Radio spectrum

{{Short description|Electromagnetic spectrum, 3 Hz – 3000 GHz}} {{about|the spectral band|the radiation|radio wave|the frequency|radio frequency|the broadcaster|Spectrum Radio}} {{MWband}}

The '''radio spectrum''' is the part of the electromagnetic spectrum with frequencies from 3 Hz to 3,000 GHz (3 THz). Electromagnetic waves in this frequency range, called radio waves, are widely used in modern technology, particularly in telecommunication. To prevent interference between different users, the generation and transmission of radio waves is strictly regulated by national laws, coordinated by an international body, the International Telecommunication Union (ITU).<ref>ITU Radio Regulations – Article 1, Definitions of Radio Services, Article 1.2 Administration: Any governmental department or service responsible for discharging the obligations undertaken in the Constitution of the International Telecommunication Union, in the Convention of the International Telecommunication Union and in the Administrative Regulations (CS 1002)</ref>

Different parts of the radio spectrum are allocated by the ITU for different radio transmission technologies and applications; some 40 radiocommunication services are defined in the ITU's Radio Regulations (RR).<ref>International Telecommunication Union's Radio Regulations, Edition of 2020.</ref> In some cases, parts of the radio spectrum are sold or licensed to operators of private radio transmission services (for example, cellular telephone operators or broadcast television stations). Ranges of allocated frequencies are often referred to by their provisioned use (for example, cellular spectrum or television spectrum).<ref>{{cite book |title=Competition and regulation in utility markets |author=Colin Robinson |publisher=Edward Elgar Publishing |year=2003 |isbn=978-1-84376-230-0 |page=175 |url=https://books.google.com/books?id=iROxMM2MHrIC&q=%22cellular+spectrum%22+%22television+spectrum%22&pg=PA175 |access-date=2020-11-02 |archive-date=2022-04-07 |archive-url=https://web.archive.org/web/20220407192811/https://books.google.com/books?id=iROxMM2MHrIC&q=%22cellular+spectrum%22+%22television+spectrum%22&pg=PA175 |url-status=live }}</ref> Because it is a fixed resource which is in demand by an increasing number of users, the radio spectrum has become increasingly congested in recent decades, and the need to utilize it more effectively is driving modern telecommunications innovations such as trunked radio systems, spread spectrum, ultra-wideband, frequency reuse, dynamic spectrum management, frequency pooling, and cognitive radio.

==Limits== The frequency boundaries of the radio spectrum are a matter of convention in physics and are somewhat arbitrary. Since radio waves are the lowest frequency category of electromagnetic waves, there is no lower limit to the frequency of radio waves.<ref name="RadioRegulations1">Radio waves are defined by the ITU as: "electromagnetic waves of frequencies arbitrarily lower than 3000 GHz, propagated in space without artificial guide", {{cite book | title = Radio Regulations, 2020 Edition | publisher = International Telecommunication Union | url = https://www.itu.int/dms_pub/itu-r/opb/reg/R-REG-RR-2020-ZPF-E.zip | access-date = 2022-02-18 | archive-date = 2022-02-18 | archive-url = https://web.archive.org/web/20220218201544/https://www.itu.int/dms_pub/itu-r/opb/reg/R-REG-RR-2020-ZPF-E.zip | url-status = live }}</ref> Radio waves are defined by the ITU as: "electromagnetic waves of frequencies arbitrarily lower than 3000 GHz, propagated in space without artificial guide".<ref>{{cite book | title = Radio Regulations, 2020 Edition | publisher = International Telecommunication Union | url = https://www.itu.int/dms_pub/itu-r/opb/reg/R-REG-RR-2020-ZPF-E.zip | access-date = 2022-02-18 | archive-date = 2022-02-18 | archive-url = https://web.archive.org/web/20220218201544/https://www.itu.int/dms_pub/itu-r/opb/reg/R-REG-RR-2020-ZPF-E.zip | url-status = live }}</ref> At the high frequency end the radio spectrum is bounded by the infrared band. The boundary between radio waves and infrared waves is defined at different frequencies in different scientific fields. The terahertz band, from 300 gigahertz to 3 terahertz, can be considered either as microwaves or infrared. It is the highest band categorized as radio waves by the International Telecommunication Union,<ref name="RadioRegulations1"/> but spectroscopic scientists consider these frequencies part of the far infrared and mid infrared bands.

