GPS and PLB advice please

[Nuts]

Spot fails when wet...read Andrews trails and tracks blog in NZ.
GPS....

Actually not correct. The Spot2 survived a couple of river swims without fuss. The problem I had was losing it when it was ripped out of its cover on my pack shoulder strap in heavy scrub, due to inadequate tethering.

A related problem was an agreement with my wife that she would alert S&R if she didn't get an "I'm ok" message from me for 24 hrs. We have since modified our escalation protocol and I will use the tracking function for status updates.

(It was my iPhone that died in the water - it was in a press lock bag, which leaked. I have since bought a Lifeproof case for the iPhone)

The spot 1 didn't come with a case, just carried it around sealed in the top compartment of the pack... seemed to still track ok, tracking points never really needed to be 100% I figured. The spot connect came with a fancy strap pouch, I lost the spot connect and bought a spot2 (which.. if I carry it will be back in the pack lid and waterproof by the sounds of it) Don't see the reason to need it on the shoulder strap so long as contacts dont panic at a skipped few signals?

[colinm]

I don't really want to come across as biased towards Spot but it does suit my requirements and has worked as advertised for me. This doesn't mean that it is perfect or the best system for others but why this continual anti Spot rhetoric? Spot is going to fail when needed (Wayno & Strider). This is not the experience of many thousands of users. Don't rely on a few negative reports. Like many comments on the unreliability of Steripen it may be user failure to read and understand the requirements to operate the unit correctly.

As one of the people who owns a steripen, and has experienced its failure, and has been derided by MarkF for being too stupid to use it, and who has also owned a Spot2, and found its performance lacking, I thought it might assist the conversation to quote a reply I got from Spot technical support (RE: Disappointing coverage. [pfCase:57515, pfTicket:5068773]) on 6/10/2010

A few points to take into account are:

1) If you are operating a dedicated GPS device within a foot or so of the spot unit the signal from the spot unit can be scrambled.

2) Environmental blockage is still an issue with the spot 2 unit, it does need to have a clear view of the sky. The unit will work harder in harsher conditions to transmit but if you are in heavily treed or mountainous terrain chances are you will miss some tracks.

I'd particularly like to draw your attention to point 1: you can't expect a Spot to transmit if you wish to operate a GPS simultaneously.

Now, I accept that this may not be your use case, but as for "work[ing] as advertised" ... really? No.

Having asked around, I have come to the conclusion that this interference is a symptom of the Spot2 transceiver being improperly shielded. Given this, I have no confidence in its ability to perform as advertised. I note, further, that nowhere in any document I read prior to purchasing the device was this "scrambling" mentioned. Furthermore, I have no reason to suppose that other devices, as yet unenumerated (say, smartphone?) won't also "scramble" the transceiver output. Given this, I conclude that I have no way to qualify the likely failure modes of the device.

In view of its unreliability, I immediately retired my Spot2, cancelled the (expensive) ongoing coverage contract, and have left it in a box somewhere.

My opinion: Waste of money, completely unreliable, not fit for any kind of emergency or other situation in which loss of messages could have a serious impact on safety.

Colin.

[colinm]

It's worth mentioning that "operating a dedicated GPS within a foot or two of the spot unit" would include operating a real PLB containing a GPS in that range. If my hypothesis as to the improper shielding of the transceiver is correct, it may also work the other way, with the spot interfering with a dedicated GPS, or perhaps PLB. I do not know that this is true, but since it is possible, and potentially catastrophic, one would be well advised to turn off the spot in the unfortunate case that one had to trigger a PLB, or in the normal case that one wished to use one's GPS.

In my case, it was not a case of spot-or-PLB. I carried both. Now, I think, I am safer and certainly financially better off carrying just the PLB.

[Nuts]

Hi Colin, did you notice this interference in use- prompting the email to Spot?
(maybe having the spot close to gps (< a ft or so) could explain some observations of some spot tracking signals being off course?)

Do plb's, plb's with gps interfere with GPS or vice-versa?

[simonm]

Thanks Colin,

That is good info.

[Mark F]

colinm - I am sorry if you think I called you an idiot. I am not able to read that interpretation into my posts but I suppose you have recognised the issue. I merely commented from my own experiences of the two devices and in assisting others to sort out issues with steripens.

