Geek Trivia: What Were Planes Detected With Before The Invention Of Radar?

Share
  • March 13, 2019
Technology

What Were Planes Detected With Before The Invention Of Radar?
  1. Pigeons
  2. Telescopes
  3. Acoustic Mirrors
  4. Ultrasound

Think you know the answer?

Source : Geek Trivia: What Were Planes Detected With Before The Invention Of Radar?

You may also like...