Because it is a fixed resource, the ''practical'' limits and basic physical considerations of the radio spectrum, the frequencies which are useful for radio communication, are determined by technological limitations which are impossible to overcome.<ref name="Gosling">{{cite book |last1 = Gosling |first1 = William |title = Radio Spectrum Conservation: Radio Engineering Fundamentals |publisher = Newnes |date = 2000 |pages = 11–14 |url = https://books.google.com/books?id=MvbZ2eK7luMC&pg=PA11 |isbn = 9780750637404 |access-date = 2019-11-25 |archive-date = 2022-04-07 |archive-url = https://web.archive.org/web/20220407192824/https://books.google.com/books?id=MvbZ2eK7luMC&pg=PA11 |url-status = live }}</ref> So although the radio spectrum is becoming increasingly congested, there is no possible way to add additional frequency bandwidth outside of that currently in use.<ref name="Gosling"/> The lowest frequencies used for radio communication are limited by the increasing size of transmitting antennas required.<ref name="Gosling" /> The size of antenna required to radiate radio power efficiently increases in proportion to wavelength or inversely with frequency. Below about 10 kHz (a wavelength of 30 km), elevated wire antennas kilometers in diameter are required, so very few radio systems use frequencies below this. A second limit is the decreasing bandwidth available at low frequencies, which limits the data rate that can be transmitted.<ref name="Gosling" /> Below about 30 kHz, audio modulation is impractical and only slow baud rate data communication is used. The lowest frequencies that have been used for radio communication are around 80 Hz, in ELF submarine communications systems built by a few nations' navies to communicate with their submerged submarines hundreds of meters underwater. These employ huge ground dipole antennas 20–60 km long excited by megawatts of transmitter power, and transmit data at an extremely slow rate of about 1 bit per minute (17 millibits per second, or about 5 minutes per character).

The highest frequencies useful for radio communication are limited by the absorption of microwave energy by the atmosphere.<ref name="Gosling" /> As frequency increases above 30 GHz (the beginning of the millimeter wave band), atmospheric gases absorb increasing amounts of power, so the power in a beam of radio waves decreases exponentially with distance from the transmitting antenna. At 30 GHz, useful communication is limited to about 1 km, but as frequency increases the range at which the waves can be received decreases. In the terahertz band above 300 GHz, the radio waves are attenuated to zero within a few meters due to the absorption of electromagnetic radiation by the atmosphere (mainly due to ozone, water vapor and carbon dioxide), which is so great that it is essentially opaque to electromagnetic emissions, until it becomes transparent again near the near-infrared and optical window frequency ranges.<ref name="Coutaz">{{cite book |last1 = Coutaz |first1 = Jean-Louis |last2 = Garet |first2 = Frederic |last3 = Wallace |first3 = Vincent P. |title = Principles of Terahertz Time-Domain Spectroscopy: An Introductory Textbook |publisher = CRC Press |date = 2018 |pages = 18 |url = https://books.google.com/books?id=zah8DwAAQBAJ&pg=PA18 |doi = |id = |isbn = 9781351356367 |access-date = 2021-05-20 |archive-date = 2023-02-21 |archive-url = https://web.archive.org/web/20230221211545/https://books.google.com/books?id=zah8DwAAQBAJ&pg=PA18 |url-status = live }}</ref><ref name="Siegel">{{cite web | last = Siegel | first = Peter | title = Studying the Energy of the Universe | work = Education materials | publisher = NASA website | date = 2002 | url = https://www.nasa.gov/audience/foreducators/k-4/features/Peter_Siegel.html | doi = | accessdate = 19 May 2021 | archive-date = 20 June 2021 | archive-url = https://web.archive.org/web/20210620092047/https://www.nasa.gov/audience/foreducators/k-4/features/Peter_Siegel.html | url-status = live }}</ref>

==Bands== {{broader|EM band}}

A '''radio band''' {{anchor|band}} is a small frequency band (a contiguous section of the range of the radio spectrum) in which channels are usually used or set aside for the same purpose. To prevent interference and allow for efficient use of the radio spectrum, similar services are allocated in bands. For example, broadcasting, mobile radio, or navigation devices, will be allocated in non-overlapping ranges of frequencies.

