Are There Legal Limits on CB Radio Power?
CB (Citizens Band) radio remains a popular choice for short-range two-way communications — from trucking and road trips to off-road adventures and emergency messaging. But it’s not a “free-for-all” when it comes to power. There are legal limits on CB radio transmission power, and violating them can lead to serious consequences. In this article, we’ll break down what those limits are, why they exist, and what you must avoid.
What Are the Legal Power Limits for CB Radios?
Under U.S. law, CB radios are regulated by the Federal Communications Commission (FCC) under 47 CFR Part 95, Subpart D.According to these rules:
- For AM (or FM) CB transmissions, the maximum permitted power is 4 watts carrier power.
- For SSB (Single Sideband) transmissions, the limit is 12 watts peak envelope power (PEP).
These are not just “recommended” limits — they are legal maximums. Operating above them voids your authorization to use the CB band.
Why These Power Limits Matter
- Regulation of Spectrum Use
Limiting power helps ensure that CB users don’t interfere with other radio services. Because CB is a shared band, too much power from one user could disrupt many others. - Safety and Equipment Integrity
Higher power means more risk. The low-to-moderate power ceiling (4W / 12W) helps keep devices safer, especially since many CB operators are civilians without professional radio training. - Preventing Illegal Amplification
The FCC explicitly prohibits external RF power amplifiers (or “linears”) to boost a CB transmitter’s signal. Using one voids your legal right to operate that radio. - Certification Requirements
CB radios must be FCC-certified (“type accepted”). If you internally modify the radio, such as increasing its power output beyond legal limits, you lose that certification — and you’re technically operating illegally.
Other Regulatory Constraints to Know
- Antenna Height Limits: For fixed (base) CB stations, there are rules on how high the antenna can be mounted: up to 60 feet (18.3 meters) above ground, or 20 feet (6.1 meters) above the highest point of the building/tree it’s mounted on, whichever is higher.
- No License Required: Fortunately, CB users do not need a license to operate — as long as they stay within the rules (power, frequencies, type-accepted gear).
- Prohibition on Selling or Using Illegal Equipment: Modifying CB gear to exceed power limits or attaching external amplifiers is explicitly disallowed.
Consequences of Violating CB Power Rules
If someone operates a CB transmitter above the legal power:
- They void their authorization to use that station.
- They risk FCC enforcement, which could include fines, confiscation of equipment, or other penalties.
- The risk isn’t just regulatory — using high-powered or modified equipment can generate interference that disrupts other users’ communications and may harm critical radio services.
Practical Takeaways for CB Users
- Always use FCC-certified CB radios — make sure they have the correct type-acceptance label.
- Do not attempt to modify your CB transmitter to output more than the legal limit.
- Refrain from buying or using external RF amplifiers for your CB setup — they’re illegal in this service.
- If you want more coverage (range), focus on better antennas (within height rules), good antenna placement, and using SSB (if your radio supports it), rather than illegally boosting power.
Yes — there are clear legal limits on how much power a CB radio can legally transmit. In the U.S., those limits are enforced by the FCC and set at 4 watts for AM/FM and 12 watts PEP for SSB. Exceeding these limits, or using unauthorized modifications or amplifiers, is a serious violation.
If you want reliable, legal CB communication, stick to certified equipment, follow the power rules, and you’ll stay on the right side of regulations while still making the most of your CB radio.
As a trusted supplier of two-way radios and communication equipment, we offer FCC-certified CB radios, antennas, and accessories that comply fully with legal power limits. If you’re looking to set up a safe, lawful CB system — whether for your fleet, your business, or recreational use — contact us today. We can help you choose the right gear, ensure proper installation, and maximize your range without breaking any rules.
