Portal Radio Clock

Cool screenshot!

Here, have a cool thing I found:

In portal 2, when all the trash comes out of the cube vent in one chamber, pick up the radio. It's playing the portal radio tune. However, if you bring it into the main room of the rattman den in the level, it starts playing meaningless, shrill, static beeping. (Probably from the transceiver in the room?)
If this beeping is ran through special audio software, a static-y image of a companion cube on the moon with the aperture logo in the corner is found. (Oh, and you get the final transmission achievement for bringing the radio to the room)