[1] It is intended to be a two-way voice communication service for use in personal and business activities of the general public, and has a reliable communications range of several miles, though the range is highly dependent on type of radio, antenna and propagation.
However, foreign governments and their representatives are not eligible to use citizens' band radio within the United States.
Transmitters must be FCC certified and may not be modified, including modifications to increase output power or to transmit on unauthorized frequencies.
[5] If a radio includes SSB, it must transmit on the upper sideband with a suppressed, reduced, or full carrier.
R/C enthusiasts usually designate them by color, and fly different-colored flags from the antenna to show who is on which channel.
[11] Because of interference from CB radios, legal or otherwise, the noise level, and the limited number of channels, most "serious" hobby radio-controlled models operate on other bands.
Instead, they operate under the FCC's Part 15 rules, which allow a wide variety of low powered devices to use the frequencies from 26.96 to 27.28 MHz, which covers CB Channels 1 through 27.
Some other of the R/C toys operate on the 49 MHz Part 15 channels, and often a pair of R/C cars will be sold with one on 27.145 and one on 49.860 to avoid interference.
In the days when CB required a license, some low-powered or toy walkie-talkies were exempt because they operated within Part 15.
However, in 1976, the FCC phased in a shift of these 100 mW[12] devices to the 49 MHz band, with operation on the CB frequencies to cease in 1983.
[13] More recently in the 1990s, low-powered handhelds using FM voice on the 27 MHz radio-control channels were also sold to operate legally under Part 15.
There is great potential for interference, as power lines were never specifically designed to shield radio frequencies.
Induction welding of plastics, and some types of diathermy machines commonly operate in this range.
[14] Adjacent frequencies are often used by illegal operators using modified CB or amateur radio equipment.