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Docs Frequencies & Regulations US Radio Legal

US Radio Legal

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Using the 433 MHz beacon in the United States: FCC Part 15 rules, the 433.92 MHz ISM allocation, and the amateur alternative.

US Radio Legal

The United States is not a CEPT country, so the rules differ from Europe in one important way: the 433 MHz band is a narrow ISM allocation with a different power regime.

The 433 MHz allocation

The FCC allocates 433.05 - 434.79 MHz as an ISM band used mainly for industrial equipment. Under Part 15 rules, unlicensed devices may operate there, but the practical regime is different from Europe: Part 15 imposes field-strength limits rather than the ERP ceiling used by CEPT, and interference protection is not guaranteed.

The honest reading

For a beacon builder in the US, the practical positions are:

  1. Part 15 operation: keep the device within Part 15 field-strength limits; the beacon at low power settings is designed to be capable of this.
  2. The higher settings exceed the unlicensed envelope and are only defensible in a genuine emergency.
  3. Receive-only use (SEARCH mode, SDR listening) is always legal.

The clean US path is an amateur radio license (Technician class and above), which opens the 70 cm band (420 - 450 MHz) with full privileges up to the power limit the license class allows. The beacon’s frequency and identification settings support this directly (see Amateur License Process and Callsign Identification).

Emergency use

The FCC’s emergency communication provisions apply: in a genuine life-threatening emergency, using the equipment to summon help is protected. The Emergency Use Legal page describes the principle, which is universal even though the implementing rules differ by country.