===Band plan=== For each radio band, the ITU has a '''band plan''' (or '''frequency plan''') which dictates how it is to be used and shared, to avoid interference and to set protocol for the compatibility of transmitters and receivers.<ref>See detail of bands: [http://www.ntia.doc.gov/files/ntia/Spectrum_Use_Summary_Master-06212010.pdf] {{Webarchive|url=https://web.archive.org/web/20140703102108/http://www.ntia.doc.gov/files/ntia/Spectrum_Use_Summary_Master-06212010.pdf|date=2014-07-03}}</ref>

Each frequency plan defines the frequency range to be included, how channels are to be defined, and what will be carried on those channels. Typical definitions set forth in a frequency plan are: *numbering scheme – which channel numbers or letters (if any) will be assigned *center frequencies – how far apart the carrier wave for each channel will be (see channel spacing) *bandwidth and/or deviation – how wide each channel will be *spectral mask – how extraneous signals will be attenuated by frequency *modulation – what type will be used or are permissible *content – what types of information are allowed, such as audio or video, analog or digital *licensing – what the procedure will be to obtain a broadcast license

===ITU=== The actual authorized frequency bands are defined by the ITU<ref>[https://www.itu.int/en/ITU-R/terrestrial/fmd/Pages/frequency-plans.aspx Frequency Plans]</ref> and the local regulating agencies like the US Federal Communications Commission (FCC) <ref>For the authorized frequency bands for amateur radio use see: [https://www.ecfr.gov/current/title-47/part-2 Authorized frequency bands]</ref> and voluntary best practices help avoid interference.<ref>US ARRL Amateur Radio Bands and power limits [http://www.arrl.org/graphical-frequency-allocations Graphical Frequency Allocations]</ref>

As a matter of convention, the ITU divides the radio spectrum into 12 bands, each beginning at a wavelength which is a power of ten (10n) metres, with corresponding frequency of 3×108-''n'' hertz, and each covering a decade of frequency or wavelength. Each of these bands has a traditional name. For example, the term ''high frequency'' (HF) designates the wavelength range from 100 to 10 metres, corresponding to a frequency range of 3 to 30 MHz. This is just a symbol and is not related to allocation; the ITU further divides each band into subbands allocated to different services. Above 300 GHz, the absorption of electromagnetic radiation by Earth's atmosphere is so great that the atmosphere is effectively opaque, until it becomes transparent again in the near-infrared and optical window frequency ranges.

These ''ITU radio bands'' are defined in the ITU Radio Regulations. Article 2, provision No. 2.1 states that "the radio spectrum shall be subdivided into nine frequency bands, which shall be designated by progressive whole numbers in accordance with the following table".<ref name="ITU2020">ITU Radio Regulations, Volume 1, Article 2; Edition of 2020. Available online at {{cite web | title = Article '''2.1''': Frequency and wavelength bands | work = Radio Regulations 2016 Edition | publisher = International Telecommunication Union | date = 1 January 2017 | url = https://www.itu.int/dms_pub/itu-r/opb/reg/R-REG-RR-2020-ZPF-E.zip | format = PDF | access-date = 18 February 2020 | archive-date = 18 February 2022 | archive-url = https://web.archive.org/web/20220218201544/https://www.itu.int/dms_pub/itu-r/opb/reg/R-REG-RR-2020-ZPF-E.zip | url-status = live }}</ref>

The table originated with a recommendation of the fourth CCIR meeting, held in Bucharest in 1937, and was approved by the International Radio Conference held at Atlantic City, NJ in 1947. The idea to give each band a number, in which the number is the logarithm of the approximate geometric mean of the upper and lower band limits in Hz, originated with B. C. Fleming-Williams, who suggested it in a letter to the editor of ''Wireless Engineer'' in 1942. For example, the approximate geometric mean of band 7 is 10 MHz, or 107 Hz.<ref>{{cite journal | author=Booth, C. F. | year=1949 | title=Nomenclature of Frequencies | journal=The Post Office Electrical Engineers' Journal | volume=42 | issue=1 | pages=47–48 }}</ref>

