What signal strength should I expect from my high definition channels? I have some that are high-90s and some that are low-90s to high-80s. I don't have a severe problem with pixelation, but every now and then there is that problem along with a short audio drop out. I'm just wondering what signal strength others are getting and what I can do to get mine on up on the channels that are weak. I already have a booster, but maybe I need another one. Thanks.