1401
As a beginner Defense
Dutch personal locator 1930s.
Two horns system Bolling Field, USA, 1921goda.
Cheshskiy- people locator.
Russian anti-aircraft gunners with a device for listening to the sky.
French locator 1930.
Marine acoustic locator from France.
Emperor Hirohito checks "military pipe" in 1930.
Experiments J M Bacon 1898god.
