FCC CB Radio Rules: Power, Antenna Height, and Amplifier Ban

The FCC CB radio rules do not require you to hold an individual license, but they do bind every operator to the technical and operating limits in 47 CFR Part 95, Subpart D. Those rules cap your power, restrict your antenna height, dictate what you can say and how long you can say it, and forbid any modification to a certified radio. Break them and your authorization to transmit disappears, exposing you to civil forfeitures or, in serious cases, criminal prosecution.

No License, But Still Regulated

Under 47 CFR 95.305, any eligible person may operate a CB station without applying for a license or being assigned a call sign.1eCFR. 47 CFR 95.305 – Authorization to Operate Personal Radio Services Stations That does not make the airwaves a free-for-all. Every time you key the mic, you are operating under a blanket authorization conditioned on your compliance with Part 95. Violate the rules and the authorization is automatically voided, which means continued transmission is unlicensed operation.2eCFR. 47 CFR Part 95 Subpart D – CB Radio Service

Who Can Operate

Eligibility is deliberately broad. There is no minimum age, no citizenship requirement, and no exam. You are eligible unless you fall into a narrow set of exclusions: foreign governments and their representatives cannot operate under Part 95 authorization, and neither can anyone currently subject to an FCC cease and desist order. Part 95 authority also cannot be used to run a U.S. Government station or a foreign government station.1eCFR. 47 CFR 95.305 – Authorization to Operate Personal Radio Services Stations

Power Limits and Authorized Modes

The FCC caps transmitter output to keep CB a short-range service. The ceiling depends on your modulation:

  • AM or FM voice: 4 watts mean carrier power maximum.
  • Single sideband (SSB) voice: 12 watts peak envelope power maximum.

Those measurements are taken at the transmitter’s final radio frequency stage, not at the antenna.2eCFR. 47 CFR Part 95 Subpart D – CB Radio Service Authorized emissions include AM voice (A3E), SSB voice (J3E, R3E, or H3E), and FM voice (F3E). FM was added in a 2017 rulemaking and is limited to a peak frequency deviation of ±2 kHz.3Federal Communications Commission. Petitions for Reconsideration of Part 95 Personal Radio Services Rules Older AM/SSB-only radios remain legal.

Channels and Transmission Limits

CB uses 40 shared channels running from 26.965 MHz (Channel 1) to 27.405 MHz (Channel 40). No operator has exclusive rights to any of them, and transmitting outside the 40 designated channels is treated as unauthorized operation on a frequency you have no right to use.2eCFR. 47 CFR Part 95 Subpart D – CB Radio Service

Two channels get special treatment. Channel 9 is reserved for emergency communications and traveler assistance only. Casual chat, radio checks, and equipment testing are prohibited there. Channel 19 has no formal status in the rules but functions as the de facto trucker channel for road and traffic information.

Any single on-air conversation is capped at five consecutive minutes. Once you finish, you have to wait at least one full minute before transmitting again on that same channel. Switching to a different channel resets the clock immediately; the cooling period only applies to the frequency you just vacated.2eCFR. 47 CFR Part 95 Subpart D – CB Radio Service

Antenna Height

The height rule sets two limits and lets you use whichever gives you more antenna:

  • A ground-mounted antenna cannot exceed 60 feet (18.3 meters) above the ground.
  • A building- or tree-mounted antenna cannot exceed 20 feet (6.1 meters) above the highest point of the structure or tree it sits on.

