All About CB Radios

Citizens' Band radio (CB) is, in most countries, a system of short-distance radio communication between individuals on a selection of 40 channels within the single 27 MHz (11 meter) band. The CB radio service should not be confused with FRS, GMRS, MURS, or amateur radio. Similar personal radio services exist in other countries, with varying requirements for licensing and differing technical standards. In many countries, CB does not require a license and, unlike amateur radio, it may be used for commercial communication.

Scope:

The Citizens' Band radio service in the United States is one of several personal radio services regulated by the FCC. These services began in 1945 to permit citizens a short-distance radio band for personal communication (e.g., radio controlled models, family communications, individual businesses). Originally, CB was located in the 460-470 MHz UHF band. There were two classes of CB: A and B. Class B radios had simpler technical requirements but were limited to a smaller range of frequencies.

At the time, the technology was not advanced enough to make a UHF radio practical for the average consumer. So, in 1958, the Class D CB service was opened at 27 MHz, and this is what is popularly known as CB. Previously, this was a government band (primary allocation to US Forest service, military, etc.) with a secondary allocation for the amateur radio service.

Most of the 460-470 MHz band was reassigned for business and public safety uses, but Class A CB is the ancestor of the present General Mobile Radio Service GMRS. Class B, in the same vein, is a more distant ancestor of the Family Radio Service. The Multi-Use Radio Service is another two-way radio service, in the VHF high band. An unsuccessful petition was made in 1973 to create a Class E CB service at 220 MHz, this was opposed by amateur radio organizations and others. There are several other classes of personal radio services for specialized purposes such as remote control devices.

While parts of this article are specific to the United States, several countries have similar radio services. While they may be known by other names, they often use similar frequencies (26 to 28 MHz), and have similar uses. Licenses may or may not be required, but eligibility is generally simple.

On the other hand, some foreign personal radio services, such as the European PMR446 and the Australian UHF CB, are more similar to the American FRS or GMRS services than the CB service and so are not covered in this article.

History:

In the 1960s, the service was popular for small trade businesses (e.g., electricians, plumbers, carpenters) and transportation services (e.g., taxi and trucking firms). "10 codes" originally used in the public service (e.g., police, fire, ambulance) and land mobile service were used for short acknowledgments. With the advancement of solid state technology (transistors replacing tubes) in the 1970s, the weight, size, and cost of the radios decreased. US truckers were at the head of the boom. Many CB clubs were formed, and a special CB slang language evolved. The prominent use of CB radios in mid- and late-1970s films (see list below), television shows such as The Dukes of Hazzard (debuted 1979), and in popular novelty songs such as C.W. McCall's "Convoy" (1976) helped to establish the radios as a nationwide craze in America from the mid-1970s to the early 1980s.

Originally, CB did require a license and the use of a call sign, but when the CB craze was at its peak, many people ignored this requirement and used made up nicknames or "handles". The use of handles instead of call signs is related to the common practice of using the radios to warn other drivers of speed traps during the time when the United States dropped the national speed limit to 55 mph (90 km/h) beginning in 1974 in response to the 1973 hike in oil prices. The FCC recommended the use of ten-codes and these were used, often in a shortened form, but also many slang terms were developed.

The low cost and simple operation of CB equipment gave access to a communications medium that was previously only available to specialists. The "boom" in CB usage in the 1970s and in Britain in the early 1980s bears several similarities to the advent of the Internet in the 1990s. The many restrictions on the authorized use of CB radio led to widespread disregard of the regulations, most notably in antenna height, distance restriction for communications, licensing and the use of call signs, and allowable transmitter power. Eventually, the license requirement was dropped entirely.

Originally, there were only 23 CB channels in the U.S.; 40-channel radios did not come along until 1977. In the 1960s, channels 1-8 and 15-22 were reserved for "intrastation" communications among units under the same license, while the other channels (9-14 and 23) could be used for "interstation" calls to other licenses.

In the early 1970s, channel 9 became reserved for emergency use. Channel 10 was used for highway communications, and channel 11 was used as a general calling channel. Later, channel 19 became the preferred highway channel in most areas as it did not have the adjacent-channel interference problems with channel 9.

