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PLBs and SPOT Beacons

I’ve found it interesting to read about the search in the Waitewaewae catchment area of the Tararuas over the weekend [1]. Summarised, a police officer was overdue when setting up a SaR exercise which had been intended for next weekend. He and his dog were reported overdue at 9pm, about 10 search teams went in the following day, a location signal was received at 2.40pm, and an Air Force Iroquois winched him and his dog out of dense bush shortly afterwards. It turned out that his intended route had been taking longer than estimated, being very wet and with lots of tree-fall. Despite being relieved to be lifted out, he’d be prepared to be stuck for longer.

What I find most interesting is the media’s reporting of his use of a “Spot-Me” device, although I think it’s far more likely that they meant to say he was using a SPOT Beacon [2]. (Google tells me that a “Spot-Me” device would be a kind’a dumb thing to take into the Tararuas [3].) The technology in use is interesting because whilst PLBs and SPOT Beacons both report positions and can be used for locating a person, they work differently and are generally intended for different purposes.

Unfortunately the reporting’s been unclear and inconsistent about exactly what technology was in use here, but it seems clear that a SPOT Beacon was in use, although a Herald article [4] from this morning specifically states that he also had a “Personal Locator Beacon”, which probably means a 406 MHz Personal Locater Beacon (PLB), the current standard for requesting a rescue. Some sources (such as that article) state that both beacons were activated on Friday night despite no signal being received until the following afternoon, whereas other sources (such as this article from the DomPost [5]) state that the “Personal Locator Beacon” wasn’t activated until Saturday afternoon. [Edit: Thanks to Heather, there’s now a more complete and detailed description of the sequence of events in the comment thread below [6].]

Whatever actually happened, it’s a nifty excuse to discuss the differences between a SPOT Beacon, and a 406 MHz PLB. SPOT Beacons are sometimes touted as drop-in replacements for PLBs, but they’re really not. Despite having learned informally, I’m not an expert on the differences between these two devices, so if anyone notices any errors or omissions in what’s below, please feel welcome to leave a comment and I’ll do my best to correct things. (In this respect, thanks Craig [7].)

Until very recently it was normal to head into the bush without any emergency communications technology at all, except perhaps a mountain radio and for various reasons they were few and far between. It’s no less safe to do so than previously simply because new technology is now available. Certainly in New Zealand’s back-country, safety is the responsibility of those taking the risks. In this case it’s hard to know from limited reports for how long the officer would have survived on his own, but at the very least it sounds as if he was prepared to survive for longer had he not been rescued so quickly, even if not in comfort.

The revolution with improving and more portable emergency communications technology is firstly that it allows for emergency assistance to be requested immediately when there’s an unexpected situation that’s either urgent (such as a head injury or possible secondary drowning) or otherwise means a party can’t get out by themselves. It also reduces the amount of time, resources and expense required for search and response services to locate someone prior to a rescue. For better or worse, this technology also makes it faster and easier to locate and rescue people who are otherwise less prepared than they should be.

Despite having some similarities, SPOT Beacons and 406 MHz PLBs are different devices intended for different purposes. While a PLB is a device meant never to be used until an emergency arises, a SPOT Beacon is designed with an intent of leaving it switched on for lengthy periods of time to continually indicate one’s position to outside observers. To achieve this, a SPOT Beacon will regularly transmit position information (obtained via GPS) using the Globalstar [8] Satphone network. The associated service then plots these positions, as received, and makes it available through a website for people to follow. SPOT Devices provide a function to send pre-programmed “I’m OK” messages via SMS, and a popular use of a SPOT Beacon is to reassure people at home of where you are at any particular time.

A SPOT Beacon is not primarily designed as an emergency device, however. The emergency function for a SPOT Beacon is more of an appendage rather than part of the fundamental design. An emergency SOS button can be used to request an emergency response, but this signal is not monitored directly or officially by New Zealand emergency services. It gets sent to a company in Texas which then takes responsibility for notifying emergency services in the appropriate country of your position, and that you’re in distress. Batteries are subject to running out as a consequence of needing to leave the device switched on for the more primary uses, even though this might depend on how a person chooses to use the device.

Probably the biggest difference of SPOT Beacons, in an emergency situation, is their method of transmitting via the Globalstar Satphone network. The Globalstar Satellites are low orbit satellites, and consequently they cross any given localised part of the sky relatively quickly and therefore work most reliably when a large part of the sky is visible. Furthermore, a SPOT Beacon requires an adequate GPS signal to know its position if that position is to be transmitted. If the sky is obscured by terrain or otherwise (like if you’re in a deep hole or valley), satellites might not be immediately visible either for GPS, or for receiving transmitted messages.

