Excerpted from NASA Statement on Loss of Columbia: “Entry Flight Director Leroy Cain declared a contingency for the shuttle Columbia at around 9:14 EST … Communication and tracking of the shuttle was lost at 9 a.m. EST at an altitude of about 203,000 feet in the area above north central Texas. At the time communications were lost. The shuttle was traveling approximately 12,500 miles per hour (Mach 18). No communication and tracking information were received in Mission Control after that time. “
http://www.unitedspacealliance.com/video/live.rpm
http://science.ksc.nasa.gov/cgi-bin/rrg2.pl?encoder/nasatv.rm
NASA TV is on AMC-2, Transponder 9C, vertical polarization at 85 degrees West longitude, 3880 MHz, with audio at 6.8 MHz.