SOUND MIRROR (30 FEET)

SN A concrete, circular concave dish 30 feet in diameter used as an acoustic listening device to detect approaching enemy aircraft.
CL MILITARY DEFENCE AND FORTIFICATION
BT SOUND MIRROR

 
 

SOUND MIRROR (30 FEET)

SN A concrete, circular concave dish 30 feet in diameter used as an acoustic listening device to detect approaching enemy aircraft.
CL MILITARY DEFENCE AND FORTIFICATION
BT SOUND MIRROR