Before Radar How Were Air Attacks Detected ? sent by Jim Smith - jsmith5bn6ada AT netscape DOT net
And you thought the Nike Acquisition Radar was old fashioned!
Before Radar How Were Air Attacks Detected ?
STRANGE ACOUSTIC "EARS"
BEFORE RADAR - LISTENING POSTS
STRANGE ACOUSTIC "EARS"
BEFORE RADAR - ON A SWIVEL
STRANGE ACOUSTIC "EARS"
BEFORE RADAR - GERMAN
STRANGE ACOUSTIC "EARS"
BEFORE RADAR - ON WHEELS
STRANGE ACOUSTIC "EARS"
BEFORE RADAR - ENGLAND
and spotted by Kevin Appert
... in this quiz question: hint - select "Acoustic Mirrors"