If you're talking about the national PBS feed - they show a HD demo loop all the time with the exception when they are showing special widescreen SD or HD. For instance: everyday @ 7:30PM (EST) they show "Smart Travels". Note: most PBS stations are doing multicasting and that means the HD channel (-1) is not true HD - 19.2Mbs but 15.0Mbs. You can check PBS's special presentations here: http://www.pbs.org/digitaltv/dtvsched.htm