Hi Barry, I have sent the box off this morning to have the mod done, what i found on my hd channels were that most would get waves of pixels, sports and movies but bbc hd would run fine, most sd channels were fine, on other days this might reverse where as the hd might be ok and the sd were bad, was very strange, got the box running better with both booster/ attenuator adjustments but hopefully this mod will be an improvement at the least.