SPOT’s technique of only working in one direction (transmitting to the satellites without receiving) also makes it impossible for the beacon to know if a particular transmission has been received. Except for an emergency signal which is transmitted continually, a SPOT Beacon will transmit a position 3 times, then it stops trying. In certain parts of the world this works better than others, and (sadly for us) New Zealand tends to be near the edge of the reach of Globalstar satellites meaning that satellites are more likely to be nearer to the northern horizon and obscured by hills or mountains. One response to this post [from Craig [7]] reckons that about 70% of SPOT Beacon positions tend to get through with typical use within New Zealand, compared with near 100% in Texas or California.

This is fine for the SPOT Beacon’s primary purpose of non-emergency situations, for which it’s reasonable to presume it unlikely that a person will remain in an obscured location for long, and it doesn’t matter too much if some transmissions aren’t received. If it’s been a while since a transmission managed to get through, however, and an emergency occurs, then it might not be practical to reach a location where the SPOT Beacon can either receive a suitable GPS fix, or adequately transmit a message.

PLBs, on the other hand, are designed to almost never be used, until there’s an emergency. As long as the device has been serviced properly, the battery shouldn’t be a problem when activated. A 406 MHz PLB will transmit to the Cospas-Sarsat satellite system, which includes both low-earth orbit and high-orbit geostationary satellites. The satellites are more visible and so it’s more likely that a signal will be received soon after activation. Unlike SPOT, if a PLB cannot obtain its position via GPS, the source of a 406MHz signal can still be derived over a period of hours by analysing the signal using a Doppler Shift technique.

The down-side of a 406 MHz PLB, compared with a SPOT Beacon, is that PLBs really are meant for emergency distress signals, and nothing else. They’re designed so a charged battery can be left inside for years at a time, knowing that it’ll work well if it’s ever needed. Then if and when something happens, you’ll have the best chance of getting a useful signal out, directly to the most relevant people and and irrespective of the availability of GPS. The device can’t be switched on for convenience beforehand to do other things, however, as is the case with a SPOT Beacon.

Generally if you activate a PLB (as with a SPOT SOS signal), you should expect to inconvenience many people and cost someone money. In New Zealand, it’ll nearly always be a combination of taxpayers’ money and often the voluntary time and resources of sponsor organisations and regular (but trained) people taking time off work. The good news is that you’re likely to be found and assisted from whatever bad predicament you’re in, within a matter of hours if weather allows. If it wasn’t activated it for a needless reason, the people involved will usually be happier to have helped out than not. Generally though, people are expected to prepare with the intent of not needing it for anything besides real emergencies, and that doesn’t include problems such as being delayed or inconvenienced behind swollen rivers, for instance.

In this particular instance the reports suggest that “It is not known why the technology signal failed”. Behind the scenes, if both devices really were activated on Friday night, it seems most likely that he was probably in a location without a clear enough view of the sky. Or perhaps the SPOT Beacon was activated initially with an I’m Okay signal and the PLB was only activated following day when it was clear that many people were out searching regardless. Maybe someone in the know who reads this can clear it up. Irrespective of the details, either of these devices has potential to succeed or fail, but a PLB is most likely to succeed in getting out an emergency signal quickly, or at all. It doesn’t make it a critical device to be carrying on any and every trip, but it’s always a good idea to consider what’s appropriate in the context of where one’s going, how many people are involved, conditions, and endless other circumstances that can affect things. Maybe you’d even be better off with a Mountain Radio [9].

Update, 1.44pm 9-May-2011: Shortly after posting this I noticed that this explanation has popped up on Stuff [10] as of a couple of hours ago, courtesy of the Manawatu Standard. The Police Press Release [11] about the incident also clarifies some things. It confirms that the officer was happily continuing (though possibly ‘happily’ is an overstatement), and presuming that the SPOT Beacon was transmitting the “I’m OK” signals based on the device’s instructions which indicated that only a clear sky was needed. It turns out they weren’t getting through, and he activated his PLB at 2.40pm on Saturday once he correctly inferred that overhead helicopters were searching for him, helping them to quickly find him and avoid a drawn out search effort. Given the search was already underway, it was a good idea to activate the PLB.

33 Comments (Open | Close)

33 Comments To "PLBs and SPOT Beacons"

#1 Comment By Amelia On 9 May, 2011 @ 5:29 pm

Good summary of the differences in the two products, and I’m glad that a SaR member was carrying multiple forms of communication and plenty of kit to stay comfortable for a while longer.

I was glad to hear that he had simply been delayed in getting out and wasnt injured.

#2 Comment By Mike McGavin On 9 May, 2011 @ 5:50 pm

Hi Amelia.

Yeah, it was ironic in some ways how this worked out. SPOT Beacons have been around for a small number of years now, but I guess it’s not been long enough for them to have been widely considered in a context of when it is and isn’t suitable to rely on them (at least in NZ conditions).

