![]() On Septem : 14 CB service class D was created on 27 MHz, and this band became what is commonly known today as "Citizens Band". Ultra-high frequency (UHF) radios, at the time, were neither practical nor affordable for the average consumer. : 13 Originally designed for use by the public sector, the Citizens Radio Corporation sold over 100,000 units, primarily to farmers and the US Coast Guard. ![]() Al Gross established the Citizens Radio Corporation during the late 1940s to manufacture class B handhelds for the general public. Class B radios had simpler technical requirements, and were limited to a smaller frequency range. There were two classes of CB radio: "A" and "B". In 1948, the original CB radios were designed for operation on the 460–470 MHz UHF band. These services began in 1945 to permit citizens a radio band for personal communication (e.g., radio-controlled model airplanes and family and business communications). The citizens band radio service originated in the United States as one of several personal radio services regulated by the Federal Communications Commission (FCC). Main article: CB radio in the United States Origins A QSL card issued by a US CB station in 1963. Some countries also have personal radio services in the UHF band, such as the European PMR446 and the Australian UHF CB. Although licenses may be required, eligibility is generally simple. While they may be known by other names, such as the General Radio Service in Canada, they often use similar frequencies (26–28 MHz) and have similar uses, and similar technical standards. Multiple countries have created similar radio services, with varying technical standards and requirements for licensing. CB radios have a range of about 5 km to 30 km depending on terrain, for line of sight communication however, various radio propagation conditions may intermittently allow communication over much greater distances. In the US and Canada, and in the EU and the UK, transmitter power is limited to 4 watts when using AM and FM and 12 W PEP when using SSB. Users on a channel must take turns transmitting. The radio is normally in receive mode to receive transmissions of other radios on the channel when users want to communicate they press a " push to talk" button on their radio, which turns on their transmitter. Like many other land mobile radio services, multiple radios in a local area share a single frequency channel, but only one can transmit at a time. In many countries, CB operation does not require a license, and may be used for business or personal communications. Citizens band is distinct from other personal radio service allocations such as FRS, GMRS, MURS, UHF CB and the Amateur Radio Service ( "ham" radio). Shown with Astatic brand D-104 desk mic Cobra 18 WX ST II mobile CB radio with microphone Cobra 50 WX ST Handheld CB RadioĬitizens band radio ( CB radio), used in many countries, is a land mobile radio system, a system allowing short-distance one-to-many bidirectional voice communication among individuals, using two-way radios operating near 27 MHz (or the 11-m wavelength) in the high frequency or shortwave band. "Base stations" are usually operated on household AC power but can also from a vehicle's DC power system if operated in a vehicle or from an emergency battery source. Land mobile radio system Typical 1980s CB radio intended for use at a fixed location and used with outdoor antenna.
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