Grounding Antenna..Why and How?
 

My Terk HDTVO antenna is way up on the roof and the manual recommends grounding.So I have a few questions about that.
I bought a grounding adaptor with two female coax ends so I can insert it into the existing cable and run a groundwire from there to a metal rod that I pound into the ground somewhere close to the house.
But how thick does that ground wire have to be? If a 50000V lightning bolt hits my antenna would that not immediately melt that wire? So does a setup like that really protect my gear and my house? Besides my tv and my DVR tuner is already grounded through the house, so do I really need the extra protection?
I also heard that grounding the antenna is mainly to reduce interference and not to protect me from lightning.
Can somebody here please clear this up for me?
Thanks