i am new , so i am not sure if this is the rite place. my Question i want to show my students how to block the signal coming from a wireless router. Pl help!? i have tried wrapping the antenna with aluminium foil and putting the whole modem in an aluminium container, none of which works. thanks. when i put my mobile phone in the aluminium container , it successfully block the mobile phone signal. why doesnt it block the signal from my modem???