View source for L band

{{Short description|Range of radio frequencies from 1-2 GHz}}
{{About|the IEEE-defined range of the radio spectrum}}
{{MWband
| name = IEEE L band
| freq = 1 – 2 GHz
| bands = {{hlist|item_style=white-space:nowrap; |[[D band (NATO)|D]] (NATO) |[[Ultra high frequency|UHF]] (ITU)}}
| wave = 30 – 15 [[Meter|cm]]
}}

The '''L band''' is the [[Institute of Electrical and Electronics Engineers]] (IEEE) designation for the range of [[Frequency|frequencies]] in the '''[[radio spectrum]]''' from 1 to 2 [[gigahertz]] (GHz). This is at the top end of the [[ultra high frequency]] (UHF) band, at the lower end of the [[microwave]] range.

== Applications ==

=== Mobile service ===
{{See also|Mobile service}}
In Europe, the Electronic Communications Committee (ECC) of the [[European Conference of Postal and Telecommunications Administrations]] (CEPT) has harmonized part of the L band (1452–1492&nbsp;MHz), allowing individual countries to adopt this spectrum for terrestrial mobile/fixed communications networks supplemental downlink (MFCN SDL). By means of carrier aggregation, an [[LTE-Advanced]] or UMTS/[[HSDPA]] base station could use this spectrum to provide additional bandwidth for communications from the base station to the mobile device; i.e., in the downlink direction.<ref>{{cite web |title=Harmonised use of the band 1452–1492{{nbsp}}MHz for MFCN SDL |url=http://www.erodocdb.dk/Docs/doc98/official/pdf/ECCDEC1303.PDF |publisher=[[European Conference of Postal and Telecommunications Administrations|CEPT]] ECC |date=2015-07-03 |access-date=2015-07-17 |archive-date=2015-07-21 |archive-url=https://web.archive.org/web/20150721005040/http://www.erodocdb.dk/Docs/doc98/official/pdf/ECCDEC1303.PDF |url-status=dead }}</ref>

In the Americas, mobile services are operated between the 1.7&nbsp;GHz to 2.1&nbsp;GHz range in the [[Personal Communication Service|PCS]] and [[Advanced Wireless Services|AWS]] bands.

=== Satellite navigation ===
{{Main|Satellite navigation}}

The [[Global Positioning System]] carriers are in the L band, centered at 1176.45&nbsp;MHz (L5), 1227.60&nbsp;MHz (L2), 1381.05&nbsp;MHz (L3), and 1575.42&nbsp;MHz (L1) frequencies. L band waves are used for GPS units because they are able to penetrate clouds, fog, rain, storms, and vegetation. Only dense environments such as heavy forest canopies or concrete buildings can cause GPS units to receive data inaccurately.<ref>{{cite book
|last = Ogaja
|first = Clement A.
|author-link=Clement Ogaja 
|title = Applied GPS for Engineers and Project Managers
|publisher = ASCE Press
|year = 2011
|doi = 10.1061/9780784411506.ap02
|isbn = 978-0-7844-1150-6
}}</ref>

The [[Galileo Navigation System]], the [[GLONASS]] System, and the [[BeiDou]] systems use the L band similar to GPS, although the frequency ranges are named differently. Modern receivers, such as those found in [[smartphone]]s, are able to take advantage of multiple systems (usually only around the oldest L1 band) at the same time.<ref>{{cite journal |last1=Nicolini |first1=Luca |last2=Caporali |first2=Alessandro |title=Investigation on Reference Frames and Time Systems in Multi-GNSS |journal=Remote Sensing |date=9 January 2018 |volume=10 |issue=2 |pages=80 |doi=10.3390/rs10010080 |bibcode=2018RemS...10...80N |doi-access=free|hdl=11577/3269537 |hdl-access=free }}</ref>

=== Telecommunications use ===
Mobile phones operate at 600–900 and 1700–2100&nbsp;MHz. [[Iridium Communications]] satellite phones use frequencies between 1616 and 1626.5&nbsp;MHz<ref>{{Cite web| title=In re Application of Motorola Satellite Communications, Inc. for Authority to Construct, Launch, and Operate a Low Earth Orbit Satellite System in the 1616-1626.5 MHz Band | url=http://www.fcc.gov/Bureaus/International/Orders/1995/da950131.txt | archive-url=https://web.archive.org/web/19970731151801/http://www.fcc.gov:80/Bureaus/International/Orders/1995/da950131.txt | archive-date=1997-07-31}}</ref> to communicate with the satellites. Iridium Communications 2-way messaging service [[Snapdragon Satellite]] would have utilized frequencies in the L Band as well. [[Inmarsat]] and [[Ligado Networks]] (formerly [[LightSquared]]) terminals use frequencies between 1525 and 1646.5&nbsp;MHz. [[Thuraya]] satellite phones use frequencies between 1525 and 1661&nbsp;MHz.

