Spot Messenger 2: thumbs down

[rsser]

I've been testing this in the snow in the Vic Alps and have had good results with accuracy and msg transmission with clear or clearish skis, but ...

1. One fix in cloud was about 400m out from the known location. In some parts of the terrain, that could have you either side of a steep-sided ridge and make it a PITA for rescuers to find you.

2. One check-in msg was not transmitted at all, despite the unit being left to run for about 20 mins and confirmation lights showing. Again, in cloud.

Have come to the conclusion that this is not a reliable distress beacon.

[photohiker]

Have come to the conclusion that this is not a reliable distress beacon.

You tested the distress mode?

[rsser]

No need.

It uses the same method of gaining and transmitting the coords as the check-in msg.

If that fails or is well out, the distress signal will be unreliable.

[ILUVSWTAS]

Another unhappy spot user.

[forest]

I have never had a message not get out on mine.
Used it every trip for the last 12 months ??

[photohiker]

No need.

It uses the same method of gaining and transmitting the coords as the check-in msg.

If that fails or is well out, the distress signal will be unreliable.

Not really. SOS uses a different frequency of signals. It also transmits indefinitely until the batteries expire. Ok is sent just 3 times over 20 minutes and that's it. The satellite network is a Low Earth Orbit Constellation so in marginal conditions the performance of the network will constantly alter depending on your position relative to the landscape, weather, and the position of the closest satellites. Even if you stay still, 2 of these factors will be changing all the time.

Ok messages:
"SPOT will send your message and GPS location to the SPOT network three times over 20 minutes"

SOS Messages:
"SPOT sends your emergency profile information and current GPS location to GEOS every 5 minutes until cancelled or the batteries run out. If SPOT cannot get a GPS signal, it will still attempt to send your message – without a GPS location."

Spot is not a PLB. I suggest you revisit the reasons you bought the Spot, and consider if a PLB might suit your needs better.

[rsser]

Thanks for the informed response Michael.

You seem to be saying that the location data will vary as the cloud cover changes. So with an SOS, Spot in Texas will be sending continually changing location data to Aus as the weather changes?

Yes, the unit is not a PLB; in fact I sold my GME PLB to buy it, so as to get some more options. They appear to come at some risk.

[photohiker]

Thanks for the informed response Michael.

You seem to be saying that the location data will vary as the cloud cover changes.

I was only talking about the sending of Ok or SOS messages. Texas has nothing to do with what Location the Spot derives from its GPS receiver. Texas relays what the Spot sends in. But yes, cloud cover can impact GPS fix.

Remember that the Spot is receiving location data from the GPS network and sending messages to the Globalstar network. These are two different satellite networks.

As I understand it, if you activate SOS, every five minutes Spot will attempt to get GPS fix and transmit it to the network. If it cannot get GPS fix then it will still send an alert. As you know, GPS reliability depends on a clear view of the sky etc. It is quite possible for a single message to be way out of whack location wise, but in the SOS situation, there would be many SOS messages sent by the time rescuers were on the ground and the Spot GPS will likely have gotten a better fix and transmitted it by then.

We have no reason to expect that a PLB would get significantly better GPS fix than a Spot in the same circumstances. My Spot2 certainly tracks pretty well, I've seen the track waver a few metres but not hundreds of metres. Maybe I get better performance because I leave it on and use the tracking feature? Dunno.

[rsser]

Well, the GME PLB with GPSr has a quad helix antenna. Said to be high quality but of course you can't test it without unwanted consequences.

What my Spot did in both cases was signal that it had a location fix and a successful msg transmit, and in the first case it was sufficiently out to make S&R a problem; and the transmission site was well in the open topo-wise, just in cloud.

In the 2nd case, it was from Bogong summit, so good access to both GPS and Globalstar sat constellations .... just cloud.

[Nuts]

All a good argument for not bothering with the unit unless you also opt for the tracking feature. Perhaps terrain dependent (or our fickle weather) but tracking does show the odd marker thrown well off route and 'sections' missed. Relate this to trying to use a good (but not ideal) messaging system to reassure an (especially nervous) loved one and it makes them less appealing.

Again, the real value (that i see) Is as a plb... with the added 'last known whereabouts' data from the tracking...and the ability to perhaps get ok messages out when 'one' decides its more likely a sprain than a break... not ideal (S&R will come regardless.. hopefully assigning priority) but at least part way and advanced from a simple panic button... Of course anyone who thinks they forked out enough already wont want to hear this..

that said, i'd be happy to dump the spot and the satellite phone as soon as someone with decent customer service along with as good a unit pops up. There are other options as seen and even linked to the irridium network but at a price.

