Young Hikers Missing in Joshua Tree Since Thursday [7/27/17]

General Palm Springs area.

Re: Young Hikers Missing in Joshua Tree Since Thursday

Postby Wildhorse » Sat Sep 02, 2017 8:44 pm

Hi Z, that is so funny. I think I will start carrying such a stone, to remind me to laugh when I have lost perspective on things. So funny. Surely this is one of the ten essentials.
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Re: Young Hikers Missing in Joshua Tree Since Thursday

Postby cynthia23 » Sat Sep 02, 2017 8:56 pm

Made me smile, Zip. :)
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Re: Young Hikers Missing in Joshua Tree Since Thursday

Postby zippetydude » Sun Sep 03, 2017 5:09 pm

I'm glad you found it fun. The first time I saw it I decided it was comedic genius. I love the one word synopsis for most of the answers, especially the last one.

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Re: Young Hikers Missing in Joshua Tree Since Thursday

Postby Perry » Sun Sep 03, 2017 10:47 pm

bretpct wrote:
Here's OtherHand's RSSI map overlaid at a low opacity. Notice that the car and SWC lie at just about 10 miles from Serin Tower.

I know in my experience, when I've tried to locate my position on an iPhone with a poor signal, the map will show me within a huge circle (probably 10+ miles). I've also experienced on my iPhone "No Service" in the Angeles Forest, despite being in visual contact with a cell phone tower, only to have a cloud float into the perfect position and give my phone three bars. Then the cloud floated on, and so did my cell service.

The more I read about cell phone pings, the less I trust them for specific locations. Especially when only one tower is in play.

That's impressive. I had no idea there was that much detail in the file. Did you make it through that web site or software on your computer?

The first cell phone link assumes maximum radii with a huge amount of error. That doesn't really match with the experiments that Tom's friend did with the Serin tower and GPS on his phone. The GPS of the phone showed a slightly larger distance from the tower than what the tower calculated, by a few tenths of a mile I think. Granted, weird things can happen with cell reception as most of us have probably experienced.

Ric Capucho wrote:
Someone has just pointed out to me that Serin Tower is a Verizon tower, and that other carriers have their own towers located elsewhere. So unless we know Orbeso was a Verizon subscriber, then the splash map for Serin is inconclusive.

I thought I had read it somewhere in an article, but I can't find it again, so maybe I was mistaken or maybe the article was later edited. The Serin tower seems like a good guess because of similar distances to the Maze parking lot and the slopes west of Smith Water. Alternatively, a tower farther west and south of Serin would create an arc that passes through the slopes east of Smith Water, and the arc north of the car would be closer to North Canyon where the footprints and scents were found.

It seems unlikely that someone at the phone company would overlook the GPS data or another tower ping in the first 3 weeks of the search and that none of the authorities would ask questions about whether GPS data existed. Maybe the GPS data was transmitted but a checksum failed and it was initially disregarded as garbage. It would be interesting to hear from a cell phone expert. A 120-degree angle segment would explain how they know the ping was in the park.

One possibility of the single ping is that they turned off phones in the beginning of their hike to conserve batteries. When in trouble they turned them on again, one phone pinged. They were unsuccessful at calling for help because of bad reception, so they turned off their phones again to save batteries.

Looking at the northeast face of peak 4172, the signal to Serin drops off. And on a satellite image, there are boulders and shadows, so it might provide relief from the heat there. There's also a region of faint reception near Smith Water between peak 4965 and peak 4416 that is the same distance to Serin tower.

Assuming an alternate tower west and south of Serin, the area near peak 3543 north of the car has spotty reception, and also the lower slopes east of Smith Water near the county line and above Quail Springs.
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Re: Young Hikers Missing in Joshua Tree Since Thursday

Postby zippetydude » Mon Sep 04, 2017 5:13 am

I think of battery life the same way you do Perry. I turn off my phone when it will pointlessly search in a dead zone to avoid ending up running out of power. My kids in their 20's do not. They tease me and tell me I am old. While they are intelligent in other matters (one is pre-med and the other is studying biomedical engineering) they seem to consider battery life infinite...until we are together in the car and they are at 1% an I am at 90%. It is possible these two, who were/are college kids, had the same perspective. When I posted early on about hoping they had saved battery life to turn on their "flashlights" at night and thereby be found, I had this same concern in mind.

BTW, how a single ping is possible, both in this case and in the Ewasko case, is beyond me. The odds of just one ping to me appear infinitesimal...like you'd have to stay just below the Verizon horizon 8) , as it were, until the last few seconds of power were left, and then pop up only for a moment? How is that reasonably possible? It seems to have happened 2 times (Bill's phone and one of the phones involved in this case) and I'm at a loss to explain how this could have occurred. 5 pings, 8 pings, 3 pings, some random but small number okay...but both exactly 1 ping? Hard to understand that. If you catch my drift, it's like spotting two steady lights at a distance, but each for only perhaps a thousandth of a second...? No conspiracy theory proposed, just at a loss.

