Editing Shortwave radio (section)

===Frequency allocations===
{{Main|Shortwave bands}}
The [[World Radiocommunication Conference]] (WRC), organized under the auspices of the [[International Telecommunication Union]], allocates bands for various services in conferences every few years. The last WRC took place in 2023.<ref>{{Cite web |title=WRC-23 – World Radiocommunication Conferences (WRC) |url=https://www.itu.int/wrc-23/ |access-date=2024-05-13 |language=en}}</ref>

As of WRC-97 in 1997, these bands were allocated for [[international broadcasting]]. AM shortwave broadcasting channels are allocated with a 5&nbsp;kHz separation for traditional analog audio broadcasting:
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{| border="0" cellspacing="2" cellpadding="1" style="float:left;margin-left:10px"
|-
! style="background:#b5b5b5;"| Metre Band
! style="background:#b5b5b5;"| Frequency Range
! style="background:#b5b5b5;"| Remarks
|-
| 120&nbsp;m
| 2.3–2.495&nbsp;MHz
| tropical band
|- style="background:#e8e8e8;"
|| 90&nbsp;m
|| 3.2–3.4&nbsp;MHz
|| tropical band
|-
| 75&nbsp;m
| 3.9–4&nbsp;MHz
| shared with the North American [[80-meter band|amateur radio 80m band]]
|- style="background:#e8e8e8;"
|| 60&nbsp;m
|| 4.75–5.06&nbsp;MHz
|| tropical band
|-
| 49&nbsp;m
| 5.9–6.2&nbsp;MHz
| &nbsp;
|- style="background:#e8e8e8;"
||  41&nbsp;m
|| 7.2–7.6&nbsp;MHz
|| shared with the [[Amateur radio frequency allocations#40 Metres|amateur radio 40m band]]
|-
| 31&nbsp;m
| 9.4–9.9&nbsp;MHz
| the most heavily used band
|- style="background:#e8e8e8;"
|| 25&nbsp;m
|| 11.6–12.2&nbsp;MHz
|| &nbsp;
|-
| 22&nbsp;m
| 13.57–13.87&nbsp;MHz
|
|- style="background:#e8e8e8;"
|| 19&nbsp;m
|| 15.1–15.8&nbsp;MHz
|| &nbsp;
|-
| 16&nbsp;m
| 17.48–17.9&nbsp;MHz
| &nbsp;
|- style="background:#e8e8e8;"
|| 15&nbsp;m
|| 18.9–19.02&nbsp;MHz
|| almost unused, could become a DRM band
|-
| 13&nbsp;m
| 21.45–21.85&nbsp;MHz
| &nbsp;
|- style="background:#e8e8e8;"
|| 11&nbsp;m
|| 25.6–26.1&nbsp;MHz
|| may be used for local DRM broadcasting
|}
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[[File:Shortwave and other bands on World Radio receiver.jpg|thumb|right|Tuning display of a cheap portable "World Radio" which includes nine shortwave bands]]
Although countries generally follow the assigned bands, there may be small differences between countries or regions. For example, in the official bandplan of the [[Netherlands]],<ref name=RijksOverheid2007/> the 49&nbsp;m band starts at 5.95&nbsp;MHz, the 41&nbsp;m band ends at 7.45&nbsp;MHz, the 11&nbsp;m band starts at 25.67&nbsp;MHz, and the 120&nbsp;m, 90&nbsp;m, and 60&nbsp;m bands are absent altogether. International broadcasters sometimes operate outside the normal the WRC-allocated bands or use off-channel frequencies. This is done for practical reasons, or to attract attention in crowded bands (60&nbsp;m, 49&nbsp;m, 40&nbsp;m, 41&nbsp;m, 31&nbsp;m, 25&nbsp;m).

The new [[digital audio broadcasting]] format for shortwave [[Digital Radio Mondiale|DRM]] operates 10&nbsp;kHz or 20&nbsp;kHz channels. There are some ongoing discussions with respect to specific band allocation for DRM, as it mainly transmitted in 10&nbsp;kHz format.

The power used by shortwave transmitters ranges from less than one watt for some experimental and amateur radio transmissions to 500 kilowatts and higher for intercontinental broadcasters and [[over-the-horizon radar]]. Shortwave transmitting centers often use specialized [[antenna (radio)|antenna]] designs (like the [[ALLISS]] antenna technology) to concentrate radio energy at the target area.