Welcome to the Community, it's really great to see a new face and thanks for your post
My apologies on channel 4HD breaking up, I can imagine that's not the best. I would like to help here and so far with my initial tests I've been able to run, it looks like you've been having some issues on the power levels. With no registered outages in the area and nothing recently closed I would like to arrange an engineer to help resolve this for you
I've sent you a 'Private Message', you can find this by clicking on the little purple envelope near the top right of the page.