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911 Power Boost
Temporary power boost reaches an out-of-range cell tower in emergencies | |
Your car runs off the interstate
during a blizzard. You're in a ditch,
stuck in the front seat with multiple
injuries, and snow is pouring in
through the smashed windscreen.
You can reach your cellphone. You
dial 911, but you're out of service
range. Do you really care about
having
two more days of standby
power on your mobile, when you're
likely to die of internal haemorraging
or exposure within a few hours?
You hit the "Emergency Power Boost"
button. It increments the transmit
power of your handset upwards in
stages until it finds a tower it can
link to. An onscreen graphic
provides an indication of estimated
call time. You also have the option
of sending a pre-composed SMS
with a single button if you are
unable to speak, or if talk time is
likely to be short.
Signal boosters are Widely Baked
http://www.dazer.com/booster.jsp
...but nothing's gonna help you if you're really out of service range. [DrCurry, Jul 17 2005]
In memory of my father's cousin
http://www.vosiznei...issing-brooklyn-man
[pashute, Aug 23 2011]
[link]
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Good idea, but would it work? I'm sure
you could have a phone with a "high
power send" option, but what about
receiving? I think (not sure) that
communication has to be two-way even
to 'send', since the phone has to
negotiate with the tower. So, you'd
need a more sensitive ariel on the
phone. Or is this not the limitation? |
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I'm disappointed - I was hoping this was going to be a way of getting a few extra horsepower out of my turbocharged flat-six. |
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Absolutely this would work. It's not even close to hard. Marine radios have two settings:
1 Watt / 25 Watts. You try 1, and if it doesn't go through you use 25. |
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//Absolutely this would work.// Not if
using your cell-phone depends on
receiving signals from the tower it
won't. I think. |
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Exactly - but even 'sending' requires
negotiation between the phone and the
base-station, as I understand it. |
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//You may be able to send but it's doubtful you would receive, unless the network signal is also boosted// But wouldn't the phone send a message as part of the negotiation saying that power had been boosted, so that the base-station could reply in a similar fashion? |
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Before the phone can do anything under the GSM standard it has to authenticate to the network. Even allowing that this may not be the case for emergency calls (I'm not sure on that point) 2-way negotiation is still required in order to set the timing advance of the phone's transmissions. The maximum diameter of a GSM cell as governed by this limiting factor is approximately 35km. Nice idea but [-] impractical. |
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How about an emergency helium bottle and weather balloon contained in the phone? Then, suspended from the balloon, the phone could rise and its signal easily cover a much wider area. How it would be traced back to the ditch-ridden would-be rescuee...I haven't worked out yet. |
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Based on the comparative size of the two transmitters, it seems reasonable to assume that the cellphone is usually the limiting factor for range, does it not? |
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Nope [Madcat], unfortunately not. The main limiting factor is as I described above the timing advance.
Because a phone is allocated a timeslot to use, if it is a long way away from the base station then in order for its signals to arrive in said slot it must set a timing advance so that it transmits earlier as compensation for the time its signals spend in transit. This advance figure can only get so big before the phone arrives at a situation where it needs to transmit its signal and receive one from the BTS simultaneously. There are other more complicated reasons why it won't work but my head hurts thinking about them.
The practical limit on GSM cell size is 35km across if you're prepared to tolerate shoddy call quality. You could get bigger cells if you lost some channels, perhaps a scheme worth considering for sparsely populated areas. This idea, however, will *not* work. |
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Just put all the ditches near cellphone
towers. |
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[basepair], no, that's impractical. I suggest that the cellphone towers be put near the ditches. Planning permission for ditches must include foundations for a cellphone tower. |
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CDMA is an entirely distinct kettle of aquatic life [UB]. I'm only just getting to grips with 3G/UMTS so I'll let someone with more knowledge field that one! |
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CDMA stands for Code Division
Multiple Access. GSM stands for
Global System for Mobiles or
something, but my understanding
is it works on TDMA (Time
Division) - hence [DocBrown]'s
anno. |
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Here in Australia, CDMA was
commissioned as a replacement
for the scrapped analogue network
in rural areas, with some promises
of better range than GSM (which is
mostly urban). |
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So -maybe- this would work with
CDMA phones. |
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Can 911 accept texts? It should. Video and email too. |
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Regardless of a signal transmission, could you set
the phone up with a screamer and have the towers
read it, triangulate, and send a location to
emergency response. It would probably interfere
with other signals on the same frequency, but a
brief pulse wouldn't be to disruptive. |
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Not as good as actual communication, but enough to
indicate a true emergency. |
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Some high-end German cars, have integrated a
'SMS' type distress alarm call function in their
installed on-board computer system. |
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The system determines is there has been a fatal
impact situation, by 'g'-force sensors, and calls for
assistance to the energency central. It might
connected to a trafic information system, dealing
also with trafic queue warnings (Auto Bahn), called
'DRS'. |
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An already existing solution, is to have a
replacement battery at hand. Or, also existing, a
supplemental, larger, external battery, to boost
charge the cell. I have one such, it itself is re-
charged via a regular USB connection. Cheap
Chinese handy-sized stuff. |
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Otherwise, : Your Porsche 911 is powerfully
endowed already, with a 3-7 kilo accumulator. A
cable car-to-cell connection will do the trick. |
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An emergency drone to be sent over area where
missing people are located, with a mobile cell for any
weak mobile phone signals could work. But then
again, during a storm a drone cannot be flown. |
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Then again, maybe this should be standard
equipment on police cars when searching in remote
areas. |
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The problem is not with the police cars, but with the police officers, who do not like to go out and search in remote areas, but prefer to stay in the station where it's warm and dry, there's a ready supply of coffee and donuts, and plenty of paperwork to make them look busy. |
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