Spot Messenger 2: thumbs down

[Ent]

Ok this means it is worthwhile spending the extra on GPS equipped ones even only to make life easier for S&R. However, someone on this site might not agree as GPS location accuracy suffers in steep valleys...

Does that someone you are referring to, happen to be me?

Yes it does Your report indicates that you lucked out twice. First with the GPS location been off (but still close enough in the end but the helicopter must have been getting near its endurance limit) and secondly the tracking frequency not helping. In fact I went looking long and hard to find if some PLBs did not have the VHF tracking feature but appears all have it. I to agree that for the sake of a few bucks all PLBs should be equipped to send GPS coordinates. But then if a few dollars is more than someone can afford then better to have a PLB than not. Probably as the market matures with mass production GPS will become a standard feature as a clock and a radio are in cars.

On frequency that has me rather interested in its role. The one used in avalanche transmitters is very low measured in kilohertz to achieve the results it does. I know with data-links by microwaves wet and foggy days plays havoc with cheap and cheerful systems but we are talking gigahertz rather than megahertz and very low power with very high gain aerials used to squeeze the most out of them. My understanding is the the ideal aerial is a neat fraction of the wavelength (one, half, quarter) and whip aerials in the past were shipped longer so they could be tuned by cutting to size. The PLB I have has a flexible wire aerial designed to flip out and likely be the most favourable length given the usual size and weight considerations. Spot uses an internal one or at least the one I used briefly did. Be interesting to see the DB rating of the respective aerials.

I was interested that the PLB uses 5 watts. Power is a trade-off with battery life so that might be the sweet spot in size to performance plus as suggested the maximum allowed for a consumer device. Still 5 watts on the UHF band gives usable results in forests in my experience assuming that I am comparing apples to apples. I was amazed how low the power was on the Spot so there might be some trick (average rather than peak power?) but I believe that the Spot can send SOS for seven days compared to the 24 hours from the PLB (that appears to use bigger battery pack) so sort of validates what I found. Still impressive using so little power to get a message out.

I would love it if S&R published reports and findings from rescues. Do not need to know names and dates so no need to compromise personal confidentially guidelines but it would be good to understand what when wrong and right especial how effective the locator beacon was or was not. That way we can learn from others. Having called an ambulance more than I few times I know the dread of that you are hoping everything is ok tinged with hoping that something is wrong enough to justify the call.

Cheers

[photohiker]

Keep in mind that the main PLB satellites (GEOSAR) are out in geostationary orbit - 35,000 km or so out from earth, while the Spot Globalstar is LEO at around 1400km out. The polar orbit component of the PLB network are LEO (LEOSAR) and circulate at 850km. PLBs have 5w output simply because they need it.

Engineers will have walked the tightrope between output, battery life, unit size, weight and cost for both systems.

[Ent]

Keep in mind that the main PLB satellites (GEOSAR) are out in geostationary orbit - 35,000 km or so out from earth, while the Spot Globalstar is LEO at around 1400km out. The polar orbit component of the PLB network are LEO (LEOSAR) and circulate at 850km. PLBs have 5w output simply because they need it.

Engineers will have walked the tightrope between output, battery life, unit size, weight and cost for both systems.

I assume that the is the square rule applying in some form. Though would it not the the first one to two hundred feet going through tree cover where the extra power might give more reliability and also deal with cloud cover better (along with lower frequency)? We know that SPOT has issues with dense tree cover and some reports indicating cloud cover is an issue with Spot (welcome to Tasmania) but I as yet can not find similar concerns with PLBs but as now often stated you can only test a PLB by using it in an emergency. Also the close orbit of the polar satellites with a PLB would be a big help given the extra power and that they are closer. I believe that there are six of them so be interesting to know the amount of time that would be required in worst case before they were overhead based on the angle of sky visible from a steep valley. They take 100 minutes per orbit and are six so I am sure someone more mathematical than me can work out based on angle of sky viable before they would pick up a signal.

