Do you have trees in the path between the antenna and stations?
Have you tried this test,
http://forum.tvfool.com/showthread.php?t=13646? Though it answers the question of 'to amp or not amp...', it's also a very basic reception test that focus on the performance of the antenna, it's location and aim. You need to determine if the antenna is receiving a reliable signal, or are you fighting an external interference problem. Until the antenna can produce a reliable signal at it's output terminals, there's no reason to trouble shoot the cable, connectors or accessories down stream. Once you know you have a reliable signal to distribute, you can turn your attention to any problems that may be present in the distribution cabling and accessories.
Also, be open to the addition of an FM interference filter.
http://www.radioshack.com/product/in...uctId=10939219