diagonal chroma noise on analog cable captures

[billqs]

Thread title says it all. On several of the analog channels of my local cable I get diagonal rainbow like lines that move across the screen. They will clear up then return. I am using a Hauppauge PVR 150 Capture card with a coax running into the tuner of the card.

I have attached an example. Can anyone help me out? At first I thought it was a weak signal, but it might also be interference perhaps?

Thanks!

[Mounir]

bad grounding on one of your devices i'd say

[billqs]

Thanks for the suggestion. I had read somewhere that having several different grounds instead of one central ground could cause "herringbone" issues. Would this be a candidate for getting a loop isolator that would remove any noise from ground loops?