Been playing with a Vector 4000. Built a teflon high powered gamma for it, and direct fed it. When mounted on the tower performance is great. Was able to dial in resonant on the analyzer, however when I install my 4 element Yagi 12 feet below the Vector, the match and resonance change, which tells me that it is interacting with the Yagi. The antenna does have a feedline choke, and shows no signs of CMC. Anyone ever run into this ? I know there are a few on here who have ton's of experience with this antenna. Any input appreciated.