15-meter band

The 15-meter band (also called the 21-MHz band or 15 meters) is an amateur radio frequency band spanning the shortwave spectrum from 21 to 21.45 MHz. Almost all countries permit amateur communications on the entire band.

The 15 meter band is considered a DX band (i.e., used for long-distance communications). Since signals on 15 meters propagate primarily via reflection off of the F-2 layer of the ionosphere, the band is most useful for intercontinental communication during daylight hours, especially in years close to the solar maximum. However, the band also sees long-distance openings during solar minima, and into evening hours, and does not require high-power station equipment to make contacts even at these times.

Because the 15-meter wavelength is harmonically related to that of the 40-meter band, it is often possible to use an antenna designed for 40 meters on the 15-meter band, as well.

History

The 15 meter band was created by the 1947 International Radio Conference of Atlantic City in part to compensate for the loss of the 160 meter band to amateurs by the introduction of Loran during World War II. The 15 meter band opened to amateurs for CW operation only in the United States on May 1, 1952, and telephony operations were authorized above 21250 kHz on March 28, 1953 [1]

Frequency allocation

United States

megahertz 21.000–21.025 21.025–21.200 21.200–21.225 21.225–21.275 21.275–21.450
Novice / Technician
General
Advanced
Extra

Key

= CW, RTTY and data (US: < 1 kHz bandwidth)
= CW, phone and image
= CW only (US Novice/Technician: 200 W PEP maximum TPO)

Canada[2]

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 21.000-21.070 21.070-21.080 21.080-21.083 21.083-21.090 21.090-21.125 21.125-21.150 21.150-21.340 21.340-21.343 21.343-21.450
Basic(+), Advanced

Key

= CW only
= CW, narrow band digital ( <= 500 Hz )
= CW, narrow band digital ( <= 500 Hz ), wide band digital
= Beacons
= CW, phone
= CW, phone, image ( <= 2700 Hz )
= Digital only
= Phone only
= TV only

See also

References

  1. ↑ "We Get 21 Mc." QST, June 1952, p. 29.
  2. ↑ Canadian 0-30 MHz Band Plan http://wp.rac.ca/wp-content/uploads/files/pdf/RAC%20Bandplan%20December%201%202015.pdf accessed 1 December 2015
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
HF 80 / 75 m 3.500 MHz – 3.800 MHz 3.500 MHz – 4.000 MHz 3.500 MHz – 3.900 MHz
60 m 5.3515 MHz – 5.3665 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
4 m1 70.000 MHz – 70.500 MHz N/A
2 m 144.000 MHz – 146.000 MHz 144.000 MHz – 148.000 MHz
1.25 m N/A 220.000 MHz – 225.000 MHz N/A
UHF 70 cm 430.000 MHz – 440.000 MHz 430.000 – 440.000 MHz
(420.000 – 450.000 MHz)3
33 cm N/A 902.000 MHz – 928.000 MHz N/A
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
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
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.
2 HF allocation created at the 1979 World Administrative Radio Conference. These are commonly called the "WARC bands".
3 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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