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The radio spectrum is the part of the electromagnetic spectrum with frequencies from 3 Hz to 3,000 GHz (3 THz).Electromagnetic waves in this frequency range, called radio waves, are widely used in modern technology, particularly in telecommunication.
Very high frequency (VHF) is the ITU designation [1] [2] [3] for the range of radio frequency electromagnetic waves (radio waves) from 30 to 300 megahertz (MHz), with corresponding wavelengths of ten meters to one meter. Frequencies immediately below VHF are denoted high frequency (HF), and the next higher frequencies are known as ultra high ...
In the U.S., the analog AMPS standard that used the cellular band (800 MHz) was replaced by a number of digital systems. Initially, systems based upon the AMPS mobile phone model were popular, including IS-95 (often known as " CDMA ", the air interface technology it uses) and IS-136 (often known as D-AMPS, Digital AMPS, or " TDMA ", the air ...
The Pan-American television frequencies are different for terrestrial and cable television systems. Terrestrial television channels are divided into two bands: the VHF band which comprises channels 2 through 13 and occupies frequencies between 54 and 216 MHz, and the UHF band, which comprises channels 14 through 36 and occupies frequencies between 470 and 608 MHz.
The SINCGARS operates on any of 2320 channels between 30 and 88 megahertz (MHz) with a channel separation of 25 kilohertz (kHz). It accepts either digital or analog inputs and superimposes the signal onto a radio frequency (RF) carrier wave. In FH mode, the input changes frequency about 100 times per second over portions of the tactical VHF-FM ...
In some large metropolitan areas, such as New York, the UHF-T band (between 470 and 512 MHz) is also used due to congestion on the standard VHF or UHF bands. There are also a number of specific frequencies, in both the VHF and UHF spectrums, that are for business use; some of these have color-coded names, such as Red Dot or Blue Star.
RCOs and RTRs may be UHF or VHF and are divided into a variety of classes determined by the number of transmitters or receivers. Classes A through G are used mainly for air/ground communications. Class O facilities were created specifically to provide ground-to-ground communication between air traffic controllers and pilots located at satellite ...
The International Telecommunication Union defines frequency allocation as being of "a given frequency band for the purpose of its use by one or more terrestrial or space radiocommunication services or the radio astronomy service under specified conditions". [2] Frequency allocation is also a special term, used in national frequency ...