CB radio in the United States

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In the United States, the Citizens Band Radio Service (CBRS), commonly called citizens band radio (CB radio), is one of several personal radio services defined under Title 47 of the Code of Federal Regulations, Part 95. [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.

Contents

CB radio is most frequently used by long-haul truck drivers for everything from relaying information regarding road conditions, the location of speed traps and other travel information, to basic socializing and friendly chatter. CB radio is also frequently used on larger farms for communication between machinery operators.

Origins

As originally constituted, what is now CB radio was Class D of the Citizens' Radio Service. Classes A and B were in the UHF radio band and served a similar purpose as Class D while Class C was interspersed among the current CB channels and used for remote control of devices, usually model craft (aircraft, watercraft, or road vehicles). Class A and B were eventually replaced by the Family Radio Service (FRS) and General Mobile Radio Service (GMRS). What was initially Class C, is now known as the Radio Control Radio Service and now includes spectrum at 72 and 76 MHz in addition to the original 27-MHz channels interspersed among voice channels as well as CB channel 23. [2]

Eligibility

There are no age, citizenship, or license requirements to operate a CB radio in the United States, and the service falls under the "License by Rule" part of the FCC rules (basically, if one follows the rules one is considered licensed). Operators may use any of the authorized 40 CB channels; however, channel 9 is used only for emergency communications or for traveler assistance. [3] The higher number channels are almost exclusively single-sideband (SSB) modulation[ according to whom? ]. Use of all channels is on a shared basis. However, foreign governments and their representatives are not eligible to use citizens' band radio within the United States.

Operation is permitted anywhere within the United States and its territories or possessions; as well as anywhere in the world except within the territorial limits of areas where radio services are regulated by a foreign government, or another US agency such as the Department of Defense.

Transmitters must be FCC certified and may not be modified, including modifications to increase output power or to transmit on unauthorized frequencies. Output power is limited to 4 watts for AM and FM transmitters and 12 watts peak envelope power for SSB transmitters. The antenna may not be more than 20 feet (6.1 m) above the highest point of the structure it is mounted to, or the highest point of the antenna must not be more than 60 feet (18.3 m) above the ground (47 CFR 95.408(c)) if installed in a fixed location. [4]

CB radios must include AM or SSB modulation and may include frequency modulation. [5] If a radio includes SSB, it must transmit on the upper sideband with a suppressed, reduced, or full carrier. The unit may also transmit on the lower sideband with carrier as noted. [6]

Channel assignments

Allocated frequencies

CB channels
ChannelFrequency
(MHz)		Typical use (US)
126.965
226.975
326.985
427.005 Off-roading
527.015
627.025Considered the "Super Bowl" channel, [7] although unrelated to the NFL Super Bowl
727.035
827.055
927.065Emergencies only. 47 CFR 95.931(a)(2): [3] "CBRS Channel 9 may be used only for emergency communications or traveler assistance. It must not be used for any other purpose."
1027.075Truckers on regional roads
1127.085
1227.105
1327.115Marine [8] and recreational vehicles [9]
1427.125Vintage walkie-talkies [10]
1527.135
1627.155Offroading
1727.165Truckers traveling north or south
1827.175
1927.185Truckers traveling east or west
2027.205
2127.215
2227.225
2327.255
2427.235
2527.245
2627.265
2727.275
2827.285
2927.295
3027.305
3127.315
3227.325
3327.335
3427.345
3527.355
3627.365
3727.375
3827.385 SSB calling
3927.395
4027.405

The CB Radio Service spectrum is divided into 40 numbered radio frequency channels from 26.965 to 27.405 MHz. Channel spacing is 10  kHz between channel centers with exceptions where CBRS channels are adjacent to Radio Control Radio Service. The initial channel allocations had a gap equal to two channel spaces between channels 22 and 23. Those channels were assigned to the Business Radio Service. Beginning in 1977, those two channels (and 15 others above CB Channel 23) were reallocated to CB use. Channel 23 was left as it was so that users of pre-1977 equipment could use that equipment with minimal confusion.

