I have an HDTV LCD TV and a satellite box. The other day, the first free HDTV program was broadcast (Robbie Williams in concert), but I could not discern any difference. Then I figured that I was only using a SCART cable, which might have degraded the HDTV signal.
What connection should I be using to hook the TV to the satellite box?
I don’t know anything about your TV/Sat Box/Provider/cabel connections, but all of those have to be just right or you just get SD. Also you might have to put your TV on a different mode. What video input (cable) are you using on the TV. For HD it will have to be DVI, RGB or component.
It’s Sky, the UK’s largest satellite provider. Standard box.
Checked, and no.
SCART.
On further research, I suspect my Sky box is not compatible. 
My Dish Network Vip622 receiver uses a HDMI cable. 
Quite possibly.
To get HDTV via satellite you need a particular kind of satellite dish (multiple pickups…SDTV usually has one, HDTV dishes may have three or more in the US).
You need an HDTV receiver (the box).
You need an HDTV capable TV (seems you do).
I am not sure if SCART can handle an HDTV signal. See here for more, albeit not totally clear for your question, info.
Just to confirm what everyone else has been suggesting, if you don’t have a new Sky HD box (Like this) then you won’t be able to receive any HD broadcasts from Sky. The box costs about £300 and adds another £10 on to your monthly subscription.
If you did have a Sky HD box, you’d have to use an HDMI cable, a DVI cable or analogue component (YPbPr) as those are the only ways the Sky box outputs HD signals. A Scart lead wouldn’t do it.
There are no dumb questions about HDTV. The whole thing is such a convoluted mess that no one understands what’s going on. But yeah, you probably need a specifically HD satellite receiver.
