CB radio (Citizen’s Band radio) is a type of short-distance radio communication system that allows individuals to communicate with each other using handheld radios, mobile radios, and base station radios. The radios operate on 40 channels within the 27 MHz (11 meter) band, with channel 9 designated as an emergency channel. CB radios were popular in the 1970s and 1980s, particularly among truck drivers, but have since declined in usage. They are still in use today, but have been largely replaced by cell phones and other forms of wireless communication.

CB radios were first introduced in the United States in 1945, and by the 1970s had become a popular way for truckers to communicate while on the road. The radios were also popular among hobbyists, who used them for personal communication and for talking to other CB enthusiasts. Many CB radios had built-in “channel scanners,” which allowed users to listen to multiple channels at once and find active conversations.

CB radios operate on a “shared” frequency, meaning that anyone with a CB radio can listen in on conversations and join in if they want to. This led to the development of a unique “CB culture” with its own jargon, traditions and etiquette. Some of the terms commonly used in CB radio include “10-4” (meaning “message received”), “breaker breaker” (used to initiate a conversation on a channel), and “handle” (a nickname used by a CB user).

CB radios are still available for purchase, but their usage has greatly decreased with the advent of cell phones and other wireless communication methods. Some people still use them for personal communication or for off-roading, but overall usage is limited.

In addition to personal and hobbyist use, CB radios have also been used in a variety of professional settings. For example, they were popular among truck drivers, who used them to communicate with each other while on the road, as well as to get information about road conditions and traffic. They were also used by construction crews and other mobile workers to stay in touch with their base of operations.

CB radios have also been used in emergency situations as a backup communication system. In the event of a natural disaster or other emergency, traditional phone and radio systems may be overwhelmed or knocked out of service. CB radios, however, can still operate, providing a way for people to stay in touch with each other and with emergency services.

CB radio usage has been regulated by the FCC (Federal Communications Commission) in the US. The FCC sets rules regarding the technical specifications of CB radios, such as maximum power output and channel spacing, and also enforces rules regarding illegal modifications to CB equipment.

CB radio is still a very niche hobby and is used by some people. There are CB clubs and groups that still active, and they conduct events, competitions and rallies.