Cell-phone location and "pings"

[calebprime]

I don't own a cell-phone, and have used one only a handful of times. I've had to ask my wife or kid what buttons to push. So I'm completely ignorant.

The reason I'm asking about this is to get some simple answers that relate to the case of Franco Garcia, a Boston College student who went missing after February 22.

This is a serious case. But my interest is mostly the result of seeing too many murder mysteries -- I have this fantasy that I can find a clue, help the investigation. As likely as winning the lottery, no doubt. The area has been thoroughly searched, by divers, by pros with dogs, and with helicopters.

Often, people are found quite close to the last place anyone saw them. (The Lindbergh kidnapping, for ex.)

He left a bar around midnight. The police found an ATM photo of him walking by at 12:18.

http://bostonherald.com/news/region..._as_cops_halt_reservoir_search_for_bc_student

The news accounts say "the last ping from his cell phone was picked up at the Chestnut Hill Reservoir at 1:17 a.m.". The reservoir is just across the street and stands between the bar and the BC campus, where his car was found still parked.

1) How often do cell-phones send out pings?

2) How small an area does the cell-phone ping indicate? (Given that this is a dense area, a suburb of Boston, are there a lot of towers?)

3) How hardy are cell-phones? If you threw one into the water, would it immediately stop working? If someone wanted to destroy his cell phone, would it be quick and easy?

4) Can the phone simply be turned off to stop pinging, or does the battery have to be depleted? How long do cell batteries last?

 

[Skeptic Ginger]

LMGTFY

The Snopes answer has a fairly comprehensive answer to your questions.

 

[calebprime]

Thanks for the Google.

I was able to get a good idea of where the police are continuing to search by observing a helicopter flying over the reservoir region.

All I found today was a dead cat, a knife, old shoes, many sodden pairs of underwear, a socket-wrench set, and a homeless-person's former hangout, with a cache of uninteresting paperback books.

But I was completely happy the whole time.

If anyone else has any thoughts about cells or this case, lemme know.

 

[Skeptic Ginger]

I wanted to volunteer to look for a missing boy in B'ham but it was too far away. Sometimes these things get to a person for unknown reasons.

In the B'ham case the boy disappeared after a party his first night away from home to start college. He was intoxicated. They found him when his drowned body floated to the surface as they do during decomposition after a couple days at the bottom.

There was a rash of disappeared college kids, all boys, all later found drowned that some people tried to connect but they could have all been coincidences. I'll see if I can find an old link.

I hope they find this kid alive but it doesn't sound good. Intoxicated kids go swimming in the middle of the night. Or sometimes they slip and fall in.

 

[Skeptic Ginger]

I see they added Dwight Clark, the B'ham boy to the list. It makes me sad to see his picture again.

Drowning in Coincidence

 

[Skeptic Ginger]

Though a body should be floating by now (it takes about a week) the reservoir does look big enough that divers might not have found him. If his body is stuck under anything, it may not float to the surface until the body comes apart. I'd keep checking on the water with binocs for a while looking for something that looks like floating clothes.

 

[Cuddles]

1) How often do cell-phones send out pings?

Fairly regularly, but you'd have to let Google tell you any more than that.

2) How small an area does the cell-phone ping indicate? (Given that this is a dense area, a suburb of Boston, are there a lot of towers?)

Depends entirely on where it is and how many towers it can actually contact. Remember that it doesn't matter how many towers are in the area - one of the reasons there need to be a lot in cities is that the buildings often block the signal. What matters is how many towers the phone can actually contact. A single ping could be triangulated down to tens of metres, maybe better, or could cover an area of several square miles.

3) How hardy are cell-phones? If you threw one into the water, would it immediately stop working? If someone wanted to destroy his cell phone, would it be quick and easy?

Water will block the signal even if the phone itself is waterproof (and yes, you can get waterproof smartphones). But for most phones, throwing them in water while they're switched on is a good way to screw them up - even if it doesn't cause permanent damage it's unlikely to work again until it's been dried out properly.

4) Can the phone simply be turned off to stop pinging, or does the battery have to be depleted?

Turning a phone off turns everything off. Plus, for pretty much every non-Apple phone you could simply take the battery out.

How long do cell batteries last?

Depends what phone and what you're doing with it. A good phone with a high capacity battery and with most features inactive can last for a couple of weeks or more if it's not being used. Turn on internet, wifi, bluetooth, GPS, music, the screen, and open lots of apps to use the CPU and RAM and the same phone will last a few hours at best. Most people tend to get no more than a day or two of normal use.

So in this particular case I can't say how accurately they can pinpoint his last location, but it's very unlikely that his phone will be heard from again.

 

[Bob001]

Interestingly, the Snopes entry recommends that if you are ever lost in a wilderness area and unable to get a cell signal strong enough to make a call, you should turn your phone on periodically in hopes that it might still be able to ping a tower and help rescuers locate you. Question: I am assuming that the phone must ping when it is first turned on. How often after that does it ping? Every few seconds? Every few minutes? Only when it loses a connection to a tower and has to find another one? Anybody know?

 

[calebprime]

Thanks, Cuddles.

As for the first question, the Snopes page said pings occur every few minutes, I think.

What's he doing in the reservoir area for an hour, or what's happened to him in that time? Or did he meet with someone before the last ping? The walk through the area would take no more than ten minutes, and the weather was in the high 30's, and he was a little under-dressed* -- from the ATM photo that shows him covering his hands with his sleeves.

No idea.

His friends said, I think, that it was his style to leave a party quietly and take a cab, but I think maybe that ATM photo shows him already walking past where I often see cabs waiting, on Beacon St.

