It looks as if you are right. Direct TV must be transmitting HD through the SD satellites on those channels. I hooked my laptop up to the KVH system and verified the antenna is locked on the same satellites it always has been. My Samsung TV has to reset itself when I switch to and from those channels which tells me it is changing resolution. I do have 16:9 aspect ratio set for all channels so the picture size really doesn't change but the quality does. But why those channels??I have been using directv since 2006. I have my motor home setup, my house setup, and my boat set up. I am very savvy with the systems. This is a change that just occurred.
View attachment 129239
View attachment 129240
Compare. The lower one is definitely in HD.
Ken