Aircraft Detection Before Radar...
I bet none of you ever saw this stuff before.
How air attacks were detected before radar...
Old time
acoustic hearing aids
ACOUSTIC "EARS"
BEFORE RADAR - ON A SWIVEL
ACOUSTIC "EARS"
BEFORE RADAR - GERMAN
ACOUSTIC "EARS"
BEFORE RADAR - ON WHEELS
ACOUSTIC "EARS"
BEFORE RADAR - ENGLAND
