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SESK: Stuff Everyone Should Know · sesk.info/ham-squelch-purpose

What does the squelch function on a receiver do?

Mutes the audio when no signal is present.

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  1. Mutes the audio when no signal is present ✔
  2. Reduces a CW transmitter's key clicks
  3. Reduces interference from impulse noise

Why: Without squelch, an FM radio hisses loudly between transmissions. Squelch keeps the speaker quiet until a signal comes in.

Huh, didn't know that: Squelch is why a handheld stays silent on a quiet channel instead of hissing all day.

The dad joke
I told my radio to stop hissing at me. It said, squelch you very much.
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References

Answer: Mutes the audio when no signal is present. Without squelch, an FM radio hisses loudly between transmissions. Squelch keeps the speaker quiet until a signal comes in.

  1. 2026-2030 Technician Class Question Pool, T2B13 ncvec.org/downloads/2026-2030%20Technician%20Pool%20and%20Syllabus%20Public%20Release%20Feb%2019%202026.pdf
    Mute the receiver audio when a signal is not present
    Checked 2026-10-09.

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