United States
Origins
The citizens band radio service originated in the United States as one of several personal radio … See more

CB was the only practical two‑way radio system for the individual consumer, and served several subsets of users such as truck drivers, radio hobbyists, and those in need of short‑range radio communications, such as electricians, plumbers, and … See more

27 MHz is a relatively long wavelength for mobile communications, and the choice of antenna has a considerable impact on the performance of a CB radio. A common mobile antenna is a quarter-wave vertical whip. This is roughly 9 feet (2.7 m) tall; it is mounted low on the … See more

Operation on frequencies above or below the citizens band (on the "uppers" or "lowers") is called "freebanding" or "outbanding". While frequencies just below the CB segment (or between the CB segment and the amateur radio 10-meter band See more

CB radio is not a worldwide, standardized radio service. Each country decides if it wants to authorize such a radio service from its domestic … See more

At the beginning of the CB radio service, transmitters and receivers used vacuum tubes; solid-state transmitters were not widely available until 1965, after the introduction of RF … See more

All frequencies in the HF spectrum (3–30 MHz) can be refracted by charged ions in the ionosphere. Refracting signals off the ionosphere is called skywave propagation, and the operator is … See more