Original sentence: It serves the whole of the Channel Islands and uses as its antenna a  tall tower built of lattice steel
Edited sentence: It serves the whole of the Channel Islands, either directly or via the relay stations at Gorey Castle, Alderney, St Brelades, St Helier, St Peter Port, Torteval and Les Touillets - the latter of which is a high power relay which covers most of Guernsey.Its its antennae are mounted on a  tall tower built of lattice steel