2 meters

The 2-meter amateur radio band is a portion of the VHF radio spectrum, comprising frequencies stretching from 144 MHz to 148 MHz in International Telecommunication Union region (ITU) Regions 2 (North and South America plus Hawaii) and 3 (Asia and Oceania) and from 144 MHz to 146 MHz in ITU Region 1 (Europe, Africa, and Russia). The license privileges of amateur radio operators include the use of frequencies within this band for telecommunication, usually conducted locally within a range of about 100 miles (160 km).

Because it is local and reliable, and because the licensing requirements to transmit on the 2-meter band are easy to meet in many parts of the world, this band is one of the most popular non-HF ham bands. This popularity, the compact size of needed radios and antennas, and this band's ability to provide easy reliable local communications also means that it is also the most used band for local emergency communications efforts, such as providing communications between Red Cross shelters and local authorities. In the US, that role in emergency communications is furthered by the fact that most amateur-radio operators have a 2-meter handheld transceiver (HT), handie-talkie or walkie-talkie.

Much of 2-meter FM operation uses a radio repeater, a radio receiver and transmitter that instantly retransmits a received signal on a separate frequency. Repeaters are normally located in high locations such as a tall building or a hill top overlooking expanses of territory. On VHF frequencies such as 2-meters, antenna height greatly influences how far one can talk. Typical reliable repeater range is about 25 miles (40 km). Some repeaters in unusually high locations, such as skyscrapers or mountain tops, can be usable as far out as 75 miles (121 km). Reliable range is very dependent on the height of the repeater antenna and also on the height and surroundings of the handheld or mobile unit attempting to access to the repeater. Line of sight would be the ultimate in reliability. The typical hand held two meter FM transceiver produces about 5 watts of transmit power. Stations in a car or home provide higher power, 25 to 75 watts, and may use a simple vertical antenna mounted on a pole or on the rooftop of a house or a vehicle.

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Wikipedia