Posted by 4DFM on February 12, 2009 at 12:30:20:
http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-09-7A1.doc
http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-09-7A2.xls
So if I am interpreting the FCC's ruling correctly, the 4 major stations in Madison (3, 15, 27, 47) can't cut off their analog signals unless certain requirements are met, including having at least one of them stay on as a "nightlight" for an extra couple of months.