For the record I do not use a Spot for tracking. For tracking I use my gps which is better designed for the job. I save the Spot battery life for sending one or two messages a day. I place the Spot in an open location and allow it to run though its full OK message routine just like the manual advises - it has worked so far. The only failure (out of 200+ messages) has been in a very deep, steep and heavily timbered gully.

I am not surprised that plbs, spots and, no doubt, mobile phones interfere with each other and will interfere with a gps - they all have quite high power radio transmitters (not a gps) and very sensitive aerials. I am actually surprised that the distance between them only needs to be 30 cm or so.

[colinm]

Hi Colin, did you notice this interference in use- prompting the email to Spot?
(maybe having the spot close to gps (< a ft or so) could explain some observations of some spot tracking signals being off course?)

Yes I did. The crux of my complaint was "although the device was powered on, carried on my pack straps, for the whole 7 hours, you can see that it only managed to send less than a dozen track messages." I mentioned that my GPS (carried on the other pack strap) managed to construct an accurate track, and the Spot guy picked up on this.

Do plb's, plb's with gps interfere with GPS or vice-versa?

I have no reason to suppose so, but I do not know. To be clear: either the satellite transceiver or the GPS receiver of the spot was interfered with by the operation of a Garmin Cx operating in its proximity. The garmin is a passive receiver of GPS, some electronics to drive the 'gui' and display, the card storage, a compass and an altimeter. None of that should have had any impact on the spot, but it did.

Here's the issue, IMO: If the GPS component of Spot was failing or the transceiver was failing (assuming there's a feedback path (as to reception, which I think there is) then it should have been signalled in some way to the operator (me.) Neither was signalled to me. The device failed in an unsafe way. Such a device has no place in my emergency or signalling plans.

It may be sufficient to be informed of the spot failure mode in documentation, before the event (which I was not.) But the very mode of failure suggests the possibility of other similar failure modes, and this suggests strongly to me that the device is not one on which I would place any reliance.

Colin.

[colinm]

colinm - I am sorry if you think I called you an idiot. I am not able to read that interpretation into my posts but I suppose you have recognised the issue. I merely commented from my own experiences of the two devices and in assisting others to sort out issues with steripens.

Mark, if I told someone they were incapable of putting a cylinder into a container of water and rotating it for 90s while holding a button, then interpreting a binary LED colour signal, you may be sure that I would be calling them an idiot. I don't see any other interpretation, but then again I am not in your social circle, and do not know what constitutes competence within it.

For the record I do not use a Spot for tracking. For tracking I use my gps which is better designed for the job. I save the Spot battery life for sending one or two messages a day. I place the Spot in an open location and allow it to run though its full OK message routine just like the manual advises - it has worked so far. The only failure (out of 200+ messages) has been in a very deep, steep and heavily timbered gully.

If it were placed at some distance from any other electronic equipment, then you would certainly not experience the failure I experienced. The device is advertised as being able to track, there is no mention of its susceptibility to interference by nearby RF-passive devices, and it is apparent that it cannot do this in all cases. I therefore reject the proposition that it functions as advertised.

I am not surprised that plbs, spots and, no doubt, mobile phones interfere with each other and will interfere with a gps - they all have quite high power radio transmitters (not a gps) and very sensitive aerials. I am actually surprised that the distance between them only needs to be 30 cm or so.

I have never experienced a mobile phone failing through proximity to another mobile phone. I was surprised, and dismayed, by the spot failure. The best ad-hoc diagnosis I have (from a hotshot EE+ham) is that the spot has an improperly shielded transmitter intermediate phase(?)

BTW, and FWIW, I wrote the transmit power monitoring and control subsystem for a satellite groundstation, those things were really powerful - the linear amplifiers had many dB of gain, as I recall, and the signal path was along strange circuits made out of gold-looking Al pipes about .5cm diameter which were bent in strange gentle curves ... wave guides? Anyway, I didn't expect, have never experienced, and do not accept, that a spot should be derailed by a nearby GPS.

I was surprised. Equipment only surprises me once, then it goes in the bin.

Colin.

[Mark F]

My apologies in advance for thread drift but there are some issues other than press a button and stir. For several models of Steripen there are a couple of issues that can cause problems and I have met several people who think their unit is faulty but proven not to be. One is that some models have a delay while the electronics initialise - I think this is about charging up a capacitor to deliver the current required to start the unit - like a fluorescent tube. If you dunk the steripen too early it doesn't work. Another is if using rechargeable CR123 batteries you need to be very selective in the brands you buy - they must be high discharge types and this isn't usually documented when buying the batteries.