There are more than few reviews by "Joe Blog" on Spot but how valid are they? Here is an example http://www.energyindustryphotos.com/a_g ... r_beac.htm

On the technical level the McMurdo uses geostationary COSPAS-SARSAT satellites and SPOT uses communication satellites like the ones used by satellite phones. The McMurdo Fastfind uses the same technology that the beacons required to be carried commercial ships and airplanes do, which is designed first and foremost to be an official emergency distress system. with rigid specifications. While EPIRB distress signals are handled by government and international agencies, SPOT emergency messages are handled through a private company, the GEOS Emergency Response Center in Houston, Texas and it's support centers around the world. I've received feedback on this article from Civil Air Patrol or CAP search and rescue team leaders who have expressed frustration over the fact that the GEOS response center used by SPOT does not communicate well with their organization.

Is the claim on poor communication with a rescue organisation scuttlebutt, maybe once true but long since rectified, or just plan wrong or worst propagating a lie? This is an underlying issue that in the absence of rigorous statements from SPOT and PLB an information vacuum exists and web trawls can and do pick up wrong information.

Though our NZ friends warn us http://www.beacons.org.nz/LAND.htm

Each country has an individual 406 code. When you purchase a 406 MHz distress beacon, make sure it is coded for New Zealand. The New Zealand Country Code is 512. If you buy one from overseas or over the Internet, it could be an expensive mistake. When an overseas beacon is activated in New Zealand, the satellite may notify the wrong rescue coordination centre, which could mean a long, potentially life-threatening delay in your rescue.

However here is a very good reason why to spend the extra on a GPS equiped PLB over one without a GPS as you do not need to wait for two satellites to get a fix (and even then it is still a big area). http://www.beacons.org.nz/LAND.htm

We strongly recommend you purchase a PLB with built-in GPS as this dramatically improves their accuracy. This means your location can be identified by the Rescue Coordination Centre New Zealand (RCCNZ) on the first contact with a satellite. Without GPS it would require two satellites to pick up your beacon signal, to resolve the ambiguity of the satellite positions. The time between satellite passes varies greatly, ranging between 20 minutes and 4.5 hours.

Now what does a satellite pass mean as stuck in a mine shaft the angle of sky will be rather narrow even compared to a steep valley.

Still looking for how much I should trust my PLB in a steep tree covered valley. As mentioned with a Spot it appears that you would well advises, if you can, to head for a clearer view of the sky. Also note tasadam's comment about triggering a PLB and heading for higher ground if you can. Sounds on the surface logical but what are S&R thoughts on constantly changing GPS location? Faced with no acknowledgement of the signal going out you are rather left in an information vacuum but the clearer the view of the sky the better the chance to get out a message. Come on S&R some feedback on what works and what does not work based on your rescues

Cheers

[Nuts]

so the likely problem for the op was user error right..

Personally i'd rather see s&r involved in s&r, if you do a search the incidents (if not reported in the press) are likely all discussed here on the site or elsewhere on the web. This discussion is in the wrong place isnt it? wasted here?

That clear sky warning is available on the spot website?

No mention of tracking?

To me, its been established (through practical examples) that all these systems 'work'. It seems as clumsy to expect more from the data than discussing any one particular incident. Its not exactly rocket science (well.. the application anyhow), these things are a poor second to prevention. Also, there are many incidents that are going to be just too immediate for a plb to be much use, others (including many of the examples of recent years) that don't Really require immediate assistance.

All this aside if taking this seriously any discussion must surely lead to two way communication as the ideal (as park employees use, as i personally have used in such occasions). Immediate access to medical advice is probably most helpful (for a general audience) in talking life or death scenario's..

Do carry on though (i think ive just repeated everything i had to say lol, sorry if it appears flippant, i can expand on anything i say but for now will assume the reader's intelligence..)

[ILUVSWTAS]

but for now will assume the reader's intelligence..)

Really? huh, generous.

[Nuts]

No, not really, seem on the whole like a pretty intelligent bunch (to me), how about you

[ILUVSWTAS]

No, not really, seem on the whole like a pretty intelligent bunch (to me), how about you

Im not smart enough to figure that out.

