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Question 204

What is one disadvantage of using a shortened mobile antenna as opposed to a full-size antenna?

  1. Short antennas are more likely to cause distortion of transmitted signals
  2. Q of the antenna will be very low
  3. Operating bandwidth may be very limitedBonne réponse
  4. Harmonic radiation may increase

Explication

Making an antenna short and resonating it with a loading coil produces a high ratio of stored to dissipated energy, which means high Q, while bandwidth is inversely proportional to Q. The usable bandwidth can shrink to a few tens of kilohertz, so the claim that such an antenna has very low Q is exactly backwards.

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