It’s still unclear exactly what measures were taken in this case, and it sounds as if he may have been slowed down somewhat unexpectedly regardless and could have just been hoping that a successful SPOT message might avert a search. But what leaps out to me with seeing this happen is that SPOT Beacons probably shouldn’t be considered a substitute for carefully setting intentions and expected exit and panic dates, especially when heading into situations when a SPOT Beacon might not be reliably transmitting states and possible changes in intentions. In other words, be really really careful about casually telling someone “I’ll be out on this date unless you get message X from my SPOT Beacon in which case I’ll be a couple of days later”.

At least with a cellphone, unreliable and impractical as they are for many reasons, if they do work then it’s likely you’ll know they’ve worked.

#3 Comment By Craig On 9 May, 2011 @ 9:57 pm

It would be interesting to get less contradictorary information on this story, about what was activated at what time etc. Via the mainstram media that is probably unlikely.

BTW, the SPOT devices use the GlobalStar network, not the Iridium network.

I believe that this case highlights how limiting one way communication devices are in an emergency situation. And inparticular, one way devices operating in a non-retransmitting mode. They send (3x) and forget, hoping that there is a satellite above you. If you need to depend on it, you want it re-transmitting persistently – not just three times.

As a SPOT (v1) owner I can say that I have found it to only get about 70% of messages out in NZ, but close to 100% in California and Texas. I’ll have more of idea about Europe in a few months. I believe this coverage difference may be due the use of the GlobalStar satellite network for which NZ is on the edge of coverage area, thus a a hill or mountain can be more
limiting than it should.

In emergency mode (not used and may it stay that way), or tracking mode the device will continue to re-transmit and the messages do find a satellite. Imperfect, but a trip plan plus track points over time are useful to alleviate parental concerns, and show rate of progress if someone is expecting you out at a certain time, or SAR need to piece together why you are not yet out.

But to sum up your point Mike, the 406 becons have three advantages – they are configured to talk to satellites that are directly above you, have a 406Mhz broadcast homing signal and are monitored by Search & Rescue in New Zealand – all three of which are incredibly useful in NZ context.

#4 Comment By Mike McGavin On 9 May, 2011 @ 10:28 pm

Thanks Craig, I’ve just fixed the Iridium/Globalstar reference and have also made some edits with respect to the 3x sending and the network edginess.

This afternoon I also noticed [11] from Saturday evening, which spells things out reasonably clearly when compared with the popular media’s accounts that are comparably confused.

I read [18] (under Redundancies, on a slightly biased comparison between SPOTs and EPIRBs) that the broadcast homing signal for nearby aircraft from a 406 EPIRB isn’t the same as the 406 MHz signal for satellites, but is transmitted (apparently in parallel) on the older 121.5 MHz band. Craig, do you know if this is correct for all 406 beacons, or is it just specific ones that that place overseas happens to be selling?

#5 Comment By Craig On 10 May, 2011 @ 12:19 am

At 2.40pm today his Spot-Me was activated alerting the Incident Management Team. His personal locator beacon was then also activated. Search and rescue teams were in the general area of the beacon and located him at a creek junction in the Waitewaewae River catchment, He and his dog were winched out by the RNZAF both tired, but in good health.

Interesting. What I would like to know, is what Satellite coverage differences occur between a SPOT and a 406, when both are in emergency mode, and what the timing differences are on SAR being notified of the activation. In this case, both worked more or less the same time. Not surprising. Both transmitted to satellites and both could see the sky….

I’m not sure if aircraft monitor 406Mhz in the same way that they used to (still can?) detect 121.5/243Mhz signals… I’ll try and find out more about the aircraft reception of 406Mhz beacons. Most aircraft probably still detect 121.5/243Mhz beacons (but satellites do not).

I remember [19] from a few years ago. The inability to test a device that can only send an emergency signal can be a real hassle when you are stuck in a snow trench waiting to not be rescued.

#6 Comment By Mike McGavin On 10 May, 2011 @ 12:43 am

Yes it would be interesting to compare. What sort of meta info about youself and your contacts do the SPOT people hold on their register for passing on in case you press the emergency button? Or do they just tell the NZ police that some guy called Craig is in distress at a certain location and leave it at that?

I’m fairly sure 121.5 is no longer officially monitored although every few months there’s another story about an old PLB activating in a rubbish tip, so there are definitely still be some aircraft out there that pick it up, but perhaps with diminishing coverage. The way I read that claim about 121.5 still being used in parallel was that if rescuers know that you’re in an approximate area then the 121.5 signal would help helicopters and the like to zero in more quickly and accurately than with the 406 MHz signal. I don’t know if this is correct for all 406 EPIRBs though.

