Citizens band radio
Al Gross established the Citizens Radio Corporation during the late 1940s to manufacture class B handhelds for the general public.
[3]: 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.
[5] Most of the 460–470 MHz band was reassigned for business and public-safety use; CB Class A is the forerunner of the General Mobile Radio Service (GMRS).
By the late 1960s, advances in solid-state electronics allowed the weight, size, and cost of the radios to fall, giving the public access to a communications medium previously only available to specialists.
After the 1973 oil crisis, the U.S. government imposed a nationwide 55 mph speed limit, and fuel shortages and rationing were widespread.
Originally, CB radios required the use of a callsign in addition to a purchased license ($20 in the early 1970s, reduced to $4 on March 1, 1975, or $22.6 in 2023 dollars).
Lax enforcement of the rules on authorized use of CB radio led to further widespread disregard of regulations (such as for antenna height, distance communications, licensing, call signs, and transmitter power).
[16] CB has lost much of its original appeal due to development of mobile phones, the internet and the Family Radio Service.
In addition, CB may have become a victim of its own popularity; with millions of users on a finite number of frequencies during the mid-to-late 1970s and early 1980s, channels often were noisy and communication difficult, which reduced interest among hobbyists.
The advantages of fewer users sharing a frequency, greater authorized output power, clarity of FM transmission, lack of interference by distant stations due to skip propagation, and consistent communications made the VHF (Very High Frequency) radio an attractive alternative to the overcrowded CB channels.
Manufacturers report an increase in sales, while social media sites like YouTube show a growing popularity in CB radio content, mainly as a hobby.
Truck drivers still use CB, which is an effective means of obtaining information about road construction, accidents and police speed traps.
From the outset, the government attempted to regulate CB radio with license fees and call signs, but eventually they abandoned this approach.
Other Australian cities which became CB radio "hotspots" were Seymour, Benalla, Holbrook and Gundagai, all located on the busy Hume Highway between Melbourne and Sydney.
Other regional cities such as Bendigo, Mildura, Mount Gambier and Port Augusta, developed lively, colourful CB radio communities.
[29] Canada's GRS uses the identical frequencies and modes as the United States citizens band, and no special provisions are required for either Canadians or Americans using CB gear while traveling across the border.
The dates are hard to confirm accurately, but early use was known around large cities such as Jakarta, Bandung, Yogyakarta, Surabaya and Medan.
[32] In Malaysia, citizens band radios became legal when the "Notification of Issuance Of Class Assignments" by the Malaysian Communication and Multimedia was published on 1 April 2000.
A short-range simplex radio communications service for recreational use is from 477.5250 to 477.9875 MHz FM mode with 38 channels and a power output of 500 mW.
MPT 1320 also restricted antennas to a maximum length of 1.5 meters (5'), with base loading being the only type permitted for 27 MHz operation.
[42] Japan's CB allocation consists of 8 voice and 2 radio control channels with a maximum power output of 500 mW.
The 27 MHz frequencies used by CB, which require a relatively long aerial antennas and tend to propagate poorly indoors, discourage the use of handheld radios.
In the United States, the number of users and law enforcement financing by the Federal Communications Commission mean that only the worst offenders are sanctioned, which makes legitimate operation on the citizens band unreliable.
By the mid-1960s "mixer" circuits made frequency-synthesized radios possible, which reduced cost and allowed full coverage of all 23 channels with a smaller number of crystals (typically 14).
Such an array is intended to enhance performance to the front and back, while reducing it to the sides (a desirable pattern for long-haul truckers).
Ground-plane kits exist as mounting bases for mobile whips, and have several wire terminals or hardwired ground radials attached.
Furthermore, illegal transmitters and amplifiers may not meet good engineering practice for harmonic distortion or "splatter", which may disrupt other communications and make the unapproved equipment obvious to regulators.
Originally a bound book that resembled a telephone directory, it contains the name and addresses of radio stations in a given jurisdiction (country).
Callbooks have evolved to include online databases that are accessible via the Internet to instantly obtain the address of another amateur radio operator and their QSL managers.
The most well known and used on-line QSL database for the 11 meter / freebander community is QRZ11.COM, designed after its "big brother" QRZ.com for amateur radio.
