The citizens’ band radio (CB) is a communication system used for short-distance communication in selected channels within a single band, usually 27MHz. This system is, more or less, a personal communication system and does not require any license to operate. It’s very popular in the United States.
CB radio systems operate in MHz between HF and UHF bands. The signals at different frequencies behave differently and thus affect the performance of the equipment. Initially, CB radios operated in the 460 to 470 MHz band. In 1958, a type of CB radio known as Class D was permitted to be used in the 27MHz band. A government band used primarily by the forest department and military, this band had a secondary band that allowed amateur radio services which later became the popular CB. With the advent of Internet and mobile communication, CB has lost some of its appeal, but many people continue to use it to communicate and as a hobby. It is still widely used by truck drivers for truck-to-truck communication. It’s also used by among hunters and farmers in remote areas where telephone landlines and cell phone towers are uncommon. People who go out in groups for camping, hiking or other outdoor activities also use this technology.
The first CB radios were of two types, A and B. Class B required less technical and less expensive equipment, but its range was smaller. As technology increased, another model, Class D, was developed using the 27 MHz band. Class D became the standard for CB radios, inexpensive and widely available. The category of 460MHz to 470 MHz band was later allocated to public safety and business purposes. The latest CB class is the general mobile radio service, which is used between friends for personal communication. This system utilizes the VHF band for two-way communication.
Uses of the CB radio
Radio activity depends on whether the transmission mode is AM or SSB. The AM mode allows communications up to a distance of approximately nine miles , depending on the quality of the antenna, interference level and terrain. SSB allows communications up to 18 miles.
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