40-meter band

The 40-meter or 7-MHz band is an amateur radio frequency band, spanning 7.000-7.300 MHz in ITU Region 2, and 7.000-7.200 MHz in Regions 1 & 3. It is allocated to radio amateurs worldwide on a primary basis; however, only 7.000-7.100 MHz is exclusively allocated to amateur radio worldwide. Shortwave broadcasters and land mobile users also have primary allocations in some countries, and amateur stations must share the band with these users.

40 meters is considered one of the most reliable all-season long distance communication (DX) bands.

History

The 40-meter band was made available to amateurs in the United States by the Third National Radio Conference on October 10, 1924,[1] 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 7.100–7.300 MHz has been allocated to short wave broadcasters outside the Americas, and not available to radio amateurs outside of 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 7.100–7.200 MHz 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.

Usage

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 500–1,500 km (300–1,000 miles) 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.

Band plans

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[2]

40 meters 7.000-7.040 7.040-7.050 7.050-7.060 7.060-7.200
IARU Region 1

IARU Region 2

The Americas[2]

40 meters 7.000-7.040 7.040-7.050 7.050-7.300
IARU Region 2

IARU Region 3

Asia-Pacific[2]

40 meters 7.000-7.025 7.025-7.030 7.030-7.040 7.040-7.300
IARU Region 3

Japan
License class 7.000–7.030 7.030-7.045 7.045-7.100 7.100–7.200
All classes

Canada

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.

License class 7.000–7.035 7.035-7.040 7.040-7.050 7.050-7.080 7.080-7.125 7.125-7.165 7.165-7.175 7.175–7.300
Basic(+), Advanced

United States
U.S. license class 7.000–7.025 7.025–7.125 7.125–7.175 7.175–7.300
Novice / Technician
General
Advanced
Extra

Key
= 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

See also

References
  1. "Frequency or wave band allocations", Recommendations for Regulation of Radio Adopted by the Third National Radio Conference (October 6-10, 1924), page 15.
  2. "IARU Regions". www.iaru.org. International Amateur Radio Union (IARU). Archived from the original on 30 December 2013. Retrieved 6 January 2014.
International amateur radio frequency allocations
Range Band ITU Region 1 ITU Region 2 ITU Region 3
LF 2200 m 135.7–137.8 kHz
MF 630 m 472–479 kHz
160 m 1.810–1.850 MHz 1.800–2.000 MHz
HF 80 / 75 m 3.500–3.800 MHz 3.500–4.000 MHz 3.500–3.900 MHz
60 m 5.3515–5.3665 MHz
40 m 7.000–7.200 MHz 7.000–7.300 MHz 7.000–7.200 MHz
30 m[w] 10.100–10.150 MHz
20 m 14.000–14.350 MHz
17 m[w] 18.068–18.168 MHz
15 m 21.000–21.450 MHz
12 m[w] 24.890–24.990 MHz
10 m 28.000–29.700 MHz
VHF 6 m 50.000–52.000 MHz
(50.000–54.000 MHz)[y]		 50.000–54.000 MHz
4 m[x] 70.000–70.500 MHz N/A
2 m 144.000–146.000 MHz 144.000–148.000 MHz
1.25 m N/A 220.000–225.000 MHz N/A
UHF 70 cm 430.000–440.000 MHz 430.000–440.000 MHz
(420.000–450.000 MHz)[y]
33 cm N/A 902.000–928.000 MHz N/A
23 cm 1.240–1.300 GHz
13 cm 2.300–2.450 GHz
SHF 9 cm 3.400–3.475 GHz[y] 3.300–3.500 GHz
5 cm 5.650–5.850 GHz 5.650–5.925 GHz 5.650–5.850 GHz
3 cm 10.000–10.500 GHz
1.2 cm 24.000–24.250 GHz
EHF 6 mm 47.000–47.200 GHz
4 mm[y] 75.500 GHz[x] – 81.500 GHz 76.000–81.500 GHz
2.5 mm 122.250–123.000 GHz
2 mm 134.000–141.000 GHz
1 mm 241.000–250.000 GHz
THF Sub-mm Some administrations have authorized spectrum for amateur use in this region;
others have declined to regulate frequencies above 300 GHz, leaving them available by default.

[w] HF allocation created at the 1979 World Administrative Radio Conference. These are commonly called the "WARC bands".
[x] This is not mentioned in the ITU's Table of Frequency Allocations, but individual administrations may make allocations under "Article 4.4". ITU Radio Regulations.. See the appropriate Wiki page for further information.
[y] This includes a currently active footnote allocation mentioned in the ITU's Table of Frequency Allocations. These allocations may only apply to a group of countries.

See also: Radio spectrum, Electromagnetic spectrum
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