2-Meter-Band
The 2- meter band is a portion of the ultra-short- wave band ( VHF) and equates to a frequency in the range of 150 MHz ( rounded), according to the formula, so the speed of light divided by the wavelength.
Depending on the user's perspective is as a two meter band, a funk band called, the different radio services is assigned: 144 MHz to 146 MHz amateur radio service, 148.01 MHz to 164 MHz Mobile Radio, 165 MHz to 174 MHz public safety radio and other services such as flight radio.
It hand-held radios are often used, but as devices are also stationary and in vehicles ( land, sea and in the air) built- in use.
- 4.1 Band Plan
Propagation conditions
The 2- meter band is part of the VHF spectrum and is primarily used for local communication. The range of a fixed radio station is in normal propagation conditions about 50 km, that of a hand-held radio unit about 5 to 10 km, depending, inter alia, the terrain profile. This distance can be enlarged by relay stations. In particular propagation conditions (eg temperature inversions, Sporadic -E ), one can achieve ranges of several 100 km in the 2- meter band.
Antennas
The 2- meter band allowed to use short and compact antennas; also directional antennas (particularly Yagi and quad antennas) can be built with little effort. Many rubber spiral antennas for walkie talkies ( " rubber sausage ", electrically shortened quarter-wave radiator ), where one in favor of the handiness takes losses in the radiation in purchasing.
2 -meter amateur band
The 2 -meter amateur band ranges 144-146 MHz ( ITU Region 1: Europe, Russia, Africa ); in the rest of the world ( ITU Regions 2 and 3, eg in the U.S.), it is sufficient 144-148 MHz.
In addition to regional amateur radio relay radio amateurs have built and launched amateur radio satellites via AMSAT organization to overcome the greatest distances. For wireless connections are possible in the whole world. Alternatively, one can use the moon as a reflector. This mode is referred to as Earth-Moon - Earth radio operation and places high demands on the transmission and reception systems.
In order to evenly distribute the various modes on the 2- m band and keep the mutual influences low, a band plan became internationally created and assigned as the individual operating modes specific segments of the 2- m band. Thus, there are the frequency 144.800 MHz for APRS and in the region from 145.8 to 146 MHz range for an amateur radio satellites.
Band Plan
- FM relay channels have a channel spacing of 12.5 kHz
- FM relay outputs are coupled to their corresponding inputs
- Channel spacing: 12.5 kHz
- FM relay channels have a channel spacing of 12.5 kHz
- FM relay inputs are coupled to their corresponding outputs
2-meter -BOS - band
As the 4- meter band and the 2- m band is divided into different channels, which in turn are divided into an upper and lower band. The operation of the radio channels (channel 201-292 ) of the 117 channels are in most cases Intercommunication in the low band. The channels 101-125 are relay controls and digital alarm reserved.
The frequency spectrum of the sub-band extends from 165.210 MHz to 169.380 MHz with a channel spacing of 20 kHz; the upper band per channel is offset by 4.6 MHz upwards.
The radio call in the 2 m band partly differ from those of the 4-meter band. For details in the article on bad radio.