[Nuts]

Last edited by Nuts on Mon 29 Aug, 2011 8:58 am, edited 1 time in total.

[north-north-west]

There are a few areas where my GPS has a lot of trouble getting a signal, especially early in the morning. I can't help wondering how a PLB (of any sort) would go in the same places.
Anyone willing to set one off at the Erica Carpark (for instance) to see what happens . . . ?

[ILUVSWTAS]

There are a few areas where my GPS has a lot of trouble getting a signal, especially early in the morning. I can't help wondering how a PLB (of any sort) would go in the same places.
Anyone willing to set one off at the Erica Carpark (for instance) to see what happens . . . ?

Is it an old GPS?? Only time I have ever lost signal on mine is when im in a cave or under rock. It always has siganl even in thick scrub or forest. I think the 410 PLB has a similar kind of GPS. I'd be surprised if it didnt work well in most places.

[Ent]

Personally i'd rather see s&r involved in s&r, if you do a search the incidents (if not reported in the press) are likely all discussed here on the site or elsewhere on the web. This discussion is in the wrong place isnt it? wasted here?

Um? Curious that one of the recommendations (requirements?) of Work Place standards is to report events and near misses so policies and procedures can be put in place to avoid future occurrences. In fact not doing this means that you will be likely to prosecuted as not providing safe systems of work and also to protect people that you invite onto your site. As mentioned numerous times on this site media reports are not always reliable and it is a brave soul that posts the nuts and bolts of their rescue on this site. Surely reporting back on performance was the catalyst of this thread, or I might be wrong.

Re Spot it would be fair based on resellers' warnings that it is not a system to rely on if under tree cover nor in steep valleys. What I can not find is advice if a PLB fairs better or worst in that regards. Happy to be pointed to a reputable site with that information

Cheers

[Nuts]

Hardly a performance report looked more like avoiding reading the manual to me

I'm pretty sure someone posted a link to a site full of S&R reports some time ago?

[Ent]

I'm pretty sure someone posted a link to a site full of S&R reports some time ago?

And that link is?

Cheers

[Nuts]

hey, your the one doing research ... first, what exactly are you looking for, reports of spot and plb tested (perhaps at the same time for comparison) from the same steep sided valleys or from under heavy tree cover? I dont think S&R reports will help with that? I can think of a handful of general reports that mention 'beacons' being used, none iirc from steep sided valleys? (P2C trail incident?)

I guess, pitfalls aside, some specific testing might be a good idea. Easy enough with phone based systems or spot tracking but spot/ plb/ irridium style beacon not so easy. I guess even without comprehensive testing they assume these systems are better (in general) to encourage than not. The AMSA website discussion of beacons does suggest two way communication desirable first choice over beacons but they avoid going into too much deatail.

Last edited by Nuts on Mon 29 Aug, 2011 8:59 am, edited 1 time in total.

[Ent]

hey, your the one doing 'research' ... first, what exactly are you looking for, reports of spot and plb tested at the same time from the same steep sided valleys or from under the same heavy tree cover? I dont think S&R reports will help with that? I can think of a handful of general reports that mention 'beacons' being used, none iirc from steep sided valleys? (P2C trail incident?)

And 'research' is in quotes for what reasons?

S&R will provide data that will give information on real life rescues. If S&R responds to people using a personal locator beacon trapped in steep sided valleys under heavy tree cover then you can say that system worked but on such a narrow sample size hard to tell if they got lucky with one the Polar orbit satellites been over head. Lets look at three incidents that people have posted bit of information about.

PLB used by one person twice. Once in river system and once under tree cover. The system worked but the GPS co-ordinates were out in the river system resulting in a delayed rescue. Also the VHF locator signal appeared not to helped. My 'research' indicates that land based rescue services are less likely to have the directional equipment compared to marine based rescued services. But that is from a USA site, not and Australian site. Given the higher percentage of PLBs going walking then maybe all rescue services should be equipped with directional finding. It may well be that they are but it does not work well in steep side valleys. Be nice to know. Also the fact that the Australian was rescued in NZ suggests good communications between the two countries' rescue services assuming that it was an Australian registered PLB. How would have Spot handled this?

