The sound mirror at Redcar on the Yorkshire coast was built in about 1916, during the First World War.
These pictures were taken in December 2002. Click on a picture to see a bigger version.
The acoustic early warning mirror at Redcar has a modern plaque explaining what it is. The base for the listening apparatus has survived, about four feet in front of the main structure.
The mirror is now surrounded by a modern housing estate.
A close up of the plaque. This reads:
REDCAR EARLY WARNING STATION
This structure is a Sound Mirror or detector, built by the Royal Engineers in 1916. It was part of an extensive Zeppelin and enemy aircraft detection system deployed down the East Coast of Britain druring the First World War. Zeppelins raided the North East Coast 15 times between April 1915 and November 1917.
The sound of approaching aircraft was reflected off the concave ‘mirror’ surface and received into a trumpet mounted on a steel column.
The trumpet was connected to a stethoscope used by the operator or ‘listener’, and the part of the dish that produced the most sound indicated the direction of the approaching aircraft. Advanced warning of an imminent attack could then be given to local people.
By the early 1940’s sound detection technology was being replaced by ‘reflective detection finding’ now known as radar.
View Sound mirrors in a larger map
The mirror is in the middle of a modern housing estate between Redcar and Marske. You can park next to it, and it is very easy to visit, once you know where to look! The mirror is at the junction of Holyhead Drive and Greenstones Road. Map.