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SESK: Stuff Everyone Should Know · sesk.info/hame-folded-dipole-impedance

What is the approximate feed point impedance at the center of a two-wire half-wave folded dipole?

About 300 ohms, four times a plain dipole.

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  1. 72 ohms
  2. 300 ohms ✔
  3. 50 ohms

Why: Folding the dipole raises the impedance to roughly four times that of a simple half-wave dipole. That is also why the folded dipole is a good match for 300-ohm line.

Huh, didn't know that: A folded dipole is a half-wave dipole with an extra parallel wire connecting its two ends (E9C08).

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References

Answer: 300 ohms. Folding the dipole raises the impedance to roughly four times that of a simple half-wave dipole. That is also why the folded dipole is a good match for 300-ohm line.

  1. NCVEC 2024-2028 Amateur Extra Question Pool, 4th Errata (Feb 4, 2026) ncvec.org/downloads/2024-2028%20Extra%20Class%20Question%20Pool%20and%20Syllabus%20Public%20Release%20with%204th%20Errata%20Feb%204%202026.pdf
    A. 300 ohms
    Checked 2026-10-11.

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