Re: "Amendment would allow the CAFOs closer to some homes"

Ann wrote:
On Tue, 28 Aug 2007 13:50:56 -0400, Elmo wrote:

Ann wrote:
On Tue, 28 Aug 2007 08:03:01 -0400, Elmo wrote:

Ann wrote:
<SNIP>

Since the wireless carriers are only required to locate within 100
meters, the technology isn't as accurate as land line Caller-ID in
high population density areas. But for someone trapped in a car
that's run off the road or a farmer, hiker, hunter, etc having a
heart attack in a rural area, 100 meters is close.


Without having the phone receive GPS satellite signals so it can
"know" where it is and tell the nearest tower[1] when it asks, the
ability to locate a phone depends on the range of the cell tower. Most cell towers have 3 antennae each of which handles 120 degrees of
arc and out to the range of the tower. In urban environments, the
number of towers is relatively higher and the antennae are configured
to point more "down" than "out". This prevents a tower from being
overloaded. In more rural areas, the range is often greater. So if
the phone can't say "I'm at GPS location gridX, gridY" the best the
tower can do is to locate the sector the particular antenna the signal
is being handled by and say "That phone is somewhere in this area."[2]


[1] Towers don't have to be on towers, many are on buildings. [2] I
learned all of this while on a jury where the location of the
defendant's cell phone over time was used to match up with other
evidence which indicated that the person who stole the car from
location A and abandoned the car at location B and the cell phone
which was near point A at the time the car was stolen was later at
point B where the car was recovered. By itself it wouldn't have been
compelling evidence but it supported other evidence.
Lesson being not to carry a cell phone with a GPS chip while committing
a crime? <g> That's interesting. From what (little) I did read about
it, the FCC keeps granting extensions for a number of cell carriers to
meet the 100 meter requirement.


This was pre-GPS cell-phones.

They had to get a techie-dude from the cell phone carrier to explain the
records which showed a call from [defendant's phone number] to
[unspecified person but I believe it would have been the accomplice who
had been convicted separately] being transferred from cell-tower to
cell-tower. They had a map of the coverage areas for the towers and
each antenna sector so you could see the progress from the "scene of the
crime" sector to the "recovery of the stolen vehicle" sector and how the
freeway ran through ALL of those sectors. The point being that 100
meters can't be guaranteed if the cell tower sector covers a big area. In this case it was somewhere within a 120 degree arc of a circle with a
radius of about a mile from the tower location.

The other thing that can affect the ability to locate non-GPS phones
(like mine -- I have an old Garmin that tells ME where I am but doesn't
let on to anyone else) is the overall coverage area. My carrier
provides very good coverage maps. My house is rated "very good" but if
I go out the door and slide down the bank to the creek level the rating
falls to "marginal". The steep slide down to the creek puts that area
in a "shadow".

Going back a bit, to what you mentioned about some towers being aimed
"down". I think that must be the case with the primary carrier here.
There is coverage in the valley, a mile away, but only up to about 1,700'
on the hillsides. (Looking at the coverage map one can surmise where the
tower is and the hills aren't in shadow.)
I'd say the towers aren't so much as in a shadow as on the wrong side of the "sun".

--
They're locking them up today they're throwing away the key
I wonder who it'll be tomorrow you or me.
.

Relevant Pages

  • Re: "Amendment would allow the CAFOs closer to some homes"
    ... But for someone trapped in a car ... heart attack in a rural area, 100 meters is close. ... ability to locate a phone depends on the range of the cell tower. ... location A and abandoned the car at location B and the cell phone ...
    (misc.rural)
  • Re: "Amendment would allow the CAFOs closer to some homes"
    ... But for someone trapped in a car ... heart attack in a rural area, 100 meters is close. ... ability to locate a phone depends on the range of the cell tower. ... location A and abandoned the car at location B and the cell phone ...
    (misc.rural)
  • Re: "Amendment would allow the CAFOs closer to some homes"
    ... But for someone trapped in a car that's run ... rural area, 100 meters is close. ... locate a phone depends on the range of the cell tower. ... A and abandoned the car at location B and the cell phone which was near ...
    (misc.rural)
  • Re: "Amendment would allow the CAFOs closer to some homes"
    ... But for someone trapped in a car that's run ... rural area, 100 meters is close. ... locate a phone depends on the range of the cell tower. ...
    (misc.rural)
  • Re: NYPD Tickets 9,016 Drivers In Cellphone Crackdown
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