Band II

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Band II is the range of radio frequencies within the very high frequency (VHF) part of the electromagnetic spectrum from 87.5 to 108.0  megahertz (MHz).

Frequency is the number of occurrences of a repeating event per unit of time. It is also referred to as temporal frequency, which emphasizes the contrast to spatial frequency and angular frequency. The period is the duration of time of one cycle in a repeating event, so the period is the reciprocal of the frequency. For example: if a newborn baby's heart beats at a frequency of 120 times a minute, its period—the time interval between beats—is half a second. Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals (sound), radio waves, and light.

Very high frequency class of radio waves

Very high frequency (VHF) is the ITU designation for the range of radio frequency electromagnetic 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 frequency (UHF).

The electromagnetic spectrum is the range of frequencies of electromagnetic radiation and their respective wavelengths and photon energies.

Contents

Radio

Band II is primarily used worldwide for FM radio broadcasting. [1]

FM broadcasting

FM broadcasting is a method of radio broadcasting using frequency modulation (FM) technology. Invented in 1933 by American engineer Edwin Armstrong, wide-band FM is used worldwide to provide high-fidelity sound over broadcast radio. FM broadcasting is capable of better sound quality than AM broadcasting, the chief competing radio broadcasting technology, so it is used for most music broadcasts. Theoretically wideband AM can offer equally good sound quality, provided the reception conditions are ideal. FM radio stations use the VHF frequencies. The term "FM band" describes the frequency band in a given country which is dedicated to FM broadcasting.

Broadcast television

Usage in Russia and in other former members of OIRT

In the former Soviet Union and other countries-members of OIRT, frequencies from 76 MHz to 100 MHz were designated for broadcast television usage. [2] Considering 8 MHz channel bandwidth used by the Russian analog television system (System D), the following television channels had been defined:

Channel Frequency Range
376-84 MHz
484-92 MHz
592-100 MHz

Broadcast television channels 1 and 2 are assigned to VHF I band, channels 6 to 12 are assigned to VHF III band.

Starting from the early 1990s, frequencies previously allotted to television channels 4 and 5 have been re-allocated for FM radio, thereby harmonizing it with the Western allocation for FM radio service.

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FM broadcasting in the United States began in the 1930s at engineer and inventor Edwin Howard Armstrong's experimental station, W2XMN. The use of FM radio has been associated with higher sound quality in music radio.

Ultra high frequency radio waves

Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300 megahertz (MHz) and 3 gigahertz (GHz), also known as the decimetre band as the wavelengths range from one meter to one tenth of a meter. Radio waves with frequencies above the UHF band fall into the super-high frequency (SHF) or microwave frequency range. Lower frequency signals fall into the VHF or lower bands. UHF radio waves propagate mainly by line of sight; they are blocked by hills and large buildings although the transmission through building walls is strong enough for indoor reception. They are used for television broadcasting, cell phones, satellite communication including GPS, personal radio services including Wi-Fi and Bluetooth, walkie-talkies, cordless phones, and numerous other applications.

TV DX and FM DX is the active search for distant radio or television stations received during unusual atmospheric conditions. The term DX is an old telegraphic term meaning "long distance."

The FM broadcast band, used for FM broadcast radio by radio stations, differs between different parts of the world. In Europe, Australia and Africa ( ), it spans from 87.5 to 108 megahertz (MHz) - also known as VHF Band II - while in the Americas it ranges from 88 to 108 MHz. The FM broadcast band in Japan uses 76 to 95 MHz. The International Radio and Television Organisation (OIRT) band in Eastern Europe is from 65.8 to 74.0 MHz, although these countries now primarily use the 87.5 to 108 MHz band, as in the case of Russia. Some other countries have already discontinued the OIRT band and have changed to the 87.5 to 108 MHz band.

Radio spectrum part of the electromagnetic spectrum from 3 Hz to 3000 GHz (3 THz)

The radio spectrum is the part of the electromagnetic spectrum with frequencies from 30 Hertz to 300 GHz. Electromagnetic waves in this frequency range, called radio waves, are extremely widely used in modern technology, particularly in telecommunication. To prevent interference between different users, the generation and transmission of radio waves is strictly regulated by national laws, coordinated by an international body, the International Telecommunication Union (ITU).

Tuner (radio) frequency selection subsystem for a radio receiver

A tuner is a subsystem that receives radio frequency (RF) transmissions like radio broadcasts and converts the selected carrier frequency and its associated bandwidth into a fixed frequency that is suitable for further processing, usually because a lower frequency is used on the output. Broadcast FM/AM transmissions usually feed this intermediate frequency (IF) directly into a demodulator that convert the radio signal into audio-frequency signals that can be fed into an amplifier to drive a loudspeaker.

