CB Channel Refresher

To simplify selection of an operating frequency, the Citizens' Band radio spectrum is divided into 40 numbered radio frequency channels from 26.965 to 27.405 MHz, with channels generally spaced 10 kHz apart. Channel numbers are not strictly sequential with frequency; there are gaps for frequencies used by radio-controlled ("R/C") devices.
Furthermore, there is a gap between channel 22 and channel 23 (which was later filled by channels 24 and 25) for historical reasons. 27.235, 27.245 and 27.255 were assigned to Business radio use while the lower spectrum was assigned to the 11 meter amateur (ham) radio band. The 11-meter band became CB Channels 1 to 22, and the last business frequency was channel 23 and shared.
The frequency allocation list shown is supplied by the FCC (Federal Communications Commission) from Part 95 - Subpart D - Rules for Citizens Band (CB) Radio Service.

 

Channel usage

Channel 19 is the most commonly used by truck drivers on highways, to the point that some radios even have a dedicated button to bring up channel 19 instantly. In most areas of the U.S. Other channels regionally used for this purpose include 10, 17, and 21. Channel 13 is preferred in some areas for marine use and for recreational vehicles.
Several countries reserve a channel for emergency use, for example, channel 9 in the United States. In CB's heyday in the 1970s, channel 9 was monitored by parties who could relay messages to the authorities, or even directly by the authorities themselves. With the popularity of cellular phones, support for Channel 9 as an emergency channel has diminished, though volunteer organizations such as REACT (Radio Emergency Associated Communications Teams), and private individuals still monitor Channel 9 in some (particularly rural) areas.

Channel assignments

North American/CEPT frequencies

CB Channel	Frequency	Typical Use (US)
Channel 1	26.965 MHz	Used by truckers in eastern USA & Canadian maritime provinces
Channel 2	26.975 MHz
Channel 3	26.985 MHz
Channel 4	27.005 MHz	Often used for 4x4's/ Off-roading
Channel 5	27.015 MHz
Channel 6	27.025 MHz	Considered the Super Bowl channel
Channel 7	27.035 MHz
Channel 8	27.055 MHz
Channel 9	27.065 MHz	Emergency communications or traveler assistance
Channel 10	27.075 MHz	Often used by truckers for regional roads
Channel 11	27.085 MHz
Channel 12	27.105 MHz
Channel 13	27.115 MHz	Considered the Marine/RV channel
Channel 14	27.125 MHz	Commonly included transmit/receive crystal in many vintage walkie-talkies
Channel 15	27.135 MHz
Channel 16	27.155 MHz
Channel 17	27.165 MHz	Used by truckers on North/Southbound Highways on the west coast (primarily I-5)
Channel 18	27.175 MHz
Channel 19	27.185 MHz	Highway trucker channel Notable as being the center frequency of the band.
Channel 20	27.205 MHz
Channel 21	27.215 MHz
Channel 22	27.225 MHz
Channel 23	27.255 MHz
Channel 24	27.235 MHz
Channel 25	27.245 MHz
Channel 26	27.265 MHz
Channel 27	27.275 MHz
Channel 28	27.285 MHz
Channel 29	27.295 MHz
Channel 30	27.305 MHz	Depending on local needs, channels numbered above 30 or 35 are generally used with SSB operation.
Channel 31	27.315 MHz
Channel 32	27.325 MHz
Channel 33	27.335 MHz
Channel 34	27.345 MHz
Channel 35	27.355 MHz
Channel 36	27.365 MHz
Channel 37	27.375 MHz
Channel 38	27.385 MHz	SSB calling channel, LSB mode.
Channel 39	27.395 MHz
Channel 40	27.405 MHz