From Wikipedia, the free encyclopedia
Radio frequency band
This article is about the amateur radio band. For the international shortwave radio band, see
shortwave bands
.
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. The band is suitable for
amateur long-distance communications
, and such use is permitted in nearly all countries.
[
citation needed
]
Because 15-meter waves 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
solar maxima
, but the band permits long-distance without high-power station equipment outside such ideal windows. The 15-meter wavelength is
harmonically
related to that of the
40-meter band
, so it is often possible to use an
antenna
designed for 40 meters.
History
[
edit
]
The 15-meter band was designated 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.
[1]
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 21.25 MHz and Novice CW operations between 21.100 and 21.250 MHz on March 28, 1953.
[2]
Frequency allocation
[
edit
]
United States
[
edit
]
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
|
|
|
|
|
|
|
=
CW
,
RTTY
and data (US: < 1 kHz bandwidth)
|
|
=
CW
, phone and image
|
|
=
CW
only (US Novice/Technician: 200 W PEP maximum TPO)
|
Canada
[
edit
]
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.
[3]
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
|
|
|
|
|
|
|
|
|
|
Japan
[
edit
]
Changed on September 25, 2023.
License class
|
21.000?21.070
|
21.070?21.150
|
21.150?21.450
|
All Class
|
|
|
narrow-band All modes
|
|
=
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
[
edit
]
References
[
edit
]
|
---|
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
|
?
|
2 m
|
144.000?146.000 MHz
|
144.000?148.000 MHz
|
1.25 m
|
?
|
220.000?225.000 MHz
|
?
|
UHF
|
70 cm
|
430.000?440.000 MHz
|
430.000?440.000 MHz
(420.000?450.000 MHz)
[
y
]
|
33 cm
|
?
|
902.000?928.000 MHz
|
?
|
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.
|
[
v
] All allocations are subject to variation by country. For simplicity, only common allocations found internationally are listed. See a band's article for specifics.
[
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 many individual administrations have commonly adopted this allocation under
"Article 4.4"
.
[
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
|
|