Hellissandur longwave radio mast

The Hellissandur longwave radio mast (Langbylgjustöðin á Gufuskálum ) is a 412 m tall guyed radio mast used for longwave radio transmissions of RÚV (The Icelandic National Broadcasting Service). It is situated at Gufuskálar, near Hellissandur on the Snæfellsnes peninsula of West Iceland. It is currently the tallest longwave radio mast in the world and the tallest above ground structure in Western Europe.

It forms part of RÚV's longwave service. It is intended to fill in gaps of the FM radio, serve seafarers and as a critical communications facility. It previously operated in parallel with the less powerful Eiðar longwave transmitter to form nationwide longwave coverage, but Eiðar was demolished in 2023.

The mast, which is among the tallest structures in Western Europe, is insulated against the ground, and guyed at five levels by steel ropes, which are subdivided by insulators. It was built in 1963 to replace the 190.5 m tall LORAN-C mast, constructed in 1959 for the North Atlantic LORAN-C chain (GRD 7970). A second, smaller, 30 m tall tower was installed by the US Coast Guard in the autumn of 1961 as part of a LORAN-A network paired with Greenland.

The LORAN-C scheme closed in 1994. In 1991, the original RÚV 1930 longwave transmitter tower at Vatnsendi (near Reykjavík) collapsed. As the Hellissandur mast was free for use, it was converted for use by RÚV (The Icelandic National Broadcasting Service) for its longwave transmissions on 189 kHz at a power of 300 kilowatts in the 1997.

As of 2023, it is still operating at 189 kHz. RÚV has announced the retirement of all its longwave transmissions by 2024, citing its inadequacy as a backup service as most vehicles and radios do not support longwave broadcasts anymore.