Until the late 1970s when synthesized radios appeared, CB radios were controlled by plug-in quartz crystals. Almost all were AM only, though there were a few single sideband sets in the early days.

In 1973, various groups petitioned the FCC for an allocation of frequencies near 220 MHz for a new "Class E" Citizen's Band service. This was opposed by amateur radio organizations as well as other government agencies and commercial users who desired this allocation for their own usage. While the "Class E" initiative was not successful early on, the Reagan Administration sponsored some of these requirements for the development of the Family Radio Service, General Mobile Radio Service and Multi-Use Radio Service. These services fulfilled a majority of the requirements (e.g., eliminate some of the interference and skip that existed on the shortwave frequencies) proposed by the petitioners in 1973. Today, these radios are quiet, affordable, and readily accessible.

Throughout the 1970s and early 1980s, a phenomenon was developing over the CB radio. Similar to the Internet chat rooms a quarter century later, the CB allowed people to get to know one another in a quasi-anonymous manner. Many movies and stories about CBers and the culture on-the-air developed.

In Britain, some people were using CB radio illegally in the 1970s, a craze which suddenly peaked in 1980, leading to legalization on 2 November 1981. However, in the summer of 1981 the British government was still saying that CB would never be legalized on 27 MHz. The government wanted a uhf frequency around 860 MHz named 'Open Channel' instead. Eventually 40 channels at 27 MHz, plus 20 channels on 934 MHz were legalized. Both allocations used frequencies unique to the UK; the 934 MHz allocation was later withdrawn in 1998. CB's inventor Al Gross made the first legal British CB call from Trafalgar Square, London.

In more recent years, CB has lost much of its original appeal due to the advancement of technologies and changing values. Some of this rapid development includes: mobile phones, the Internet, and Family Radio Service. The changing radio wave propagation for long-distance communications, due to the 11 year Sunspot cycle, is always a factor for these frequencies.

CB Frequencies Worldwide:

Similar radio services exist in other countries around the world. Frequencies, power levels, and modes (such as FM, AM and SSB) may vary from country to country, and usage of foreign equipment may be illegal. However, many countries have adopted the American frequencies.

In Canada, the "General Radio Service" has the identical frequencies and modes as the United States "Citizen's band", and no special provisions are required for either Canadians or Americans using CB gear while traveling across the border.

In Europe, the CEPT adopted the North American channel assignments, except that FM is used instead of AM. Some member countries permit additional modes and frequencies.

Before CEPT, most of the member countries used some subset of the 40 USA channels. The United Kingdom, on the other hand, originally had 40 unique 27 MHz channels, known as the 27/81 Bandplan. See CB radio in the United Kingdom. With the CEPT channels added, the UK now has 80 channels. Germany also has 40 unique channels at 26 MHz for a total of 80.

The frequencies for the 40 North American/CEPT channels are as follows. Note that for historical reasons, some frequencies are not in ascending order:

Channel 01 26.965 MHz Channel 02 26.975 MHz Channel 03 26.985 MHz Channel 04 27.005 MHz Channel 05 27.015 MHz Channel 06 27.025 MHz Channel 07 27.035 MHz Channel 08 27.055 MHz Channel 09 27.065 MHz Channel 10 27.075 MHz Channel 11 27.085 MHz Channel 12 27.105 MHz Channel 13 27.115 MHz Channel 14 27.125 MHz Channel 15 27.135 MHz Channel 16 27.155 MHz Channel 17 27.165 MHz Channel 18 27.175 MHz Channel 19 27.185 MHz Channel 20 27.205 MHz Channel 21 27.215 MHz Channel 22 27.225 MHz Channel 23 27.255 MHz Channel 24 27.235 MHz Channel 25 27.245 MHz Channel 26 27.265 MHz Channel 27 27.275 MHz Channel 28 27.285 MHz Channel 29 27.295 MHz Channel 30 27.305 MHz Channel 31 27.315 MHz Channel 32 27.325 MHz Channel 33 27.335 MHz Channel 34 27.345 MHz Channel 35 27.355 MHz Channel 36 27.365 MHz Channel 37 27.375 MHz Channel 38 27.385 MHz Channel 39 27.395 MHz Channel 40 27.405 MHz

In the UK the requirement to have a license has been dispensed with, but all permission for the public to use the UK-specific frequencies may be withdrawn in 2010, under plans to reassign the frequencies to the Community Audio Distribution System service.[1]

In Poland (and probably some other former Warsaw-pact countries) the channels are shifted 5kHz down, so for example channel 30 is 27.300MHz, many operators add a switch that can change between the "zeroes" (the Polish channel assignment), and the "fives" (the international assignment).

