måndag 1 juli 2013

L-Band (LEO)


L band
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L band
Frequency rangeIEEE: ~1–2 GHz
NATO: 40–60 GHz
ITU Radio Band Numbers
1 2 3 4 5 6 7 8 9 10 11 12
ITU Radio Band Symbols
NATO Radio bands
IEEE Radar bands
L band refers to four long different bands of the electromagnetic spectrum: 40 to 60 GHz (NATO), 1 to 2 GHz (IEEE), 1565 nm to 1625 nm (optical), and around 3.5micrometres (infrared astronomy).



NATO L band[edit]

The NATO L band is defined as the frequency band between 40 and 60 GHz (5–7.5 mm).

IEEE L band[edit]

Military use[edit]

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 as in most of the world, but other countries also use VHF and UHF bands.


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.

Telecommunications use[edit]

GSM mobile phones operate at 800–900 and 1800–1900 MHz. Iridium Satellite LLC phones use frequencies between 1616 and 1626.5 MHz[1] to communicate with the satellites. Inmarsat and LightSquared terminals use frequencies between 1525 and 1646.5 MHz to communicate with the satellites. Thuraya satellite phones use frequencies between 1525 and 1661 MHz to communicate with the satellites.

Amateur radio[edit]

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

Digital Audio Broadcasting (Earth Orbital)[edit]

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

DAB L band usage[edit]

The following blocks are used for T-DAB (terrestrial) broadcasts:
BlockCenter Frequency
LA1452.960 MHz
LB1454.672 MHz
LC1456.384 MHz
LD1458.096 MHz
LE1459.808 MHz
LF1461.520 MHz
LG1463.232 MHz
LH1464.944 MHz
LI1466.656 MHz
LJ1468.368 MHz
LK1470.080 MHz
LL1471.792 MHz
LM1473.504 MHz
LN1475.216 MHz
LO1476.928 MHz
LP1478.640 MHz
The following blocks are used for S-DAB (satellite) broadcasts:
BlockCenter Frequency
LQ1480.352 MHz
LR1482.064 MHz
LS1483.776 MHz
LT1485.488 MHz
LU1487.200 MHz
LV1488.912 MHz
LW1490.624 MHz
Note: Canada uses slightly different central frequencies for L-band DAB while in many European countries DAB is limited part of Band III due to television and mobile two way radio using the rest.

Physics issues relating to band use[edit]

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.

Optical communications L band[edit]

L band is also used in optical communications to refer to the wavelength range 1565 nm to 1625 nm.

Infrared astronomy[edit]

Atmospheric windows in the infrared. The L band is the transmission window centred on 3.5 micrometres
In infrared astronomy, the L band refers to an atmospheric transmission window centred on 3.5 micrometres (in the mid-infrared).

Other microwave bands[edit]

The microwave spectrum is usually defined as electromagnetic energy ranging from approximately 1 GHz to 100 GHz in frequency, but older usage includes lower frequencies. Most common applications are within the 1 to 40 GHz range. Microwave frequency bands, as defined by the Radio Society of Great Britain (RSGB), are shown in the table below:
L band1 to 2 GHz
S band2 to 4 GHz
C band4 to 8 GHz
X band8 to 12 GHz
Ku band12 to 18 GHz
K band18 to 26.5 GHz
Ka band26.5 to 40 GHz
Q band30 to 50 GHz
U band40 to 60 GHz
V band50 to 75 GHz
E band60 to 90 GHz
W band75 to 110 GHz
F band90 to 140 GHz
D band110 to 170 GHz
Footnote: P band is sometimes incorrectly used for Ku Band. "P" for "previous" was a radar band used in the UK ranging from 250 to 500 MHz and now obsolete per IEEE Std 521, see [1] and [2]. For other definitions see Letter Designations of Microwave Bands

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