#7 Comment By Mike McGavin On 10 May, 2011 @ 11:52 am

[20] about the flat battery case in 2004, which doesn’t require a subscription. It was too soon after the rescue to mention the flat battery, but the December 2004 NZLSAR News ( [21]) describes the PLB problems from the bottom of page 7. It’s interesting that the club they borrowed it from was reportedly in the dark, since at the time of purchase they’d been told that the batteries wouldn’t need servicing until 2005 (when they’d expired in 2001). So yes I see your point about being able to test, and clearly it’s important that you trust the supplier. At least some 406 EPIRBs include a Test button that does something, though I don’t know what they’re testing.

#8 Comment By Heather On 11 May, 2011 @ 8:01 pm

We are waiting for the required approvals to start a research project to compare the emergency function SPOT with 406 PLB’s. This is long overdue to take the guesswork out of these discussions. This response is my opinion and may not represent the opinion of organisations I am associated with.

Firstly there are positives and negatives for all communication systems. I recommend having 2 forms of different types of communication systems suitable for the trip. With hindsight the SPOT and 406 PLB were perhaps too similar although had some complimentary features.
This incident highlights some of the positives and negatives of both systems. On one hand the lack of OK messages led to the search being launched earlier than it would have if only a 406 PLB had been carried. On the other the search was made easier by having an OK message location on Thursday, and it was an OK message on Saturday that ended the search. When both the emergency button on the SPOT and 406 PLB had been activated only the SPOT message was received (see below), although the 406 activation may have eventually been received. However the homing system of the 406 PLB was detected and used in the final pick-up, this may have sped up the pick-up.
There is no evidence for or against whether the message would have been received from a 406 PLB activated in the places the OK messages were activated but not received. The satellite systems are completely different and different transmitting frequencies used. Without going into technical details there is some reason to believe that the 406 MAY be better at sending a signal through the canopy and the SPOT MAY have a better chance of the signal being received when the window of sky is restricted (eg canyons, deep valleys, against a cliff etc). However this is yet to field tested.
Like a registered 406 PLB the data about the owner is known about the SPOT units. This information MUST be registered in order to use the SPOT and there is the ability to add information trip by trip. This enables the information about party number, trip plan and key medical information to be at hand even if the contact can not be contacted – there is no delay while this info is followed up. An agreement exists giving the protocol to be followed in case of an emergency SPOT activation.
This incident involved the older v1 SPOT. A user of the v2 SPOT says it is a lot faster and seems to work a bit better in not so clear view of the sky but if he really wants the message to get out he will find the best place he can to put it and wait as long as he can.

From the person involved in the incident:
I had the SPOT satellite personal tracker (v1), an ACUSAT PLB (Personal Locator Beacon), telecom coverage cellphone, Garman 60CSx GPS, NZ Topo 50 maps of the area and Silva compass. I was not using the ‘tracking function’ rather I was periodically activating the OK message. I set off the SPOT (OK) message on 7 occasions only two messages got through. Although I had a view of the sky each time it is fair to say that the activations were under canopy, always wet, sometimes dense. One in a river bed wasn’t under canopy but was in a gorgey part of the river.

The 1441 OK message on Saturday was received immediately on the home computer by my son who immediately notified SAR Base and emailed through the message. An RNZAF Iroquois was in the immediate vicinity having just dropped a team in down river. SAR Base retasked them to pick me up.

Having seen a hut book entry that a search was underway I decided to activate both the SPOT and PLB so after the 20 minute OK cycle was completed I activated both devices (PLB and SPOT 911) at 1508 hrs. The Iroquois arrived back at 1520 hrs so I turned the PLB off at that time. It took me a little longer to turn off the 911 because I had forgotten how to do it.

RCCNZ received NO INDICATION of a 406 beacon activation. This was due to the short activation time and the fact that there were no LEO satellites in the area at that time and the terrain precluded seeing the geostationary satellite. The RCCNZ did however receive a call from SPOT in Texas at 1521 alerting them that a 911 activation had been made at that location. However the RCCNZ were also alerted by an aircraft flying overhead that a homing beacon was activating in the area (from the PLB). The Iroquois used their DF equipment to hone in on the homing signal which may have reduced the time involved.

The brochures on both the SPOT and PLB devices stress that for a successful activation the user must have a CLEAR VIEW OF THE SKY. That means one must see more than just patches of sky thru the trees. Dave Adamson at Adamson and Holland stress to his customers that they should have a 45 degree view of sky on both sides of the device, i.e. 90 degree view of the sky. I think that might be a tad excessive but it is still a good guideline.

Media Inaccuracies:
The PLB was NOT set off on Friday night, taking 12 hrs to alert RCCNZ.
I was NOT going to do 30 km off-track in ‘just over a day’.