A freestanding tower can go to 60 feet. An antenna on top of a 50-foot building can extend 20 feet above the roofline, reaching 70 feet above the ground, because the building-mount calculation produces the larger allowable figure.2eCFR. 47 CFR Part 95 Subpart D – CB Radio Service

If you live near a military or public-use airport, additional restrictions kick in. As a general rule, the antenna’s highest point cannot exceed one meter of height for every 100 meters of distance from the nearest runway, and structures over 20 feet may trigger FAA notification requirements.4eCFR. 47 CFR 95.317 – Registration of Antenna Structures That May Constitute a Menace to Air Navigation

What You Cannot Transmit

Several categories of communication are off-limits under 47 CFR 95.333 and 95.933:

  • Obscene, profane, or indecent language.
  • False or deceptive communications, including fake distress calls.
  • Intentional interference with other stations.
  • Music, whistling, or sound effects transmitted for entertainment.
  • Advertising or soliciting the sale of goods or services.
  • Political campaign advertising, though the organizational side of a campaign can use CB.
  • One-way transmissions, except when trying to initiate a two-way contact, making emergency calls, or in other specifically permitted situations.
  • Transmissions intended for broadcast on a radio or TV station, though gathering news material over CB is allowed.

5eCFR. 47 CFR 95.333 – Prohibited Uses6GovInfo. 47 CFR 95.933 – Prohibited CBRS Uses Using CB in furtherance of any activity that violates federal, state, or local law is also independently prohibited.

Talking Across Borders and Long Distances

You can communicate with General Radio Service stations in Canada, but contacting stations in any other country is prohibited. Bring your radio abroad and you are subject to the host country’s rules while you are there.6GovInfo. 47 CFR 95.933 – Prohibited CBRS Uses

The old 250-kilometer (roughly 155-mile) distance cap is gone. Under certain atmospheric conditions CB signals can bounce off the ionosphere and travel hundreds of miles, a phenomenon known as skip. The FCC concluded that skip propagation did not meaningfully increase harmful interference and eliminated the distance restriction.7Federal Communications Commission. Review of the Commissions Part 95 Personal Radio Services Rules Long-distance skip contacts are now legal, provided you stay within the power and equipment rules.

Certified Equipment and the Amplifier Ban

Every CB radio sold in the United States must be certified through the FCC’s equipment authorization program. A manufacturer submits the unit to an FCC-recognized Telecommunication Certification Body, which verifies compliance with technical standards for power, frequency stability, and emission type. Certified radios carry an FCC ID label.8Federal Communications Commission. Equipment Authorization No label, no legal operation.

Once certified, the radio has to stay the way it left the factory. The frequency-determining circuitry, including crystals and programming controls, must remain internal and inaccessible from the outside. Opening the case to boost power, add channels, or alter emission characteristics voids the certification, and operating the modified unit becomes unauthorized transmission.2eCFR. 47 CFR Part 95 Subpart D – CB Radio Service

External radio frequency power amplifiers, sometimes called linear amplifiers or “boots,” are flatly illegal on CB. The rule has no exceptions. The FCC also prohibits manufacturing, importing, selling, or offering to sell an external amplifier capable of operating below 144 MHz that is intended for CB use.2eCFR. 47 CFR Part 95 Subpart D – CB Radio Service This is the area where the Commission most consistently brings enforcement actions.

Penalties

Enforcement runs on two tracks. Most violations draw a civil forfeiture. Under 47 U.S.C. 503, the statutory base is up to $10,000 per violation or per day of a continuing violation, capped at $75,000 for any single continuing act.9Office of the Law Revision Counsel. 47 USC 503 – Forfeitures The FCC adjusts these figures for inflation, so an actual penalty may run higher than the statutory floor.

Willful and knowing violations can trigger criminal charges. A first conviction under 47 U.S.C. 501 carries a fine of up to $10,000, up to one year of imprisonment, or both. A second conviction doubles the maximum prison term to two years.10GovInfo. 47 USC 501 – General Penalty Criminal referrals are uncommon for routine infractions but have followed cases involving persistent illegal amplifier use, intentional interference with emergency communications, and operators who ignore warnings.

When setting a penalty, the Commission weighs the severity of the violation, any history of prior offenses, ability to pay, and whether the conduct was intentional. An operator who runs past the five-minute transmission limit occasionally is in a very different position than one running an illegal amplifier on Channel 9 after receiving a warning letter.