UKH

I hope posting this link is ok: I started writing a short account of a couple of problems I had, and ended up trying to make a comprehensive list of the way smartphones can fail in mountains. Hope it's useful to those of us who navigate with them.

https://omnisplore.wordpress.com/2018/02/15/unexpected-smartphone-failures-...

Mine failed just a few days ago somewhere underneath the Aiguille du Blaitiere, because it fell out of an unzipped inside chest pocket, got caught in my jacket by the belly strap of my backpack, and then at some point during the day when the backpack got taken off, it fell out and into the snow.

I'm not too bothered though, to be honest. Last autumn, I accidentally left behind an iPhone 5 on the summit of the Aiguille du Plan, but a few weeks later I found an iPhone 6 on the north face of the Aiguille du Midi.

So, after losing it again somewhere under the Aiguille du Blaitiere, I assume that in a few weeks I'll just get an iPhone 7 from somewhere up by the Charmoz-Grepon.

There was a good tip on TV the other day - whilst moving about, if you need a signal and don't have one; send a text to yourself. When your phone beeps you know you have signal again.

That's a good one.

It's also worth registering your mobile so you can text message to 999. Could be useful if there's not enough signal for reliable speech transmission:

http://www.emergencysms.org.uk/

To OP:

Although your article is aimed at using a phone with no map, an app like Grid Reference gives you a massive white text on black backround OS grid ref that fills the screen. You can use that with a map in poor visibility to get a rapid fix on where you are. You can easily share the location by text etc if you need help.

Sitting on your phone in a pocket, or crushing it in a chest pocket when mantling / cuddling the rock.

GPS - being on one side of a mountain will block out half the sky and give poor reception / accuracy. Use the GPSstatus app to see your satellites and accuracy. Make sure the almanac is downloaded in the valley so it doesn't have to spend time working out where it is.

Drizzle renders touchscreens unusable, if you're texting at the time your messages look like sgyusfhu;phal;hjua;fa'[werifhawer[eeeoa'[eirhju[aeriogju]aeoprhj]aepohja]erpoj]aeopgh (if the phone buffer can cope). Turning the screen off and on normally resets the touchscreen so you can use it again (assuming you've dried it off).

Update all your apps on wifi before leaving the valley so they won't try to update over 3/4G and hammer your battery / data allowance.

Newer signal technology normally drains battery faster than older eg. 4G>3G>2G. 4G is especially battery heavy, and newer phones will use multiple carrier frequencies at the same time for faster speeds and subsequent higher battery use. Often 2G aerials use the oldest lower frequencies (8/900Mhz) which work better at long range and indoors, although networks are now re-using frequencies to give themselves better 4G performance.

Cached Googlemaps only have the map layer, not photos. Some paths disappear at highest zoom bizarrely.

Text messages only need a sniff of signal to go, voice calls need much better signal strength.

The problem I have with them is the disparaging looks from map-wielding luddites who don't understand how to download a map (OS Maps/Viewranger), turn on flight mode, then turn on the GPS, and plug in a battery pack. By the time I've shown 500 of them why paper maps are obsolete, my phone has died from overuse. I also get a dry mouth from explaining how a phone can be dropped/blown away/get wet just as easily as a paper map.

*removes tounge from cheek*

In all seriousness, I hardly ever carry a paper map anymore, I use the OS app and my phone. With a waterproof case and a battery pack, I've never had a problem. Always take a proper compass though. 

Edit: In response to the twighlight mode issue you were having, my phone (iPhone 6) has a light sensor on the front which auto-dims the screen. They don't work when they get grubby - could be a fix?

I had mine i  my pocket  and it seems the biutton got pressed a number of times making it think i was trying to unlock it...

When i got it out to take a nice skiing photo it informed me i had made too many failed passcode attempts and had locked me out for 30 mins... couldn't use it for anything

Good but not perfect, texts require much less signal time so can be sent and received on the slimmest and fleeting connection. It could have easily disappeared or be not good enough for call time .

The problem with any tool is the person using it, seen lots of people carrying maps and compass who have no idea how to use them.

If you don't know how to use a map then a phone is far more useful. 

But essentially I use the phone as a less annoying way of displaying a map, with the added bonus that should you loose track of where you are, it will show you. You still need to know how to use a map - a phone in the hills will not give you turn-by-turn instructions!

Not quite on the point, but there's an interesting article in the Guardian today about people having a misleading compass owing to the magnetic field created by mobile phones, and also something I wasn't aware of, the fact that many items of outdoor clothing have magnetic closures, instead of a zip perhaps.

Sorry that was a generic reply not one aimed at you. I'm a big fan and user of maps on phones. 

I made the mistake last weekend of pressing the unlock button on my phone for too long which switched it off. I assumed that the cold had killed the battery and that I had lost mapping, GPS and the ability to call mountain rescue if I broke myself. 

I did have a map, compass and a good idea of where I was so it wasn't a drama but it was disconcerting. 

In this circumstance I'd agree: before leaving home, use the phone to call somebody who can teach you how to use maps, and arrange a lesson before going anywhere remote at all.