Thesaurus Term/Concept: SOUND MIRROR (200 FEET)
| Identifier | 123557 |
|---|---|
| Class | DEFENCE OF BRITAIN |
| Status | Preferred |
| Index? | Yes |
| Scope Note | A concrete, concave wall 200 feet in length used as an acoustic listening device to detect approaching enemy aircraft. |
| Identifier | 123557 |
|---|---|
| Class | DEFENCE OF BRITAIN |
| Status | Preferred |
| Index? | Yes |
| Scope Note | A concrete, concave wall 200 feet in length used as an acoustic listening device to detect approaching enemy aircraft. |