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Re: Young Hikers Missing in Joshua Tree Since Thursday

Postby Ric Capucho » Mon Sep 04, 2017 6:57 am

zippetydude wrote:I think of battery life the same way you do Perry. I turn off my phone when it will pointlessly search in a dead zone to avoid ending up running out of power. My kids in their 20's do not. They tease me and tell me I am old. While they are intelligent in other matters (one is pre-med and the other is studying biomedical engineering) they seem to consider battery life infinite...until we are together in the car and they are at 1% an I am at 90%. It is possible these two, who were/are college kids, had the same perspective. When I posted early on about hoping they had saved battery life to turn on their "flashlights" at night and thereby be found, I had this same concern in mind.

BTW, how a single ping is possible, both in this case and in the Ewasko case, is beyond me. The odds of just one ping to me appear infinitesimal...like you'd have to stay just below the Verizon horizon 8) , as it were, until the last few seconds of power were left, and then pop up only for a moment? How is that reasonably possible? It seems to have happened 2 times (Bill's phone and one of the phones involved in this case) and I'm at a loss to explain how this could have occurred. 5 pings, 8 pings, 3 pings, some random but small number okay...but both exactly 1 ping? Hard to understand that. If you catch my drift, it's like spotting two steady lights at a distance, but each for only perhaps a thousandth of a second...? No conspiracy theory proposed, just at a loss.

z


Not only does this millennial generation *not* switch off their smart phones (in case they miss a critical message about haircare products from one of their various social media accounts) but they tend to use the moving maps on their smart phones for primary navigation.

I use MotionX all the time when I'm out on my mountain bike (or hiking) primarily to record my distances/efforts for posterity. The moving map it comes with is best when I have a signal, but sometimes whites out when out of service. Not sure what Maps or Google Maps does when out of service. Anyone know?

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Re: Young Hikers Missing in Joshua Tree Since Thursday

Postby Ed » Mon Sep 04, 2017 9:19 am

It was only a year or two ago that I learned that my cellphone quickly exhausts its battery when left on in a remote location. Learned it from leaving my cell phone on, contrary to my normal practice. Took me two or three experiences, and a little research on the web, to realize what was going on.

I've learned a lot from this discussion, and doing research on the web. Started from near zero, since I had not followed the Bill Ewasko discussion. But the more I learn, the more uncertainty there seems to be. For example, unlike Europe, there seem to be no requirements in the US for what information cell phone providers keep, or how long they keep it. Except for 911 calls, which seem by law to trigger more information being sent and stored.

By the way, there seem to be 'Cell Phone Forensics Teams' associated with SAR, the NPS, and other organizations involved in SAR. The use of the term 'Forensics' suggests that this stuff is not slam dunk, even with far more information and expertise than we have.
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Re: Young Hikers Missing in Joshua Tree Since Thursday

Postby bretpct » Mon Sep 04, 2017 12:41 pm

Perry wrote:That's impressive. I had no idea there was that much detail in the file. Did you make it through that web site or software on your computer?


I just uploaded the picture from Tom's website onto CalTopo, then aligned it on the map, and turned downed the opacity until I could see the base layer. CalTopo's an awesome tool if you haven't checked it out.
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Re: Young Hikers Missing in Joshua Tree Since Thursday

Postby Perry » Wed Sep 06, 2017 11:46 am

Seems like a survivalist and former girl scout would turn off their phones. But maybe a dying battery could explain 1 ping.

According to this site
http://www.cellreception.com/towers/tow ... ate_abr=ca
there's 2 T-Mobile antennas on Joshua Lane in Yucca Valley, but when I zoom in on each I see an office building and a baseball diamond with football field.

The AT&T tower is way over on the east side of 29 Palms. That location would not create an arc that passes through Maze parking and Smith Water.

Does anybody know what this meant?
Sunday started with a briefing and the deployment of K9 teams, who might have picked up a scent. “There’s an area the dogs have some interest in, in a very rocky area in the northeast corner of the park,” Messaros said.

from http://www.hidesertstar.com/news/articl ... 967e7.html
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Re: Young Hikers Missing in Joshua Tree Since Thursday

Postby Ed » Thu Sep 07, 2017 8:50 am

If you Google 'Cell Phone Forensics for Search and Rescue', you can download a pdf copy of a presentation on the subject. Seems to be dated 11/14/2015, in the title. If you follow the flow chart on the fourth page for the case we are discussing, it seems to agree with what I believe OtherHand has suggested, so much depends on the 'registration' data received and retained by the cell phone provider. Certainly there are plenty of explicit warnings in the presentation that this is not a simple subject.
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