1592953613000 1312632483000 term-60844 1616541207338 1312632556000 1616289981966 adlib fitz-online adlib-term-60844 5d274d6e-c5ea-3e55-aa95-49534814e717 2 1 scope note Use for concrete structures of various forms, usually including a concrete dish linked to microphones, acting as early warning systems to detect and transmit the sound of incoming zeppelins; installed along the English coast facing Europe during the early 20th century. reference term-60843 adlib-term-60843 4adceed5-7c68-382a-bbab-10e9be3e8e11 sound mirror V.RK.AFU.ALO.ALO.ARI.ALO 1 code V.RK.AFU.ALO.ALO.ARI.ALO 1 sound mirrors reference term-60855 adlib-term-60855 6ea2b31b-ab8c-30ec-a6d1-3ab107a6ec62 <communications structures> sound mirrors term