Technology on the Trail: Part 3: iPhone
Wednesday, December 7, 2016 2:42 pm

The backbone of my communication, internet, and mapping needs on the Appalachian Trail was, not surprisingly, my iPhone 6s.

I think it may have started out in a pants pocket, but my phone very quickly migrated to the left hipbelt pocket on my pack, from where it observed the vast majority of the Appalachian Trail, and it quickly became an indispensable part of my hike.

Snug in the pocket (especially once it got a case), and usually sticking half-out for ease of access, it fell out only a handful of times: only when I fell, and even then, not every time.


Being so easily accessible, it’s no wonder that I took almost 2500 photos during my hike, a little over one per mile.

The camera in the iPhone 6s is nothing short of amazing, given how tiny it is. All of the pictures I posted while on the trail came from my iPhone. Although I certainly would have made use of a better camera had one been available, the only time I really felt my iPhone wasn’t sufficient was in scenes that could have benefited from a zoom lens.

I should have gotten an attachment to use my trekking poles as a selfie stick. Maybe next time…

Cell Signal

My cellular provider was AT&T. AT&T service was somewhat sporadic in the south. While I generally had signal sometime during the day, it was not necessarily a given that I’d have signal at the evening’s campsite. Only rarely did I go more than a day or two without getting a signal at some point. (Hikers with Verizon phones tended have signal more often.)

Once I reached Shenandoah, AT&T service started to become more reliable, and from Shenandoah to (I think) somewhere in Massachusetts, I had signal almost every time I checked. (The one specifically curious place without cell service was at Pine Grove Furnace State Park, just past the halfway point on the trail.)

In PGFSP, I needed to make a phone call and remembered that AT&T supported wifi calling. After setting that up, I found that wifi calling worked even when in airplane mode (with wifi turned on), and so as I got further north, I often left the phone in airplane mode even when in town, since I didn’t need cell reception to make or receive calls or text messages. Wifi tended to be fairly available; most hotels or hostels provided it, as well as many restaurants.

North of Massachusetts, cell coverage did get more sporadic, and by the time I got to Maine, it was not uncommon to not have cell service at all. My longest stretch without any cell service whatsoever was, unsurprisingly, in the Hundred Mile Wilderness.

Overall, I was relatively pleased with the amount of cell coverage I had; it was far less sporadic than I had initially expected. In fact, I’d have preferred there have been less coverage. Too often, I wound up wasting time on Facebook or Reddit. (This was a key factor in causing my breaks to gradually lengthen as as I traveled further north.)


When not in active use, the two largest power draws on an iPhone are the cellular radio, and GPS (when location tracking is turned on). The cell radio especially consumes copious amounts of power when signal is weak or nonexistent. Accordingly, my phone was in airplane mode for the vast majority of the hike. Bluetooth stayed turned on so my watch could stay updated. Wifi was always off unless I was in town (since it’d be a waste of power leaving it on when there’s nothing to connect to.)


The app I used essentially continuously on the trail was GPSTrack, the iPhone app I initially developed several years ago to record GPS traces (and now sorely in need of an update). With some custom modifications, I gave it the ability to submit recorded tracks to this blog, which appeared in each entry that involved hiking, and also in the overall map which I added after I got home.

GPSTrack, in combination with Apple’s maps, also helped me a few times when I accidentally hiked off the trail. Apple Maps, surprisingly, shows the AT’s path. Combined with GPSTrack showing my prior path, and direction of travel, I was able to locate where the trail should have been and hike in that direction. (Alternatively, I could have retraced my steps, and that was actually necessary once in Maine where the terrain was far too rugged to move in a direct line to the trail.)

One of my concerns was power use. While power performance on the iPhone 6s seemed better than on my older iPhones, running the phone with GPS turned on usually resulted in about a 10% power draw per hour. Normally, this is acceptable, but a ten hour runtime on the trail would have required recharging mid-day on more than a few occasions.

Thus, I was very happy when I accidentally discovered that GPS would work with airplane mode on my first day on the trail. Being able to shut off the cellular antenna, especially in areas with weak or no signal, meant that the power draw when GPS tracking was closer to 5-6% per hour, letting it easily run an entire day.

While I’m fairly certain that GPS actually didn’t work in airplane mode on older versions of iOS on older devices, I’m unclear when that changed. It’s possible I didn’t notice because being in airplane mode significantly hinders the initial GPS signal acquisition.

Whether it’s a matter of being able to listen to cell towers (even those it can’t connect to) for assisted-GPS, or if allowing the cell antenna to be on improves some other part of GPS reception, I found that I usually had to disable airplane mode in the morning in order for my phone to determine where it was. Once it had acquired a GPS signal, I could turn airplane mode back on to conserve power, and not have a problem recording GPS tracks for the rest of the day.


I spent most of my first month on the trail without listening to any music from my phone at all, instead opting to concentrate most of my attention on hiking without tripping over rocks and roots. The first time I listened to my “favorites” playlist was on my last day in the Smokies, a particular easy (and mostly downhill) hike, and the music helped me maintain a surprisingly brisk pace.

It was astonishing how often music cues fit in so perfectly with the terrain; one particularly impressive case was the the first time the End Credits to Star Trek: First Contact on the way out of the Smokies. The main theme to Star Trek: TNG played as I was cresting a hill, followed by the movie’s somewhat somber theme, which played as I passed by one of the (relatively few) scenic views in the Smokies, followed by a more upbeat reprise of the TNG theme just as I started to climb the next hill.

My only regret was not having a specifically “upbeat” or “high energy” playlist. My favorites playlist includes a fair number of slow or somber tracks that I found entirely unsuitable to play while hiking. A good upbeat track would often provide additional energy to hike faster, or ignore that I was on uphill number 27 of the day. Slower tracks would tend to sap my speed, and I had to skip them as quickly as possible to keep up my pace.