Channel usage

Channel 19 is the most commonly-used channel by truck drivers on highways, to the point that some radios even have a dedicated button to bring up channel 19 instantly. In many areas of the US, other channels have been used in the past for similar purposes including 10, 17, and 21. [9] Channel 13 has been used in some areas for marine use [8] and for recreational vehicles. [9]

Channel 9 is reserved by regulation [3] for emergency use and to provide traveler assistance. In decades past, the channel was monitored by volunteers who could relay messages to the authorities, and often monitored directly by the authorities themselves. With the popularity of cellular phones since the 1990s, support for Channel 9 as an emergency channel has diminished, though volunteer organizations such as Radio Emergency Associated Communication Teams (REACT), and private individuals still monitor Channel 9 in some areas.

Regional mode conventions include Channels 30 or 35 through 40 for SSB operation, often with 38 known as a calling channel. There is no consensus yet for FM operation, legalized in 2021.

Shared radio services

Remote control

Remote-control channels
ChannelFrequencyMaximum
transmit
power
3A26.995 MHz4 W
7A27.045 MHz4 W
11A27.095 MHz4 W
15A27.145 MHz4 W
19A27.195 MHz4 W
2327.255 MHz25 W

Among several other services that share the CB frequencies is the former Class C Citizens Band service, renamed to the Radio Control Radio Service (RCRS) in 1976, outlined in Subpart C of the Part 95 rules for radio-controlled ("R/C") devices. No voice transmissions are permitted. It has six channels in the 27 MHz band. Five are unused 10 kHz CB assignments between channels 3–4, 7–8, 11–12, 15–16 and 19–20, and the sixth is shared with Channel 23. R/C transmitters may use up to 4 watts on the first five channels and 25 watts on the last, 27.255 MHz. Some in-house paging systems, and car alarms with a paging feature, also use these frequencies, especially 27.255 MHz, where the higher power is permitted.

The 27 MHz RCRS channels are not officially numbered by the FCC. 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. [11]

The RCRS service has 50 channels just for model aircraft in the 72–73 MHz range, and 30 more channels for surface models such as cars and boats in the 75.4–76 MHz range. 0.75 watts is allowed on these numbered channels. Licensed amateur radio operators can use any amateur frequency for R/C, but those enthusiasts tend to use frequencies in their 6-meter band. [11]

Part 15 devices

Many toy R/C cars and wireless keyboards and mice operate on the 27 MHz R/C channels, especially 27.145 MHz. But most of these devices run far less than 4 watts and do not operate under the RCRS service. 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. This allows less selective, and therefore less expensive, receivers to be used than if they were using channels in the same band.

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.

Broadband over Power Lines (BPL) technology uses a wide range of HF frequencies to transmit data (3.5 through 30 MHz), which includes the CB frequencies. There is great potential for interference, as power lines were never specifically designed to shield radio frequencies. RF leakage from BPL is regulated under Part 15 and is a big problem for amateur radio operators across all frequencies that the BPL uses.

ISM devices

Another class of devices operating in the 27 MHz band are ISM (Industrial, Scientific and Medical) devices regulated by the FCC's Part 18 rules. Induction welding of plastics, and some types of diathermy machines commonly operate in this range. These devices centered on 27.12 MHz with a tolerance of ±163 kHz, that is, 26.957 to 27.283 MHz. [14]

Adjacent frequency bands

Adjacent frequencies are often used by illegal operators using modified CB or amateur radio equipment. Operators sometimes refer to this activity as freebanding.

The Industrial/Business Radio Pool of the Private Land Mobile Radio Services has several channels just above the Citizen's Band, at 27.430, 27.450, 27.470, 27.490, 27.510, and 27.530 MHz. [15]

The federal government has the frequencies from 27.540 up to 28.000. Many civilian agencies use, or used to use, the frequencies 27.575 and 27.585 for low-power use. The US Coast Guard Auxiliary uses 27.980 MHz, it is similar to the Civil Air Patrol Frequency 26.620 MHz. [16] [17] [18]

Amateur radio has an allocation starting at 28.000 MHz in the 10-meter band. [19]

Below the Citizen's Band, the military has the frequencies from 26.480 to 26.960 MHz. The Civil Air Patrol has 26.620 MHz, though it now uses mostly VHF frequencies. [20] In the 1950s through the 1970s CAP volunteers with crystal-controlled CBs would put this frequency in their radios. Currently VHF military frequencies are more often used (the CAP is part of the US Air Force), as among other reasons, VHF radios are easier to acquire through military logistics than CB radios.

