I'm looking to set up a attic antenna. I have a typical new built 2 story house. All four bedrooms on the second level have a cold air return. In the attic there is flexible duct work connecting the return on one bedroom to the other. I can access the duct from that in the attic. My issue is the one bed room that had the cold air return down the wall seems to have a metal plate that Im hitting right around where the 1st floor ceiling would be. Looking it the basement where the cold air connects to the furnace it looks like it should be a straight shot down the wall.