I have a CM4228 antenna with a winegard preamp. Mounted as high on the house as I can get it. I receive fairly solid OTA signals from the Des Moines, IA stations that are located over 80 miles away, however my local ABC station from Kirksville, MO is not coming in. The signal bounces all over the place. From 80 to 40 to 70 to 0 back to 40. It never seems to lock in. Is this what they call multipathing? If so what are some solutions to this problem? The ABC tower is 33 miles from my house.