FCC Part 15 rules are the federal regulations that let you operate low-power wireless devices — Wi-Fi routers, Bluetooth speakers, garage door openers, cordless microphones, and low-power AM or FM transmitters — without a broadcast license, as long as the device doesn’t cause harmful interference to licensed radio services and accepts any interference it receives.1eCFR. 47 CFR Part 15 – Radio Frequency Devices Modify the antenna, boost the signal, or ignore an FCC shutdown notice, and the civil forfeiture can exceed $25,000 per violation, with pirate broadcasters facing fines above $2.4 million.2eCFR. 47 CFR 1.80 – Forfeiture Proceedings
The Two Conditions Every Part 15 Device Lives Under
Section 15.5 sets the floor for everything else. Your device cannot cause harmful interference to any licensed radio service, and it must accept any interference it receives, even if that interference degrades its performance or causes it to malfunction.3eCFR. 47 CFR 15.5 – General Conditions of Operation “Harmful interference” means any emission that seriously degrades, blocks, or repeatedly interrupts an authorized communications service.4Federal Communications Commission. Interference Limits Policy
If the FCC notifies you that your device is causing a problem, you have to stop operating it and cannot resume until the issue is fixed. The trigger is notification from the agency, not self-diagnosis. You aren’t required to constantly monitor for interference, but once the FCC tells you there’s a problem, compliance is immediate.
One point catches people off guard: operating a Part 15 device gives you no permanent right to any frequency. Even if your equipment was properly certified and has run for years without issues, the FCC can require you to stop if circumstances change. Licensed users of the spectrum always have priority.
What Part 15 Actually Covers
Part 15 sorts devices into three categories based on how they produce RF energy.5eCFR. 47 CFR 15.3 – Definitions Intentional radiators are devices designed to emit RF energy on purpose: Wi-Fi routers, Bluetooth headsets, walkie-talkies. Unintentional radiators generate RF energy internally but aren’t designed to broadcast it, and the energy leaks out as a byproduct; your laptop’s processor and a USB hub sit here. Incidental radiators create RF noise as an unavoidable side effect of mechanical operation, like an electric motor or a light switch.
A handful of low-risk digital devices are exempt from the detailed technical standards, though the general no-interference rule still applies. Exempt categories include digital components embedded in appliances like microwaves and dishwashers, specialized medical equipment, devices consuming less than six nanowatts, digital devices used only in vehicles, and simple peripherals like joysticks and computer mice that contain only basic conversion circuitry.6eCFR. 47 CFR 15.103 – Exempted Devices
Power Limits for Wi-Fi and Bluetooth
Section 15.247 governs devices using spread-spectrum techniques in three bands: 902–928 MHz, 2,400–2,483.5 MHz, and 5,725–5,850 MHz.7eCFR. 47 CFR 15.247 – Operation Within the Bands 902-928 MHz, 2400-2483.5 MHz, and 5725-5850 MHz For digital modulation systems, which covers standard Wi-Fi, the maximum conducted output power is 1 watt across all three bands. Frequency-hopping systems used in some Bluetooth and industrial devices can also reach 1 watt, but only if they hop across enough channels. In the 2.4 GHz band, a frequency-hopping system needs at least 75 non-overlapping channels to qualify for the full 1-watt limit; systems with fewer channels are capped at 0.125 watts.
Higher-gain antennas trigger a reduction. The 1-watt conducted power limit assumes an antenna with no more than 6 dBi of gain. If you use a more directional antenna, conducted power must drop by the same amount the antenna gain exceeds 6 dBi. A 9 dBi antenna requires a 3 dB power reduction. The rule blocks anyone from working around the power budget by attaching a bigger dish.
Low-Power AM and FM Broadcasting
Part 15 also lets hobbyists broadcast on the AM or FM dial without a license, though the limits keep the signal from carrying much beyond the property line. Under Section 15.219, a low-power AM station in the 510–1,705 kHz band cannot exceed 100 milliwatts of input power to the final RF stage, and the combined length of the antenna, transmission line, and ground lead cannot exceed 3 meters — roughly 10 feet total, from transmitter to antenna tip and including any ground wire.8eCFR. 47 CFR 15.219 – Operation in the Band 510-1705 kHz Emissions outside the band must be at least 20 dB below the unmodulated carrier level.
Low-power FM transmitters in the 88–108 MHz band are limited to a field strength of 250 microvolts per meter at 3 meters, and emissions must stay within a 200 kHz window centered on the operating frequency and falling entirely inside the FM broadcast range. Anything leaking outside that window must meet the general emission limits in Section 15.209.9eCFR. 47 CFR 15.209 – Radiated Emission Limits; General Requirements
In practical terms, these limits cover a room or a small yard. People use Part 15 transmitters for holiday light shows, drive-in church services, and real estate open houses. If your signal reaches across the neighborhood, you’ve almost certainly exceeded the legal limit.
