Has this been done before? I don't know how useful it is, but I did it just for kicks and it turned out pretty cool. I realized that my strong signal (what is that?!) which is desentizing the the receiver is repetitive by day. Perhaps it's something at the hospital! Days are 3/7/2011 through 3/12/2011, separated by black lines.
Higher resolution image here:
Cool stuff. All right, I'm outta here.