The band name "tremendously low frequency" (TLF) has been used for frequency and wavelength of 1–3 Hz | 300,000–100,000 km (1000 Mm),<ref name="Duncan 2021 235–247">{{Cite book |last1=Duncan |first1=Christopher |last2=Gkountouna |first2=Olga |last3=Mahabir |first3=Ron |chapter=Theoretical Applications of Magnetic Fields at Tremendously Low Frequency in Remote Sensing and Electronic Activity Classification |series=Transactions on Computational Science and Computational Intelligence |date=2021 |editor-last=Arabnia |editor-first=Hamid R. |editor2-last=Deligiannidis |editor2-first=Leonidas |editor3-last=Shouno |editor3-first=Hayaru |editor4-last=Tinetti |editor4-first=Fernando G. |editor5-last=Tran |editor5-first=Quoc-Nam |title=Advances in Computer Vision and Computational Biology |chapter-url=https://link.springer.com/10.1007/978-3-030-71051-4_18 |language=en |location=Cham |publisher=Springer International Publishing |pages=235–247 |doi=10.1007/978-3-030-71051-4_18 |isbn=978-3-030-71050-7}}</ref> but the term has not been defined by the ITU.<ref>{{cite web |title=Nomenclature of the frequency and wavelength bands used in telecommunications |url=https://www.itu.int/dms_pubrec/itu-r/rec/v/R-REC-V.431-8-201508-I!!PDF-E.pdf |website=International Telecommunications Union |access-date=7 April 2023 |location=Geneva, Switzerland | date=2015}}</ref>

{| class="wikitable" style="text-align:center" ! Band name !! Abbreviation !! ITU band number !! Frequency and wavelength !! Example uses |- | Extremely low frequency || ELF || 1 || {{convert|3|-|30|Hz|km|sigfig=1|disp=br|abbr=on}} (100 Mm) ||{{left}} Communication with submarines |- | Super low frequency || SLF || 2 || {{convert|30|-|300|Hz|km|sigfig=1|disp=br|abbr=on}} (10 Mm) ||{{left}} Communication with submarines |- | Ultra low frequency || ULF || 3 || {{convert|300|-|3000|Hz|km|sigfig=1|disp=br|abbr=on}} (1 Mm) ||{{left}} Communication with submarines, communication within mines, landline telephony, fax machines, fiber-optic communication |- | Very low frequency || VLF || 4 || {{convert|3|-|30|kHz|km|sigfig=1|disp=br|abbr=on}} ||{{left}} Navigation, time signals, communication with submarines, landline telephony, wireless heart rate monitors, geophysics |- | Low frequency || LF || 5 || {{convert|30|-|300|kHz|km|sigfig=1|disp=br|abbr=on}} ||{{left}} Navigation, time signals, AM longwave broadcasting (Europe and parts of Asia), RFID, amateur radio. |- | Medium frequency || MF || 6 || {{convert|300|-|3000|kHz|sigfig=1|disp=br|abbr=on}} ||{{left}} AM (medium wave) broadcasts, amateur radio, avalanche beacons, magnetic resonance imaging, positron emission tomography, electrical telegraph, wireless telegraphy, radioteletype, dial-up internet. |- | High frequency || HF || 7 || {{convert|3|-|30|MHz|sigfig=1|disp=br|abbr=on}} ||{{left}} Shortwave broadcasts, citizens band radio, amateur radio, over-the-horizon aviation communications, RFID, over-the-horizon radar, automatic link establishment (ALE) / near-vertical incidence skywave (NVIS) radio communications, marine and mobile radio telephony, CT scan, magnetic resonance imaging, positron emission tomography, ultrasound, cordless phones. |- | Very high frequency || VHF || 8 || {{convert|30|-|300|MHz|sigfig=1|disp=br|abbr=on}} ||{{left}} FM broadcasts, television broadcasts, cable television broadcasting, radars, line-of-sight ground-to-aircraft communications, aircraft-to-aircraft communications, emergency locator beacon homing signal, radioteletype, land mobile and maritime mobile communications, amateur radio, police, fire and emergency medical services broadcasts, weather radio, CT scan, magnetic resonance imaging, positron emission tomography, ultrasound, cordless phones. |- | Ultra high frequency || UHF || 9 || {{convert|300|-|3000|MHz|cm|sigfig=1|disp=br|abbr=on}} ||{{left}} Television broadcasts, cable television broadcasting, microwave oven, radars, microwave devices/communications, radio astronomy, radars (L band), mobile phones, wireless LAN, Bluetooth, Zigbee, GPS and two-way radios such as land mobile, emergency locator beacon, FRS and GMRS radios, amateur radio, satellite radio, LoRa Networks (ISM band), police, fire and emergency medical services broadcasts, remote control systems, ADSB, cordless phones, internet, dial-up internet, satellite broadcasting, communication satellites, weather satellites, satellite phones (L band), satellite phones (S band). |- | Super high frequency || SHF || 10 || {{convert|3|-|30|GHz|cm|sigfig=1|disp=br|abbr=on}} ||{{left}} Radio astronomy, microwave devices/communications, wireless LAN, DSRC, most modern radars, communications satellites, cable and satellite television broadcasting, DBS, amateur radio, satellite broadcasting, communication satellites, weather satellites, satellite radio, cordless phones, internet, satellite phones (S band). |- | Extremely high frequency || EHF || 11 || {{convert|30|-|300|GHz|mm|sigfig=1|disp=br|abbr=on}} ||{{left}} Radio astronomy, satellite broadcasting, communication satellites, weather satellites, high-frequency microwave radio relay, microwave remote sensing, directed-energy weapon, millimeter wave scanner, Wireless Lan 802.11ad, internet. |- | Terahertz or tremendously high frequency ||THF|| 12 || {{convert|300|-|3000|GHz|mm|sigfig=1|disp=br|abbr=on}} ||{{left}} Experimental medical imaging to replace X-rays, ultrafast molecular dynamics, condensed-matter physics, terahertz time-domain spectroscopy, terahertz computing/communications, remote sensing |}