[rsser]

Yes, there are now 4 comm sat constellations serving Aus and soon the unit and call rates must come down.

As for tracking, maybe, but I'm just off Bogong and we had 3 days mostly of cloud.

The itin was pretty clear on the map but included a lot of steep-sided spur or ridge travel - Long Spur, Cleve Cole to Audax Point etc. 400m out is just not good enough.

[South_Aussie_Hiker]

Hi there everyone.

Just a few points of note with regard to GPS:

1. Cloud has little or no affect on GPS accuracy or ability to get position information.
- GPS satellite signals are very, very weak. They are, in fact, weaker than background atmospheric electromagnetic "noise" (which seems weird, I know!)
- If you consider that the signal gets sent in space (close enough to a complete vacuum) and then travels through the ever denser atmospher to sea level, it's obvious that GPS has to be immune to errors caused by changes in density of the transmission medium. This is why a cloud (which is maybe 0.5% more dense than clear air) has no affect.
- The frequency of GPS transmissions compared to the size of water droplets found in the atmosphere (cloud or rain) means that they do not act as a physical barrier (the same reasoning means AM radio can be received clearly on the other side of a mountain).
- If GPS was affected by cloud/rain/wind/smoke/hail etc then it would not be viable for use in aircraft.

2. The accuracy of GPS
- GPS calculates position by measuring the time it takes for a GPS signal to get from the satellite to the receiver, than converting this to a distance and triangulating position from multiple satellites.
- It can take significant time for a few satellites to come online, and the initial position will be somewhat inaccurate. As more satellites come online, the receiver will slowly narrow down the position accuracy.
- If the GPS receiver is told the exact date and time and a rough position by the user, it can usually get a position much more quickly. I wouldn't have thought a SPOT would have this capability. This is why car GPS is very quick - it already knows roughly where it is and the time, so it knows where the satellites are and which ones to search for.
- An accuracy of +/- 400m within 5 minutes of turning on a SPOT device is probably quite reasonable. Sometimes in jet airliners, even with accurate time/date/initial position information, the GPS can still take up to 8 minutes to meet the required accuracy standard. Aircraft also have barometric aiding which essentially simulates another satellite input and allows a position to be obtained more quickly, and more accurately.

I'd say the 400m error was because the SPOT hadn't been tracking continually and was still in the process of getting enough satellites for an accurate position.
I have no idea why the message wasn't received, maybe the Globalstar side of things? I've never had much luck with sat phones which also use Globalstar - they just don't seem to work first time, every time with any consistency.

[rsser]

Could be it.

But the unit has a GPS indicator which flashes when it thinks it's got a fix.

My Garmin handheld GPSr claims accuracy down to metres with around 6 to 8 sats received, in the same kind of country.

My sample is not large. Only 2 cases in cloud. Could be random variation, but not what you want in a distress beacon (note, not a PLB).

Globalstar were supposed to have got all their 2nd gen sats up a couple of months ago; prior to that you could expect time gaps in coverage of Aus.

[South_Aussie_Hiker]

The Garmin will nearly always get a more accurate fix, more quickly because it's has a rough idea of the current time and approximate location (from last time is was used).
The SPOT does not retain this info because it would degrade battery life unnecessarily for an emergency device.
The manufacturers of the SPOT could just delay the time of switching on to position transmission to say, 10 minutes, so as get the accuracy down to around 10m. This, however, would defeat the purpose of an emergency device, which should transmit as soon as possible.
If it is turned on in a real emergency, it remains on and would quickly resolve the 400m error on subsequent transmissions.

[Nuts]

Back when we first got the Spot1 I posted some/one of the(?) trials here somewhere. I don't think it was ever that far (400m) out but it did throw the odd signal from well off the route during tracking... It can also miss groups of signals. So time lag doesn't really explain all the inaccuracy?

That said, I dont see this as a big negative. The real need for accuracy is during beacon mode where the unit would be continuously transmitting as in Michael's/your explanation. In the few rescues iv'e heard about the transmission has been successful.

[photohiker]

Globalstar were supposed to have got all their 2nd gen sats up a couple of months ago; prior to that you could expect time gaps in coverage of Aus.

