For giggles I reran the TV signal Analysis at 35 ft(below) and 40 ft; from my perspective they are marginally different. But when I ran it at 50ft (below) it changed quite a bit.
35 FT
http://www.tvfool.com/?option=com_wr...51344226589ada
50 FT
http://www.tvfool.com/?option=com_wr...5134fd2f4301ef
Bottom line, if I try an antenna (e.g. DB8e or DB4e) and do not like the results, one solution is UP!! Although at 50 ft it will not be ME installing it.