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Module 13. Aircraft aerodynamics, structures and systems

The ATC aerial has a polar diagram which is

  • directional
  • omni-dirrectional
  • limacon shaped

Explanation

The ATC transponder antenna must reply to interrogations from any bearing, so its horizontal radiation pattern is essentially omnidirectional. A directional or limacon-shaped pattern would leave the aircraft unable to respond to ground or TCAS interrogations approaching from certain directions.

Dusiata asking:

Directional? Maybe they have in mind radar antenna?

Community Comments (1)

J
Jordi Posts: 198 30.04.2021 / 17:27
i think at first that it is omni-directional but i looked in my notes and it says ,ATC has a polat diagram which is directional.

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