Thank you for responding.
I think vertical stacked VHF balun polarity was correct.
The SiliconDust tuner diagnostic reports 10% quality improvement
over single VHF antenna
I can view KNTV (RF 12) when signal quality is above 55%. There is more
variation in recent months. Symbol quality sometimes goes to zero. Multipath
issues continue.
I agree it is likely the terrain and tree.
I will first try replacing baluns.
Will check out the AVS forum.