His Facebook page shows he likes to party, and bands associated with partying, but it gives off a very cheerful vibe, no clues there.

Pharmacy worker and chemistry major = access to or interest in drugs?

Idle speculation, such speculation would be offensive to anyone who knew him, probably.

The simplest explanation is that he fell into the reservoir, and that many searches by divers have failed to turn up anything -- just by some fluke.


* The ATM photo shows him wearing a light-colored pullover of some kind, not the dark North Face jacket that the Missing Person posters mention.

----------------------------------------

Yikes, I'm turning into an armchair detective, speculating based on nothing.

 

[Skeptic Ginger]

...Water will block the signal even if the phone itself is waterproof (and yes, you can get waterproof smartphones). But for most phones, throwing them in water while they're switched on is a good way to screw them up - even if it doesn't cause permanent damage it's unlikely to work again until it's been dried out properly.....

In Dwight's case the phone quit pinging underwater (all the more reason to think this kid is in that reservoir).

My son dropped his phone in the water once. It killed the battery but the phone worked fine with a new battery once the phone dried out.

 

[Dan O.]

Cell phones won't ping unless they need to. They need to ping if they've been turned off and might have missed a message or when they move to a different cell group. Otherwise they save their battery by just listening for incomming messages and tracking the nearest towers. Some features like location tracking send periodic data that force the phone to transmit.

I've found that many cheap amplified speaker systems will pick up the cell phone transmissions and create an audible noise. If you hang around such systems you can learn how often your phone transmits.

 

[Mikemcc]

I've had an HTC phone die complete completely after less than a couple of minutes immersion, it didn't recover after dring out (don't go punting in Cambridge after it's been raining...)

When phones are initially powered up adn if they don't have contact with your provider they transmit at high-power, this is why the power capacity is caned if you aren't connected to your own provider. If you need to make an emergency call in Europe, dial 112, it will connect to the nearest tower, irrrespective of network provider. You may be able to connect even if you cannot connect to your normal provider.

 

[Kestrel]

What was the weather like on the night he disappeared? On a warm summer night, it would be tempting to walk back to BC on the lake shore path. But not on a winter night with any kind of wind.

 

[calebprime]

What was the weather like on the night he disappeared? On a warm summer night, it would be tempting to walk back to BC on the lake shore path. But not on a winter night with any kind of wind.

I looked up the weather report for Feb. 22. High 30's with scattered showers, and from the photo taken by the ATM when he walked by, he was cold enough to have his hands tucked into his sleeves. He also appears slightly hunched over, as if he were cold. He was not wearing a coat.

The reservoir is big enough that divers might have missed him. Visibility is only around ten feet. (They also had sonar, though.) But it's small enough that you can see small things such as muskrats on the surface at any point, from any point. If a body surfaces, it will be painfully obvious.

Franco Garcia lived in Newton. He might have been walking up to Commonwealth Ave. to start walking home, maybe hailing a cab along the way. If he was too buzzed, he wouldn't be heading toward his car, perhaps. But it would have been too cold for him to make the walk all the way, lightly dressed as he was. I'm sure the police are talking to the cabbies.

Yesterday, I found an old wallet full of credit cards and a drivers license -- just off a path above the reservoir. It belonged to former BC nursing student Katheryn A W------. (She now works at a local hospital.) It was absurdly easy, with Google, to get a message to her to see if she wants it returned. It had been lying there for over 5 years. That shows how long little things, like a cell phone, can go missing. There's all kinds of crap like that buried in the leaves around there. It felt a little creepy tracking down nurse Katheryn, and calling the hospital, because I now know a lot about her life, without even being particularly curious.

Hunting for stuff: It reminds me of those nerdy guys you see on the beach with the metal detectors, looking for buried treasure. Very relaxing.

 

[Kestrel]

I looked up the weather report for Feb. 22. High 30's with scattered showers, and from the photo taken by the ATM when he walked by, he was cold enough to have his hands tucked into his sleeves. He also appears slightly hunched over, as if he were cold. He was not wearing a coat.

The reservoir is big enough that divers might have missed him. Visibility is only around ten feet. (They also had sonar, though.) But it's small enough that you can see small things such as muskrats on the surface at any point, from any point. If a body surfaces, it will be painfully obvious.

Franco Garcia lived in Newton. He might have been walking up to Commonwealth Ave. to start walking home, maybe hailing a cab along the way. If he was too buzzed, he wouldn't be heading toward his car, perhaps. But it would have been too cold for him to make the walk all the way, lightly dressed as he was. I'm sure the police are talking to the cabbies.

He could also have taken public transportation. A bus or the T line, if they still operate that late at night. Or accepted a ride from someone.

The last cell phone ping connecting to a tower near the reservoir is a clue that he didn't leave the area, but it's not absolute proof.

Yesterday, I found an old wallet full of credit cards and a drivers license -- just off a path above the reservoir. It belonged to former BC nursing student Katheryn A W------. (She now works at a local hospital.) It was absurdly easy, with Google, to get a message to her to see if she wants it returned. It had been lying there for over 5 years. That shows how long little things, like a cell phone, can go missing. There's all kinds of crap like that buried in the leaves around there. It felt a little creepy tracking down nurse Katheryn, and calling the hospital, because I now know a lot about her life, without even being particularly curious.

Hunting for stuff: It reminds me of those nerdy guys you see on the beach with the metal detectors, looking for buried treasure. Very relaxing.

We might even be hard wired to enjoy looking for stuff. Our ancestors had to do it to survive.

 

[GlennB]

We might even be hard wired to enjoy looking for stuff. Our ancestors had to do it to survive.

I think you're right. It never bothered me if I lost a golf ball in the woods but there was always a slight thrill in finding one that was not my own