The superphone

By Marcus Wilson 29/11/2013

Something isn't right. Our laboratory facilities contain a couple of Faraday-shielded rooms. The idea is that electromagnetic radiation can't get in (or, for that matter, out). That means mobile phones shouldn't work in there. And they don't. Mine has no reception at all – others in our research group report either no reception or 'one-bar' reception occasionally, and that with the door open. At least, that used to be the case. Then a summer student arrived. With him came an extremely new 4G phone which WORKS JUST FINE inside the Faraday shield with the door closed. Not only that, but the student reports that he gets better reception in the room than at home. THIS IS NOT SUPPOSED TO HAPPEN. 

For sure, we don't expect the room is perfect. It needs to have holes in it, such as letting internet cables through (no wireless reception, obviously) and, a little more importantly, air. But there shouldn't be much radiation at all. In fact, we have two shielded rooms across a corridor from each other – one is used for electrophysiology (where we look at very tiny voltage signals) and the other for simulating lightning strikes on electronic equipment (where voltages are very high). The fact that the lightning experiments don't interfere with the electrophysiology ones shows that it's working. So how does my student's phone get really good reception? This is still a bit of a mystery.