I have a lot of space available for antenna installation and i am
wondering if installing a 4 or 8 wavelength antenna would provide
increased performance or problems. For instance, instead of a 120 ft
dipole for 3900 khz a 480 ft or 960 ft.

I would be installing across a valley so ends would be about 25-30 ft
off the ground and the center would be about 80-90 ft off the ground.

Thanks