There is a hidden control panel that allows you to set up the HD input, which is unavailable as it comes from the factory. Unfortunately, I can't remember what it is, as I did it on my 65903 a long time ago.

With the input enabled, I can watch HDTV from a Unity Motion receiver, which will also accept OTA HD broadcasts if you have them locally (I think a Dish 6000 can too). There are no local stations here at all so I use only satellite, one Canadian DSS and a C-band dish as well.

I also watch HD from a Starchoice receiver and a 4dtv receiver through the Motorola HDD-200.