If you can - add a gaseous lightning and static discharge unit in the coaxial line, and earth it as well - but to (b). See below!
Copper plated steel rods are usual for both jobs, though some say pure copper will last longer! You'll need a sledge hammer and some patience, and a brass clamp for holding wires to the top of it!
You 'should' also run a wire from the (pre or integrated) amp's 'signal earth' screw to this ground.
(b) it is also good idea to earth the mast of any exterior antenna, and I would suggest that this be separate from the 'signal earth' post. This is to provide a SHORTer path for 'lightning / static' high voltage spikes down the mast and to ground rather that through yr tuner adn sound system.
Overkill!? I guess it depends on and how common lightning strikes ARE where you live. AND, how much of a perfectionist you are!
And, yes some areas are MUCH more prone to strikes than others. Where I live has lots of aquifers / ground water ~ 10 to 25ft down* - thanks to being on the weather-ward-side of a substantial and steep hill. It's a more changable atmosphere above us, and the runoff becomes ground-water which is 'a good earth'!
Viz. Even in the horrific drought we are now in, all our bigger trees are still doing fine including Birches, Ashes, and a big grey conifer. Indeed it has been our experience, even during the previous long drought, that any new tree will be fine once their height/root depth reaches the ground water! And OFF they go!!!
Warmest
Timbo in Oz
The Skyptical Mensurer and Audio Scrounger
And gladly would he learn and gladly teach - Chaucer. ;-)!
'Still not saluting.'