Cable is cable…
And don’t go buying any ‘boosters’ for the signal...It is known that they will degrade the picture even more, including Sky.
Secondly...the more devices you put scart leads thru..the more the signal degrades by the time it reaches the back of your TV.
Asterix is right about HD capable devices such as PS3...The picture is only as good as the HD signal coming into the back of the TV from an HD enabled device......A HD Sky Box will give you HD picture… and buy the best Scart leads you can buy...They do make a difference…
Check out the web...There are loads of forums and advice websites, especially for Sky HD..
DB