Australia now has the 40 North American channels, though previously it had only approved the use of the first 22 channels. On the other hand, New Zealand and Japan have unique allocations that don't correspond to any other country's.

A gray market trade in imported CB gear does exist in many countries. In many instances, sale or ownership of foreign-specification CB gear is not illegal, but the actual use of it is. With the FCC's minimal enforcement of its rules regarding CB radio, enthusiasts in the USA often use "export" radios, or possibly European FM CB gear to get away from the overcrowded AM channels. American AM gear has also been exported to Europe.

Using radios outside their intended market can be dangerous as well as illegal. For example, the British frequencies clash with a radio service used by ambulance services in Ukraine.


CB Radios Today:

CB is still a popular hobby in many countries though its utility as a method of communication among the general public has diminished, due to developments such as mobile phones and Internet chat rooms. CB radio is still a near-universal method of communication among semi truck drivers in America and also remains very popular in rural areas with farmers and hunters, plus sometimes even acting as a sort of "party line" phone system in deep-rural areas too far from major cities to have phone lines.

Commercial drivers use CB to communicate to other truck drivers directions, traffic problems, and other things of importance. Channel 19 is the most commonly used for this purpose, to the point that some radios even have a dedicated button to bring up channel 19. In some areas of the U.S., different channels are customarily used on highways running North-South versus East-West, and sometimes even for specific roads. Other channels regionally used for this purpose include 10, 17, and 21.

Also, Neighborhood Watch/Citizens on Patrol groups use CB radios for communication between the base station operator and the patrol units of the citizen on patrols to monitor their safety and liaison between you and the police department while patrolling their neighborhoods. The National Sheriffs' Association's Neighborhood Watch Program: http://www.usaonwatch.org/

Legitimate, short-range use of CB radio is sometimes made difficult by uncooperative users or illegal high-power transmitters, which are capable of being heard hundreds of miles (kilometres) away. In the United States, the vast number of users and the low financing of the regulatory body mean that the regulations are only actively enforced against the most severe interfering stations, which makes legitimate operations on the Citizen's band unreliable. Other services, such as Multi-Use Radio Service in the VHF band or FRS and GMRS in the UHF band, exist now to provide the reliable short-range communication service originally envisioned for the Citizen's Band.

The maximum legal CB power output level is four watts for AM and 12 watts (peak envelope power or "PEP") for single side band, as measured at the antenna connection on the back of the radio. More powerful external linear amplifiers are commonly used.

Citizens' Band radios in the United States use frequencies near 27 MHz. During periods of peak sunspot activity, even low-powered transmitters can sometimes be heard for hundreds or even thousands of miles (kilometres). This "skip" activity, in which signals which bounce off the ionosphere, contributes to interference on CB frequencies. Working "skip" is illegal in the United States, since it contradicts the short-range intended use of the service, though the regulation is widely ignored.

Many radio hobbyists operate illegitimately in the so-called "free band", (which is often referred to as 11 meters, similar to how hams refer to their bands by the approximate wavelengths) using either Citizens' Band equipment that has been modified for extended frequency range and higher power, or else amateur radio equipment operated outside the assigned amateur 10 meter band. Such operations are not part of the legally authorized Citizen's Band service and should not be called "CB". Out-of-band operations may interfere with licensed, public safety, commercial, or military users of these frequencies. Illegal transmitters may not meet good engineering practice for harmonic distortion or "splatter", and resulting interference to licensed radio spectrum users will often attract the attention of regulating authorities.

In its heyday in the 1970s, you were likely to find CB Channel 9 monitored by parties who could relay messages to the authorities, or even directly monitored by the authorities themselves. However, with the popularity of cellular phones, support for Channel 9 as an emergency channel has largely vanished. If you are in dire need of help on the road and your only communications tool is a CB radio, you are much more likely to find help on Channel 19.