Doesn't effect Spot:

Recent satellite problems

According to documents filed with the SEC on January 30, 2007, Globalstar's previously identified problems with its S-band amplifiers used on its satellites for two-way communications are occurring at a rate faster than expected, possibly eventually leading to reduced levels of two-way voice and duplex data service in 2008. The company's simplex data services used to support the asset tracking products as well as the SPOT Satellite Messenger are not affected by the S-band satellite issue mentioned above. Globalstar also launched eight ground spare satellites in 2007 to help reduce the impact of the issue.

[rsser]

Well all those points are worth serious consideration.

The fact remains that in cloud in a sample of 2, one msg had the coords out by about 400m and the other msg wasn't transmitted within 20 mins.

OK, in the second case, leaving it on longer may have helped, despite the fact that confirmation of the fix and the msg send was well within the 20 min window.

Bottom line for me is that in the test conditions, that degree of unreliability can readily make the diff btwn rescue or death from hypothermia. Search in lasting cloud will be on foot; 400m variation say on the Razorback or the ridge running from the south to Bogong will mean looking on both sides and if snow has fallen there'll be no indication of which to look on.

Still not happy Jan.

[tastrax]

As a regular user of both Spot and GPS's I think this just shows that you need to know your equipment well before you use and rely on it. I have had GPS points out by 400 metres on occasions for no apparent reason (maybe selective availability was degraded by the yanks?). I have also learnt that a standard GPS is best used by turning it on and waiting in one place for a while before recording your waypoint. At least on the GPS you can generally see how many satellites you are getting data from - not so on the Spot device. Spot may have a fix but how many satellites 3, 4, 8, 10? 3 or 4 satellites only could give a 400 metre discrepancy pretty easily I would think.

I have also had Spot not "send" a message but on reflection I had turned up at a new location (miles from my last location), turned it on, pressed the OK button and then turned it off in a pretty short amount of time. I now usually sit down for lunch, turn it on, make lunch, press the OK, make a brew, eat lunch, pack up, check Spot and if all OK - turn it off, back into pack. If you did this at each meal I would be surprised if any messages were lost (subject to not being underground or in a deep canyon with poor satellite view).

I have also found that the Spot tracking occasionally misses a fix or put a spot miles away - but hey so does the GPS sometimes (if your GPS doesn't automatically exclude these points from your view).

Thankfully I have never had to test the SOS component but I am confident that the device will work as expected (subject to batteries, view of sky etc). It wont be my only means of communication so I am happy that it provides one means to alert folks of my situation.

I suggest next time you do the test turn on your gps and Spot at the same time - wait for the GPS to get a good solid signal (8+ satellites or +- 5 metres) and then record both a waypoint and a Spot OK (if it says it has a fix) - then compare them when you get back home. That might help us to understand if its a GPS availability/sensitivity problem or a "messaging" problem or a combination of both.

Cheers - Phil

[taswegian]

South Aussie Hiker is correct regarding cloud - has no effect on the GPS signal and should not affect the location.
I was told SPOT was not for Tasmania due to its relative inaccuracies. But that was a while ago when they first appeared but I can't see why it would be different now.
As explained by South Aussie Hiker regarding the paths/ orbits SPOT satellites take. If they are a low orbit then the signals would get degraded and in some places would even block some satellites.
Also the 'maths' has a battle calculating accurate fixes from low intersecting lines (signals) and the room for error is large.
You can't make a silk purse from a sows ear if you get my drift.

Also what is a 'lock' for a Spot may be far different to a 'lock' for a Garmin. Depends on the specifications (acceptable solutions) hardwired into the brains of each device.

One thing that affects any GPS and also communications gear is the sun activity. Sun activity will over the next few years cause some headaches in many areas of our lifestyles.

The sun has been rather active lately and may also account for some odd things happening. (talking electronics here - not peoples behaviour)
And no - I am not tugging your chain - if you doubt then Google 'coronal activity and gps' and if you want detailed explanations read on.

[photohiker]

Also what is a 'lock' for a Spot may be far different to a 'lock' for a Garmin. Depends on the specifications (acceptable solutions) hardwired into the brains of each device.

GPS's lock with a minimum of Sat's and then fine tune the location as more satellites come online. You can see this on your Garmin when you first turn it on by watching the number of Satellites and the accuracy in metres. There is no reason to suspect that the spot works any different although you are correct in saying that we cannot see what it is doing, it's a bit of a black box in that regard apart from the GPS 'lock' light.

[South_Aussie_Hiker]

Just read the user manual for the SPOT 2. IMHO, the way the product is designed combined with the instructions has potential to be very confusing. I'm happy to be corrected if I've interpreted any of the following incorrectly...

