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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 ...
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 idea to give each band a number, in which the number is the logarithm of the approximate geometric mean of the upper and lower band limits in Hz, originated with B. C. Fleming-Williams, who suggested it in a letter to the editor of Wireless Engineer in 1942. For example, the approximate geometric mean of band 7 is 10 MHz, or 10 7 Hz. [14]
50–54 MHz: amateur radio 6-meter band. 108–118 MHz: Air navigation beacons VOR and Instrument Landing System localizer. 118–137 MHz: Airband for air traffic control, AM, 121.5 MHz is emergency frequency; 144–146 MHz: amateur radio 2-meter band (Extends up to 148 MHz in some Regions).
On 10 October the Third National Radio Conference made three shortwave bands available to U.S. amateurs [19] at 80 meters (3.75 MHz), 40 meters (7 MHz) and 20 meters (14 MHz). These were allocated worldwide, while the 10 meter band (28 MHz) was created by the Washington International Radiotelegraph Conference [ 20 ] on 25 November 1927.
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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 ...