Denge Sound Mirrors - History and Facts | History Hit

Denge Sound Mirrors

Shepway, England, United Kingdom

The Denge Sound Mirrors are an intriguing example of an early warning system on Britain's south coast.

Lily Johnson

13 Apr 2021

About Denge Sound Mirrors

The Denge Sound Mirrors are an intriguing example of Britain’s attempts at early warning systems for enemy aircrafts during the interwar period. Today the site can be accessed via guided tour and provide an insight into the development of radar in Britain.

Denge Sound Mirrors history

From 1916 to the mid 1930’s, Dr William Sansome Tucker developed an early warning system known as the ‘sound mirrors’. These were strange looking concrete buildings, designed to listen for enemy planes arriving from the continent.

They worked in much the same way as the modern radio telescopes do today, with three designs built to explore the technology and perfect the concept. These can all be seen on the Dungeness peninsular, although there are many other examples of the dishes elsewhere in Britain (notably Hartlepool, Seaham, Redcar and Sunderland in the North East, Dover, Romney Marsh and Selsea in the South).

The first version is a 70m curved wall, around 5m high, and the other two are dishes around 5m in diameter. All used the same principal of microphones at the focus of each structure. The intention was to set up a string of sound mirrors to determine the direction as well as the distance of planes approaching.

Although the sound mirrors were obsolete by the start of World War Two, the concept behind them had the great merit of developing the infrastructure to enable radar to be used efficiently, as it used the same principles of having a string of listening posts throughout the country.

Denge Sound Mirrors today

Today the site of the Denge Sound Mirrors is managed by the RSPB, and is a must-see for anyone interested in the development of radar and early warning systems. The Sound Mirrors lie on an island in the middle of an old gravel pit at Greatstone Lakes, with access via a swing bridge.

This is only accessible a few times a year during RSPB open days, guided tours, and photography sessions that usually run in the summer. They can however also been seen quite clearly from a footpath that runs along the east side of the south lake and from the land side of the swing bridge.

A half-an-hour drive away at Hythe, there is a working model of a Sound Mirror that visitors can try out with the help of a friend!

Getting to Denge Sound Mirrors

The Denge Sound Mirrors are located in Romney Marsh in Kent, and can be reached by taking Junction 10 from the M20 and following the A2070 towards Brenzett, then the A259 towards New Romney. From there head south along the coast to Romney Marsh, where parking is available at Lade Car Park. Bus services 11, 102, 105, and 553 run to Romney Sands, following which it is a 10-minute walk to the site, while the Romney Sands railway station is also an 8-minute walk to the site.