FYI....the antenna is 60 feet right above my head. So, I think that elephant has been spotted.
The greater the distance between the shack & antenna, the more it sounds like RF that is conducted into the shack. Do you have the shields of the feedlines grounded at the point of entry into your house? Doing that greatly reduced my RFI problems. According to Tom W8JI on this page about Station Ground
If an antenna or tower system has common-mode current problems, caused by a faulty design or installation, a ground can help reduce common mode noise reaching the antenna.