It says the GPS light flashes when it is LOOKING for GPS position OR if it has a fix. WT *$&#? What that translates into for me... flashing GPS light really means jack ****. It might know where you are, or it might still be trying to work it out.

As for the message light... once the GPS knows where it is and starts transmitting, the message and GPS lights flash in unison for 15 seconds. But then it says after the 15 seconds, the message light will continue to blink. Then it supposedly sends the message another two times in the 20 minute period. And then, when that 20min message cycle is complete, the message light will keep on blinking for one hour after the 20 minutes finished.... WT *$&#???
So a blinking message light could mean it has just sent the first of the three messages, or it's somewhere halfway through the 20 minute sending cycle, or it finished sending 55 mins ago.

Wouldn't it make more sense if:
1. GPS LIGHT
flashing green - trying to obtain position, leave me alone to do my thing
steady green - position obtained
flashing red - can't obtain position
2. MSG LIGHT
flashing green - currently in 20 min message cycle, leave me alone to do my thing
steady green - message cycle successfully completed
flashing red - message can not be sent

Is it possible, rsser, that you saw the blinking green message light and assumed it had done it's thing (when it might have only just started the 20 min message cycle)?

The fact remains that in cloud in a sample of 2, one msg had the coords out by about 400m and the other msg wasn't transmitted within 20 mins.

I guess the catch here is to get the reliability of the three messages in 20 minutes, you need to wait 20 mins after the gps and msg lights blink in unison for 15 seconds for the first time, not 20 minutes after the device is first turned on.

If there's anything to be annoyed about rsser, I'd say it's the stupid design of the lights and the even more confusing user manual!

[photohiker]

You could be right SAH, I notice the manual is somewhat dumbed down to remove detail, and could be clearer. It smacks of someone trying to write a multipage manual for something simple and landing up without a clear message.

This is the take home message I have from the manual:

Green – The GPS light blinks green while SPOT sees the GPS satellites and is looking for a GPS location. Once the GPS location is obtained, the GPS light and Message Sending light blink green approximately 15 seconds to notify you that your message was sent with your GPS location.

Red – The GPS light blinks red if SPOT doesn’t see the GPS satellites and/or can’t find your GPS location. You should move to a location with a clearer view of the sky.

So the GPS light will flash red if the spot has tried to send a message but has not got GPS lock. Not rocket science, but usable. I'd prefer a small LCD with some status info on it, but what we have is adequate in my experience.

I carry mine on my shoulder strap and occasionally watch it to see that it's working (on) and happy (flashing green) as I walk. I use the tracking feature, (really cannot understand why you'd buy one of these and not use tracking), so I do get relevant feedback from the Spot throughout the day. I have rarely seen the GPS light run red, only time I can remember is after picking the pack up when it had been on the ground on top of the spot...

[rsser]

Thanks; v. instructive observations. I'll persist given this added info but remain concerned about the inaccuracy of the fix.

I think that the whole op smacks of amateurville as far as customer support and concise user info goes (I won't bother you with the details of the difficulty I had registering mobiles for SMSs, the dead mailto on the Aus website and the incompetence of Spot in 'tracking' my emails on the matter).

My next step in due course will be to move to a Satphone as unit prices and sizes come down. Some are avail. with inbuilt GPS; dual band(= includes mobile pone); Telstra has a project underway to incorporate a proper PLB; we now have 4 sat comm constellations servicing Aus and call rates must come down.

[rsser]

A competitor for Spot Connect with more functionality:

http://www.yellowbrick-tracking.com/?p=1327

Not exactly cheap though.

[Ent]

Hi

I to looked long and hard at various emergency communication devices but the deal breaker and maker was a PLB is a dedicated locator beacon. This means it has a few tricks that the Spot does not have. The first it does not need a GPS fix to get a reasonable accurate position as the system will triangulate to within a searchable area. In fact the base model PLBs do not support a GPS location. Secondly those with a built in GPS should match the Spot for location accuracy. Third and a big one is a PLB sends out a homing signal while the Spot does not. This helps in difficult terrain such as steep valleys. Finally Spot is an adjunct to a satellite phone system while a PLB links into a dedicated emergency system.

I agree that the Spot tracking and increasing ability to send out custom text messages plus you can replace batteries makes it tempting but if the purpose is to get help in the most reliable way then a PLB is a better device.

