http://forum.tvfool.com/showthread.php?t=233 . And read and understand this ->
http://forum.tvfool.com/showthread.php?t=695 . 13 to 20 miles is Close , the NM Noise Margins in the green are Very Strong. If your house is not wrapped with any type or kind of metal , like metal siding or stucko with stucko Wire , the reception with a indoor antenna should be fine. And as always , a out side antenna is better. And a out side antenna that has a clear shot at the transmitters is the best.