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The 2-meter amateur radio band is a portion of the VHF radio spectrum that comprises frequencies stretching from 144 MHz to 148 MHz [1] in International Telecommunication Union region (ITU) Regions 2 (North and South America plus Hawaii) and 3 (Asia and Oceania) [2] [3] and from 144 MHz to 146 MHz in ITU Region 1 (Europe, Africa, and Russia).
Shortwave bands are frequency allocations for use within the shortwave radio spectrum (the upper medium frequency [MF] band and all of the high frequency [HF] band). 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 ...
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]
The 2 200 metre band is available for use in several countries, and the 2007 World Radiocommunication Conference (WRC-07) recommended it as a worldwide amateur allocation. Before the introduction of the 2 200 metre band in the U.K. in 1998, operation on the even lower frequency of 73 kHz, in the LF time signal band, was allowed from 1996–2003.
The power of an AM radio signal plotted against frequency. fc is the carrier frequency, fm is the maximum modulation frequency. In radio communications, a sideband is a band of frequencies higher than or lower than the carrier frequency, that are the result of the modulation process. The sidebands carry the information transmitted by the radio ...
The 2-meter band (144-148 MHz) lies within cable channel 18, but at 4 MHz wide, it is too narrow to fit the full 6 MHz bandwidth of an NTSC analog channel; its audio carrier lies outside the band. To be used as a television frequency, some narrow-bandwidth format incompatible with most televisions must be used and converted.
Several countries in ITU Region 1 have access to frequencies in the 70 MHz region, called the 4-meter band. The band shares many propagation characteristics with 6 meters. The preferred location for beacons is 70.000–70.090 MHz; [5] however, in countries where this segment is not allocated to Amateur Radio, beacons may operate elsewhere in ...
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.