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Why do most solid-state transmitters reduce output power as SWR rises?

To protect the RF output amplifier transistors.

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  1. To meet FCC spectral purity rules
  2. To lower the SWR on the feed line
  3. To protect the RF output amplifier transistors ✔

Why: High SWR sends power back toward the radio. The transmitter turns itself down so its final amplifier transistors don't overheat or fail.

Huh, didn't know that: This automatic power cut is often called SWR foldback.

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My transmitter folded under pressure. Turns out the SWR was really high.
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References

Answer: To protect the RF output amplifier transistors. High SWR sends power back toward the radio. The transmitter turns itself down so its final amplifier transistors don't overheat or fail.

  1. NCVEC 2026-2030 Technician Question Pool (February 19, 2026 errata) ncvec.org/downloads/2026-2030%20Technician%20Pool%20and%20Syllabus%20Public%20Release%20Feb%2019%202026.pdf
    A. To protect the RF output amplifier transistors
    Checked 2026-10-09.

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