What you see is a lightning arrester.
This particular one is for a high-tension power line. It's a device designed to keep a lightning strike from traveling down a wire and ruining everything, because let's face it, one lightning strike can (and will) ruin your entire day.
It seems like this is the sort of thing that you should have on your satellite dish, and several of our customers have asked whether or not we sell something like this for dishes. The answer: well sort of.
Lightning arrestors are used for large, high-tension lines. With antennas and satellite dish we use ground blocks
, which act differently from lightning arresters but serve the same purpose of protecting your home. While a lightning arrester forms a gap between wires and the rest of the structure, a ground block gives lightning a more attractive place to go rather than taking it into your home. A ground block takes takes current traveling down from your antenna or dish (not signal,
that's something different) and makes it travel down a separate copper wire where it can disperse harmlessly into the ground. That's a very important part of installation, and you can find out more about grounding in our White Paper
, downloadable (of course) for free!