I'm new here but have been learning alot from all the threads posted here. I've recently developed a problem with my HD signal and was wondering if someone could explain how I lose some HD signals but not others. For example, I can go to ESPN 9424 and have a great picture and about a 90-100 signal strength, but if I go to ESPN2, TNT or A&E I will lose signal and get alot of pixelation. LOS could be a problem because of the trees, but why does it work well on some stations and not others?