Citizen’s band started life in the mid-1940s with the FCC designating 23 channels for CB use in 1958. Fast forward to the 1970s and CB radio was getting very popular and the channel allocation was increased to 40 in 1977.

Note: I’ve seen some charts that incorrectly assume the 10khz step between each channel is uniform – it isn’t!
Table of Contents
USA – FCC Channel Allocation
Channel | Frequency (MHz) | Channel | Frequency (MHz) |
---|---|---|---|
1 | 26.965 | 2 | 26.975 |
3 | 26.985 | 4 | 27.005 |
5 | 27.015 | 6 | 27.025 |
7 | 27.035 | 8 | 27.055 |
9 | 27.065 | 10 | 27.075 |
11 | 27.085 | 12 | 27.105 |
13 | 27.115 | 14 | 27.125 |
15 | 27.135 | 16 | 27.155 |
17 | 27.165 | 18 | 27.175 |
19 | 27.185 | 20 | 27.205 |
21 | 27.215 | 22 | 27.225 |
23 | 27.255 | 24 | 27.235 |
25 | 27.245 | 26 | 27.265 |
27 | 27.275 | 28 | 27.285 |
29 | 27.295 | 30 | 27.305 |
31 | 27.315 | 32 | 27.325 |
33 | 27.335 | 34 | 27.345 |
35 | 27.355 | 36 | 27.365 |
37 | 27.375 | 38 | 27.385 |
39 | 27.395 | 40 | 27.405 |
Channel 23 is out of sequence and also has a 30 KHz jump. It was also shared with radio controlled devices. When the allocation was increased to 40 channels these gaps were filled in.
There are also gaps between 3 and 4, 7 and 8, 11 and 12, 15 and 16, and 19 and 20. These are all reserved for radio controlled devices.
In September 2021 the FCC finally allowed FM to be used alongside AM / SSB.
TRANSMIT POWER: 4 Watts AM / FM and 12 Watts SSB
UK CB Frequencies – 27/81
The UK finally found itself with legal CB radio in November 1981. To help stop the rogue CBers a couple of things happened. The channels that were allocated were located higher up the 27MHz band to prevent the existing, illegally imported, radios being used. Not only that the channels were offset by 1.25KHz so even radios with high channels would be off frequency.
A final twist was the new radios used FM rather than AM that the radios illegally imported from the USA operated on. This actually made sense because FM was much less likely to interfere with other electrical devices. Remember, this was the early 1980s and electrical wasn’t so good at interference suppression. The UK is much more densely populated so the chances of wiping out your neighbors’ television was quite high.
Channel | Frequency (MHz) | Channel | Frequency (MHz) |
---|---|---|---|
1 | 27.60125 | 2 | 27.61125 |
3 | 27.62125 | 4 | 27.63125 |
5 | 27.64125 | 6 | 27.65125 |
7 | 27.66125 | 8 | 27.67125 |
9 | 27.68125 | 10 | 27.69125 |
11 | 27.70125 | 12 | 27.71125 |
13 | 27.72125 | 14 | 27.73125 |
15 | 27.74125 | 16 | 27.75125 |
17 | 27.76125 | 18 | 27.77125 |
19 | 27.78125 | 20 | 27.79125 |
21 | 27.80125 | 22 | 27.81125 |
23 | 27.82125 | 24 | 27.83125 |
25 | 27.84125 | 26 | 27.85125 |
27 | 27.86125 | 28 | 27.87125 |
29 | 27.88125 | 30 | 27.89125 |
31 | 27.90125 | 32 | 27.91125 |
33 | 27.92125 | 34 | 27.93125 |
35 | 27.94125 | 36 | 27.95125 |
37 | 27.96125 | 38 | 27.97125 |
39 | 27.98125 | 40 | 27.99125 |
As you can see, channel 40 is right under the 10m amateur band which starts at 28.0 MHz. You can see why those running too much power and/or over-modulation might annoy local hams.
TRANSMIT POWER: 4 Watts FM
UK / Europe CB Frequencies – CEPT (Europe)
In 1987 UK CBers got another 40 channels, the CEPT band. These matched up with the European frequencies and completely inline with the FCC / USA frequencies that were lobbied for original. However, just as in Europe, FM was the mode of choice.
Finally in June 2014 AM and SSB was now allowed on the CEPT band. This now meant under ideal DX conditions, UK users could finally talk to US CBers without having to use illegal radios.
Channel | Frequency (MHz) | Channel | Frequency (MHz) |
---|---|---|---|
1 | 27.60125 | 2 | 27.61125 |
3 | 27.62125 | 4 | 27.63125 |
5 | 27.64125 | 6 | 27.65125 |
7 | 27.66125 | 8 | 27.67125 |
9 | 27.68125 | 10 | 27.69125 |
11 | 27.70125 | 12 | 27.71125 |
13 | 27.72125 | 14 | 27.73125 |
15 | 27.74125 | 16 | 27.75125 |
17 | 27.76125 | 18 | 27.77125 |
19 | 27.78125 | 20 | 27.79125 |
21 | 27.80125 | 22 | 27.81125 |
23 | 27.82125 | 24 | 27.83125 |
25 | 27.84125 | 26 | 27.85125 |
27 | 27.86125 | 28 | 27.87125 |
29 | 27.88125 | 30 | 27.89125 |
31 | 27.90125 | 32 | 27.91125 |
33 | 27.92125 | 34 | 27.93125 |
35 | 27.94125 | 36 | 27.95125 |
37 | 27.96125 | 38 | 27.97125 |
39 | 27.98125 | 40 | 27.99125 |
TRANSMIT POWER: 4 Watts AM / FM and 12 Watts SSB