In January 2025 [[China Telecom]] Satellite Application Technology Research Institute, in association with Huawei, and others industry announced the [[Tiantong (Satellite)|Tiantong]]  was capable of providing regular [[smartphone]]s bidirectional access to satellite communications within their allocated [[L-band]] frequency (as opposed to  specific [[satellite phones]]).<ref>[https://newatlas.com/technology/tiantong-satellite-direct-to-cell/ Move over, Starlink, there's a new satellite-to-cell service in town ]</ref> Starlink has beta-tested a similar direct-to-cell service with T-Mobile since December 2024, operating in the upper L-Band (1900 MHz).<ref>[https://www.cnet.com/tech/mobile/t-mobiles-starlink-phone-service-is-launching-july-23-but-everyone-can-sign-up-for-the-free-beta-right-now/ T-Mobile's Starlink Phone Service Is Launching July 23, but Everyone Can Sign Up for the Free Beta Right Now ] </ref>

=== NOAA ===
[[NOAA]] cyclically broadcasts weather data from its two geosynchronous satellites on 1694.1 MHz.

=== Aircraft surveillance ===
The aircraft L-band ranges from 960–1215{{nbsp}}MHz. Aircraft can use [[Automatic dependent surveillance-broadcast]] (ADS-B) equipment at 1090&nbsp;MHz to communicate position information to the ground as well as between them for traffic information and avoidance. The 1090&nbsp;MHz frequency (paired with 1030&nbsp;MHz) is also used by [[Secondary surveillance radar|Mode S]] transponders, which ADS-B augments when operated at this frequency. The TCAS system also utilizes the 1030/1090{{nbsp}}MHz paired frequencies. ADS-B information can also be broadcast on the L band frequency of 978&nbsp;MHz.  DME and TACAN systems are also in this frequency band.

=== Amateur radio ===
The Radio Regulations of the [[International Telecommunication Union]] allow [[amateur radio]] operations in the frequency range 1,240–1,300&nbsp;MHz, and [[amateur satellite]] up-links are allowed in the range 1,260–1,270&nbsp;MHz.  This is known as the [[23-centimeter band]] by radio amateurs and as the L-band by [[AMSAT]].

=== Digital audio broadcasting ===
In the [[United States]] and [[Territories of the United States|overseas territories]], the L band is held by the [[United States Armed Forces|military]] for [[telemetry]], thereby forcing [[digital radio]] to [[in-band on-channel]] (IBOC) solutions. The standard [[Digital Audio Broadcasting]] (DAB) allowed many broadcasting bands including 1452–1492{{nbsp}}MHz, but now only uses [[Band III]].

[[WorldSpace]] [[satellite radio]] used to broadcast in the 1467–1492&nbsp;MHz L sub-band.

=== Digital video broadcasting ===
[[DVB-H]], [[DVB-SH]], and [[DVB-T2]] can operate in the L band.

=== Digital multimedia broadcasting ===

[[T-DMB]] can operate in the L band.

=== Astronomy ===
The band contains the hyperfine transition of neutral hydrogen (the [[hydrogen line]], 1420&nbsp;MHz), which is of great astronomical interest as a means of imaging the normally invisible neutral atomic hydrogen in interstellar space. The band also contains [[hydroxyl radical]] transition lines at 1665 and 1667 MHz.  Consequently, parts of the L band are protected [[radio astronomy]] allocations worldwide.<ref>{{Cite web |date=2011-03-02 |title=Radio Spectrum Allocation |url=https://www.fcc.gov/engineering-technology/policy-and-rules-division/general/radio-spectrum-allocation |access-date=2023-02-09 |website=Federal Communications Commission |language=en}}</ref> Specifically, the 1400–1427 MHz and 1660.6–1670.0 MHz regions are protected.<ref>{{cite web |title=RA.314:Preferred frequency bands for radio astronomical measurements |url=https://www.itu.int/rec/R-REC-RA.314/en |website=www.itu.int}}</ref>

== References ==
{{Reflist}}

{{Radio spectrum}}
{{EMSpectrum}}
{{Audio broadcasting}}

[[Category:Microwave bands]]
[[Category:Satellite broadcasting]]