[Antennas] Lightning Protectors

[Jim Isbell]

I have a very old coaxial lightning protector that has a ground screw on 
the side and a "gap" internally that is supposed to shunt lightning off 
the center conductor of the antenna lead in.

Do these work well?

Where is the best place to put them??

I dont understand how it would protect the equipment just because it 
shunted part of the lightning to ground.  Surely some would continue on 
down the cable to the receiver, wouldn't it??