I'm looking at buying myself something similar to those SPOT devices, as alongside hillwalking and mtb-ing, I'm a forestry surveyor and spend a lot of time on my own in remote Scottish uplands.
I've had a SPOT (can't remember which model), and found it was great when in the open, but very patchy when under a forest canopy, so that rules out that one. Are there other similar and better devices around? What about mobile phone apps as a substitute?
I use an old garmin foretrex 101 for grid refs (I really only navigate with a paper map) for times when there are too few landmarks/too little viz. I cant say Ive ever had a problem under trees, but you often need to give it a few minutes to sort itself out and find as many satellites as possible to get an accurate location. But it does show you how many (and where) the sats it has found are so can move around a bit to get a better "view" for triangulation of the GPS signal from a satelite in a different spot of the sky.
Hi, Garmin are great and I use a c62Csx when out working. But I'm looking for more of a passive device which sends out location info at regular intervals in case I'm knocked unconscious or something.
I've just noticed an old thread here on STW recommending the DeLorme inReach, which has now been bought by Garmin so is the Garmin inReach SE+. Costs a fair bit though, and then a subscription is needed on top of that too.
Any satellite based system will struggle under tree cover. Also if you are in a glen then the distribution of satellites might mean that many are below the horizon.
The DeLorme devices need a subscription but unlike SPOT you can do it on a per month basis whereas SPOT is an annual subscription or nothing. I don't know if SPOT and DeLorme use the same comms satellites for their systems, they don't use the US DoD GPS satellites for the back channel.
I'd try the latest SPOT. I'd be surprised if there's that much difference between the makes / models in an identical situation. The main issue comes from lack of satellite visibility (city canyons are the worst where sky scrapers on both sides obstruct the view), which will affect all receivers.
I use a SPOT. I've had a couple of times when the signal has been lost for a few miles but it normally works really well. Keeping the device horizontal helps, though that might be difficult when walking unless you have some sort of pack you can strap it to the top of.
The subscription is around £100-120 / year. I reckon it's worth it for the many occasions I'm in places that phone signals aren't available and that's just as a leisure user.
Thanks for the replies folks.
I like the look of the SPOT 3, however my employer has done an evaluation on one and really wasn't happy with it. I'm hoping to use it for my own cycling etc alongside work, but the boss will be picking up the tab, so that rules out the SPOT unfortunately.
Looks like the Garmin has much better signal reception and works off the Iridium satellite network, so coverage is extensive. Price is a big downer though.
Looking at what phone app options are out there now, I remember one that used whichever mobile tower was in range, regardless of whether that was part of your subscription network.
I use a McMurdo FastFind 220 GPS PLB. It doesn't track and has to be activated to send out a signal so no use if I'm unconscious but it doesn't come with a subscription.
Uses two signals. It transmits a unique ID and current GPS co-ordinates via COSPAS-SARSAT on 406 MHz (you have to register it with the Maritime & Coastguard Agency) and also a lower powered signal on 121.5Mhz that SAR can use to home in on you.
That looks like a definite option, might be what he's looking for. Don't think it's that great for lone mtb-ing as it has to be activated, but still looks like a definite option for the lone working side of things. I see the similar ACR ResQLink is replaced free of charge if ever activated.
Garmin GPSMAP64 - will give positions to known accuracy and will update them with further measurements. EGNOS reception too.