Not quite.. It was just an upconverted signal, not true hd..
I compared SD and HD signals from the local Fox station. On the HD signal
there was a wider field of view. It's more like the SD was a down convert.
It's a little like when I play a DVD in Dolby 5.1 at home, and friends
listening to it say that the 5-speaker stereo variant sounds like the "real
deal" instead of the 5.1.
Much clearer, sharper, better color saturation, and more lifelike than any
SD I had ever seen before, so I couldn't believe it was just SD. My TV menu
confirmed it.
Interesting. I've never heard of that format, it explains why the aspect
ratio look correct but the detail level wasn't up to HD standards. Still
it's better than 4:3.
Your tv is doing the 1080i from the cable output. The actual signal to the
cable company wasn't hd. I have my cable box connected with an hdmi cable
and the box is set to 1080i so all the channels are 1080i no matter what
they are.