Below that is a broadcast auxiliary service band, the 11-meter shortwave band, and the 12-meter amateur band. [21]

Related Research Articles

The ISM radio bands are portions of the radio spectrum reserved internationally for industrial, scientific, and medical (ISM) purposes, excluding applications in telecommunications. Examples of applications for the use of radio frequency (RF) energy in these bands include RF heating, microwave ovens, and medical diathermy machines. The powerful emissions of these devices can create electromagnetic interference and disrupt radio communication using the same frequency, so these devices are limited to certain bands of frequencies. In general, communications equipment operating in ISM bands must tolerate any interference generated by ISM applications, and users have no regulatory protection from ISM device operation in these bands.

<span class="mw-page-title-main">Citizens band radio</span> Land mobile radio system

Citizens band radio 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 in the high frequency or shortwave band. Citizens band is distinct from other personal radio service allocations such as FRS, GMRS, MURS, UHF CB and the Amateur Radio Service. In many countries, CB operation does not require a license and may be used for business or personal communications.

Citizens band radio is a system of short-distance radio communications between individuals on a selection of 40 channels within the 27-MHz band. In the United Kingdom, CB radio was first legally introduced in 1981, but had been used illegally for some years prior to that.

<span class="mw-page-title-main">Radiotelephone</span> Communications system for transmission of speech over radio

A radiotelephone, abbreviated RT, is a radio communication system for conducting a conversation; radiotelephony means telephony by radio. It is in contrast to radiotelegraphy, which is radio transmission of telegrams (messages), or television, transmission of moving pictures and sound. The term is related to radio broadcasting, which transmit audio one way to listeners. Radiotelephony refers specifically to two-way radio systems for bidirectional person-to-person voice communication between separated users, such as CB radio or marine radio. In spite of the name, radiotelephony systems are not necessarily connected to or have anything to do with the telephone network, and in some radio services, including GMRS, interconnection is prohibited.

<span class="mw-page-title-main">General Mobile Radio Service</span> Land-mobile FM UHF radio service for short-distance two-way communications

The General Mobile Radio Service (GMRS) is a land-mobile FM UHF radio service designed for short-range two-way voice communication and authorized under part 95 of the US FCC code. It requires a license in the United States, but some GMRS compatible equipment can be used license-free in Canada. The US GMRS license is issued for a period of 10 years by the FCC. The United States permits use by adult individuals who possess a valid GMRS license, as well as their immediate family members. Immediate relatives of the GMRS system licensee are entitled to communicate among themselves for personal or business purposes, but employees of the licensee who are not family members are not covered by the license. Non-family members must be licensed separately.

Code of Federal Regulations, Title 47, Part 15 is an oft-quoted part of Federal Communications Commission (FCC) rules and regulations regarding unlicensed transmissions. It is a part of Title 47 of the Code of Federal Regulations (CFR), and regulates everything from spurious emissions to unlicensed low-power broadcasting. Nearly every electronics device sold inside the United States radiates unintentional emissions, and must be reviewed to comply with Part 15 before it can be advertised or sold in the US market.

In the United States, the Multi-Use Radio Service (MURS) is a licensed by rule two-way radio service similar to the Citizens band (CB). Established by the U.S. Federal Communications Commission in the fall of 2000, MURS created a radio service allowing for licensed by rule operation in a narrow selection of the VHF band, with a power limit of 2 watts. The FCC formally defines MURS as "a private, two-way, short-distance voice or data communications service for personal or business activities of the general public." MURS stations may not be connected to the public telephone network, may not be used for store and forward operations, and radio repeaters are not permitted.

