How to block cell phone signal?
Now the latest device for jamming mobile phones is called a cell phone scrambler.
All cell phones which use GSM800 have their transmitted and received frequencies always separated by 45MHz. So when the mobile phone tries to call, it is blocked by its own signal returning to it! Isn’t that cool? When the phone blabber annoys you – turn your mobile phone jammer on and that wrongdoer will hear own voice in his or her cell phone.