2 metres: Difference between revisions
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2 metres is probably the most heavily-used band in the United States. Most newly-licenced [[Technician|Technician-class]] operators get their start in amateur radio on 2 metre [[Modes#Frequency Modulation (FM)|FM]]. | 2 metres is probably the most heavily-used amateur band in the United States. Most newly-licenced [[Technician|Technician-class]] operators get their start in amateur radio on 2 metre [[Modes#Frequency Modulation (FM)|FM]]. | ||
==Equipment== | ==Equipment== | ||
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Much of the early equipment deployed by radio amateurs on 2 metre FM was surplus, built originally for commercial land-mobile use on bands elsewhere in the 130-174MHz spectrum and converted to the 144-148MHz amateur band. Users of adjacent spectrum range from marine radiotelephone and public safety to dispatch radios used by taxis and service vehicles. As commercial two-way radio frequencies became more crowded, spacing between channels was reduced, leading to many existing radios becoming available as surplus. The oldest of this equipment was crystal-controlled and provided use of a limited number of FM voice frequencies; modern equipment is frequency-synthesised and often also capable of receiving out-of-band services such as weather and marine radio. | Much of the early equipment deployed by radio amateurs on 2 metre FM was surplus, built originally for commercial land-mobile use on bands elsewhere in the 130-174MHz spectrum and converted to the 144-148MHz amateur band. Users of adjacent spectrum range from marine radiotelephone and public safety to dispatch radios used by taxis and service vehicles. As commercial two-way radio frequencies became more crowded, spacing between channels was reduced, leading to many existing radios becoming available as surplus. The oldest of this equipment was crystal-controlled and provided use of a limited number of FM voice frequencies; modern equipment is frequency-synthesised and often also capable of receiving out-of-band services such as weather and marine radio. | ||
Commercial land-mobile base station equipment has also been adapted readily to construct repeaters, although factory-built repeaters designed specifically for amateur use are now commercially available. | Commercial land-mobile base station equipment has also been adapted readily to construct repeaters, although factory-built repeaters designed specifically for amateur use are now commercially available. This ready availability of a wide selection equipment at reasonable cost has made 2 metres the most commonly-used band for mobile voice communication. | ||
==Modulation== | ==Modulation== | ||
Revision as of 19:57, 5 June 2009
Other VHF/UHF/Microwave wiki pages : 13 centimetres, 9 centimetres, 6 centimetres, 3 centimetres 1.25 centimetres and Bands above 24GHz.
| Band: 2m | |
| Bands | |
| 160m 80m 60m 40m 30m 20m 17m 15m 12m 10m 6m 4m 2m 1.25m 70cm 33cm 23cm 3cm | |
| Band Privileges | |
| US Extra | 144.000-148.000 |
| US Advanced | 144.000-148.000 |
| US General | 144.000-148.000 |
| US Technician | 144.000-148.000 |
| UK (all) | 144-146 |
2 metres is probably the most heavily-used amateur band in the United States. Most newly-licenced Technician-class operators get their start in amateur radio on 2 metre FM.
Equipment
Equipment for operation on two metres is plentiful; many well-known manufacturers produce new base, mobile and handheld transceivers intended specifically for the 2 metre amateur radio band. In some cases, additional bands (most often 70 centimetres but occasionally also additional VHF bands) will be supported.
Much of the early equipment deployed by radio amateurs on 2 metre FM was surplus, built originally for commercial land-mobile use on bands elsewhere in the 130-174MHz spectrum and converted to the 144-148MHz amateur band. Users of adjacent spectrum range from marine radiotelephone and public safety to dispatch radios used by taxis and service vehicles. As commercial two-way radio frequencies became more crowded, spacing between channels was reduced, leading to many existing radios becoming available as surplus. The oldest of this equipment was crystal-controlled and provided use of a limited number of FM voice frequencies; modern equipment is frequency-synthesised and often also capable of receiving out-of-band services such as weather and marine radio.
Commercial land-mobile base station equipment has also been adapted readily to construct repeaters, although factory-built repeaters designed specifically for amateur use are now commercially available. This ready availability of a wide selection equipment at reasonable cost has made 2 metres the most commonly-used band for mobile voice communication.
Modulation
The most common application of 2 metre radio is in FM voice transmission, either operated directly between stations or via automated repeaters. Individual FM channels are normally spaced at 15kHz or 20kHz intervals. Repeater inputs below 147MHz are typically set 600kHz below the output frequency; above 147MHz this pattern is reversed.
The 2 metre band is a popular choice for digital packet transmission, with 144.39MHz (North America) and 144.8MHz (Europe) commonly used for APRS operation.
Propagation
Signals in this band travel primarily line-of-sight or slightly further. It is not uncommon for a powerful, well-situated repeater to be accessible to mobile stations at up to fifty miles distance. During unusual atmospheric conditions (such as temperature inversion) the VHF signals' range may be significantly but temporarily increased.
Australian Bandplan
| Bands | |
| HF and MF | 160 metres * 80 metres* 60 metres * 40 metres * 30 metres * 20 metres * 17 metres * 15 metres * 12 metres * 10 metres |
| VHF | 6 metres * 4 metres * 2 metres * 1.25 metres |
| UHF | 70 centimetres * 33 centimetres * 23 centimetres * 13 centimetres |
| Microwave | 9 centimetres * 6 centimetres * 3 centimetres * 1.25 centimetres * Bands above 24GHz |
| See also | US bandplan |