jmshep

I had a Faraday cage installed in a workshop some years ago. The test after it was constructed was to place a fairly high powered transmitter inside and make sure that nothing was received on the outside. The testers' party trick was to put a £5 note in the door seal and with the door closed, a signal was received out side.
Incidentally the room had two 300mm square vents for air conditioning and these were of a honey comb construction, each segment being about 6mm across.
The walls, floor and ceiling were a sandwich of two sheets of steel with particle board in between. It was ok to screw things to the wall as long as you did not bridge the gap.