I know that you shouldn't fly a UAS close to power lines because they can interfere with the compass, etc. But is there a "Rule of thumb" distance to keep in mind? The closest place to my house to launch (right across the street) is a huge field. It has one power line running through it. This isn't a huge set of lines on big towers, etc, just two little lines on wood poles like you'd see in any given neighborhood. I can set up to fly several hundred feet from them in either direction, but what about when flying over them? I'm sure on longer flights there's no getting around flying over power lines on occasion right?