===IEEE radar bands{{anchor|IEEE}}=== Frequency bands in the microwave range are designated by letters. This convention began around World War II with military designations for frequencies used in radar, which was the first application of microwaves. There are several incompatible naming systems for microwave bands, and even within a given system the exact frequency range designated by a letter may vary somewhat between different application areas. One widely used standard is the ''IEEE radar bands'' established by the US Institute of Electrical and Electronics Engineers.

{| class="wikitable" |+ Radar-frequency bands according to IEEE standard<ref name=ieee>[https://standards.ieee.org/ieee/521/768/ IEEE Std 521-2002 ''Standard Letter Designations for Radar-Frequency Bands''] .</ref> |- ! Band designation !! Frequency range !! Explanation of meaning of letters |- | HF || 0.003 to 0.03 GHz || High frequency{{refn|name=ieee_names|Table 2 in <ref name=ieee />}} |- | VHF || 0.03 to 0.3 GHz || Very high frequency<ref name=ieee_names /> |- | UHF || 0.3 to 1 GHz || Ultra-high frequency<ref name=ieee_names /> |- | L || 1 to 2 GHz || Long wave |- | S || 2 to 4 GHz || Short wave |- | C || 4 to 8 GHz || Compromise between S and X |- | X || 8 to 12 GHz || Used in World War II for fire control, X for cross (as in crosshair). Exotic.<ref name="Friedman2006">{{cite book|author=Norman Friedman|title=The Naval Institute Guide to World Naval Weapon Systems|url=https://books.google.com/books?id=4S3h8j_NEmkC&pg=PR13|year=2006|publisher=Naval Institute Press|isbn=978-1-55750-262-9|pages=xiii|access-date=2016-10-13|archive-date=2023-02-21|archive-url=https://web.archive.org/web/20230221211534/https://books.google.com/books?id=4S3h8j_NEmkC&pg=PR13|url-status=live}}</ref> |- | Ku || 12 to 18 GHz || {{lang|de|Kurz}}-under |- | K || 18 to 27 GHz || {{langx|de|Kurz}} (short) |- | Ka || 27 to 40 GHz || {{lang|de|Kurz}}-above |- | V || 40 to 75 GHz || |- | W || 75 to 110 GHz || W follows V in the alphabet<ref>{{Cite journal |last1=Banday |first1=Yusra |last2=Mohammad Rather |first2=Ghulam |last3=Begh |first3=Gh. Rasool |date=February 2019 |title=Effect of atmospheric absorption on millimetre wave frequencies for 5G cellular networks |url=https://onlinelibrary.wiley.com/doi/10.1049/iet-com.2018.5044 |journal=IET Communications |language=en |volume=13 |issue=3 |pages=265–270 |doi=10.1049/iet-com.2018.5044 |issn=1751-8636|url-access=subscription }}</ref> |- | mm or G || 110 to 300 GHz{{refn|group=note|The designation mm is also used to refer to the range from 30 to 300 GHz.<ref name=ieee />}} || Millimeter<ref name=ieee /> |} {{reflist|group=note}}

