Band I
Band I is the name of a radio frequency range within the very high frequency part of the electromagnetic spectrum. Band I ranges from 47 to 68 MHz, and it is primarily used for broadcasting service (television broadcasting) in line to ITU Radio Regulations (article 1.38). Channel spacings vary from country to country, with spacings of 6, 7 and 8 MHz being common.
Television broadcasting usage
In the UK, Band I was originally used by the BBC for monochrome 405-line television;[1] likewise, the French former 455-line (1937-1939) then 441-line (1943-1956) transmitter on the Eiffel Tower in Paris, and some stations of the French monochrome 819-line system used Band I. Both 405-line and 819-line systems were discontinued in the mid-1980s. Other European countries used and still use Band I for 625-line analogue television, first in monochrome and later in colour.
This is now being gradually phased out with the introduction of digital television in the DVB-T standard, which is not defined for VHF Band I.
In the United States, use of this band is for analog NTSC (ended June 12, 2009) and digital ATSC (current). Digital television has problems with impulse noise interference, particularly in this band.
Europe
In many Western European countries the band is subdivided into three channels for television broadcasting, each occupying 7 MHz (System B).
Italy also uses a "outband" "channel C" (video : 82.25 MHz - audio : 87.75 MHz). It was used by the first transmitter brought in service by the RAI in Torino in the Fifties. This channel now also widely used by private local stations will be discontinued with the coming of digital television.
| Channel | Frequency Range |
|---|---|
| E2 | 47-54 MHz |
| E2A | 48.5-55.5 MHz |
| E3 | 54-61 MHz |
| E4 | 61-68 MHz |
| C | 82.25-87.75 MHz |
Some countries use slightly different frequencies or don't use Band 1 at all for terrestrial broadcast television. The fast growing of digital television in all European countries is accompanied by the progressive closedown of band I analog transmitters, e.g. former French-language Swiss Television transmitter at La Dôle near Geneva on channel E4 or French analog transmitters used by Canal Plus for its Pay-TV VHF network, e.g. Besançon (Lomont) and Carcassonne (Pic de Nore) both on French channel "L-3".
In Eastern European countries , the table is as follows:
| Channel | Frequency Range |
|---|---|
| R1 | 48.5-56.5 MHz |
| R2 | 58-66 MHz |
| R3 | 76-84 MHz |
| R4 | 84-92 MHz |
| R5 | 92-100 MHz |
North America
The band is subdivided into five channels for television broadcasting, each occupying 6 MHz (System M).
| Channel | Frequency Range |
|---|---|
| 1* | 44-50 MHz |
| A2 | 54-60 MHz |
| A3 | 60-66 MHz |
| A4 | 66-72 MHz |
| A5 | 76-82 MHz |
| A6 | 82-88 MHz |
| A6A | 81.5-87.5 MHz |
FM Radio Usage
The upper end of this band, 87.5 to 88 MHz, is the lower end of the FM radio band. In the United States, the FCC will occasionally issue a license for 87.9 MHz (though it only does so on rare occurrences and special circumstances; KSFH is the only standalone station that uses 87.9 currently); 87.7, which is approximately the same frequency as the audio feed of channel 6, is used by some television licenses to broadcast primarily to radio, such as Pulse 87's stations.
See also
References
- ↑ Paulu, Burton (1981-10-01). Television and Radio in the United Kingdom. U of Minnesota Press. p. 91. ISBN 9780816609413. Retrieved 11 April 2012.