CLEAR VIEW OF THE SKY means more that I thought.
Even with a PLB and SPOT I should have still taken a radio (either SAR HF or Mountain Radio)

#9 Comment By Heather On 11 May, 2011 @ 8:06 pm

Reply to a previous comment not directly related. The 121.5 PLB are NOT being monitored and should be disposed of correctly. Although activation of one MAY get picked up, unless they are flying low and close by the location is so inaccurate as to not even tie down whether it is North or South Island. A second chance pick-up is required to give more precision. This occurred Xmas 2009 when an old 121.5 PLB was activated by an overdue party. This was eventually picked up by a high flying plane but was so imprecise this was not linked to the search in progress. It was picked up much later on by the helicopter going in to check huts (which would have found them sheltering at the hut anyway).

#10 Comment By Mike McGavin On 14 May, 2011 @ 10:51 pm

Hi Heather. Thanks for forwarding such a comprehensive summary of what actually happened, and for filling in the gaps. It makes much more sense getting it from a first-hand source without the media filter. It’s good to know there’s a formal comparison study in the pipeline.

#11 Comment By Rick Percival On 16 May, 2011 @ 8:21 pm

I’ve used both the v1 and v2 SPOT devices, about a year for each. Have used the v1 device for about 40-45 nights of tramping and the v1 device for about 7-8. Every night I would send an OK message to my daughters to let them know where I was (being a solo tramper). While the v1 device is much less sensitive I have to say that I don’t think I’ve ever had a failed “ok” message. The problem with these SPOT devices seems to be that people expect them to work in all situations. They do need a decent view of the sky, have to face up and can take 15-20 minutes to send the message (acquire satellite and send etc).

Even with the v1 SPOT I have been successful in sending messages under light foliage, with the V2 I’ve been able to send a message in a deep valley and a limited view of the sky (Mid Waihone hut in the Tararuas for example). If I was to buy a device for a family member I would get them a PLB because of the one button and help will come mode, however, for myself, the SPOT device is 100% reliable and I mean 100%, not 99 or 98%.

I guess the problem with SPOT devices is they do need to be used right, facing upright, left for 20 minutes to send their message and have a bit of a view of the sky. I’ve heard people say that the SPOT has limited coverage in NZ but I think that’s completely untrue based on my experience (50+ nights, sending an OK message 2-3 times a day/night).

I’ve recently been through the exercise of deciding whether to stick with the SPOT or buy a PLB and have decided even though PLB’s have come down drastically in price that the SPOT is for me. I’ve used it extensively and am very satisfied with it’s reliability.

#12 Comment By Mike McGavin On 1 June, 2011 @ 12:28 pm

Thanks for the notes, Rick. I think the biggest thing that stands out to me is in not knowing for certain if a message got through. Not that an EPIRB is any better in this respect obviously. Out of interest with the experience you’ve had, would you rely on it much to send messages about being out late or significant changes of plans?

But yeah, I’m still speaking from experience of never having owned one.

#13 Comment By Robb On 4 June, 2011 @ 4:13 pm

Kia ora Mike,
I must write the subject of your post hits home after the experience I just went through with my son. I am definitely thinking of investing in an EPIRB device after that, and also as a backup to my frequent solo tramps. Though I did manage to get up to the open tops in the morning to use my cellphone, and EPIRB would have saved time, and allowed me to search the river further up without wondering how far, and how long, as the next decision was to climb in the growing darkness – which I did leave to late and thus my son spent a cold chilly night on the river, albeit well supplied. Fortunately it all turned out well, but has given me much to think about. Hope all is well Mike.

#14 Comment By Heather On 6 June, 2011 @ 1:21 pm

Hi Robb,
I have read your message and blog with interest and I agree your experience shows the need for 2 different forms of communication. For this trip you had 2 people and you were in an area not likely to have cellphone reception. So I would have considered a Mt Radio & EPIRB or SPOT for this trip. The extra weight is worth the advantages. In this situation you would have been able to pass an exact message to police search and rescue so they would have know what the level of urgency was and what sort of help to send. They would have known exactly what your intentions were and you could communicate with them when you found your son.
With solo trips a Mt Radio is less desirable because if you are injured it would be difficult to put up the long aerial. So for solos a cellphone & EPIRB or SPOT might be the best choice (although as is often the case where you were the cellphone has very minimal value as a back-up).
It depends on your trip as to the best form of communication. Mt Radios can be hired – see [9] – this link also has info for other areas. EPIRB’s and SPOT’s can be hired (try Bivouac, tramping shops or Hunting & Fishing). The Manawatu branch of MSC [22] has a couple of v1 SPOT’s for hire; these are free if you are also taking a Mt Radio.
If you had taken as you suggest a cellphone & EPIRB and had activated it in the late afternoon/evening the rescue co-ordination centre would not have any idea what the level of urgency was and what sort of help was needed. As such it needs to be treated as very urgent and if possible a helicopter would have been sent – this may have been in weather or visual conditions that put the searchers at much more risk than was warranted in this case. Otherwise a land base team would have been sent again in conditions at a risk level which may not have been warranted. If activating an EPIRB you need to consider the timing carefully as you can not provide any communication or cancel the call (eg if your son had made his way back to you). I would have activated the EPIRB in the morning and stayed put. That way searchers know where you are. If you move the signal may be lost and techniques such as triangulation are affected. The rule of thumb is to stay put unless your safety is compromised (eg to find shelter or water).
Remember that even with an EPIRB you don’t just push the button and help will arrive within minutes. There may be a long delay (possibly hours) for an EPIRB to get a signal to a satellite, this is especially true if the view of the sky is restricted (eg if you are in a deep valley). Once the message is received it may not be possible for a helicopter to come, if one is available. It may take some time for a land based team to get in to you.
I am really pleased things worked out well in the end and has not put any dent for your love of the Ruahine and any wild places. I hope Taylor has not been put off either. I loved the reflections you have made in your blog. It is not so much the mistakes we make as the lessons we learn from them. I can see that you and hopefully Taylor are intending to learn from your mistakes. I hope you and Taylor have many great adventures.

