Sound Mirrors

Geluidspiegels om geluid van vliegtuigen te kunnen horen, voordat ze in het zicht zijn.

dit is een schaamteloze kopie van
this is a shameless copy from
Webmaster is Keith Slate
I hope to mirror this page, in order to save it for the future, some time.
I have seen so many interesting websites vanishing

Sound Mirrors or reflectors were first built in the 1920's as an early warning system that listened for the sound of airplane engines. A concrete bowl shaped reflector focused the sound waves onto a microphone at the focus of the bowl in much the same way that a satellite dish works with radio waves. Many different sizes and types were tried in an attempt to get that vital early warning of attack by enemy planes, but the system was rendered obsolete by the advent of Radar.
The pictures below were taken at various times and locations, mostly on the South Kent Coast.


Sound Reflectors above Langdon Bay to the east of Dover.


Close up of right hand Sound Reflector.

Photos by Ray Harlow taken circa 1978.


Sound Mirror above Abbot's Cliff to the east of Folkestone.

Photo taken Summer 2000.


Sound Mirrors at Lade, Dungeness to the south west of Folkestone.

Note metal pole in dish that carried the microphone.

Rear of Sound Mirrors.

The water is due to a later flooded gravel pit.


Rear of Sound Mirror showing huge size- about 200 ft. long.

Pictures taken April 2001.


Ruined Sound Mirror on beach at Warden Point, Isle of Sheppy.


Closer view of base of Sound Mirror.

I believe it to have been well above sea level originally, as the coastline here is being heavily eroded.

Rear of Sound Mirror, at Warden Point, with broken sections of bowl laying on beach.

For more pictures of WW2 bunkers/observation posts click here.

Pictures taken November 2001.


Sound Mirror (circled) on hills to the west of Hythe, Kent.

Water in foreground is the Hythe Military Canal, dug as an obstacle to invasion in Napoleonic times.


Another view of Sound Mirror overlooking Romney Marsh near Hythe, Kent.


Closer view of above Sound Mirror.


White post at bottom centre of bowl is where post for microphone was mounted.


Rear view of Sound Mirror near Hythe showing hemispherical construction of this mirror.

Pictures taken December 2001.