Which, of course, was the primary reason behind our construction of the two cages. In our case, we were trying to isolate birdies in our tuned cavities and needed the ambient rf levels to fall below the -115 dBm level. The only way you are going to accomplish that is with a cage. It is pretty easy to find and fix the birdies in equipment when you can isolate all transmission energy to just the equipment and not having to look at the intermod/multipath from a dozen Broadcast transmitters.