[unisog] Wireless in residence building - Tricky problem

Mitch Collinsworth mitch at ccmr.cornell.edu
Wed Nov 5 19:05:42 GMT 2003


On Wed, 5 Nov 2003, Stephen C Woods wrote:

> On Wed, Nov 05, 2003 at 01:13:30PM -0500, Mitch Collinsworth wrote:
> >
> > On Wed, 5 Nov 2003, Marc Jimenez wrote:
> >
> > > > Two signal strength-and-direction reading 10-15 foot apart in the hallway
> > > > and some triangulation would do it.  It's the electromagnetic version
> > > > of "which room has the annoyingly loud stereo in it?", which is also
> > > > solvable without a search warrant.... :)
> > >
> > > Absolutely true, we can certainly determine to *our* satisfaction that the
> > > AP is in the room, but incontravertable proof (which is what our school's
> > > disciplinary board requires) is a bit harder to come by. If you've got a
> > > more ... reasonable ... set of proof requirements, more power to you. I
> > > wish I did....
> >
> > I don't see why triangulation wouldn't be considered incontravertable,
> > though it's safer to do it with 3 samples, since doing it with 2 only
> > gets you to one of 2 possible locations.
>
>    Well it you can pick up a 100Mw 2.4GHz signal from the other side of the
> earth....

When using 2 sampling points that produce 2 possible locations, the
2nd possible location is not on the other side of the earth.  It's on
the other side of the line segment that connects the 2 sampling points.
Hence...

>    You don't need incontravertable all you need is enough to convince a
> judge to get a warrant.   It's a real strong signal and our
> triangaluation indicates it's originating 3 feet from the inside of the
> wall of that room.   With a warrant you can get the University Police
> to enter the room and see the AP sitting on the table.

...if you took the 2 sampling points from the hallway outside the room,
as suggested, then the 2nd possible location is in the room directly
across the hall from the suspected room!

-Mitch



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