===EU, NATO, US ECM frequency designations===

{| class=wikitable ! colspan="6" | NATO letter band designation<ref name="BelovSmolskiy2012">{{cite book|author1=Leonid A. Belov|author2=Sergey M. Smolskiy|author3=Victor N. Kochemasov|title=Handbook of RF, Microwave, and Millimeter-Wave Components|url=https://books.google.com/books?id=bHhYjINB6KMC&pg=PA28|year=2012|publisher=Artech House|isbn=978-1-60807-209-5|pages=27–28}}</ref><ref name="Friedman2006"/><ref>NATO Allied Radio Frequency Agency (ARFA) HANDBOOK – VOLUME I; PART IV – APPENDICES, ... G-2, ... NOMENCLATURE OF THE FREQUENCY AND WAVELENGTH BANDS USED IN RADIOCOMMUNCATION.</ref>

! colspan="2" rowspan="3" align="left"| Broadcasting band designation |- align="center" ! colspan="2"| 1978<ref>AFR 55-44/AR 105-86/OPNAVINST 3430.9A/MCO 3430.1, 27 October 1964 superseded by AFR 55-44/AR 105-86/OPNAVINST 3430.1A/MCO 3430.1A, 6 December 1978: Performing Electronic Countermeasures in the United States and Canada, Attachment 1, ECM Frequency Authorizations.

PDF [https://www.marines.mil/Portals/1/Publications/MCO%203430.1A%20W%20CH%201%20-%202.pdf]</ref>-Present nomenclature!! bgcolor="#CCCCCC" | ! colspan="2"| Pre-1978 nomenclature!! bgcolor="#CCCCCC" | |- align="center" ! Band !! Frequency (MHz) !!bgcolor="#CCCCCC"| ! Band !! Frequency (MHz) !!bgcolor="#CCCCCC"| |- bgcolor="#CCCCCC" align="center" | colspan="7"|

|- align="center" |rowspan="3"| '''A''' ||rowspan="3"| 0 – 250 ||bgcolor="#CCCCCC" rowspan="3"| ||rowspan="2"| '''I''' ||rowspan="2"| 100 – 150 ||bgcolor="#CCCCCC" rowspan="2"| || Band I 47 – 68 MHz (TV) |- align="center" | Band II 87.5 – 108 MHz (FM) |- align="center" |'''G''' || 150 – 225||bgcolor="#CCCCCC"| | Band III 174 – 230 MHz (TV)

|- align="center" | '''B''' || 250 – 500 ||rowspan="1" bgcolor="#CCCCCC"| || '''P''' || 225 – 390||bgcolor="#CCCCCC"| ||

|- align="center" |rowspan="2"| '''C''' || rowspan="2" | 500 – 1 000 ||rowspan="2" bgcolor="#CCCCCC"| |rowspan="2"| '''L''' ||rowspan="2"| 390 – 1 550 || rowspan="2" bgcolor="#CCCCCC"| | Band IV 470 – 582 MHz (TV) |- align="center" | Band V 582 – 862 MHz (TV)

|- align="center" | '''D''' || 1 000 – 2 000 ||bgcolor="#CCCCCC"| ||rowspan="3" |'''S''' || rowspan="3" |1 550 – 3 900 | rowspan="3" bgcolor="#CCCCCC"| || rowspan="3"| |- align="center" | '''E''' || 2 000 – 3 000 ||bgcolor="#CCCCCC"|