PS. As I understand it Spot gets the GPS lock before it transmits and it only transmits in very short blocks. Also most of these devices (mobile phones and others with internal antennae) use fractal based aerials and thus the wave and squiggle patterns that you see inside the case.

Last edited by Mark F on Sun 16 Jun, 2013 6:38 pm, edited 2 times in total.

[Ent]

I would imagine that the GPS satellite signal is very weak so any electronic device that leaks radiation from its circuits could be a problem. But having said that I would have assumed that most GPSs are well shielded.

The point with the Spot is it needs a GPS to be found. Look at the antenna on say a Garmin 62s and the one in the Fenix and the better the antenna the better the reception. A Spot antenna is internal. Even my Garmjn 62s can be spoofed in deep valleys and as mentioned the Fenix can not get a signal. No idea on the quality of the Spot's GPS receiver. A PLB does not need a GPS signal to be found. A GPS equipped PLB well improve accuracy and hopefully speed of rescue. Also a PLB sends out a homing signal, something a Spot does not.

Cheers

[Nuts]

Thanks Colin. I'm not sure the situation will be an issue for me but good to know nevertheless.

[paddlpop]

@Andrewbish
Apologies if I got confused between spot and iPhone getting waterlogged.....it was a while since I read the blog. My bad

[sthughes]

I think it is important that we differentiate a few things regarding the Spot system. A failure to transmit an accurate "breadcrumb" track is quite different to a failure to transmit an "SOS" message.

In the "Tracking" mode the Spot powers up every 10 minutes, checks your GPS location (if possible) and transmits the last three know GPS locations, then powers down. If no GPS position can be found at all of these last 3 times no data will be sent, as will be the case if the Globalstar phone network can't be found. This means that if at each of the 10 minute windows there is no GPS lock then nothing is transmitted.

When the "Check in/ok" function is activated the device powers up and tries to send the message with your position 3 times over a 20 minute period. But if it cannot get a GPS lock it does not send anything at all!!

When the "Help" function is activated it powers up and tries to send the message with your position every 5 minutes for a one hour period. If no GPS lock is found it sends the message anyway!

When the "SOS" function is activated it powers up and tries to send the message with your position every 5 minutes until the batteries go flat or you cancel it! If no GPS lock is found it sends the SOS anyway!

As anyone who has ever been a bit of a GPS "enthusiast" will tell you, if you turn on your GPS in tough terrain, with tree coverage, while still moving, and only give it a short amount of time to get a lock before turning it off again - it often won't work. But if you turn it on and remain stationary for a few minutes (or hours in this case!) it usually finds itself eventually.

So to summarise:
SOS is more reliable than Help!
Help is more reliable than Check in/ok!
Check in/ok is more reliable than tracking!
Tracking is unreliable in poor conditions!

Hence the idea that a Spot failing to check in/ok or especially to provide sufficient tracking points ordinarily, is a very different scenario to that of an emergency! On top of this assuming you are not solo walking, normally it isn't too hard to imagine a party member being able to find at least a partially clear view of the sky nearby where the device can be positioned (indeed this would be ideal with a PLB as well).

[sthughes]

And to add to that, regarding the tracking performance:
There is no way a Spot will ever track like a dedicated GPS. A dedicated GPS is powered up continuously and saves the data internally. For a Spot to track as well as that it would also need to be powered up continuously (both GPS and Globalstar chips remember), which is just not possible without eating batteries like they are going out of fashion. On the set of 2 AA lithium batteries in my Spot at the moment I have had 9 days of tracking and a few check-in/ok points transmitted, and still no low-battery light. To put it in perspective, in the same 9 days my Garmin Rino has eaten 4 Eneloop XX 2500mAh AA's as well as it's Lithium ion battery pack - and it has not had to transmit a single thing to a sat phone network!

