Scattered along the Kent coastline lie a few giant concrete bowls. Whilst they look like an old satellite dish or part of another structure, they’re actually sound mirrors.
The First World War saw the threat of an airborne attack become reality for the first time, leading scientists to try and create something to alert us to the threat. The ‘listening ears’, as they are also known, were developed and built from World War 1 on wards. They were designed to pick up the engine sounds of aircraft flying towards Britain, and would have given us an early warning that they were approaching. The devices work by sound from an aircraft hitting the dish and bouncing to the person stationed there so that they could hear the aircraft before seeing it. An operator would have stood on a small platform in front of the dish to monitor the skies. Although an initiative design, as aircraft became faster they could be seen by the time they were heard and radar systems eventually replaced them.
Hythe Sound Mirror
The sound mirror at Hythe can only be reached by a trek through a field with sheep. Once you have walked up the hill, you are able to see the mirror, which is fenced off to prevent vandalism.
Abbot’s Cliff Sound Mirror
The sound mirror along Abbot’s Cliff is along one of the England Coastal paths. With stunning views on a clear day, the Port of Dover and France is visible. The mirror is different in design to the Hythe one, as this dish is part of a concrete block, whereas the Hythe one is a rounded structure. This one appears to be in a good condition, despite a bit of graffiti.
Denge Sound Mirror
Inaccessible to us and most other explorers, the Denge mirrors are situated on an island in the Dungeness Nature Reserve. The site is only accessible on open days when the RSPB provide a bridge to access to the mirrors. Three mirrors are at the site; a 200 foot mirror and a 30 and 20 foot mirror. The largest is a 60 metre curved wall, thought to be only one of two in the world. One of the smaller dishes still has the metal microphone holder in place. The RSPB have an annual open day event for visitors.
Kilnsea Sound Mirror, East Yorkshire
The acoustic mirror at Kilnsea in Yorkshire, east of Hull near Spurn Point, is one of a number built on the northeast coast of England during the First World War. The dish is around 15 feet in diameter facing the sea. The microphone would have been fitted to the metal post set in a concrete block in front of the mirror, listened to with headphones.