||This article includes a list of references, related reading or external links, but its sources remain unclear because it lacks inline citations. (November 2011)|
The 40-meter or 7-MHz band is an amateur radio frequency band, spanning 7000-7300 kHz in ITU Region-2, and 7000-7200 kHz in Regions 1 & 3. It is allocated to radio amateurs worldwide on a primary basis.
40 meters is considered one of the most reliable all-season DX bands.
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The 40-meter band was made available to amateurs in the United States by the Third National Radio Conference on October 10, 1924 and allocated on a worldwide basis by the International Radiotelegraph Conference in Washington, D.C., on October 4, 1927.
For many years the portion of the band from 7100–7300 kHz has been allocated to short wave broadcasters outside the Americas and not available to radio amateurs outside ITU Region 2. At the World Radio Conference WRC-03 in 2003 it was agreed that the broadcast stations would move out of the section 7100–7200 kHz on 29 March 2009 and that portion would become a worldwide exclusive amateur allocation afterwards. Releasing the remaining 100 kHz of the band to amateurs at a later date is an IARU aim for future conferences.
Radio propagation characteristics
This band supports both long distance (DX) communications between late afternoon and a few hours after sunrise, and short distance NVIS contacts during most daylight hours.
With its unique combination of intra- and intercontinental communications possibilities, 40 meters is considered a key band in building a winning HF contesting score during any part of the sunspot cycle.
The band is most useful for inter-continental communication for one or two hours before sunset, during the night and for one or two hours after sunrise. It is extremely useful for short to medium distance contacts from local contacts out to a range of 500–1500 km or more, depending on conditions, during the day. In higher latitudes, daytime intercontinental communication is also possible during the short days of winter, for example a good path often opens between Japan and northern Europe in the hours leading up to European midday from late November through late January, with a long path opening to the west coast of the United States and Canada after midday.
Due to the 24-hour nature of the band, the wide variety of ranges that can be spanned with it, and its shared nature, it tends to be extremely crowded, and interference from other amateurs and broadcasters can be a serious limiting factor. In recent years amateurs in east and southeast Asia have also suffered severe interference from illegal users.
In most jurisdictions the subdivision of the band into different operating modes is according to informal convention rather than legal requirement.
IARU Region 1
Europe, Africa, Middle East and Northern Asia
|IARU Region 1|
IARU Region 2
|IARU Region 2|
IARU Region 3
|IARU Region 3|
Canada is part of region 2 and as such is subject to the IARU band plan. Radio Amateurs of Canada offers the bandplan below as a recommendation for use by radio amateurs in that country but it does not have the force of law and should only be considered a suggestion or guideline.
|U.S. license class||7.000–7.025||7.025–7.125||7.125–7.175||7.175–7.300|
|Novice / Technician|
|= CW only (US Novice/Technician: 200 W PEP maximum TPO)|
|= CW, RTTY and data (US: < 1 kHz bandwidth)|
|= CW, RTTY, data, MCW, test, phone and image|
|= CW, phone and image|
|= CW and SSB phone|
|= CW, RTTY, data, phone and image|
- "IARU Regions". www.iaru.org. International Amateur Radio Union (IARU). Retrieved 6 January 2014.
- "ARRLWeb: US Amateur Bands". Archived from the original on 7 September 2005. Retrieved August 3, 2005.
- "RAC Web: Canada HF Band Plan" (PDF). Retrieved July 8, 2008.
- "RSGB Band Plans (UK)". Retrieved March 17, 2011.
- "Ham Radio QRP". Retrieved August 3, 2005.
- "IARU Region 1 Bandplan" (PDF). Retrieved August 3, 2005.
- "IARU Region 2 Bandplan". Retrieved March 3, 2012.
|International amateur radio frequency allocations|
|Range||Band||ITU Region 1||ITU Region 2||ITU Region 3|
|LF||2200 m||135.7 kHz - 137.8 kHz|
|MF||600 m||472 kHz - 479 kHz|
|160 m||1.810 MHz - 1.850 MHz||1.800 MHz - 2.000 MHz||1.800 MHz - 2.000 MHz|
|HF||80 / 75 m||3.500 MHz - 3.800 MHz||3.500 MHz - 4.000 MHz||3.500 MHz - 3.900 MHz|
|60 m1||5.250 MHz - 5.450 MHz|
|40 m||7.000 MHz - 7.200 MHz||7.000 MHz - 7.300 MHz||7.000 MHz - 7.200 MHz|
|30 m2||10.100 MHz - 10.150 MHz|
|20 m||14.000 MHz - 14.350 MHz|
|17 m2||18.068 MHz - 18.168 MHz|
|15 m||21.000 MHz - 21.450 MHz|
|12 m2||24.890 MHz - 24.990 MHz|
|10 m||28.000 MHz - 29.700 MHz|
|VHF||6 m||50.000 MHz - 52.000 MHz1||50.000 MHz - 54.000 MHz||50.000 MHz - 54.000 MHz|
|4 m1||70.000 MHz - 70.500 MHz|
|2 m||144.000 MHz - 146.000 MHz||144.000 MHz - 148.000 MHz||144.000 MHz - 148.000 MHz|
|1.25 m||222.000 MHz - 225.000 MHz|
|UHF||70 cm||430.000 MHz - 440.000 MHz||420.0 or 430.0 MHz - 450.000 MHz3||420.000 MHz - 450.000 MHz3|
|33 cm||902.000 MHz - 928.000 MHz|
|23 cm||1.240 GHz - 1.300 GHz|
|13 cm||2.300 GHz - 2.450 GHz|
|SHF||9 cm||3.400 GHz - 3.475 GHz3||3.300 GHz - 3.500 GHz||3.300 GHz - 3.500 GHz|
|5 cm||5.650 GHz - 5.850 GHz||5.650 GHz - 5.925 GHz||5.650 GHz - 5.850 GHz|
|3 cm||10.000 GHz - 10.500 GHz|
|1.2 cm||24.000 GHz - 24.250 GHz|
|EHF||6 mm||47.000 GHz - 47.200 GHz|
|4 mm3||75.500 GHz1 - 81.500 GHz||76.000 GHz - 81.500 GHz||76.000 GHz - 81.500 GHz|
|2.5 mm||122.250 GHz - 123.000 GHz|
|2 mm||134.000 GHz - 141.000 GHz|
|1 mm||241.000 GHz - 250.000 GHz|
|THF||Sub-mm||Some administrations have authorized spectrum for amateur use in this region.|
1 This is not mentioned in the ITU's Table of Frequency Allocations, but individual administrations may make allocations under Article 4.4 of the ITU Radio Regulations. See the appropriate Wiki page for further information.
|See also: Radio spectrum · Electromagnetic spectrum|