[Ent]

And to add to that, regarding the tracking performance:
There is no way a Spot will ever track like a dedicated GPS. A dedicated GPS is powered up continuously and saves the data internally. For a Spot to track as well as that it would also need to be powered up continuously (both GPS and Globalstar chips remember), which is just not possible without eating batteries like they are going out of fashion. On the set of 2 AA lithium batteries in my Spot at the moment I have had 9 days of tracking and a few check-in/ok points transmitted, and still no low-battery light. To put it in perspective, in the same 9 days my Garmin Rino has eaten 4 Eneloop XX 2500mAh AA's as well as it's Lithium ion battery pack - and it has not had to transmit a single thing to a sat phone network!

Except the UHF "messages" and the screen display

Great write-up as it explain a few issues with Spot on tracking performance compared to likely emergency use

Rather amazed on it needing a GPS lock to transmit "I am ok" logic design as the message is often more important than the location. Experience with GPS in deep valleys confirms that GPSs are much better if left on and tracking. The Fenix was not too bad tracking once it found a lock but on start up it was a non event. With my cobbled together solutions such as IPAQ and C/F GPS you might as well throw the units away if you started them up in a east/west valley. The iPhone does not fair too badly but not perfect. The Rino is quicker than the 62S and both are quicker than an Extrex 10 but an Extrex 10 is no slouch so perfectly acceptable.

The Spot appears to be compromise of battery life to performance and size. I am tending nowadays to classify things into toys and tools. A tool is something that just works while a toy is something that can be very handy but not to be relied upon. Does not mean a toy is fragile just has some vital logic flaw. Bit like my Spark 300 headlamp. Absolutely brilliant (excuse the pun) and nearly indestructible but a poor logic assumption by the designers to get full light from fading batteries and when it can not then stop is not very friendly. The Zebralight logic is to do the same but when power management can not get the brighter settings then it just does its best and a dim light is better than no light.

Spot, tool or toy? That is for individuals to make their mind up. For me it is a very useful toy.

Cheers

[GPSGuided]

Spot, tool or toy? That is for individuals to make their mind up. For me it is a very useful toy.

+1. And with a significant ongoing cost.

[Nuts]

Haha, toy or tool. Must be an 'enthusiast' argument Good explanation stH.

[colinm]

I think it is important that we differentiate a few things regarding the Spot system. A failure to transmit an accurate "breadcrumb" track is quite different to a failure to transmit an "SOS" message.
...
Hence the idea that a Spot failing to check in/ok or especially to provide sufficient tracking points ordinarily, is a very different scenario to that of an emergency! On top of this assuming you are not solo walking, normally it isn't too hard to imagine a party member being able to find at least a partially clear view of the sky nearby where the device can be positioned (indeed this would be ideal with a PLB as well).

My experience wasn't a failure to transmit an accurate breadcrumb, but a failure to transmit at all, over 7 hours.

As far as I can ascertain from the tech, the problem was one of transmission being 'scrambled', this is consistent with the observed behaviour - spot did not report failure to transmit, as one would have expected it to if it was unable to acquire GPS, but just kept on acting as if it was transmitting.

So, assuming that is the case, failure would extend to transmission of any message. I'm guessing, though, because this 'scrambled' mode is as far as I'm aware, not advertised.

Toy, in my view. And pretty expensive one, at that.

Colin.

[Nuts]

Yes, you would expect a warning, if not through a feedback signal on the spot device then at least in the manual or various instructions.
I'm sure that in an emergency you would have taken it off the pack strap so maybe not an issue if it had come to an emergency.
They are all 'toys'.

[roysta]

oh I love my inReach

[LandSailor]

oh I love my inReach

Agree. Delorme Inreach is great if you want to send/receive msgs but gets a bit pricey if you want to include tracking.
And as GPSGuided mentioned, its expensive on an Australian plan, a basic US plan is much more cost-effective.

I sometimes use it to get weather forecast sent to me. Tried to find a way to automate this process but doesnt look like its possible.
Have to rely on the wifey to login to my Inreach page and send it to me.

[GPSGuided]

Is there any issues with the purchase of InReach device and subscribing to a US plan for an Australia based user? I know that it's not the best arrangement for a PLB. Not sure about InReach.

[simonm]

Well this has been a worthwhile debate for me. I have had a re-think about what I want from a piece of emergency equipment, and that is that it has the greatest chance of getting me help when I most need it. So the winner for me is a PLB . I think it was Ent's statements of tool or toy that made me realise the ability to inform people I am ok along the trail is a nice feature (toy) and possibly helpful in an emergency situation but essentially at the end of the day I just want to be rescued (tool) if I should need it, and the PLB is the better bet - not perfect, but nothing is, but gives me more confidence that it will work if I should need it. There were just too many variables with the SPOT in the end for my liking.

