Mobile phones

[kerrymoralee9280]

I'm sure I've read something like this here before but can't find it. Is there a device that can be used in classrooms to block the mobile phone signals.

I may be well off here but like I say I'm sure I've seen it somewhere.

[sidewinder]

Im pretty sure that jamming frequencies like that is illegal. But yes there are devices

[linkazoid]

you want to be looking for devices that work like a farday cage.

[elsiegee40]

Most of the threads I have seen have been along the lines of detecting kids phones using bluetooth, rather than about blocking phone signals

If you block the phones, chances are your wifi and any cordless phones in school won't work too.

[localzuk]

Im pretty sure that jamming frequencies like that is illegal. But yes there are devices

Yep, blocking by using a jammer is illegal. However, blocking with some form of paint which blocks signals is allowed as far as I'm aware.

[Jona]

I'm not entirely sure of the science but making a Faraday cage with paint, mesh or foil isn't that practical if you still want to have windows.

Car's are pretty good faraday cages but you can still use phones inside them...

Other signals such as mobile phone signals penetrate the skin of cars and aircraft because the wavelength of the signal is significantly smaller than the holes present on the surface of the conductor (the windows).

Ref: http://en.wikipedia.org/wiki/Faraday_cage

Also if you did manage to achieve this it will probably break any wi-fi (or at least restrict it to one side or other of the cage)

Cheers
Jona

[dhicks]

I'm sure I've read something like this here before but can't find it. Is there a device that can be used in classrooms to block the mobile phone signals.

I bet it would be a lot easier to make a device to simply detect a mobile phone signal... Hand-held maybe, or an arch in the doorway, or ceiling mounted like a CCTV camera?

--
David Hicks

[enjay]

Most of the threads I have seen have been along the lines of detecting kids phones using bluetooth, rather than about blocking phone signals

Only works if a) the phones have b/t, b) it is enabled, and c) the phone isn't hidden. I always have my b/t turned on so my phone can connect to the hands-free in my car, but it is hidden so searches for b/t devices won't find my phone.