#15 Comment By Robb On 6 June, 2011 @ 5:46 pm

Kia ora Heather,
Appreciate your thoughts very much, and reading the comment you wrote prior has given me cause to think between which device to select. As I normally do a fair bit of solo tramping as well. I guess my reflections upon being in the situation of someone missing and having to make the call, particularly grueling when it is your own child, was to keep a cool head at all times and be thinking of my options in the waning light of day. I knew I was hours away from getting any help, at least that night, and considered I was better off trying to find Taylor myself. In retrospect I should have kept going down river towards Otukota and would have eventually found him when he FINALLY realized his error. We may have well both spent the night on the river but at least would have been together. In the moment though it is hard to not think I may have missed him possibly injured or worse, and as I had lost his footprints in the narrowing river, decided to go back, leave a well marked path for him, then try to climb to get help. We probably missed each other by 30 minutes or so, and as I climbed up the darkening spur towards Point 1450 I knew time was against me. Thus began a long night in the hut. I knew I could get cell reception at Puketaramea as I had in the past, and that was a memorable climb. To see Taylor walk around that corner on the river after I returned tired and about to head down river again still makes me cry. My point being that nothing would gotten us out of that jam any sooner, and it made me realize when things go a bit awry how remote our back country is. On my own I have always knew and accepted that, but with others we love and care for it is a little more problematic. So for the sake of the people I love out here it makes sense for me to carry an additional device, certainly not under the illusion that the device in itself will prevent or save me from bad decisions, illness, or an accident (which has always been my reasoning solo against a mountain radio), but simply that if I do need to raise the alarm, and can’t climb high, that I do have an alternative.
Climbing the spur up to Puketaramea ridge in the dawns light, I couldn’t help at times as I paused to rest for a few moments but look out into the mist covered valley and far off peaks and still see it as beautiful. I knew the possibility was quite high that these mountains I love so much may have claimed forever my oldest son. Fortunately I do not have to deal with that possibility, but the experience, while not at all changing how I feel, has given me scope for an awful lot of thought and thinking. Places like this, and thoughts such as yours, help clear the mist a bit, so Kia Ora.

#16 Comment By Rick Percival On 6 June, 2011 @ 6:50 pm

Rob, sounds like you had all the bases covered. I have two daughters that I love to take tramping and the thought of getting separated is always in my mind. It’s very easy for it to happen. Maybe a satellite phone is the option in your case? I like the SPOT V2 because I can send “I’m OK” messages and even a preset custom message, which I have setup to say “Need help, but it’s not life threatening” which is kind of a compromise with the full on emergency buttons of a SPOT or PLB.

Mike, I’m completely confident in the SPOT 2, have just come back from 3 days on the Lake Waikeremoana track and it worked there perfectly as well and have just tonight renewed my next year’s service. At $115 USD per year it’s expensive but for me, it has the edge over a PLB like a McMurdo Fastfind…although, after reading Rob’s comments I would love to find a sat phone that would give me true two way communications.

P.S. if anyone has a use for a SPOT v1 I have one that I am willing to donate, free.

#17 Comment By Mike McGavin On 7 June, 2011 @ 11:31 am

Thanks for the comments and thoughts everyone. For the benefit of anyone who stumbles upon this thread in the future, I should add that Robb’s referring to [23].

I’m not sure I could add much that hasn’t already been said by Heather and Rick. Trying a Mountain Radio is a good idea. It makes sure there’s always someone on the other end keeping an eye out for your wellbeing, and there’s a good local outdoor community behind it. I was also going to also mention Satphones, which Rick’s already covered. They tend to be expensive to buy and to operate compared with other options, which is probably why few people seem to use them, but I heard of at least one rescue somewhere in the Tararuas in the last year or so which involved one. It might be the sort of thing that’s better to rent for a short term than buy. Clearly there’s a lot of benefit in having two way communication in an emergency, though, or even just an uncomfortable situation.

