How do lightning arrestors (the kind that go on an outdoor antenna feed line, bonded to ground) function? what do they look like internally?
#hamRadio
most of them are an air-gapped connection to ground like you said. normal signals can't cross the gap, but lightning is high enough voltage to arc, and it will arc to ground instead of whatever expensive electronics are connected to the antenna.
---from antenna----TV--| ~air~ |----to ground---
---from antenna----TV--| ~air~ |----to ground---