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SESK: Stuff Everyone Should Know · sesk.info/ham-radio-wave-speed

How fast does a radio wave travel through free space?

At the speed of light.

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  1. At the speed of sound
  2. At 0.86 times the speed of light
  3. At the speed of light ✔

Why: Radio waves are electromagnetic waves, like light. In free space they travel at the speed of light, about 300 million meters per second.

Huh, didn't know that: A radio signal could circle the Earth about seven times in one second.

The dad joke
I tried to outrun my radio signal. Didn't even make it out of the shack.
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References

Answer: At the speed of light. Radio waves are electromagnetic waves, like light. In free space they travel at the speed of light, about 300 million meters per second.

  1. 2026-2030 Technician Class Question Pool, T3B04 ncvec.org/downloads/2026-2030%20Technician%20Pool%20and%20Syllabus%20Public%20Release%20Feb%2019%202026.pdf
    Speed of light
    Checked 2026-10-09.

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