the efficacy of COSPAS-SARSAT system.
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gdurkee
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Re: The Case for PLBs

Post by gdurkee »

Jim: Somewhere buried in my junk is an analysis of about 100 PLB activations and how close they were to actual location. I'll try to dig it out and post it. There's currently some controversy over the switch to 400 mhz. Whoever the governing body is advocating going exclusively to that and dropping 121.5. There's a fair amount of opposition in the SAR community (those aware of it) because getting the gizmo to try to home in on 400 is just another expense and more difficult (I don't know the details). Of course, it would take years for any actual change to work it's way through -- the rate of conversion and buying new PLBs. Apparently the thought is that with a GPS, it's unnecessary to have to locate by local signal. But the wizard who's putting the opposition together is pointing out that, even with a GPS, they're not reliable to better than, say, a kilometer or two. Better than nothing but in bad weather not as useful as it needs to be.

OH. Always read all the previous post....: COSPAS-SARSAT is the system -- and the only system -- for PLB, ELT & EPIRB. Those are the ones that eventually go to AFRCC in the US. As noted, the interpretation and resultant solutions really require sophisticated analysis by SAR, and that's often what causes imprecise location results and SAR response to an area.

I'm leaving for a week but, as mentioned, will try to post documents when I get back.

g.
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Re: The Case for PLBs

Post by BSquared »

I just picked up this old thread because I'm contemplating a couple of short solo jaunts this summer, and I wonder if anyone has more recent comparisons, specifically of the InReach and the (gen3) SPOT? After just a quick look at the plans and prices, it looks as though for a summer-only hiker (who probably needs only a month or two of service), the InReach might actually be less expensive (because of the mandatory 1-year SPOT subscription vs. the month-by-month InReach subscription). That's pretty cool, given that one also gets two-way communication (yes, for 50 cents a message, but still...).

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Re: The Case for PLBs

Post by sambieni »

I am kinda same boat as you BSquared. I just picked up an InReach to make the wife happy. It was more $ up front - about $100 more in fact for the cheaper InReach of the 2 available. But plans seemed roughly the same. It looked like to me both have month-to-month contracts available. So that negated that as a side-by-side issue. It looked like roughtly $100 difference on the whole,but I liked that InReach had a bit more options (including weather) and also texting/message controls/flexibility rather than pre programmed. Given that this is in major part to keep the family at home a bit more at ease during my trips, I felt less with the Spot was really less. Plus it looked as if InReach had less failure in pinging folks in an emergency. I am still waiting on the product to arrive this week. But was wrapped in this dilemma just a week ago. Maybe this helps.
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Re: The Case for PLBs

Post by psykokid »

My wife got me a Gen 3 Spot for christmas last year. For single sided tracking it does it's job well. In dense canyons I've had some location pings not make it out, and every time i've sent a Check In/OK notification it has made it through. You have to be aware of the devices limitations though. You need a clear shot of the sky for the messages to make it out. The downside with the spot there is that it's a one way device and there is no notification on the user side of the device to let you know that your message made it out ok. \

Spot had a mail in rebate over the holiday season that covered the $150 purchase price of the device, but in order to qualify you had to activate the device and sign up for 1 year of service ($150) and also have the unlimited tracking package ($50) which allows the device to send a location ping every 5 min at a maximum. If you want the extreme tracking package it's $150 and increases the frequency of the location pings to every 2.5 minutes.

Here you can see the GPS track from the hike I did this weekend: http://caltopo.com/m/ECJE
- The green track is the GPS track my Garmin e-trex 20 recorded of the loop
- The blue track is the GPS track created from the individual location tracking pings from the spot device.

The Spot and Garmin were both turned on at the same time. I placed them both on the hood of my truck for about 5 minutes so that they could get a good satellite lock before I started hiking. You can see that the Spot didnt send it's first location ping until I was a bit up the trail. You can see the spot was pretty accurate with the location pings being right on the GPS track.

For front country stuff, the SPOT works fine. But having used it for the first half of this year, I see myself selling it and purchasing the Inreach. The higher price point for the initial device and the higher fees for the service, to me, are worth having the ability to communicate two ways versus the one way for the spot. My wife is quite the nervous type and the ability to communicate directly while way out in the middle of no where will allow me greater freedom and cause my wife less worry.
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Re: The Case for PLBs

Post by BSquared »

Evidently I'm confused about the SPOT plans available. On their web page, I see a Basic Plan for $149.99 per year, and while there is a column labeled "monthly cost" (14.99/month), in fine orange print at the top of the column it says, "12-month term applicable." This implies to me that I can pay by the month but would still be committed to pay for 12 months. I've used the SPOT (gen 2, borrowed from various friends) several times before, and I think it does what I want, but could someone who actually owns one set me straight about whether it really is possible to purchase a plan for just a month or two?
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Re: The Case for PLBs

Post by freestone »

I have the Gen 3 for several years now and have never been offered an option to pay for only when I use it.
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Re: The Case for PLBs

Post by LMBSGV »

When I had a SPOT and asked them point blank about a monthly plan due to that confusing entry on their website, they told me there was no possibility of paying by the month. It was the entire year or nothing. When I replied this is rather deceptive on their part, they simply shrugged it off, which is typical of their customer service.

When my SPOT totally failed to work on a trip (it would not turn on--and yes, I tried changing batteries), they were willing to replace it for free. I sent them the bad one and they never figured out what happened. It was simply called equipment failure with no explanation as to why.

Since my wife's anxiety is rather high when I'm out solo and we didn't want to trust a SPOT anymore, we shot part of our savings and got an ISAT2 satellite phone. After the initial expense, it's the same cost or less than a SPOT or InReach. It always works. It even worked once when I was inside the tent in a downpour. It's built like a tank (soldiers take them into combat). The phone can send the same sort of email tracking message as SPOT or InReach without wasting talk time. The battery does not need recharging for at least two weeks if one doesn't turn it on except for calls and tracking messages. So my wife and I talk for a few minutes once or twice a day and have a real conversation and I also send a tracking message or two during the day. If I'm ever actually in a dire emergency, the Yosemite, Inyo, and SEKI 24 hour search and rescue numbers are programmed in so if I'm capable of pointing it south and pushing two buttons, I'll reach help. Obviously, everyone has different personal priorities about what is most important in one's life, but from my perspective, it's the best luxury expense I ever incurred after my camera.
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