Heather, I notice you suggested activating an EPIRB in the morning and staying put. Do you think it’d be reasonable to activate an EPIRB, then go searching but leaving the EPIRB behind with a detailed note about where you’re looking? Or would this likely create more problems than it solves?

Rick, thanks for confirming your impression of the SPOT 2. It’ll be really interesting to see what kinds of conclusions are reached by the tests Heather mentions. Heather, out of interest is it LandSAR or the Mountain Safety Council that’s running this?

#18 Comment By Mike McGavin On 7 June, 2011 @ 12:14 pm

Coincidentally, less than an hour ago [24] popped up on a SAR-related blog in Josephine County Oregon. (Actually a reprint of a thing [ [25]] on [26] )

#19 Comment By Heather On 8 June, 2011 @ 6:36 am

Hi Mike:
Yes I agree that 2 way comms is more than just for emergency situations as you can talk through an uncomfortable situation or your decision making process or get medical advice even if evacution is not required.

A word of caution on sat phones, these don’t always work either as they rely on satellites so can be affected by narrow window to sky also.

I asked 2 senior SAR members what they thought about leaving the EPIRB then go searching as described. Their response was united: stay put.
If you move, no matter how detailed you think your instructions will be, things could change, rapidly. Otherwise for example
– you would be leaving YOUR comms behind (what if YOU then broke your ankle or you needed to detour for whatever reason),
– you may be getting yourself into whatever pickle lost person had got into (what if the track had collapsed for example),
– searchers find lost person …. then need to find you etc (what if they found the lost person, injured …. and then were delayed looking for you before they could leave).

It is Manawatu MSC doing the research on the SPOT’s although it is with the knowledge of SAR and approval of Rescue Co-ordination Centre and requires approval by SPOT officials.

Thanks for the link, it was very interesting. A good example of why you stay put when you activate the emergency button.

#20 Comment By Mike McGavin On 28 July, 2011 @ 10:52 am

Continuing this topic, the August edition of [27] (note that it’s 5 pages) that looks at some of the impact that the introduction of SPOT beacons, as opposed to just PLBs, has had on emergency callouts. I’m unsure how much of it applies in New Zealand to date, but it’s an interesting read all the same. It seems to cover a broad base of perspectives.

Matt Scharper, the 48-year-old deputy chief of the California Emergency Management Agency, says that not long ­after Spot devices were introduced in 2007, he started noticing that SAR teams were spending a lot of time responding to false alarms. He began collecting data from the 58 counties and three national parks within his purview and found that, out of a sample of 77 distress calls ­involving beacons from June 2007 to April 2011, 48 percent had no merit at all.


Steve Howe is pleased with the progress that equipment ­designers have made in rooting out glitches like the one he experienced, and he believes the devices solve more problems than they create. “I think the OK signals prevent far more unneeded call-outs from worried spouses, parents, and relatives than beacons create through false alerts,” he says. When problems do occur, it’s usually the person—not the device—that should get the blame. “The problem isn’t whether beacons should be part of the wilderness experience,” he says. “It’s whether some people should be allowed out of their yard.”

#21 Comment By gazza On 28 July, 2011 @ 11:48 am


The story about the skier was the best one.

Feel a little sorry for the lady mentioned on the first page, sounds like a PCT thru walker and therefore might have been out on the trail for a while and not have up to date weather forecasts. She hit the 911 button a lot sooner than I would have but she sounds (like alot of PCT hikers) to have been going super light weight so i am guessing her shelter and sleeping bag would be quite lightweight as well. If the storm had ended up getting worse instead of better she could have ended up in a bad way. I suspect if the weather hadn’t cleared up the rescuers would have been praising her decision to call for help earlier on.

A lot of the other stories are just idiotic though.

#22 Comment By Mike McGavin On 28 July, 2011 @ 12:04 pm

Many of the problems mentioned seem similar to the kinds of problems that we’ve seen just with EPIRBs. I can’t quite figure out if the article’s suggesting there’s a big leap in numbers because people are more likely to press the emergency button on a SPOT than an EPIRB, or if EPIRB-like devices were never really used in the US until SPOT made them very popular and suddenly there’s a swarm of false alarms.

#23 Comment By Mike McGavin On 28 July, 2011 @ 12:06 pm

And the story on page 4 is a wake-up call. In the age of helicopters it’s not a natural association to think of an emergency button as something that’d cause someone to have to walk 24 km to come and find you.

Finding out it was just a person who had some long-disappeared leg cramp would tick anyone off.

