Capabilities, Limits, and Preparedness Value

Citizen Band (CB) radio is one of the most recognizable and accessible radio services in the U.S. Long associated with truckers and road communication, CB remains legally available to the public without licenses, exams, or registration. For preparedness-minded individuals and Mutual Assistance Groups (MAGs), CB occupies an important—but very specific—niche in the communications toolbox.

This page explains how CB works, what frequencies and modes it uses, its realistic range, and how it compares to other common radio options used for preparedness.

What Is Citizen Band (CB)?

CB radio operates in the 27 MHz HF spectrum (technically HF, but near the upper edge). In the U.S., CB is regulated by the Federal Communications Commission and is limited to:

40 fixed channels
4 watts output on AM/FM
12 watts PEP on Single Sideband (SSB)
No encryption
No repeaters
No licensing

CB radios can be base stations, vehicle-mounted, or handheld, though vehicle and base setups dominate due to antenna size requirements.

CB Channels, Modes, and Common Usage

Below is a summary of the most relevant CB channels for practical use. All CB channels share the same frequency spacing (10 kHz).

Common CB Channels (U.S.)

All U.S. CB radios operate in the 27 MHz HF band, with 10 kHz channel spacing. These channels are fixed by regulation.

Channel	Frequency (MHz)	Authorized Modes	Common / Notable Use
1	26.965	AM / FM / USB / LSB	General communications
2	26.975	AM / FM / USB / LSB	General communications
3	26.985	AM / FM / USB / LSB	Rural / local
4	27.005	AM / FM / USB / LSB	Local traffic
5	27.015	AM / FM / USB / LSB	General
6	27.025	AM / FM / USB / LSB	High-power / skip activity (often noisy)
7	27.035	AM / FM / USB / LSB	General
8	27.055	AM / FM / USB / LSB	General
9	27.065	AM only	Emergency / traveler assistance
10	27.075	AM / FM / USB / LSB	Local
11	27.085	AM / FM / USB / LSB	Calling channel (historic)
12	27.105	AM / FM / USB / LSB	General
13	27.115	AM / FM / USB / LSB	Marine / RV (informal)
14	27.125	AM / FM / USB / LSB	Local
15	27.135	AM / FM / USB / LSB	General
16	27.155	AM / FM / USB / LSB	General
17	27.165	AM / FM / USB / LSB	North–south highway traffic
18	27.175	AM / FM / USB / LSB	General
19	27.185	AM / FM	Primary highway / trucker channel
20	27.205	AM / FM / USB / LSB	General
21	27.215	AM / FM / USB / LSB	General
22	27.225	AM / FM / USB / LSB	General
23	27.255	AM / FM / USB / LSB	General
24	27.235	AM / FM / USB / LSB	General
25	27.245	AM / FM / USB / LSB	General
26	27.265	AM / FM / USB / LSB	General
27	27.275	AM / FM / USB / LSB	General
28	27.285	AM / FM / USB / LSB	General
29	27.295	AM / FM / USB / LSB	General
30	27.305	AM / FM / USB / LSB	General
31	27.315	AM / FM / USB / LSB	General
32	27.325	AM / FM / USB / LSB	General
33	27.335	AM / FM / USB / LSB	General
34	27.345	AM / FM / USB / LSB	General
35	27.355	AM / FM / USB / LSB	General
36	27.365	USB / LSB	SSB long-range
37	27.375	USB / LSB	SSB long-range
38	27.385	USB / LSB	SSB calling / coordination
39	27.395	USB / LSB	SSB long-range
40	27.405	USB / LSB	SSB long-range

Important notes:

Channel 9 is monitored but not guaranteed to be answered.
Single Sideband (USB/LSB) is where CB gains its maximum useful range.
FM is legal in the U.S. but not universally supported by older radios.

Mode Clarifications (Important for Preparedness)

AM
Most common, most crowded, most noise-prone.
FM
Clearer audio, similar range to AM, not supported on all radios.
USB / LSB (Single Sideband)
- Legal on all channels, but primarily used on 36–40
- Greater range and efficiency
- Requires compatible radios and disciplined operation

Preparedness takeaway:
If CB is in your plan, SSB capability is strongly recommended.
If CB is part of your plan, SSB capability matters.

Power Limits (U.S.)

AM / FM: 4 watts carrier
SSB: 12 watts peak envelope power (PEP)
Repeaters: Not permitted
Encryption: Not permitted

Practical Preparedness Notes

Channel 9 is designated for emergencies but monitoring is inconsistent
Channel 19 provides real-time situational awareness during evacuations
SSB channels (36–40) are the only realistic option for extended CB range
CB should be considered a monitoring and fallback layer, not primary command-and-control

Realistic CB Range

CB range is heavily dependent on antenna quality, terrain, and atmospheric conditions.

Typical Ranges

Setup	Expected Range
Handheld to handheld	1–3 miles
Vehicle to vehicle	3–10 miles
Base station (good antenna)	10–25 miles
SSB with favorable conditions	20–50+ miles
Skip (ionospheric bounce)	Hundreds to thousands of miles (unreliable)

Skip can extend range dramatically—but it is unpredictable, noisy, and often unusable for coordination.