Article on using your phone in the wild...getting found

Very interesting and useful.

Thanks for posting that link!

"Know what method your carrier uses to fix location. GSM phones (AT&T, T-Mobile) use radio signals to triangulate your position; climb to high ground to reach more towers. CDMA phones (Verizon, Sprint-Nextel) use internal GPS receivers; find an unobstructed view of the sky and wait a few minutes for the phone to lock on to satellites. Smartphones (BlackBerry, iPhone) combine both methods for the most accurate position. "

Thats not accurate either. I've found that make and model of phone will use different methods but most anymore have some kind of gps chip combined with the agps trangulation, its not on a per carrier basis.

The article needs one addition -

STAY IN TOWN!

I suggest you ask the James Kim family their opinion on relying on cell phones.

I think given that the magazine is specific to Backpackers, they didn't feel the need to reiterate advice on carrying multiple means of navigation. So, I can see them just focusing on the subject at hand. Magazines do have to deal with space limitations.

The artical seems good for those that go into town or suburbian locations. The issue I have is that cellphones are infastructure based objects. Once the infastructure is gone,, so isn't its usefullness (except for the part about making a fire with the battery)

When I did trail crew (back when dinasors romed the earth) our trail boss had a cellphone (bag phone, remember them) he left it in the truck becouse it only worked in one area in Baxter State Park in Maine. Now That Was Maine, and that was back in 1991/1992.

The previous statment of using a phone on the top of a mountain or clearing is absolutly spot on.


Also don't forget to keep the phone on the INSIDE of your jacket during the winter, and NOT on you belt where the cold can kill your battery.



I had always thought it would be a cool idea to take thin metal wire and a baloon or a kite (baloon would be better) and have it so that it hooks to your phones antena (back when antenas ports were on phones. Then inflate the balooon and let the thin wire act as the antena. My therory on this was that about 100 or 200 feet of this thin wire (very thin wire) would act as the antena for a short time allowing you connect to towers seeminly out of reach.

If anyone wants to do something with this idea have at it. I think it would be awsome

I had always thought it would be a cool idea to take thin metal wire and a baloon[/quote]

What method of inflation would be compact enough to still remain practical? The only device I have ever seen that small is a spare air for breathing under water, but that is oxygen not helium.

Field expedient antenna-throw the wires up into the trees.

In theory a candle. The heat could lift up the baloon. But I can imagane that it could be very unreliable (strong wind) or it could even end with disaster - the baloon crashes into the trees and the candle sets them on fire.

the 15gm CO2 cartriges used for Airsoft and the like would work well... ok, well CO2 wouldn't elevate a balloon, but the SIZE would work well.

I don't know how much help an extra antenna would be. Cell phone signals are microwave and are pretty much line of sight transmissions. They are not like AM radio signals and they dont do the skywave or bounce off the stratosphere trick either.
There is a bit of follow to the curve of the earth, but it is not much.
I know one spot on a highway where there is clear reception for 1/4 mile. There is no reception at all for the 35 miles either side of that. It just happens to be where the topography allows line of sight to one tower which is a long distance away but blocks all the rest. Once you leave that 1/4 mile all the towers are below the line of sight because there is a range of hills between the highway and them.

So as a result of this line of sight signal trait you quite often can get a signal if you climb higher up a mountain or if you can get a sight line through a pass to where the towers are.

I thought it was a good article, though they obviously had to keep it pretty simple to fit the column.

Kinda, but it would help.

As long as the wire was actually connected to the antenna of the phone, the it is theoretically entering into line of site. Cell sites have patterns to their transmissions.....


Wait a minute, I am about to get way too far into this.

Synopsis: It might help, but good luck getting the long wire connected to the actual antenna.

One other thing:


Dougwalkabout recommended a Wilson Booster when we were discussing my possible trip to rural areas of Canada. It has to have a power source, but sounds like a good idea to me for in the vehicle.

BTW, the trip may be back on again......

I was going to start off with an intro post, but thought I might save someone the time of building a bottle rocket antenna launcher when it won't help.

As mentioned above, cell phones in the US and Canada run at .8 GHz or higher, which is about 1000 times the frequency of AM radio. At these frequencies, reception is almost completely line of sight, which means that a higher antenna helps, but that's not the only thing that changes. Long wire antennas won't work, the loss in the wire is too high, and "long" at .8 GHz is measured in inches. Losses in transmission lines are very high at these frequencies, so much so that even a good external cell antenna connected with 10 feet of decent quality coax probably wouldn't work much, if any, better than the phone's built in antenna. Much better to move the whole phone up in the air somehow.