Most recent was the broken ankle incident in which it appears that the Spot was triggered with a clear view of the sky. If we look carefully at the facts as reported it appears that local S&R is rather enamoured by roads and failed to identified a locked gate and the often impassable nature of tracks. Plus there appeared to be another issue that delayed rescue regarding where they thought the person was. Big issue as I found that when calling an ambulance is what locals call a road is occasionally not the actual name. Also was asked where in Victoria was the address Yes I used a mobile phone. Learning, where every possible use a land line as the ambulance can trace that much easier. I believe that mobile phone calls are now better traced so my experience is likely not to be repeated.

We have our friend from New River that had to endure a battery of negative posts. In that case they made it to high ground and then triggered the Spot successfully. What would have the situation been had they been trapped in the valley?

We have a media report from the PCT but I have no idea of the device and the situation rescued from. It did sound a steep but was it tree covered? Did they position themselves in a basin of the river so had a reasonable view of the sky?

It is very easy to question 'research' and use a multitude of Smilies hiding the lack of information in a post but having been a researcher for a Uni professor many years back often research data has to come from indirect means. Sure I would love to see empirical tests of PLBs and even a video on what to consider. Maybe Mythbusters? But in the absence of that the only other option is to look at real life rescues for clues.

Sure make numerous statements behind a multitude of Smilies as is your internet right but it would be appreciated if actual links could be given.

Regards.

[photohiker]

With all due respect, I think the way this thread has gone can be summarised as below:

Given the same difficult scenario, a PLB _Should_ get out better in a radio compromised emergency situation than a Spot because:

*) It uses a combination of Geostationary and polar orbit satellites.
*) It is a single use device, focussed on a single purpose
*) It has more broadcast power.

There are no guarantees however. Individual scenarios could favour one device over the other.

The above qualities take nothing from the Spot. Both PLB's and Spot's work, have been proven to work. They are not the same and can only be compared as emergency beacons, which is all of a PLB's function, but only a fraction of a Spot's functions.

Both devices are subject to the vagaries of GPS reception and obstructions to Satellite broadcast transmissions. We have heard about this from user reports on this forum.

We can argue about the merits of the devices we each may have bought, invoking the cognitive bias of Post Purchase Rationalisation but in reality, those of us who have bought either of these devices have something that may well alert the authorities if we are beset by an emergency in a remote area and are able to actually press the button.

If we are unable to press the button, those of us using a Spot in tracking mode will have reduced the search area for our body.

How about we all get over this now?

[Nuts]

nope, still nothing to hide and still just as proud of the lack of content. I don't aim to cloud the key points with needless 'content' and believe the key points have been made. In another way: if a member of S&R was to pop up and give an account of an incident where a beacon (or any device) worked in a situation that involved a canyon or thick tree cover that would be nice to know but would hardly be conclusive (similar to Michael's take) (and now yours big fella, almost in the same breath...)

It could, however, in fact lead (those perhaps lacking in other skills) to be even more reliant on these devices in planning as well as expectation.

The reason i wasn't over repeating myself long ago was for the sake of balance of these things in a bigger picture and so there are a few other thoughts for those who don't already own a personal rescue device to consider.

It wasn't an aim to belittle anyone's contribution other than may happen by offering the odd fact or thought. Unfortunately there is not much I can do about any offense this may bring, whoever it may come from.

[tastrax]

If you are after data I would suggest contacting these folk - they may well have undertaken some research on various devices. They may may also have a database of rescues etc.

http://natsar.amsa.gov.au/

Some of their reports may also provide some local leads for you.

http://natsar.amsa.gov.au/Council_Reports/index.asp

Most of the reports have some data on PLB and Spot rescues (but not complete I would suggest)

[Nuts]

Hi Phil, I did see those state reports (before i ran out of energy) some seem a little dated. iirc the ones linked here (somewhere?) were the individual incident reports in detail but more recently ( i think they were linked in response to an event that had just happened (perhaps a couple of years back). They may have been NSW/state based (the ones linked).

