■ قبل از اختراع رادار- چگونه هواپیماهای دشمن را شناسایی میکردند؟ بخش عمومی

How incoming enemy aircraft were detected before the advent of radar.

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