I am a bit of a dinosaur where these things are concerned but have just bought a new smart TV , it has been installed and the picture is really good unless you are running it through a the Sky box in which case it’s really grainy . The man who installed it while I was out said that it was because my Sky box is old and it needs a newer one for the Sky to give a clear picture . To me I would have thought that as the old TV had a clear picture and the new one is getting the same signal from the Sky box then it should be clear also . I suppose he’s right , your thoughts would be welcome .

Is your sky box HD? If not, yes that will have a significant impact on picture quality.

No it’s not HD but the picture quality is way worse than it was with the previous TV through the same Sky box .

How’s it connected?

What was your old set? Could be that the old one masked imperfections that the new one is showing up.

Is the new TV 4k?

If so, and your Sky box is not even HD, then the TV will be having to do a lot of interpolating to fill the screen.

HD pixels only take up 1/4 of a 4k screen, so the equivalent standard definition will be even less (around a 16th, I reckon).
That means the TV is having to ‘guess’ a lot of pixels.

SD output from our freeview box to our 4k TV looks pretty rubbish.

Also is the screen bigger? Bigger screen = more blurry SD image than on a smaller screen.

If the Sky box is pre-HD then it will be using an analogue SCART connection, so not only SD, but grainy picture as well.

You should be able to pick up an HD box from places but stick with SD subscription if you don’t want to pay extra. The HDMI connection from an HD box will still be a lot better on a big screen, and you can either set the box to output everything as 1080i or 720p HD or let the TV upscale.

Thanks everybody , new sky box it is

Make sure the cable is plugged in properly, then try a different cable