So thanks all for changing my mind . Now the question will be which PLB?

[GPSGuided]

Now the question will be which PLB?

I just went through this and went with Ocean Signal's PLB1. It's the smallest and lightest unit out there at this time. To me, larger units are more likely to be left at home or in the car. However, if a saving of around $100 over 7 years (battery life) is relevant, then there are some larger older models. Trek and Travel in Sydney amongst a few others stores carry PLB1.

Last edited by GPSGuided on Tue 18 Jun, 2013 8:29 pm, edited 1 time in total.

[LandSailor]

Is there any issues with the purchase of InReach device and subscribing to a US plan for an Australia based user? I know that it's not the best arrangement for a PLB. Not sure about InReach.

Im not sure what the situation is now. I got my InReach before Delorme set up a dealer network in Australia. So Ive been on the US plan since then.
Ive had no problems with it at all although Im not a heavy user. I got mine at rei.com.

[GPSGuided]

Ive had no problems with it at all although Im not a heavy user. I got mine at rei.com.

Thanks! REI is a great source for outdoor items.

Also whilst surfing on outdoorgearlab.com, I note that the transmission power of these devices varies. A PLB transmits at 5W while InReach and SPOT transmit at 1.6W and 0.4W respectively. Not sure how the frequency of transmission affects signal delivery, but I'd think 5W has more chance of getting through with all else being equal.

http://www.outdoorgearlab.com/Emergency ... s-Reviews/

[vicpres]

At the Australian Search and Rescue Forum meeting last week, AMSAs view was that the preferred emergency device for land based use is a GPS enabled PLB. A signal from such a device will be picked up a satellite within about 10 minutes and AMSA will be notified pretty much immediately, no matter where in the world the PLB is activated, and appropriate action initiated. Note: If your home country is Australia, only buy a GPS in Aus. The accuracy of a PLB with GPS is minimum of 120m. A non-GPS unit is as accurate but depending on field conditions can take up to 5 hours to be picked up.

With a SPOT however, notification to S&R relies on a message being sent to someone, who will then need to read and react. If that person is unavailable for any reason ..........SOS messages sent from a SPOT also take longer to be picked up/sent, you need to pay for an expensive subscription to a US based service provider too, and while they monitor SOS messages etc they are not a dedicated S&R organisation.

AMSA also advised that beacon technology is improving rapidly and next generation devices are in the design pipeline. New features may include the ability to send a basic message e.g. to state what the emergency is.

[photohiker]

With a SPOT however, notification to S&R relies on a message being sent to someone, who will then need to read and react. If that person is unavailable for any reason ..........SOS messages sent from a SPOT also take longer to be picked up/sent, you need to pay for an expensive subscription to a US based service provider too, and while they monitor SOS messages etc they are not a dedicated S&R organisation.

Whilst I have the highest regard for AMSA, I have to say that all S&R operations are based on "a message being sent to someone"

Here is what Delorme say about their "message being sent to someone" service:

Behind every inReach is GEOS. Behind GEOS is the IERCC — formally known as the International Emergency Response Coordination Center. Send an SOS message through inReach, and it goes directly to the IERCC. More specifically, it goes to a secure underground bunker located north of Houston. It has redundant electrical grids, generators, and a potable water supply from an underground well. In short, complete self-dependence if the outside world “goes away.”

The team at the IERCC is staffed and ready 24/7, 365 days per year, with SAR Mission Coordinators and Duty Officers. As soon as they receive your message, they’ll track your device and notify emergency contacts and responders in the area — they’ll also stay connected to provide updates on your location or to communicate with you. As soon as you activate your inReach, you have full, free access to the IERCC through GEOS SOS monitoring and emergency dispatch. How’s that for comforting?

As I understand it, Spot uses the same or similar service.

[findbuddha]

Do you think it would be worth waiting for the next gen devices? Any idea if the messaging function will only be available during an emergency broadcast? Or will they capable of the 'don't worry, I'm just running late' type messages as well?

Cheers

[GPSGuided]

There'll always be the next generation. And the next gen device won't save you from the present.