L band

The L band is the Institute of Electrical and Electronics Engineers (IEEE) designation for the range of frequencies in the radio spectrum from 1 to 2 gigahertz (GHz).

Applications

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 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.^[1]

Satellite navigation

The Global Positioning System carriers are in the L band, centered at 1176.45 MHz (L5), 1227.60 MHz (L2), 1381.05 MHz (L3), and 1575.42 MHz (L1) frequencies.

• The Galileo Navigation System uses the L-band similarly to GPS.
• The GLONASS System uses the L-band similarly to GPS.

Telecommunications use

Mobile phones operate at 800–900 and 1700–2100 MHz. Iridium Satellite LLC phones use frequencies between 1616 and 1626.5 MHz^[2] to communicate with the satellites. Inmarsat and LightSquared terminals use frequencies between 1525 and 1646.5 MHz. Thuraya satellite phones use frequencies between 1525 and 1661 MHz.

Aircraft surveillance

The aircraft L-band ranges from 962–1213 MHz. Aircraft can use Automatic dependent surveillance-broadcast (ADS-B) equipment at 1090 MHz to communicate position information to the ground as well as between them for traffic information and avoidance. The 1090 MHz frequency (paired with 1030 MHz) is also used by Mode S transponders, which ADS-B augments when operated at this frequency. The TCAS system also utilizes the 1030/1090 MHz paired frequencies. ADS-B information can also be broadcast on the L band frequency of 978 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 MHz, and amateur satellite up-links are allowed in the range 1,260–1,270 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 overseas territories, the L band is held by the military for telemetry, thereby forcing digital radio to in-band on-channel (IBOC) solutions. Digital Audio Broadcasting (DAB) is typically done in the 1452–1492 MHz range in most of the world, but some countries also use VHF and UHF bands.

WorldSpace satellite radio broadcasts in the 1467–1492 MHz L sub-band.

Astronomy

The band also contains the hyperfine transition of neutral hydrogen (the hydrogen line, 1420 MHz), which is of great astronomical interest as a means of imaging the normally invisible neutral atomic hydrogen in interstellar space. Consequently, parts of the L-band are protected radio astronomy allocations worldwide.

References