I live in a two story wood frame house with an asphalt roof. I am planning on putting an antenna for HDTV in my atttic. Any info on the signal loss due to the asphalt shingle roof? I am about 40 mi. away from Raleigh, NC according to www.antennaweb.org. The stations there broadcast in the 900 - 1000 KW range. I am looking at an antenna from www.hdtvantennas.net that have a gain of around 14DBi and using a pre-amp. Any thoughts on my chances of receivning HDTV broadcasts with my Dish 811 receiver.?