The article is pretty good. Cell phones do eat up their batteries trying to connect when they can't. They don't mention exactly why you should try turning around to get a good signal - it's because your head does a decent job of blocking the signal going through it. Holding the phone straight up in the air can help. Height is good, and being in the clear is good. Trees can reduce signal.

It's also probably good to know how your phone's GPS works, if it has GPS. With some, you can use the phone to display GPS coordinates even if you don't have cell service. The map won't work, but you should already have a map. By marking out a couple of points, you could use it as a really terrible compass, too.

One thing they forgot to mention was using the lit face of your cell phone as a beacon.

If aerial searchers are in the vicinity and they have night-vision goggles, they can spot a lit face of a cell phone, a small flashlight, and other small sources of light for over a mile.

Of course, it would be pointless to wave your cell phone at the sky with no one out there looking.

Sue

Another tip - the SMS / text messaging function on a cell phone can get a message through with a fraction of the signal strength needed for a voice call.
The phone will also keep trying to send the message.

Wilson Booster? Nope, wasn't me. But who knows, they may work.

Until last year, the best way to pump out a cell signal on the fringes was an old Motorola analog flip phone. Remember those? Three watts of unapologetic ionizing radiation. And you could put it in a pillowcase to whomp bears with, probably without damaging the phone.

Wooops must have been Swamp Donkey

Actually the Motorola flips were 600 mW (.6W), the bag phones and mobiles were 3 Watts. In both cases I sure hope it was non-ionizing radiation or we're all in trouble.

Mammal-whomping? I agree, a substantial weapon...

Many thanks for the article; I must be way behind the times, as I usually don't take a cell phone to the mountains because when I first began carrying one in 2000, there wasn't any coverage, and hadn't thought to check since. That, and my cell is very heavy to pack, being a few years old. Looking at the carrier's map, it still looks like a lot of areas around me are still not covered. (Even the service where I live is rather spotty)

Would it be better to get a PLB instead? Or should I wait until I get a newer generation phone?

I don't know if this will do any good, but somebody might find it interesting.
http://www.cellreception.com/towers/

It is a mapping of cell coverage.

Something to think about re: long-wire antennas:

In order to function optimally, antenna's work best when they are "tuned". That is, a wire length is selected that 1) provides electromagnetic resonance at the frequency of operation, and 2) offers a feedpoint impedance that matches the impedance of the transmitter output.

Failure to do so may result in 1) degraded performance, and/or 2) possibly damaging the output circuitry of the transmitter rendering it non-functional. This may be more critical at microwave frequencies.

Actually, I'm not certain how critical the impedance-matching factor is these days. It may have been largely resolved in modern integrated circuit transmitters, but this resolution may actually involve some protection circuitry that automatically reduces power in cases of impedance mismatch in order to prevent cooking the micro-electronics from reflected power from the antenna. If so, using the regular cellphone antenna may provide the highest and safest signal output.

I know some phones have the option of using external antennas.

While they may not be much longer than the phone's native antenna, it does allow for one to place the antenna somewhere that may get better reception (say, up a tree or something) without requiring the user to place themselves in danger just to get a signal.

With that said, if I actually needed a cell phone that I could somewhat rely upon in remote places....I would probably be looking into a satellite phone, or at the very least, a modern bag phone (which is still allowed to operate at 2 watts). Typical consumer phones tend to fall short when it comes to rural/remote use.

At the risk of being called old again, does anyone remember the Motorola bag phones? Now there was a bear whomper!

Not to mention five watts of power. Here in Texas, the farmers resisted the change to digital for so long, their phones just finally quit working. Local carriers kept the legacy system going for several years beyond their original cut off date because the farmers/ranchers just wouldn't give up the old mounted phones in their trucks. Those old unite would get a call out much farther from a tower than the newer 2G and 3G handsets.

I've use a Wilson external cell phone antenna on my old "smartphone", (worst cell phone I've ever had the occasion to use by the way but I digress), it definitely helped when using the phone up in the high deserts.

I now use a Blackberry, no external antenna connection on it. After talking to some sales reps from Wilson I learned that the only way to get the benefit of an external antenna with it is to use the booster amplifier along with my original antenna.

Couple of hundred bucks for the booster, haven't purchased one yet.

I hiked the Grand Canyon last weekend. I did not take my cell in with me but others did. I made a call and text from the 1.5 mile resthouse on Bright Angel using a friends phone.

Texts work on less 'bandwidth' than calls but you still need an active signal. IME, I have tried many times sending text just outside a signal area under the impression it would continue to resend until I walked into the signal in the next ten minutes or so. This is not the case with my phone. It alerts it cannot send it and goes to drafts.