Where the feed lines enter the building✓Bonne réponse
On the antenna, opposite the feed point
In series with each ground lead
At the closest power pole ground electrode
Explication
The point of an arrestor is to divert surge energy to the ground system before it can travel inside, so it is installed where the feed lines enter the building and bonded to the same grounding electrode system as the electrical service. An arrestor placed anywhere further along the path leaves the run into the building unprotected.