The 2-meter amateur radio band is a portion of the VHF radio spectrum that comprises frequencies stretching from 144 MHz to 148 MHz in International Telecommunication Union region (ITU) Regions 2 and 3 and from 144 MHz to 146 MHz in ITU Region 1 . The license privileges of amateur radio operators include the use of frequencies within this band for telecommunication, usually conducted locally with a line-of-sight range of about 100 miles (160 km).

The 33-centimeter or 900 MHz band is a portion of the UHF radio spectrum internationally allocated to amateur radio on a secondary basis. It ranges from 902 to 928 MHz and is unique to ITU Region 2 (Americas). It is primarily used for very local communications as opposed to bands lower in frequency. However, very high antennas with high gain have shown 33 centimeters can provide good long-range communications almost equal to systems on lower frequencies such as the 70 centimeter band. The band is also used by industrial, scientific, and medical (ISM) equipment, as well as low-powered unlicensed devices. Amateur stations must accept harmful interference caused by ISM users but may receive protection from unlicensed devices.

<span class="mw-page-title-main">6-meter band</span> Amateur radio frequency band

The 6-meter band is the lowest portion of the very high frequency (VHF) radio spectrum internationally allocated to amateur radio use. The term refers to the average signal wavelength of 6 meters.

LowFER refers to experimental radio communication practiced by hobbyists on frequencies below 300 kHz, a part of the radio spectrum known as low frequency. The practitioners are known as "LowFERs".

Shortwave bands are frequency allocations for use within the shortwave radio spectrum. Radio waves in these frequency ranges can be used for very long distance (transcontinental) communication because they can reflect off layers of charged particles in the ionosphere and return to Earth beyond the horizon, a mechanism called skywave or “skip” propagation. They are allocated by the ITU for radio services such as maritime communications, international shortwave broadcasting and worldwide amateur radio. The bands are conventionally named by their wavelength in metres, for example the ‘20 meter band’. Radio propagation and possible communication distances vary depending on the time of day, the season and the level of solar activity.

The 10-meter band is a portion of the shortwave radio spectrum internationally allocated to amateur radio and amateur satellite use on a primary basis. The band consists of frequencies stretching from 28.000 to 29.700 MHz.

Modulated continuous wave (MCW) is Morse code telegraphy, transmitted using an audio tone to modulate a carrier wave.

The R. L. Drake Company is a manufacturer of electronic communications equipment located in Springboro, Ohio. It is also known for its line of equipment for amateur radio and shortwave listening, built in the 1950s through the 1980s. The company operates as a separate entity owned by Blonder Tongue Laboratories, Inc.

Amateur radio frequency allocation is done by national telecommunication authorities. Globally, the International Telecommunication Union (ITU) oversees how much radio spectrum is set aside for amateur radio transmissions. Individual amateur stations are free to use any frequency within authorized frequency ranges; authorized bands may vary by the class of the station license.

A radio transmitter or just transmitter is an electronic device which produces radio waves with an antenna. Radio waves are electromagnetic waves with frequencies between about 30 Hz and 300 GHz. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. When excited by this alternating current, the antenna radiates radio waves. Transmitters are necessary parts of all systems that use radio: radio and television broadcasting, cell phones, wireless networks, radar, two way radios like walkie talkies, radio navigation systems like GPS, remote entry systems, among numerous other uses.

<span class="mw-page-title-main">Amateur radio repeater</span> Combined receiver and transmitter

An amateur radio repeater is an electronic device that receives a weak or low-level amateur radio signal and retransmits it at a higher level or higher power, so that the signal can cover longer distances without degradation. Many repeaters are located on hilltops or on tall buildings as the higher location increases their coverage area, sometimes referred to as the radio horizon, or "footprint". Amateur radio repeaters are similar in concept to those used by public safety entities, businesses, government, military, and more. Amateur radio repeaters may even use commercially packaged repeater systems that have been adjusted to operate within amateur radio frequency bands, but more often amateur repeaters are assembled from receivers, transmitters, controllers, power supplies, antennas, and other components, from various sources.

