The longwave radio mast Hellissandur is a 412 metre high guyed radio mast for longwave transmissions at Gufuskálar in the vicinity of Hellissandur on the Snæfellsnes peninsula of Iceland. This mast, which is among the tallest structures in Western Europe, is insulated against the ground and guyed in five levels by steel ropes, which are subdivided by insulators. It was built in 1963 as replacement for a 190.5 metres (625 ft) tall LORAN-C tower, which was built in 1959, for the North Atlantic LORAN-C chain (GRD 7970). After the LORAN-C scheme was shut down in 1994 the longwave radio mast Hellissandur was converted to an aerial mast for a longwave broadcasting transmitter of the Broadcasting Service of Iceland, for a longwave radio frequency of 189 kHz and a power of 300 kilowatts.
The second, smaller 100 foot tower was also installed by the US Coast Guard in the fall of 1961 as part of a LORAN A network paired with Greenland.