Earthing of TV aerials or satellite dishes is a rarity in Australia. I've never seen or worked on an installation where there has been a separate earthing conductor. The only earthing is by default either by a distribution amplifier or TV with a three core mains cable.
Virtually all Australian made TV sets had a transformer isolated and earthed chassis; hence the aerial would be earthed by the power mains via the ribbon or coax, so it was a matter that no one really gave much consideration to.
These days, with all the two core mains leads and switchmode power supplies with all their capacitive leakage, an aerial system can have enough voltage superimposed upon it to give a bit of a tingle. The more TV's, DVD players etc., connected to the system the worse it gets. And the lack or earthing on these appliances means lots of RFI radiated from their cheap power supplies. I have a hard disc recorder that ruins AM radio reception which was so easily fixed by connecting a clip lead between it and the metal case of a earthed appliance. Now it's out of warranty, the mains cable will be replaced with three core flex and the concentric squares on the back removed. Double insulation first came out with power tools; that's where it should stay.
