You're correct jeff.
As for this new channel 6 that I'm picking up, its all because of a new FM radio station that went on the air. Chicago had a smooth jazz station, 95.5 WNUA. That station went off the air and became some spanish station. WNUA was the only smooth jazz station. WLFM supposedly picked up the abandoned format on March 22, 09 and put it on 87.7 mHz, which just so happens to be the sound carrier for TV channel 6 and is broadcast off the hancock tower downtown. Apparently it is required by the FCC that if audio is being broadcast on a TV channel, that video information must also be sent.
This makes total sense now. There does not appear to be any attempt to shut down this low powered station, which is quite helpful. It atleast gives me a good VHF analog signal to work with when I work on my old sets. As long as its not total snow across the entire band, I'm happy.
http://www.wlfm877.com/