Citizens' band radio (CB) is a system of short distance communication between individuals on a selection of 40 channels within the single 27 MHz (11 meter) band. radio frequencies.
Following a decision in 1945 by the US government that its citizens should have this right, the US Federal Communication Commission allocated a frequency of 467 MHz FM for the General Mobile Radio Service. The CB radio service should not be confused with GMRS or Amateur (Ham) Radio. CB does not require a license. Both GMRS and Amateur Radio do require licenses and Amateur (Ham) Radio also requires the passing of exams before a license and call sign is issued by the FCC. In 1958 extra, lower-frequency channels were introduced on AM to encourage use. The 11-meter band was taken from the Amateur Radio service for the Citizen's Band. But it was not until the 1970s, when technology had advanced to reduce costs, that the CB market prospered, US truckers being at the head of the boom. Many CB clubs were formed and a special CB language evolved.
In the US, CB radio seems to adhere to the following defacto plan:
Channel 1 Local community calling and working
Channel 6 High power illegal activity
Channel 7 Local community calling and working
Channel 8 Truckers in Australia
Channel 9 Emergency calling (State troopers and highway patrol vehicles in the US usually monitor this channel)
Channel 17 North/South freeway traffic and trucks (except in California where all traffic is on 17)
Channel 19 East/West traffic and trucks
Channel 30 and above SSB (There seems to be a bootlegger's gentleman's agreement that long distance SSB be done above channel 30)
The 27MHz FCC Bandplan shows the channels available and their associated frequencies.
Although CB was created in the USA it is also used in many different countries around the world.
CB Radio In The UK
See also amateur radio