Antenna Restrictions
Antenna modifications are where Part 15 enforcement gets personal. Section 15.203 requires intentional radiators to be designed so no antenna other than the one provided by the manufacturer can be used with the device.10eCFR. 47 CFR 15.203 – Antenna Requirement The antenna is either permanently attached or connects through a proprietary coupling that won’t accept off-the-shelf connectors. Standard antenna jacks and electrical connectors are explicitly banned.
Manufacturers can design a device so a broken antenna is replaceable, but the replacement must use the same proprietary connection. Swapping in a higher-gain aftermarket antenna through an adapter, something that takes about 30 seconds with the right parts, invalidates the device’s authorization entirely. At that point you’re no longer operating under Part 15; you’re operating an unauthorized transmitter. The tested emission profile that kept your device legal was measured with a specific antenna, and a different antenna changes the radiation pattern and effective power in ways the original certification never accounted for.
One exception applies to devices requiring professional installation, like perimeter security systems and certain field disturbance sensors. Those systems are measured at the installation site rather than in a laboratory, so the specific antenna choice becomes part of a site-specific compliance evaluation, and the installer takes on responsibility for keeping the system within Part 15 limits.
How to Tell If a Device Is Legal
Before any Part 15 device can be sold in the United States, it has to clear an authorization process. Intentional radiators — transmitters, routers, and similar equipment — must go through certification, which involves testing at an FCC-recognized laboratory accredited under ISO/IEC 17025:2005.11Federal Communications Commission. Testing Laboratory Qualifications Each certified device receives a unique FCC ID, a string of characters you can look up in the FCC’s public database to verify authorization and review testing data.12Federal Communications Commission. FCC ID Search
Unintentional radiators like computers and monitors can use a lighter process called Supplier’s Declaration of Conformity, where the manufacturer or importer runs its own compliance testing and doesn’t need an FCC-recognized accredited lab.13eCFR. 47 CFR 2.906 – Suppliers Declaration of Conformity Equipment produced by any entity on the FCC’s Covered List (companies identified as national security risks) cannot use this path and must go through full certification.
Every authorized device has to carry a compliance label in a visible location. For most consumer devices, the statement says the device complies with Part 15, may not cause harmful interference, and must accept any interference received.14eCFR. 47 CFR 15.19 – Labeling Requirements Small devices can carry the statement in the user manual and on the packaging instead. For multi-component systems sold together, only the main control unit needs the physical label.
Federal law prohibits manufacturing, importing, selling, or operating any radio frequency device that fails to comply with FCC regulations.15Office of the Law Revision Counsel. 47 USC 302a – Devices Which Interfere With Radio Reception Individuals can import up to three RF devices for personal use without prior authorization, but only in limited categories like unintentional radiators and consumer ISM equipment, and the devices cannot be resold.16Federal Communications Commission. Equipment Authorization – Importation
What It Costs to Violate Part 15
The FCC has a graduated enforcement toolkit, and the financial consequences get serious fast.
Civil Forfeitures
For general Part 15 violations, like operating a modified device that exceeds emission limits, the FCC can impose a forfeiture of up to $25,132 per violation. If the violation continues across multiple days, each day counts separately, up to a total cap of $188,491 for a single act.2eCFR. 47 CFR 1.80 – Forfeiture Proceedings These figures are inflation-adjusted and current as of 2026.
Pirate radio broadcasting carries dramatically higher stakes. Anyone who willfully and knowingly operates an unauthorized broadcast station faces a fine of up to $2,453,218, plus up to $122,661 for each day the violation continues. Congress set the numbers this high because pirate stations can interfere with aviation communications and emergency services.
Criminal Penalties
Willful and knowing violations of the Communications Act carry criminal consequences beyond fines. A federal court can impose up to $10,000 in criminal fines and up to one year of imprisonment, with the maximum prison term doubling to two years on a second conviction.17Office of the Law Revision Counsel. 47 USC 501 – General Penalty Criminal prosecution is rare for accidental interference from consumer devices, but it’s a real possibility for anyone intentionally running an unlicensed transmitter after being told to stop.
Equipment Seizure
Any device used with willful and knowing intent to violate the FCC’s licensing or equipment compliance rules can be seized and forfeited to the United States.18Office of the Law Revision Counsel. 47 USC 510 – Forfeiture of Communications Devices The FCC itself doesn’t execute seizures; the Department of Justice handles the physical confiscation through federal court process. In practice, many violations end through voluntary compliance, with a field agent showing up, explaining the problem, and the operator agreeing to shut down or fix the equipment on the spot.
How to Report Interference
If you’re experiencing interference from what you believe is a non-compliant device or unauthorized transmitter, the FCC accepts complaints through its Consumer Inquiries and Complaints Center at consumercomplaints.fcc.gov. Select “Radio Issues” to report pirate stations, unauthorized transmitters, or interference problems. You can also reach the FCC by phone at 888-225-5322. Filed complaints feed directly into the agency’s enforcement tracking, so even if an individual report doesn’t trigger an immediate investigation, it helps the FCC identify patterns and prioritize targets.