No need to go into the depper science behind these antennae boosters, suffice to say that without it activated (so the green light is on) you will not get any TV signals for watching when you are using the roof antennae. On the other side, turn it off if you are connected to cable service provided at various campgrounds. Remember to also program the actual television to scan for "air" or "cable" source for your programming pleasure, found in the televison menu options.
Ken and Terry
2010 Georgetown 330TS being pushed by our
2017 GMC Terrain toad (4 wheels down)