|- align="center" | '''F''' || 3 000 – 4 000 ||bgcolor="#CCCCCC"| |- align="center" | '''G''' || 4 000 – 6 000 ||bgcolor="#CCCCCC"| ||'''C''' || 3 900 – 6 200 || bgcolor="#CCCCCC"| ||

|- align="center" | '''H''' || 6 000 – 8 000||bgcolor="#CCCCCC"| ||rowspan="2" |'''X''' ||rowspan="2" |6 200 – 10 900 ||rowspan="2" bgcolor="#CCCCCC"| ||rowspan="2"| |- align="center" | '''I''' || 8 000 – 10 000 ||bgcolor="#CCCCCC"|

|- align="center" | '''J''' || 10 000 – 20 000 ||bgcolor="#CCCCCC"| || '''Ku''' || 10 900 – 20 000 ||rowspan="2" bgcolor="#CCCCCC"| ||rowspan="2"| |- align="center" | '''K''' || 20 000 – 40 000 ||bgcolor="#CCCCCC"| || '''Ka''' || 20 000 – 36 000

|- align="center" | rowspan="2" | '''L''' ||rowspan="2"| 40 000 – 60 000 ||rowspan="2" bgcolor="#CCCCCC"| ||'''Q''' || 36 000 – 46 000 ||rowspan="2" bgcolor="#CCCCCC"| ||rowspan="2"| |- align="center" |'''V''' || 46 000 – 56 000

|- align="center" | '''M''' || 60 000 – 100 000 ||bgcolor="#CCCCCC"| ||'''W''' || 56 000 – 100 000 ||bgcolor="#CCCCCC"| ||

|- bgcolor="#CCCCCC" align="center" | colspan="7"| |- align="center" |colspan="5"| US Military/SACLANT ||bgcolor="#CCCCCC"| |- align="center" | '''N''' ||colspan="4"| 100 000 – 200 000 ||bgcolor="#CCCCCC"| || |- align="center" | '''O''' ||colspan="4"| 100 000 – 200 000 ||bgcolor="#CCCCCC"| || |}

===Waveguide frequency bands=== {{see also|Waveguide (electromagnetism)#In practice}} {| class="wikitable" |- " ! Band !! Frequency range <ref>{{Cite web |url=http://www.microwaves101.com/encyclopedia/waveguidedimensions.cfm |title=www.microwaves101.com "Waveguide frequency bands and interior dimensions" |access-date=2009-11-16 |archive-date=2008-02-08 |archive-url=https://web.archive.org/web/20080208220945/http://www.microwaves101.com/encyclopedia/waveguidedimensions.cfm |url-status=dead }}</ref> |- | R band || 1.70 to 2.60 GHz |- | D band || 2.20 to 3.30 GHz |- | S band || 2.60 to 3.95 GHz |- | E band || 3.30 to 4.90 GHz |- | G band || 3.95 to 5.85 GHz |- | F band || 4.90 to 7.05 GHz |- | C band || 5.85 to 8.20 GHz |- | H band || 7.05 to 10.10 GHz |- | X band || 8.2 to 12.4 GHz |- | {{Ku band}} || 12.4 to 18.0 GHz |- | K band || 18.0 to 26.5 GHz |- | {{Ka band}} || 26.5 to 40.0 GHz |- | Q band || 33 to 50 GHz |- | U band || 40 to 60 GHz |- | V band || 50 to 75 GHz |- | E band || 60 to 90 GHz |- | W band || 75 to 110 GHz |- | F band || 90 to 140 GHz |- | D band || 110 to 170 GHz |- | Y band || 325 to 500 GHz |}

===Comparison of radio band designation standards=== none|thumb|611x611px|Comparison of frequency band designations The frequency of 1–3 Hz<ref name="Duncan 2021 235–247"/> has been called by the band name TLF but the term has not been defined by the ITU.<ref>{{cite web |title=Nomenclature of the frequency and wavelength bands used in telecommunications |url=https://www.itu.int/dms_pubrec/itu-r/rec/v/R-REC-V.431-8-201508-I!!PDF-E.pdf |website=International Telecommunications Union |access-date=7 April 2023 |location=Geneva, Switzerland | date=2015}}</ref>

