An LNB - Low Noise Block (also called an LNC- Low Noise Converter), is used for communications (broadcast) satellite reception. The LNB is usually affixed either in or on the satellite dish.
The purpose of the LNB is to utilize the super heterodyne effect; and amplify and convert a wide block (band) of frequencies. This helps compensate the signal loss associated with typical coaxial cable at relatively high frequencies.
The term 'low noise' relates to the quality of the...
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The Ku band (Kurtz-under band) is primarily used for satellite communications, particularly for editing and broadcasting satellite television. This band is split into multiple segments broken down into geographical regions, as determined by the ITU (International Telecommunication Union).
The Ku band is a portion of the electromagnetic spectrum in the microwave range of frequencies ranging from 11.7 to 12.7GHz. (downlink frequencies) and 14 to 14.5GHz (uplink frequencies).
The most common...
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Satellite images were initially the exclusive realm of military and government agencies.
Soon, satellite images became commercially available, at very steep prices.
Now, technology has improved to the point where satellite images are available so inexpensively that they are now provided to end users for free.Free Satellite Images on the Web
The best and by far the most popular source of web-based free satellite images is Google Maps. This product can be directly used from the web...
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Geostationary satellites are located exactly above the earth’s equator and revolve around the earth in a circular orbit. Its revolving speed and direction (west to east) is exactly same as that of the earth, which makes it look stationary from the earth’s surface. The exact altitude of these satellites above the equator is approximately 36,000 Kilometers (22369 Miles). The phrase geostationary evolves from the fact that this kind of a satellite looks practically stationary in the sky as...
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QPSK (Quadrature Phase Shift Keying) is a phase modulation algorithm.
Phase modulation is a version of frequency modulation where the phase of the carrier wave is modulated to encode bits of digital information in each phase change.
The "PSK" in QPSK refers to the use of Phased Shift Keying. Phased Shift Keying is a form of phase modulation which is accomplished by the use of a discrete number of states. QPSK refers to PSK with 4 states. With half that number of states, you will have BPSK...
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VSAT is an abbreviation for a Very Small Aperture Terminal. It is basically a two-way satellite ground station with a less than 3 meters tall (most of them are about 0.75 m to 1.2 m tall) dish antenna stationed. The transmission rates of VSATs are usually from very low and up to 4 Mbit/s. These VSATs' primary job is accessing the satellites in the geosynchronous orbit and relaying data from terminals in earth to other terminals and hubs. They will often transmit narrowband data, such as the...
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C Band is the original frequency allocation for communications satellites.
C-Band uses 3.7-4.2GHz for downlink and 5.925-6.425Ghz for uplink.
The lower frequencies used by C Band perform better under adverse weather conditions than the Ku band or Ka band frequencies.C Band Variants
Slight variations of C Band frequencies are approved for use in various parts of the world.BandTX FrequencyRX FrequencyExtended C Band5.850 - 6.425 GHz3.625 - 4.200 GHzSuper Extended C-Band5.850 - 6.725 GHz3.400...
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FSK (Frequency Shift Keying) is also known as frequency shift modulation and frequency shift signaling. Frequency Shift Keying is a data signal converted into a specific frequency or tone in order to transmit it over wire, cable, optical fiber or wireless media to a destination point. The history of FSK dates back to the early 1900s, when this technique was discovered and then used to work alongside teleprinters to transmit messages by radio (RTTY). But FSK, with some modifications, is still...
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GPS stands for Global Positioning System. GPS uses satellite technology to enable a terrestrial terminal to determine its position on the Earth in latitude and longitude.Navigation Using GPS
GPS receivers ascertain their position and height by measuring the signals from three or more satellites simultaneously and determining their position using the timing of these signals.
GPS operates using trilateration. Trilateration is the process of determining the position of an unknown point...
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A transponder is an automatic electronic monitoring or control device that receives, cross-examines, amplifies and retransmits the arriving signal. It is primarily implemented in wireless communication. The word ‘Transponder’ itself is a combination of two words; transmitter and responder (occasionally abbreviated to TPDR, TR, XPNDR, and XPDR).
A transponder works by receiving a signal on a component called "interrogator" since it effectively inquires for information, then automatically...
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