As for GPS accruacy. All GPSs are not created equal. My Garmin 62S kills any other GPS I have had. In a deep and steep valley some GPS I have used have not got a fix while the Garmin 62S has not let me down. Now on user friendly software the Garmin 62S is not so good. Great hardware rather indifferent maps and user interface.

Cheers.

[Nuts]

If the spot was tracking the searchers would know you were in thee whether or not you were able to set off the beacon .. i'm tending to think they both are much of a muchness, at least spot has other uses and has been successful in practice as a plb. I'm sure a miss hit exists somewhere? Not cheap though.

[tasadam]

Well, I thought enough time had passed without response, so here is this...

On 9th August 2011 at 11:24 am, I went to this address
http://au.findmespot.com/en/contactus/index.php#

I completed the form...

Email address and phone number edited out.

online-enquiry.JPG (86.92 KiB) Viewed 11435 times

The full text of the online enquiry is as follows:

Hello. I am one of the admins at http://www.bushwalk.com and I write to you to give your company an opportunity to clarify the claims being made by a SPOT 2 owner on the forum. Feel free to take a look here –
viewtopic.php?f=15&t=7369
Should you not wish to join the forum to reply directly, feel free to respond to me via email where I will post on your behalf.
I am sure that your response will benefit many people, not just the members of the forum.
Thank you and regards,
Adam.

And that brought absolutely zero response.
Not entirely inspiring us with confidence in their willingness to publicly discuss the features and reliability of the product, does it?

Having said that, I think a lot of responses are on the right track - have the unit turned on for long enough before using it, ensuring a good number of satellites have been picked up. My thoughts anyhow.
FWIW, I carry a GME MT410G PLB.

[ninjapuppet]

nearly 2 weeks and no reply? hmmmm..

Please correct if this is misinformation but I have heard during conversations that PLBs use military satellites while spot2 uses civilian satellites for signalling the messages across. There was a general consensus among us that military satellites were a higher spec than those of the civy sats, but please take this information with a grain of salt as I have done no research into it.


however I do have all 3 - spot 2, GME PLB and a satellite phone and here are some of my personal comments:

1 PLB
I have had a GPS equipped PLB for a while, and when activated in November last year, please note it took 3 HOURS for the helicopter to find us. Helicopter came near us and could be heard within 10 minutes but hovered around for another 2H50mins looking for us because the GPS reading it gave the pilot was out. Finally we made a smoke signal big enough that they could see. waiting 3 hours was a real big surprise to me.

2 SPOT
After my friend's spot 2 failed on first use here: http://bushwalk.com/forum/viewtopic.php?f=15&t=6507&p=79578&hilit#p79547. This obviously tells you there is a Quality control issue here. However to be fair, his replacement model worked well so I have also gotten one just for the ease of sending OK messages out. As mentioned they do sometimes fail sending out SMS but these dont worry us too much as I have told my family that if no messages get sent out, dont panic and assume i'm dead right away. my perception is that it does not seem as robust and well built as the GME plb. PLB's batterys is like throw into your pack and forget. with spot, i have to be mindful of battery life with OK messages incase i need to send out an emergency signal.

3 SAT phone
These are cream of the crop for expeditions. we were able to get accurate mountain weather forecasts, send sms, and even call in a helicopter for another party to get down a mountain (paid for ofcourse, not SAR chopper) when they were running low on food. However I only use prepaid and only when going away on big trips, so dont take this with me most the time. Calls are expensive so I use it as just to send SMS to a family member who has been advised to regularly check their mobile. SMSs also sometimes have failed to be sent if i have been in valleys. I know if they have been sent easily because i get a SMS relply back from family.

Most expeditions are not done alone so it would make sense for different members of parties to carry 2 of the above in the group.
for walking just in nsw, i'd likely carry a spot2. I do trust the PLB's signal more than my spot 2, but SPOTs light weight, small size and the occasional OK message that gets thru makes up for it's small tiny risk of not being able to work.
if i'm going remote, i top up my satphone account and also bring along the PLB.

I dont know all the technical ins and outs, but from my own experience derived from my own usage, my Spot is at toy that stays home on serious trips.

[ninjapuppet]

just to add, I dont know whats it with that homing device on the PLB, but it certainly didnt work for us. not sure if its because our SAR chopper didnt have the device to detect the homing signal, or if the signal is weak, but hearing a chopper hovering around nearly 3 hours looking for us made us very very nervous.

[rsser]

The homing signal is just another radio signal; useless if the searchers don't have a directional antenna to pick it up.

AFAIK a PLB without GPS can mean a search radius of a km or more cp. with GPS which can get it down to metres.