<span class="mw-page-title-main">Citizens band radio in India</span>

Citizens band radio is a system of short-distance radio communications between individuals on a selection of channels within the 27-MHz band. In India, this frequency band extends from 26.957 MHz to 27.283 MHz. There are several different channel plans in use. Citizens band is distinct from the Family Radio Service, GMRS, Multi-Use Radio Service and amateur radio (Ham). In many countries CB operation does not require a license, and it may be used for business or personal communications. Like many other two-way radio services, any citizens band channel is shared by many users. Only one station may transmit in a channel at a time; other stations must listen and wait for the shared channel to be available. Also, the system works in half-duplex mode, which means we may transmit and receive information, but not both at the same time.

<span class="mw-page-title-main">Personal radio service</span> Group of radio services

A personal radio service is any system that allows individual to operate radio transmitters and receivers for personal purposes with minimal or no special license or individual authorization. Personal radio services exist around the world and typically use light-weight walkie talkie portable radios. The power output, antenna size, and technical characteristics of the equipment are set by regulations in each country. Many regions have standardized personal radio service rules to allow travelers from one country to use their equipment in another country. Examples of standardized services include PMR446 and FM Citizens Band Radio (CB) in the EU and several other countries/regions. 26–27 MHz CB radio is the oldest personal radio service and is used in nearly every country worldwide, with many countries and regions copying the United States 40-channel frequency plan. In many countries, CB radio is less popular due to the availability of other personal radio services that offer shorter antennas and better protection from noise and interference.

References

  1. ↑ "Federal Register :: Request Access".
  2. ↑ "Radio Control Radio Service (RCRS)". 3 November 2011.
  3. 1 2 3 "47 CFR 95.931(a)(2)". ECFR.gov.
  4. ↑ "eCFR — Code of Federal Regulations". www.ecfr.gov. Archived from the original on 2017-05-29.
  5. ↑ "Federal Register :: Request Access".
  6. ↑ "47 CFR 95.971(b)". ECFR.gov.
  7. ↑ "Idiot's guide to shooting skip – CB radio 11 Meters Skip Conditions | CB Radio Magazine". 15 April 2020.
  8. 1 2 Chilton Automotive Editorial Department (1977). Chilton's CB Handbook. Radnor, Pennsylvania: Chilton Book Company. p. 12. ISBN   0-8019-6623-X.
  9. 1 2 3 Kneitel, Tom (1988). Tomcat's Big CB Handbook. Commack, New York: CRB Research Books. pp. 203–204. ISBN   0-939780-07-0.
  10. ↑ "TRC-235 3-Channel CB Walkie-Talkie 210-1620 Adding Crystals". support.radioshack.com. Archived from the original on December 22, 2015. Retrieved December 24, 2021.
  11. 1 2 3 "Radio Control Frequency List (with flag information)". Archived from the original on 20 February 2008. Retrieved 18 June 2014.
  12. ↑ These Part 15 devices are now regulated by field strength, not transmitter input power.
  13. ↑ Chilton Automotive Editorial Department (1977). Chilton's CB Handbook. Radnor, PA: Chilton Book Company. p. 20. ISBN   0-8019-6623-X.
  14. ↑ Article 5 RR 171 Radio regulations annexed to the International Telecommunication Convention (Atlantic City, 1947) Archived July 10, 2012, at the Wayback Machine
  15. ↑ 47 CFR 90.35
  16. ↑ "(CB) Radio Frequencies". Right Channels Radio. Retrieved 25 January 2023.
  17. ↑ "(10 meter) Band Plan". American Radio Relay League. Retrieved 25 January 2023.
  18. ↑ "11 Meter broadcast Band". NARKIVE. Retrieved 25 January 2023.
  19. ↑ "(10 meter) Band Plan". American Radio Relay League. Retrieved 25 January 2023.
  20. ↑ Hughes, Gene; Richard Barnett (2000). Police Call, Vol. 1, 2001 edition. Los Angeles: Hollins Radio Data. pp. 277, 384–385, 387. OCLC 46316778.
  21. ↑ "11 Meter broadcast Band". NARKIVE. Retrieved 25 January 2023.
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