To All: I currently have a Force-12 C4XLD yagi (covers 40 through 10 meters) on a 54-foot crank-up tower. I desire to add a 5 or 6-L six-meter yagi and place it above the Force-12. What is the absolute minimum separation between the two must I have for near zero mutual effect? Any assistance will be greatly appreciated. Semper Fi, Tommy - K6YE DX IS