Scrying EM Fields

I’m still trying to wrap my head around this one. The idea behind scrying is to reveal hidden data – i.e. electromagnetic fields within a structure. (Like those created by a metal building/computers/etc) It does have other uses besides artistic – it can be used to analyse the 2.4ghz spectrum among other things. It looks like an interesting project, despite the odd description. (Lets just say that it’s an eccentric bit of reading)