What rules do you need to know in order to operate your cell phone in a survival situation?

I found the following in a book and would like to know if they apply?:

If you only have a faint or intermittent cellular signal, try dialing the emergency number as this works at a higher intensity than normal calls. If neither brings response, try turning your phone on and off in an SOS pattern. You might be heard by one of the military or civilian ‘ears in the sky’, which monitor all signals. Short Morse code-like signals are the easiest to separate from other background electronic ‘noise’.

It might take a day or two before your distress message is analyzed, but it could be your pathway to rescue.

The Japanese rescue service urges lost parties to keep cellular phones on or to turn them on as soon as they hear aircraft, as all cellular phones regularly emit unique ‘pings’, or identification patterns. These help the cellular network locate you during the sending and receiving of calls on your number.

Thank you!

the signal doesn't increase when you dial an emergency number.
Turning on and off in an sos pattern would be useless as the cellphone will just make its first ping once powered up then ping at regular intervals afterward so you can't really make much of an sos pattern unless you spread it out to minutes for each dot or dash and then no one is going to listen to one frequency long enough to notice.
The pings are not to help the network locate you while sending and receiving calls, they have complex protocols based on the signal strength during the call for this, the pings happen while your not making calls so the phone can check signal strength to switch between cell towers.

This webpage has some good related info.

Sounds like nonsense to me. Can you cite references for all these things?

My suggestions are:

1) If you have faint or intermittent signals use text messaging.
2) If you have faint or intermittent signals keep your phone turned off to save battery life.
3) Always tell someone where you are going and what time they should expect you there (or back).

The reason for (1) is that text messaging uses less bandwidth than voice, and can be sent in a short time (i.e. can make the most of windows of opportunity as the signal becomes available). The reason for (2) is because if the cellphone cannot contact a cell tower it will keep increasing its transmit power in an attempt to do so. If there are no cell towers then it will be using full power to no avail. I suggest you keep your phone off but have a schedule- say every hour. This leads on to (3). The reason for (3) is "D'uh!". Not only can this person who knows your travel plans initiate help if you don't show up, but they will also know that you will be checking your cellphone only every hour to save batteries. Maybe you have an FRS or ham radio too, which should be turned off except for regular schedules to save power.

Or rather, that's my opinion.

A

The only other thing that would probably help is to try to get up as high as possible. Since the radio signal at cell phone frequencies behave similarly to light, you have to be able to 'see' the cell tower (line of sight). Mountain ridges and peaks may be the best place, canyons and low places the worst.

These two previous posts are pretty much dead on. Modern cell systems are continuously adjusting the phone power to minimize interference from adjacent phones and to maximize the battery life of the phone. If your signal is weak, the phone is probably already running the transmit amplifier as high as it can.

It is also true that control channel signalling is going on continuously while the phone is on. Some of this signalling may get through even though you can't establish a voice call. It's also true that any given carrier may log this data in different ways and have differing abilities to access the information. It's not something that happens every day, so the switch techs may or may not immediately know how to do it.

The FCC has required that all carriers have the capability of obtaining location data from cell calls within a defined level of accuracy. However, not all carriers may have this equipment yet, and rural carriers are likely to get it last. GPS in the cell phone provides the greatest level of location accuracy, but not all phones have this yet. There are several location technologies that do not require GPS in the cell phone, but they are potentially much less accurate (miles).

It's true that messages may get through where voice calls can't. Voice calls require a constant data path while a packet message doesn't. Similarly, if you are in a disaster situation where the voice network is tied up, short messages might get through. In particular, EVDO (Sprint, Verizon) runs on a completely separate radio network than the voice system, and is likely to be less busy. Working with a Salvation Army Canteen unit in Mississippi post-Katrina, they were getting emails slowly while voice calls rarely made it through.

The antenna and terrain are huge issues when considering the ability of the phone to make a call. I used to have a larger phone with an extendable antenna. It tended to work pretty well. Newer, tinier phones with no external antennas make it harder to get a good RF link. If your phone can take an external antenna, it will have a much easier time getting out. You lose a lot of signal making a call from the inside of a car.

Getting the phone up high with respect to the surrounding terrain and trees will make a big difference. If you have a bluetooth headset, it could be possible to put the phone on a tall stick and make a call from the headset. Maybe tie the phone on a string and throw it up on a tree limb. My bluetooth hands-free thingy in the truck works 30-40 ft outside my truck.

To Ame,

This information was extracted from a book titled, "Outdoor Survival, The essential guide to equipment and techniques", by Garth Hattingh - copyright 2003.

I'm sort of concerned about all the information that is in this book, now.

To everyone, thank you all so very much for this information.

NO, no no no. And no.

