[Al Skierkiewicz]

Scott,
The tree with a dish is not a solution. Trees grow...
I would move to a yagi at the tree location. It has a bit wider aperture and doesn't need to stay pointed in exactly the right direction.
In reading your original specs, you have one dish mounted 80' feet up on a 60' tower? There is also some panel antennas that have pretty decent gain and a great front to back ratio. We are using those to link to the university next door (they rent space here). Approx path is a few hundred meters. They are powered over ethernet. I have to ask why you are mounting one at 80 feet. Do you have some obstacles?