When you’re pointing an antenna or dish, you have to be aware of obstructions. An obstruction can be anything: a tree, a hill, even a person. It’s anything that comes between you and the broadcast source.
Finding obstructions when you’re pointing a TV antenna is easy. We recommend a site like TVfool.com to figure out where your towers are. Then go up on the roof with a compass and point yourself in the direction of the towers. If there’s something big between you and the sky, well what you have there my friend… is an obstruction.
Obstructions can be a little harder to figure out with satellites, because you have multiple satellite locations and you have to figure that the satellites are up in the sky, not on the ground. We prefer a site like dishpointer.com to find where the satellites are; it will even show you on a google map and draw a line that will help you figure out those obstructions. However, you need to also keep in mind the elevation angle of the dish; a ground-based obstruction like a tree might not be a problem, but a power line that crosses at just the right angle might be.
In a perfect world, we’d all put our antennas up plenty high in the middle of an open field, but in the real world, there’s always something to worry about that could get in the way.