Mobile phones are limited in power output and do not have the ability "raise their power"

Turning ON and leaving ON a cell phone does broadcast a signal. They use cell phone tracking here in NYC to locate victims in the WTC rubble. Just leave it on.

One think to consider in a "Wilderness Survival Situation" where your cell phone will normally be off because you are out of cell phone range is that a cell phone is a Line-of-Sight communication device. That means that you can climb to high ground (Insert: a mountain or large hill)and you may be able to call out on the phone from a location far from any cell tower. I have actually experimented with this in the Rocky Mountains and reached a cell tower over 50km away.

Also when you are out of range your battery usually drains faster. Part of this is due to some phones falling back on an older technology such as analog which takes more power and partly because the cell phone will 'ping' more often trying to find a tower. You may need to power off to conserve energy.
We stopped buying analog capable phones this last round as the analog network is slowly going away. A tower near my parents must have been taken offline sometime last summer as we stopped getting a signal there unless we go half way up the mountain. Our phones would constantly go dead then trying to find a signal.
Also text messaging, as others have stated, takes less time, just a fraction of a second is all it needs and a text message wil stay queued up and send when the phone does find a signal enev if only for a brief time. I made sure our phones are text capable enev though we get charged for them since we don't have text built into our plan, in an emergancy the cost is a small price to pay.

One thing I'd like to throw in is the benefit of using phones which have a GPS built in.

I recently purchased a new Blackberry Pearl 8130 which has a GPS built in. I live downtown and have had mixed results with getting a lock amongst all the buildings with some GPSs. Yesterday I fired up google maps (the mobile application for phones and PDAs) and it gave me the option to find my location without the GPS signal using tower information. It pin pointed me to within 300m.

Granted this requires the phone to be able to talk to a tower but if for any reason the GPS won't work (heavily wooded area? Weather? etc?) and you're within range of a tower (there are quite a few areas in Jasper which are like this), it's just another tool in the box which can help you find yourself. The other benefit with google maps is that if there is a road, cut line, etc. nearby it is likely to show in the satelite images.

A lot of phones have a fake GPS though (called aGPS which IMHO is a very bad name) so their location doesn't work without cell service.

If you depend on your cell phone as a survival tool, there are only two rules -

1. Verify you are going to an area that has cell service.
2. Verify you are equipped to keep it running.

Study the results of those that didn't - i.e.

- James Kim & family
- Mt. Hood climbing team
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What model phone do you have? I've done a lot of testing on this with several and can't find one that will do this. With no signal, they would attempt to send and fail. I could manually try to resend the message over and over until I had a signal but they would never automatically resend when a signal came up. Cell signals here in Idaho can be very spotty so this would be very useful.

last time I tried was with a qualcom phone. The cheap LG ones we had didn't last long enough to test it, I still need to try with the new phone, haven't been in an area without service yet.

Most Modern Phones have the antenna built into the body of the phone. Ancient phones like the Ericsson SH888 (my first phone 1998 ) pictured below have an external antenna.



A trick to increase the antenna gain would be to get a old coffee tin can or something similar and at the centre of the base of the tin a small hole large enough just to insert the cell phone antenna would be made. Pointing the tin and cell phone at the base (just slowly rotate through 360 degrees at the highest available point until the signal strength meter indictated the highest signal strength) would dramatically increase the cell phones range.
Its a similar technique to the long distance mesh networks being created in Africa.
Sadly though most phones do not now have external antennas.

This is the best and most to the point reply yet....

You'll save much-much more if you can turn off the screen back light. I believe the phone will last longer with BT headset because the screen is completely off when you use it (though BT itself will consume some additional power).

Regarding the aGPS feature. It's useless in the forest compared to the real GPS. You will need at least 3 towers in range (such an overlapping is rarely used in rural regions) to use it and they are all near the horizon. The GPS satellites are always above you head, just find a bit more open to the sky place. However, Hacksaw is right, aGPS may beat the real GPS in urban jungles - no doubt.

Also I've heard that it is possible to improve the reception with aluminum foil reflector. Though only used the foil once to _reduce_ the signal strength in close proximity to the powerful tower in the park (it was a rare problem with strong signal interference with it's own reflections).

There is a solution for the cars:
http://www.repeaterstore.com/products/repeaterkits/wilson/40db-vehicle-801201.html
In fact it's a wireless repeater (no wire to the phone antenna required).

They have even more portable devices: http://www.repeaterstore.com/products/repeaterkits/index.html

Those button sounds don't take that much battery life, they are coming from the same tiny speaker as the voice. I never turn mine on though since they are just annoying.

While a lot of cell phones may not have an external antanna, a lot do have a small port to connect one. Usually there will be a tiny yellow plug, though someone told me on newer Motorola its built into the USB port which seems odd to me. But for most you can buy a ~$50 antanna and plug it in.