Possibly your antenna is not powerful enough?
Check out http://www.antennaweb.org/aw/Address.aspx , just entering your zip code should work, I suggest your street address for more accurate data.
http://www.digitalhome.ca/ota/superantenna/design.htm
Plus, it is amplified as well. Problem is on the transmitting end.
I am within 10 miles of every station in Phoenix’s transmitting towers and half of them are too weak now for me to get with my cheap bunny ears like I used too. So now I either have to make my own bowtie or buy a new powered antenna which is BS.