Antennas

Why is the value of the radiation resistance of an antenna important?

Answer

Knowing the radiation resistance makes it possible to match impedances for maximum power transfer.

Knowing the radiation resistance lets you match the feed line and transmitter to the antenna for maximum power transfer.

Source: FCC Element 3 question pool, 3J

Not the answer

  • Knowing the radiation resistance makes it possible to measure the near-field radiation density from transmitting antenna.
  • The value of the radiation resistance represents the front-to-back ratio of the antenna.
  • The value of the radiation resistance represents the front-to-side ratio of the antenna.

Practice this

The FCC Element 3 (General Radiotelephone) exam is 100 questions and takes 75 correct — 75% — to pass. Element 1, the other half of the licence, is 24 questions and takes 18 correct. The app’s page carries a free ten-question test drawn from the same bank, marked as you go.

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