It turns out that NASA's video material isn't only available through the Internet. In fact, NASA has its own TV channel, which is carried by many satellite and cable providers. The channel may also be syndicated by local public-television broadcasters or by amateur broadcasters, who likely use UHF frequencies. Remember, Meilingers' video baby monitor is like a TV. While we don't know which model of Summer Infant baby monitor the family owns, all of Summer Infant's video baby monitors use either the 900 MHz or 2.4 GHz frequencies. That would put them smack in the UHF range, which includes frequencies up to 3 GHz. Although UHF television stops at 812 MHz, an amateur broadcaster may be illegally broadcasting the signal at a higher frequency. If this is the case, the monitor is in essence acting like an old-style television, picking up the NASA signal through direct reception.
Of course, it's possible that something else is going on, but as far as we can tell, this is the most likely explanation. In fact, if the Meilingers (or anyone else living nearby) have a 900 MHz or 2.4 GHz cordless phone, they may be able to pick up some of the audio from the NASA television feed -- in case they're using their baby monitor's second channel (which is functioning normally) to actually watch their baby.
For more information about baby monitors, NASA and to see footage of the Atlantis astronauts at work, please check out the links on the next page.