If you have access to a free preamp, then by all means, give it a try. If it helps, great. If it overloads or acts like a noise source, you can remove it.
You are correct, when I say 'adjust the aim point', I mean turn the antenna to the left and right while checking the effect on signals from desired stations.
More rules of thumb:
- When mounting an antenna, select a mounting location with the least amount of (anything other than air) between it and the broadcast antenna.
- Keep the antenna as far as practical from metal objects.
If the attic wall is constructed of wood or vinyl, clearance is less an issue. If there is metal, including foil on insulation or wire mesh behind masonry or springy wire in plastic duct tubing..., ALL of the metal should be behind or to the side of the antenna by at least 4'... more would be better. That infers that some attics are simply going to be poor choices for installing an antenna. But it's still worth trying to find a 'sweet spot' if it will keep the antenna protected from the elements... in the attic, an antenna can last a lifetime.