Band III is the name of the range ofradio frequencies within thevery high frequency (VHF) part of theelectromagnetic spectrum from 174 to 240megahertz (MHz). It is primarily used forradio andtelevision broadcasting. It is also calledhigh-band VHF, in contrast to BandsI andII.
The band is subdivided into seven channels for television broadcasting, each occupying 6 MHz.[1]
| Channel | Frequency Range |
|---|---|
| 7 | 174-180 MHz |
| 8 | 180-186 MHz |
| 9 | 186-192 MHz |
| 10 | 192-198 MHz |
| 11 | 198-204 MHz |
| 12 | 204-210 MHz |
| 13 | 210-216 MHz |
European Band III allocations vary from country to country, with channel widths of 7 or 8 MHz.
The standard channel allocations for European countries that useSystem B with 7 MHz channel spacing are as follows:
| Channel | Frequency Range |
|---|---|
| E5 | 174-181 MHz |
| E6 | 181-188 MHz |
| E7 | 188-195 MHz |
| E8 | 195-202 MHz |
| E9 | 202-209 MHz |
| E10 | 209-216 MHz |
| E11 | 216-223 MHz |
| E12 | 223-230 MHz |
TheIrish (8 MHz) system is shown below.
| Channel | Frequency Range |
|---|---|
| D | 174-182 MHz |
| E | 182-190 MHz |
| F | 190-198 MHz |
| G | 198-206 MHz |
| H | 206-214 MHz |
| i | 214-222 MHz |
| J | 222-230 MHz |
Australia has allocated 8 channels in Band III for digital television, each with 7 MHz bandwidth.[2]
| Channel | Frequency Range |
|---|---|
| 6 | 174-181 MHz |
| 7 | 181-188 MHz |
| 8 | 188-195 MHz |
| 9 | 195-202 MHz |
| 9A | 202-209 MHz |
| 10 | 209-216 MHz |
| 11 | 216-223 MHz |
| 12 | 223-230 MHz |
Russian analog television is transmitted usingSystem D with 8 MHz channel bandwidth.
| Channel | Frequency Range |
|---|---|
| 6 | 174-182 MHz |
| 7 | 182-190 MHz |
| 8 | 190-198 MHz |
| 9 | 198-206 MHz |
| 10 | 206-214 MHz |
| 11 | 214-222 MHz |
| 12 | 222-230 MHz |
The band came into use for radio broadcasting at the turn of the 21st century and is used forDAB (Digital Audio Broadcasting).
It is subdivided into a number of frequency blocks used formultiplexes:
| Block | Centre Frequency |
|---|---|
| 5A | 174.928 MHz |
| 5B | 176.640 MHz |
| 5C | 178.352 MHz |
| 5D | 180.064 MHz |
| 6A | 181.936 MHz |
| 6B | 183.648 MHz |
| 6C | 185.360 MHz |
| 6D | 187.072 MHz |
| 7A | 188.928 MHz |
| 7B | 190.640 MHz |
| 7C | 192.352 MHz |
| 7D | 194.064 MHz |
| 8A | 195.936 MHz |
| 8B | 197.648 MHz |
| 8C | 199.360 MHz |
| 8D | 201.072 MHz |
| 9A | 202.928 MHz |
| 9B | 204.640 MHz |
| 9C | 206.352 MHz |
| 9D | 208.064 MHz |
| 10A | 209.936 MHz |
| 10B | 211.648 MHz |
| 10C | 213.360 MHz |
| 10D | 215.072 MHz |
| 10N | 210.096 MHz |
| 11A | 216.928 MHz |
| 11B | 218.640 MHz |
| 11C | 220.352 MHz |
| 11D | 222.064 MHz |
| 11N | 217.088 MHz |
| 12A | 223.936 MHz |
| 12B | 225.648 MHz |
| 12C | 227.360 MHz |
| 12D | 229.072 MHz |
| 12N | 224.096 MHz |
| 13A | 230.784 MHz |
| 13B | 232.496 MHz |
| 13C | 234.208 MHz |
| 13D | 235.776 MHz |
| 13E | 237.488 MHz |
| 13F | 239.200 MHz |
Grayed frequencies aren't used for DAB. Furthermore, some countries like Germany don't use channel 13's frequencies to prevent interference with aviation frequencies.[3]
In the UK and part of Ireland, Band III was originally used formonochrome405-linetelevision; however, this was discontinued by the mid-1980s. Other European countries (including Ireland) continued to use Band III for analogue625-line colour television.
Digital television in theDVB-T standard can be used in conjunction with VHF Band III and is used as such in some places. The use of sub-band 2 and sub-band 3 band forDigital Audio Broadcasting is now being widely adopted. Sub-band 1 is used for MPT-1327 trunked PMR radio, remote wireless microphones and PMSE links.
In North America, use of the band for television broadcasts is still widespread. Favorable propagation characteristics and reasonable power limits (up to 65 kW forfull-powerdigital television, versus 20 kW or less onVHFBand I) has meant that many US broadcasters elected to move their full-powerATSC stations fromUHF frequencies to Band IIIVHF when all full-powerNTSCanalog television services in the US shut down in 2009.[4]
Amateur (Ham) Radio has a small allocation of the band, known as the 1.25meter band, from 219 to 220MHz and 222.0 to 225.0MHz for communications.[5][circular reference]
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