Television channel frequencies Wikimedia list article

The following tables show the frequencies assigned to broadcast television channels in various regions of the world, along with the ITU letter designator for the system used. The frequencies shown are for the analogue video and audio carriers. The channel itself occupies several megahertz of bandwidth. For example, North American channel 2 occupies the spectrum from 54 to 60 MHz. See Broadcast television systems for a table of signal characteristics, including bandwidth, by ITU letter designator.

In North American broadcast television frequencies, channel 1 is a former broadcast (over-the-air) television channel. During the experimental era of TV operation, Channel 1 was moved around the lower VHF spectrum repeatedly, with the entire band displaced upward at one point due to an early 40 MHz allocation for the FM broadcast band.

6-meter band amateur radio frequency allocations

The 6-meter band is the lowest portion of the very high frequency (VHF) radio spectrum allocated to amateur radio use. The term refers to the average signal wavelength of 6 meters.

Apex radio stations was the name commonly given to a short-lived group of United States broadcasting stations, which were used to evaluate transmitting on frequencies that were much higher than the ones used by standard amplitude modulation (AM) and shortwave stations. Their name came from the tall height of their transmitter antennas, which were needed because coverage was primarily limited to local line-of-sight distances. These stations were assigned to what at the time were described as "ultra-high" frequencies, between roughly 25 and 44 MHz. They employed AM transmissions, although in most cases using a wider bandwidth than standard broadcast band AM stations, in order to provide high fidelity sound with less static and distortion.

Band III is the name of the range of radio frequencies within the very high frequency (VHF) part of the electromagnetic spectrum from 174 to 240 megahertz (MHz). It is primarily used for radio and television broadcasting. It is also called high-band VHF, in contrast to Bands I and II.

Band I is a range of radio frequencies within the very high frequency (VHF) part of the electromagnetic spectrum. The first time there was defined "for simplicity" in Annex 1 of "Final acts of the European Broadcasting Conference in the VHF and UHF bands - Stockholm, 1961". Band I ranges from 47 to 68 MHz for the European Broadcasting Area, and from 54 to 88 MHz for the Americas and it is primarily used for television broadcasting in line to ITU Radio Regulations. Channel spacings vary from country to country, with spacings of 6, 7 and 8 MHz being common.

Television frequency allocation has evolved since the start of television in Australia in 1956, and later in New Zealand in 1960. There was no coordination between the national spectrum management authorities in either country to establish the frequency allocations. The management of the spectrum in both countries is largely the product of their economical and political situation. New Zealand didn't start to develop television service until 1965 due to World War 2 and its economic harm in the country's economy.

The frequency modulation radio broadcast band in Japan is 76-95 MHz. The 90-108 MHz section was used for television for VHF channels 1, 2 and 3 until the analog shutdown occurred on July 24, 2011. The narrowness of the Japanese band limits the number of FM stations that can be accommodated on the dial.

Weatheradio Canada is a Canadian weather radio network that is owned and operated by Environment and Climate Change Canada's Meteorological Service of Canada division. The network transmits in both official languages from 230 sites across Canada. Weatheradio Canada like their telephone service, uses the Starcaster Text to Speech, which has been used for many years and is owned by STR-SpeechTech Ltd.

CCIR System B was the 625-line analog broadcast television system which at its peak was the system used in most countries. It is being replaced across Western Europe, part of Asia and Africa by digital broadcasting.

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 through 216 MHz, and the UHF band, which comprises channels 14 through 83 and occupies frequencies between 470 and 890 MHz. These bands are different enough in frequency that they often require separate antennas to receive, and separate tuning controls on the television set. The VHF band is further divided into two frequency ranges: VHF low band between 54 and 88 MHz, containing channels 2 through 6, and VHF high band between 174 and 216 MHz, containing channels 7 through 13. The wide spacing between these frequency bands is responsible for the complicated design of rooftop TV antennas. The UHF band has higher noise and greater attenuation, so higher gain antennas are often required for UHF.

CCIR System I is an analog broadcast television system. It was first used in the Republic of Ireland starting in 1962 as the 625-line broadcasting standard to be used on VHF Band I and Band III, sharing Band III with 405-line System A signals radiated in the north of the country. The UK started its own 625-line television service in 1964 also using System I, but on UHF only - the UK has never used VHF for 625-line television except for some cable relay distribution systems.

References

  1. Tooley, Mike (2007). Electronic Circuits - Fundamentals & Applications. Routledge. ISBN   9781136407383.
  2. "GOST 7845-92 : Broadcast television system. Main specifications. Methods of measurements. (In Russian)". Russian Federal agency for technical regulations and measurements. p. 10.