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South Africa has a 23 channel AM / SSB 29 MHz CB allocation (called "29 Megs" or "29 MHz CB") from 29.710 to 29.985 MHz in 12.5 kHz steps. South Africa also permits use of standard CB channels 19–27 (27.185–27.275 MHz) with AM / SSB permitted. Many radios sold in South Africa feature both the 27 MHz and 29 MHz bands.
The carrier frequency is 1.25 MHz above the lower edge of the 6 MHz wide channel. This effectively makes the system AM at low modulation frequencies and SSB at high modulation frequencies. The absence of the lower sideband components at high frequencies must be compensated for, and this is done in the IF amplifier.
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).
Brazil allows higher power levels than the US and most of Europe. New Zealand has two 40-channel HF CB bands available, the NZ-specific "NZ CB Band" 26.330–26.770 MHz (40 channels, AM and SSB allowed) and the standardized "mid band" 26.965–27.405 MHz (40 channels, AM and SSB allowed) for a total of 80 HF CB channels.
The International Telecommunication Union uses an internationally agreed system for classifying radio frequency signals. Each type of radio emission is classified according to its bandwidth, method of modulation, nature of the modulating signal, and type of information transmitted on the carrier signal.
Most amateur digital modes are transmitted by inserting audio into the microphone input of a radio and using an analog scheme, such as amplitude modulation (AM), frequency modulation (FM), or single-sideband modulation (SSB). Amateur teleprinting over radio (AMTOR) D-STAR (Digital Data) a high speed (128 kbit/s), data-only mode.
A Compatible sideband transmission, also known as amplitude modulation equivalent (AME) or Single sideband reduced-carrier (SSB-RC), is a type of single sideband RF modulation in which the carrier is deliberately reinserted at a lower level after its normal suppression to permit reception by conventional AM receivers. The general convention is ...
Five 2.8 kHz-wide channels are available in the U.S., centered on 5.332, 5.348, 5.368, 5.373, and 5.405 MHz. Since most radios in SSB mode display the (suppressed) carrier frequency, in USB mode the dial frequencies would all need to be set 1.5 kHz lower. Voice operation is generally in upper sideband mode, which is mandatory in the U.S. . The ...