BOB wrote:
> We do not know the legality of this project but there is some one spying=
=20
> on us with a toy QUADCOPTER.  It transmits the picture by WIFI.
> Is there some way to detect when a wifi signal comes into range and=20
> possibly get a directional fix on it.
>  =20
I'm sure there is a way, whether it's economical is another matter.

A spectrum analyser is less than ideal because it can miss stuff due to=20
the combination of wifi's intermittent transmission with the swept=20
nature of the instrument. Still with a video transmission i'd expect to=20
see something after a few sweeps in peak hold mode.

I'm not sure if standard wifi adaptors can be set in a mode where they=20
will detect all packets even those they can't decrypt. Something like an=20
ettus/NI USRP could certainly be programmed to do that kind of stuff but=20
it doesn't come cheap.

For a directional fix I'd think the only economical way would be a=20
rotating antenna mount. Phased arrays could be used in theory but i'm=20
pretty sure the data acquisition and processing hardware would fall into=20
the category of "if you have to ask you can't afford it".


--=20
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