{| class="wikitable" |- ! rowspan="2" colspan="2" | Frequency ! rowspan="2" | IEEE<ref name=ieee /> ! rowspan="2" | EU, NATO, US ECM ! colspan="2" | ITU |- ! no. ! abbr. |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | | style="border-left: none; width: 0.5em" | | | rowspan="9" | A | colspan="2" | |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 3 Hz | style="border-left: none" | | | align="right" | 1 | ELF |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 30 Hz | style="border-left: none" | | | align="right" | 2 | SLF |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 300 Hz | style="border-left: none" | | | align="right" | 3 | ULF |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 3 kHz | style="border-left: none" | | | align="right" | 4 | VLF |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 30 kHz | style="border-left: none" | | | align="right" | 5 | LF |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 300 kHz | style="border-left: none" | | | align="right" | 6 | MF |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 3 MHz | style="border-left: none" | | HF | align="right" | 7 | HF |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 30 MHz | style="border-left: none" | | rowspan="2" | VHF | rowspan="2" align="right" | 8 | rowspan="2" | VHF |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 250 MHz | style="border-left: none" | | rowspan="2" | B |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 300 MHz | style="border-left: none" | | rowspan="2" | UHF | rowspan="4" align="right" | 9 | rowspan="4" | UHF |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 500 MHz | style="border-left: none" | | C |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 1 GHz | style="border-left: none" | | L | D |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 2 GHz | style="border-left: none" | | rowspan="2" | S | E |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 3 GHz | style="border-left: none" | | F | rowspan="9" align="right" | 10 | rowspan="9" | SHF |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 4 GHz | style="border-left: none" | | rowspan="2" | C | G |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 6 GHz | style="border-left: none" | | H |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 8 GHz | style="border-left: none" | | rowspan="2" | X | I |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 10 GHz | style="border-left: none" | | rowspan="3" | J |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 12 GHz | style="border-left: none" | | Ku |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 18 GHz | style="border-left: none" | | rowspan="2" | K |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 20 GHz | style="border-left: none" | | rowspan="3" | K |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 27 GHz | style="border-left: none" | | rowspan="2" | Ka |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 30 GHz | style="border-left: none" | | rowspan="6" align="right" | 11 | rowspan="6" | EHF |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 40 GHz | style="border-left: none" | | rowspan="2" | V | L |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 60 GHz | style="border-left: none" | | rowspan="2" | M |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 75 GHz | style="border-left: none" | | rowspan="2" | W |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 100 GHz | style="border-left: none" | | rowspan="2" | |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 110 GHz | style="border-left: none" | | mm |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 300 GHz | style="border-left: none" | | | | align="right" | 12 | THF |- | style="border-top: none; border-bottom: none; border-right: none; text-align: right; vertical-align: top" | 3 THz | style="border-left: none" | | | | colspan="2" | |}

== Applications == {{see also|Applications of radio}}Radio has many practical applications, which include broadcasting, voice communication, data communication, radar, radiolocation, medical treatments, and remote control.

==Notes== {{Reflist}}

==References== *ITU-R Recommendation V.431: [http://www.itu.int/rec/R-REC-V.431/en Nomenclature of the frequency and wavelength bands used in telecommunications]. International Telecommunication Union, Geneva. *IEEE Standard 521-2002: Standard Letter Designations for Radar-Frequency Bands *AFR 55-44/AR 105-86/OPNAVINST 3430.9A/MCO 3430.1, 27 October 1964 superseded by AFR 55-44/AR 105-86/OPNAVINST 3430.1A/MCO 3430.1A, 6 December 1978: Performing Electronic Countermeasures in the United States and Canada, Attachment 1, ECM Frequency Authorizations.

==External links== *[http://www.unwantedemissions.com UnwantedEmissions.com] A reference to radio spectrum allocations. *[http://ec.europa.eu/information_society/policy/ecomm/radio_spectrum/index_en.htm "Radio spectrum: a vital resource in a wireless world"] European Commission policy.

Category:Radio spectrum