#24 Comment By gazza On 29 July, 2011 @ 9:12 am

Maybe the SPOT beacons have been used over there right from the start? I know they have only recently started to penetrate into the NZ market but perhaps they have been around a lot longer in the US?

Or perhaps the different message types on a SPOT make people less heistant to actually push the “rescue me” button? If they have them out several times a day, using them to send an “I am ok” message, then maybe they have a different “feel” to them than a EPIRB that just sits in a dark corner of the pack waiting for an emergency to occur?

I don’t know really because I don’t own or use either, although I would consider hiring one for a longer trip.

#25 Comment By Mike McGavin On 29 July, 2011 @ 11:01 am

They’ve only been around at all since 2007, I think. [28] (which I haven’t read yet). In the photo, note the 911 and Help buttons on the front that look as if they’d be painfully easy to press accidentally, even though it’s necessary to press and hold for 2 seconds. I guess this is what that earlier article meant with respect to how they’ve been redesigned with a cover over them after a high profile incident in which it went off inside someone’s pack.

#26 Comment By gazza On 29 July, 2011 @ 4:13 pm

Skimmed through the article, despite it being dated I noticed a few interesting things:

1) 911 alert needs an active subscription.
2) 911 alert can be cancelled by the user later on (by holding down the button for three secs) which would have been useful for that lady hiking the PCT.

It looks like a interesting read, will go over it in more detail later.

#27 Comment By Mike McGavin On 29 July, 2011 @ 4:17 pm

Yep, though keep in mind that article is ~4 years old. I think cancelling an alert can also be confusing. In one of the cases described, a person cancelled their alert but the searchers went out searching anyway because they didn’t know why it was cancelled and thought she might have been thinking irrationally and what-not.

#28 Comment By gazza On 1 August, 2011 @ 9:57 am

Yeah, thats a good point about the cancelled alerts being confusing.

I wonder if the company behind the device would forward on any ok messages that come through after the cancelled 911 alert to the searchers? I guess it probably depends on how much communication passes back and forth. If you got a cancelled 911 alert followed by one or more ok messages than that might be a better indication that the person is no longer in trouble.

#29 Comment By Mike McGavin On 1 August, 2011 @ 10:50 am

I guess they probably would but I suppose you never quite know. One of the criteria I’d consider when buying an emergency beacon is if there were an official channel to emergency services with clear procedures, which for SPOT and New Zealand at present I don’t think is the case.

That said, in a crappy situation it’ll always be better to have options and the procedural side of SPOT anecdotally seems pretty good, and (as already said), there are a plenty of other reasons to get a SPOT. Reporting emergencies probably isn’t at the top of the list. Like Craig pointed out first in one of the early comments, though, you really can’t beat 2-way communication.

#30 Comment By Chris Fransham On 9 August, 2011 @ 10:38 pm


Re your query about whether New Zealand 406 MHz EPIRBs transmit the ‘parallel’ signal on 121.5 MHz for aviation traffic – I believe this is the case for all of them. I was working in marine SAR when the changeover happened, and our spotter plane used exactly the same frequency (the old 121.5 MHz) for EPIRB pinpointing.


#31 Comment By Mike McGavin On 13 August, 2011 @ 8:43 pm

Hi Chris. Thanks for filling that one in.

#32 Comment By Tony On 20 August, 2011 @ 10:25 pm


I just walked next door to RCCNZ to confirm my belief and Chris is 100% correct, all EPIRB’s/PLBs also transmit on 121.5 MHz to provide the homming component of the 406 MHz EPIRB.

There is good info at [29]

My additional comment would be to stress that when purchasing a 406 MHz Beacon to fill in the registration details paying careful attention to your contacts. When RCCNZ receives an 406 MHz beacon alert one for the first things they do is ring the contact numbers. If they rang your cellphone and you were out of coverage they would ring the next number on the list (wife/partner perhaps) and they would confirm to RCC “oh yes, Tony has gone tramping in the Tararuas this weekend, heading up xxxxx track then going to xxxxxx hut etc etc” Of course RCCNZ arranges the appropriate helicopter search regardless of making contact with the people on the contact list or not, but the information that can be obtained from the contact is very helpful, number of people in the group, intended route, etc – info the EPIRB cannot transmit.

Mike, email me if you’d like to visit to RCC (I can show you around. )(its at the Avalon TV Studio complex) (I work in the Maritime Radio section next door – dealing with Maritime SAR, including EPIRBs from vessels at sea. And believe it or not even the odd hunter in the bush that has access to a marine VHF Radio!)


#33 Comment By Mike McGavin On 25 August, 2011 @ 8:42 pm

Hi Tony. Thanks very much for checking that out — obviously good advice with registration of details which I should have noted above. And thanks for the offer with RCC. I’m actually in Australia at the moment for some time yet ( [30]), so as much as I’d enjoy the opportunity I’m afraid it’s not very practical.