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What FCC Part 15 rules apply to antennas?

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In the US, unlicensed intentional radiators are governed by 47 CFR Part 15. Section 15.203 requires that the antenna be permanently attached or use a unique coupling so users cannot fit unauthorized antennas, and transmitters may be used only with antenna types they were authorized with. Power rules such as 15.247 and 15.407 tie maximum conducted power to antenna gain, so the antenna is part of the certified system.[1][2][3][4]

What does 15.203 require?

An intentional radiator must be designed so that no antenna other than the one furnished by the responsible party can be used. Permanently attached antennas or unique connectors satisfy this; professionally installed equipment has some exceptions. Changing to a higher-gain antenna generally requires the antenna type to be covered in the equipment authorization.[2][1]

For digital transmission systems and frequency-hopping systems with at least 50 channels in 902–928 MHz, and DTS in 2400–2483.5 and 5725–5850 MHz, maximum conducted output is 1 W. If antenna gain exceeds 6 dBi, conducted power must be reduced by the amount over 6 dBi; fixed point-to-point systems at 2.4 GHz reduce 1 dB per 3 dB above 6 dBi, and at 5725–5850 MHz need no reduction.[3]

What about other Part 15 bands?

U-NII devices at 5 and 6 GHz have sub-band-specific power and power spectral density limits under 15.407; 76–81 GHz vehicle radar is covered by 15.253; ultra-wideband devices by Subpart F. Always read the current eCFR text for the specific device class.[4][5][6]

Frequently asked questions

Can I swap the antenna on a certified Wi-Fi router?

Only with antenna types covered by its authorization; higher gain may violate the rules.

Does 15.203 apply to licensed radios?

No; it is a Part 15 requirement for unlicensed intentional radiators.

Where are the rules published?

In Title 47 of the Code of Federal Regulations, available on eCFR.

References

Online sources accessed October 21, 2026; printed works cited by edition. See all sources.

  1. “47 CFR Part 15 — Radio Frequency Devices”. U.S. Federal Communications Commission, eCFR. current text.
  2. “47 CFR 15.203 — Antenna requirement”. U.S. FCC, eCFR. current text.
  3. “47 CFR 15.247 — Operation within the bands 902-928 MHz, 2400-2483.5 MHz, and 5725-5850 MHz”. U.S. FCC, eCFR. current text.
  4. “47 CFR 15.407 — General technical requirements (U-NII devices)”. U.S. FCC, eCFR. current text.
  5. “47 CFR 15.253 — Operation within the band 76-81 GHz”. U.S. FCC, eCFR. current text.
  6. “47 CFR Part 15 Subpart F — Ultra-Wideband Operation”. U.S. FCC, eCFR. current text.
Categories: Regulations and safety