Picture quality loss on sky?

I have sky+ in my living room but have a coaxal cable going from the box to my tv in the bedroom with the use of magic eye for the remote. The picture used to be ok but not perfect, but yesterday it became like a terrestrial channel picture that hasnt been tuned in right. The only thing that changed is I have a signal booster for the tv in the living room as the tv has freeview on it but it shouldnt effect sky as it doesnt touch the wires for it or the coax going through to the bedroom so why am I losing the picture quality on just that channel and not the others?