[Azza]

Most recent was the broken ankle incident in which it appears that the Spot was triggered with a clear view of the sky. If we look carefully at the facts as reported it appears that local S&R is rather enamoured by roads and failed to identified a locked gate and the often impassable nature of tracks. Plus there appeared to be another issue that delayed rescue regarding where they thought the person was. Big issue as I found that when calling an ambulance is what locals call a road is occasionally not the actual name. Also was asked where in Victoria was the address Yes I used a mobile phone. Learning, where every possible use a land line as the ambulance can trace that much easier. I believe that mobile phone calls are now better traced so my experience is likely not to be repeated.

If you are referring to the incident last weekend was I was involved. Its a bit like Chinese whispers...
The emergency services correctly identified there was a gate and sought the key, the issues after that were unfortunate. There was confusion that appear to steam from the fact that older copies of the Tasmap has some incorrect information that when provided to the landowner - gave him the completely wrong location and thus provided the wrong keys to the police. So from the emergency services point of view I think their response was correct - just unfortunate that things didn't execute so smoothly.

On a couple of other points:
Mobile phone triangulation is a waste of time unless you in an urban area - by the very nature of it, you need multiple phone towns to triangulate the signal. The mobile phone tower only receives the triangulation details as calculated by the 3g handset. So they'll never work out exactly where you are in a remote location.

VHF directional gear is in pretty much every aircraft. Its how you locate airports when flying around. When your trying to find a beacon on the ground its a very time consuming process likely to take an hour or more. You end up having to fly search patterns looking for where the signal is strongest and turning 90 degrees, repeat process until you find the source. So your be better off just getting a proper signal out to the satellite in the first place.

Personally I think people need to understand the technology rather than bag stuff out when it doesn't live up to the hype, nothing is a 100% guarantee.

Comments from S&R were that they actually quite like the spot device because of the fact you can get out the I'm OK, I need some help but I'm not in big trouble, and Emergency messages.

[tastrax]

Hi Phil, I did see those state reports (before i ran out of energy) some seem a little dated. iirc the ones linked here (somewhere?) were the individual incident reports in detail but more recently ( i think they were linked in response to an event that had just happened (perhaps a couple of years back). They may have been NSW/state based (the ones linked).

I remember them as well but no amount of searching the forum or the web has been able to turn them up - I will keep looking

[Nuts]

No worries phil, as i mentioned (to me, in my mind) they wont mean much. I do remember thinking they were very useful as far as they convey the sorts of things that go wrong and how S&R react.

We could probably look for US reports, i'm sure they have many more. Perhaps many would only be relevant for the area also as we are a long way south and relatively remote (in Tassie) which (as others have said) may have some effect on LEO type beacons. Maye AMSA/ S&R would let someone here (maybe from a gov agency...) do some beacon testing from deep valleys etc ? I guess the results (down here) would at least be useful for Australia generally?

I'd admit that comprehensive data from testing all these devices (and those to come) would be good. Perhaps there is a case for the companies themselves providing verifiable evidence that they work (and how well) from numerous locations/testing sites before they are released into a country. As is the case now though, people seem to buy up in droves regardless of any testing. While i don't have the same view on who should be responsible and to what extent (or reliance on such devices in general) this part i agree with.

[Ent]

Hi Azza

Thanks for the update. Bit more involved than what first posted on the thread that covered this matter. Um? As more than few know I am rather concerned over Tasmap's data on a few maps not in least due to the time since the maps were last updated. One that troubled me was updated in 1984 with a review in 1987 and that is a current map been sold. At least what you say does suggest that the land manager was rather harshly treated on that thread, even the title now appears suspect so maybe a moderation is in order Be good if you could repost your post there for completeness on that thread.

