Low Noise Block-downconverter (so called because it converts a whole band or "block" of frequencies to a lower band).
Types of LNBs
1) Standard LNB 10.0 GHz L.O. Often called a "Marconi switching LNB". Works in one band. Noise Figure usually 1.0 dB or better but older "Blue cap" types can be much worse. Integral feed horn, usually with 40mm neck but flange type available to special order and other neck sizes have been made (especially 22.5mm). Marconi also made a "Bullet" shape LNB of this type that used a PTFE insert instead of a horn. Polarisation switching is controlled by dc voltage supplied by the receiver. 12.5v to 14.5v gives vertical and 15.5 to 18v gives horizontal polarisation. A higher voltage than that can damage the LNB. A voltage that is too low will prevent the LNB from working correctly.
2) "Enhanced" LNB 9.75 GHz L.O. Works 10.7-11.7 GHz. Noise Figure usually 1.0 dB or better. Integral feed horn with 40mm neck. Normally used with later type receivers that have a 2GHz tuner but no 22kHz tone generator. Designed specifically for Astra satellite reception from satellites 1A, 1B, 1C and 1D. Polarisation switching is controlled by dc voltage supplied by the receiver. 12.5v to 14.5v gives vertical and 15.5 to 18v gives horizontal polarisation. A higher voltage than that can damage the LNB. A voltage that is too low will prevent the LNB from working correctly.
3) "Universal" LNB 9.75 and 10.60 GHz L.O. Works in 2 bands* 10.7-11.8 and 11.6 - 12.7 GHz. (22 kHz tone switched). Noise Figure usually 1.0 dB or better. Integral feed horn with 40mm neck but flange type available to special order. *If your receiver tuning range is less than 2.15GHz you will have a gap between high and low bands. Refer to calculations, below. In effect, this is a "Quad Band" LNB. A Universal LNB requires a 22kHz tone at 0.5v p-p to switch its Local Oscillator to 10.6GHz ("high band"). Otherwise it uses its 9.75GHz oscillator. Polarisation switching is controlled by dc voltage supplied by the receiver. 12.5v to 14.5v gives vertical and 15.5 to 18v gives horizontal polarisation. A higher voltage than that can damage the LNB. A voltage that is too low will prevent the LNB from working correctly.
4) "FSS" LNB 10.0 GHz L.O. Normally bolted to separate polariser and feed horn. Works in one band: 10.9 - 11.7 GHz. Receiver with standard 0.95 - 1.75GHz tuner may be used. Noise figures vary. Very old ones can be 3.0 dB!
5) "DBS" LNB 10.75 GHz L.O. Normally bolted to separate polariser and feed horn. Works in one band: 11.7 - 12.5 GHz. Receiver with standard 0.95 - 1.75GHz tuner may be used. Noise figures vary. Normally bolted to separate polariser and feed horn. However, Marconi made a voltage-switching version with integral feed horn*. Works in one band: 11.95 - 12.75 GHz. Receiver with standard 0.95 - 1.75GHz tuner may be used. (* identified by a serial number label with a red corner, although some were incorrectly marked). Noise figures vary.
7) "Dual band" LNB Normally bolted to separate polariser and feed horn. Works in 2 bands 10.9 - 11.7 and 11.7 - 12.5 GHz. Receiver with standard 0.95 - 1.75GHz tuner may be used. Band switching achieved by supply voltage of either 14 volts or 18 volts. Noise figures vary.
8) "Tripleband" LNB Normally bolted to separate polariser and feed horn. Works in 2 bands 10.9-11.8 and 11.8-12.75 GHz. Receiver with 0.95 - 2.0 GHz tuner should be used. Noise figures vary.
9) "Quadband" LNB Normally bolted to separate polariser and feed horn. Works in 2 bands 10.7-11.8 and 11.7-12.8 GHz. Receiver with 0.95 - 2.05 GHz tuner should be used. Noise figures vary.
10) "Twin output" LNB Currently available in Standard, Enhanced and Universal form, the twin output LNB provides two outputs to feed two separate receivers. Each output can be switched by 13/17 volt input by the individual receiver to change polarisation.
11) "Dual output" LNB Currently available in Standard, Enhanced and Universal form, the dual output LNB provides two outputs to feed two separate receivers. Each output has a fixed polarisation; one horizontal and one vertical. This type of LNB should be used with switching boxes such as the "Mini Magic" which will feed four separate receivers.
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