The Black Mountain transmitting station is a broadcasting and telecommunications facility, situated on land 301 metres (988 ft) above Ordnance Datum (mean sea level) to the west of the city of Belfast, in Northern Ireland (grid reference J278727). It includes a guyed steel lattice mast which is 228.6 metres (750 ft) [1] in height. The height of the top of the structure above mean sea level is 529 metres (1,736 ft).