Probably a more practical idea would be to actually go out and test your rig, perhaps with someone on a second radio, stationary at your home location, then drop pins in googleearth so you can clearly determine line of sight distances and elevations, as well as obstructions that may affect your actual range. This has the added benefit of providing actual experience communicating and learning that sometimes you only need to move 50 feet in one direction or another to have acceptable comms.