My concern is, and will be, are the two competing system roughly equivalent in reliability of getting a signal out or is one significantly better? Yes Spot has some very nice features (why not confirmation of message received as it is based on a telephone system?) but as even the resellers write that it is not to be relied on under tree cover with the seed post suggesting performance issues under cloud cover. The low transmit power gives a logical reason why Spot system has this failing. Sadly we buyers have limited data to establish if both systems are as good/poor as each other in getting a message out. Yes a PLB having 31 times the power and a frequency likely better at penetrating cloud cover appears promising but as mentioned in previous posts that does not give the complete story. In Tasmania and other rural areas we were sold a pup with GSM mobile phone system compared to the analogue system which while GSM is much better system for cities it was a poor system for rural areas. Yes 3G is much better but why in rural Australia did we have to buy GSM then CDMA phones only to have them obsolete in such a short period of time? I am concern that the same thing might be the case with the competing locator systems.

As said more data is required but I can not find it. This is not a case of justifying a purchase decision, as easy that is say for a debating point A PLB has a use by date of between five to seven years with battery replacement cost likely making it uneconomical to change the battery. This means an increasing number of units are nearing end of life. Sadly get ready for a flood of false alarms as the irresponsible set of units past their use by date. Be good if people choosing replacements had the information to make an informed choice and also the ability to compare between the different models.

Cheers

[photohiker]

This means an increasing number of units are nearing end of life. Sadly get ready for a flood of false alarms as the irresponsible set of units past their use by date. Be good if people choosing replacements had the information to make an informed choice and also the ability to compare between the different models.

Cheers

Nope. Why would we have a rash of false alarms? If the 'irresponsible' haven't already set off their PLB's without due cause, reaching their expiry isn't going to make them do it now.

[Jellybean]

My concern is, and will be, are the two competing system roughly equivalent in reliability of getting a signal out or is one significantly better? ...... Be good if people choosing replacements had the information to make an informed choice and also the ability to compare between the different models.

While I agree this would be good, I am struggling to understand why the same point is being made over and over and over again, it was heard the first time or am I been (or is that "being"?) harsh?

Last edited by Jellybean on Mon 29 Aug, 2011 11:39 pm, edited 1 time in total.

[eddie the eagle]

Just some real data.

Sydney, backyard, Spot I (original) unit lying face up on a trampoline, with a completely unobstructed view of the sky (140 degrees or so) Approx June 2009

Cloudless night.

Set to 'tracking' mode.

Approx 4 out of 5 signals were received/registered on the tracking site. (80% successful transmission.) Similar success rate on 'I'm OK' messages. Spot messenger sends signals three times, registers the first successful transmission.

Assuming that the tracking function and the messaging system have the same success rate.

Chance of the first message not being received = 20%
Chance of the first *AND* second message not being received = 20% of 20% = 4%
Chance of the first, second *AND* third message not being received = 20% of 4% = 0.8%

Therefore, the chance of a message being sent and received from the SPOT I is 99.2%

Note that in rainforest, the unit has not transmitted through the forest canopy for a total of 12 hours.

Perhaps someone could repeat this with the SPOTII?

Just an (actual) data point on the SPOT 1 for info.

Cheers,

eddie

[tasadam]

I recall they used a Spot on the Alexander Pearce memorial crossing a few years ago.
You'll get good intel on the Spot accuracy if you can dig that up.

EDIT...

http://www.stormplanet.com/tracking.htm

[Dale]

Backpacking Light did 80 days testing of the Spot II over a variety of terrain - forests, canyons etc... and recorded 100% of OK messages and 90% of its tracking points.

[ILUVSWTAS]

Backpacking Light did 80 days testing of the Spot II over a variety of terrain - forests, canyons etc... and recorded 100% of OK messages and 90% of its tracking points.

I wonder how much they got paid for that.

[Dale]

Backpacking Light did 80 days testing of the Spot II over a variety of terrain - forests, canyons etc... and recorded 100% of OK messages and 90% of its tracking points.

I wonder how much they got paid for that.

It was BPL not a Current Affair !