Once or twice, I tried to listen to the podcast backlog I had before starting the trail. Both times, I switched back to music after not even five minutes. Podcasts wound up being too unevenly paced, and I found the trail was demanding too much concentration, so attempting to listen to podcasts while hiking wound up being a detriment.

When in town, I was able to download TV episodes from iTunes (finishing up the third season of Agents of S.H.I.E.L.D., and starting the fourth season of Orphan Black). I stopped watching TV episodes in early Pennsylvania, though. I suspect it was as a result of being more mentally occupied or exhausted past that point as the weather got hotter and the trail gradually got more difficult. Still, though, it was nice to have the option to watch some TV if I wanted.

Facebook and Reddit also provided some distractions on the trail. I was quite pleased to have missed most of the presidential election cycle, but Facebook and Reddit didn’t really help in that regard.

Other Apps

A favorite app was Dark Sky, which provides “hyperlocal” weather forecasts. When I was on the trail and had signal, Dark Sky was handy in suggesting how long I could keep hiking before needing to worry about rain.

I made unexpectedly heavy use of the Notes app to make notes on the trail as I hiked, and then turned the notes into my daily blog posts. I had intended to type notes directly into this site’s admin interface, but the admin section proved to be somewhat less usable than I had intended due to lack of time to make a more usable interface.

I also used Notes to keep my daily log of progress, and resupply plan, until I realized that a spreadsheet was a far better way to manage those, and switched to Numbers. Both of those spreadsheets grew gradually more complicated as I progressed up the trail.


The iPhone 6s, while not waterproof, is better than all prior iPhones in that regard, which is why I was perhaps a bit too casual in letting it get wet.

For two months and a day, I used my iPhone without a case, until it (and I) got completely drenched in the first day of heavy rain I experienced on the trail. The next day, after it was uncharacteristically fritzy, I picked up a waterproof case, which I used for the rest of my hike.

The case worked well in keeping my phone dry and protecting it from scratches, but it was somewhat bulky, and made it quite difficult to perform gestures originating at the bottom edge of the screen (for example, to open the Control Center). It also was a very tight fit against the mute switch, and since taking the case off, the mute switch doesn’t work properly. The bulk, though, made it a little easier to hold, and the plastic and rubber edges and back were a fair bit grippier than the smooth metal case on the iPhone, making it far less slippery.

The case’s front camera lens cover was also prone to collecting dust and grime, and the majority of the photos I took with the front camera looked blurry, fuzzy, and generally not awesome. Cleaning the lens cover wasn’t terribly difficult, but it wasn’t easy to do in the field, and I often forgot to clean it when I arrived in town.

Taking the case off after my hike was almost like getting a brand new phone. The case added substantial thickness, and after removing it, my phone felt almost impossibly thin.

Unresponsive When Wet

The iPhone’s screen, being a capacitive device, doesn’t work very well when there’s water or significant moisture on the screen, reading spurious touches — or none at all. The same goes for the Touch ID sensor. This wound up being a problem any day it rained, but even high-humidity days could cover the screen and Touch ID sensor with so much moisture that they would fail to respond properly to touch. After drying out for a few minutes, the phone would usually dry off enough to start working correctly again, with the screen typically regaining full functionality before the Touch ID sensor was able to correctly read fingerprints.

One thing I’m surprised I never bothered to do was put my phone in a plastic bag on rainy or especially humid days. This would have made it considerably more useable under those circumstances by significantly reducing the amount of water allowed to collect on its surface. (While the plastic bags I had were needed for food storage, I managed to find an extra bag to keep my paper trail guide dry, so it wouldn’t have been that hard to find an extra bag.)

Heat and Cold

The iPhone has a thermal limiter that prevents it from running when it is either too hot or too cold, to prevent damage to the battery. I ran afoul of this twice: once at Clingmans Dome in the Smokies, where my phone shut off while I was on the observation tower at the highest point on the AT, due to below freezing temperatures and high winds for most of the day’s hike to that point; and once in Maine, when cool temperatures, heavy winds, and heavy usage after I got turned around in low-visibility conditions depleted the battery to the point where it shut off.

Cold temperatures cause batteries to discharge faster than when they’re at room temperatures. This meant that whenever it was cool out, I wound up sleeping with my phone, watch, and battery (and in near-freezing temperatures, my water filter) in my sleeping bag. Unsurprisingly, this was often quite uncomfortable, but there was little else to be done.

Typing on a Slab of Glass is Not So Fun

While on the trail, I typed over 120,000 words (over 650,000 characters) for this website, almost all of which were typed on my iPhone’s keyboard in landscape mode. That’s an awful lot of tapping on a glass screen.

While the iPhone’s keyboard isn’t too bad, compared to a desktop keyboard, typing that much text was slow and annoying, and editing text was especially tedious. Force touch on the iPhone 6s made text editing significantly easier though, by allowing precision movement of the cursor. Autocorrect, while occasionally fairly wrong, made the glass keyboard at least bearable.

Although I never actually did, by late in the hike, I was seriously considering getting some sort of small bluetooth keyboard to make things easier.

Still Plenty of Life Left

Now back at home, my phone shows few signs of wear from its extended trek, and doesn’t seem plagued by the battery shutdown problems some other iPhone 6s users have been having. There’s a couple of places where the paint is starting to flake (or has been polished) off, but otherwise, it’s working as well as it was on day one. Now a year old, it’ll get to relax a bit before the next big adventure…

Technology on the Trail series

This post is part of my “Technology on the Trail” series: