On 16 Oct 2003 at 16:02, David Brodbeck wrote:

> On Thu, 16 Oct 2003, Matthew wrote:
>
> > i know a few people that work in the national security sector (people
> > that can't tell me what they do and who or where they work)... even if a
> > cell phone is turned off and the battery is out, the cell phone tower

>
> I'm not convinced of this, though if you have a citation for it I'd like
> to see it.  Would be easy for someone to verify with a frequency counter,
> I suppose.
>
> I'm pretty sure my phone doesn't transmit a signal when it's off because I
> can hear the data bursts interfering with my car radio when it does
> transmit.
>

I agree.  I am afraid he's been told some tall tails.  There is no way the tech
community would have missed something like this.  It is not hard at all to tell
when one of these little beauties transmits a burst.  Popular Communications
has a ton of devices for sale on it's pages that can tell you quite easily.

It is certainly possible to get a rough position from multiple cell towers of a
given active phone's position, but that's a different matter entirely.  To get
an accurate one, you would need timing info from at least 3 towers, with
resolution and accuracy (both) of around 10 nanoseconds.  Speed of light is
roughly 300 meters per microsecond, so 10 nS would get you within 3 meters, at
best.  And cell systems weren't designed to do this sort of thing.  At least
not yet.

Anyway, it's not friday yet, and I will speak no more of this.

tom

------
Tom Ring K0TAR, ex-WA2PHW  EN34hx
85 Westphalia GL Albert
96 Jetta GL The Intimidator
taring@taring.org

"It is better to go into a turn slow, and come out fast, than to go into a turn
fast
and come out dead." Stirling Moss