Editing Low-noise block downconverter (section)

==Multi-output LNBs==

[[Image:octo lnb.jpg|thumb|right|120px|An eight-output, or octo, LNBF]]

=== Dual, twin, quad, and octo LNBs ===
[[Image:twin universal flange lnb.jpg|thumb|120px|A twin-output universal LNB with a C120 flange fitting for a separate feedhorn]]
An LNB with a single feedhorn but multiple outputs for connection to multiple tuners (in separate receivers or within the same receiver in the case of a twin-tuner PVR receiver). Typically, two, four or eight outputs are provided. Each output responds to the tuner's band and polarization selection signals independently of the other outputs and appears to the tuner to be a separate LNB. Such an LNB usually may derive its power from a receiver connected to any of the outputs. Unused outputs may be left unconnected (but waterproofed for the protection of the whole LNB).

Note: In the US an LNB with two outputs is termed a ''dual LNB'', but in the UK the term ''dual LNB'' historically described an LNB with two outputs, each producing only one polarisation, for connection to a multiswitch (the term and the LNBs fell out of use with the introduction of the universal LNB and the multiswitch equivalent, the quattro LNB – see below). Today ''dual LNB'' (and ''dual feed'') describes antennas for reception from two satellite positions, using either two separate LNBs or a single monoblock LNB with two feedhorns. In the UK, the term ''twin-output LNB'', or simply ''twin LNB'', is usually used for an LNB with a single feedhorn but two independent outputs.<ref name="WS article"/>

=== Quattro LNBs ===
A special type of LNB (not to be confused with Quad LNB) intended for use in a shared dish installation to deliver signals to any number of tuners. A quattro LNB has a single feedhorn and four outputs, which each supply just one of the K<sub>u</sub> sub-bands (low band/horizontal polarization, high band/vertical polarization, low/vertical and high/horizontal) to a [[multiswitch]] or an array of multiswitches, which then delivers to each connected tuner whichever sub-band is required by that tuner.<ref>{{cite web|url=http://www.onastra.com/288905/glossary?category=q|title=Astra Glossary - Quattro LNB|publisher=SES ASTRA|access-date=December 30, 2010|archive-date=July 15, 2011|archive-url=https://web.archive.org/web/20110715002315/http://www.onastra.com/288905/glossary?category=q|url-status=live}}</ref>

Although a quattro LNB typically looks similar to a quad LNB, it cannot (sensibly) be connected to receivers directly. Note again the difference between a quad and a quattro LNB: A quad LNB can drive four tuners directly, with each output providing signals from the entire K<sub>u</sub> band. A quattro LNB is for connection to a multiswitch in a shared dish distribution system and each output provides only a quarter of the K<sub>u</sub> band signals.

[[Image:Unicable.jpg|120px|thumb|SCR LNB with three SCR taps for daisy-chaining multiple tuners]]

===Satellite channel router (SCR), or unicable LNBs===
Multiple tuners may also be fed from a [[satellite channel router]] (SCR) or [[unicable (technology)|unicable]] LNB in a [[single cable distribution]] system. A Unicable LNB has one output connector but operates in a different way to standard LNBs so it can feed multiple tuners daisy-chained along a single coax cable.

Instead of block-downconverting the whole received spectrum, an SCR LNB downconverts a small section of the received signal (equivalent to the bandwidth of a single transponder on the satellite) selected according to a [[DiSEqC]]-compliant command from the receiver, to output at a fixed frequency in the IF. Up to 32 tuners can be allocated a different frequency in the IF range and for each, the SCR LNB downconverts the corresponding individually requested transponder.<ref>Bains, Geoff. "Inverto Unicable LNB" ''What Satellite & Digital TV'' (February, 2006) pp60-62"</ref>

Most SCR LNBs also include either a legacy mode of operation or a separate legacy output which provides the received spectrum block-downconverted to the whole IF range in the conventional way.

[[Image:FibreLNB.jpg|thumb|right|120px|An optical fibre LNB (with fibre connection and conventional F-connector for power input)]]

===Wideband LNB===
ASTRA Universal Wideband LNBs with an oscillator frequency of 10.40 or 10.41&nbsp;GHz are entering the market. The intermediate frequency band is much wider than in a conventional LNB, as the high and low band are not split up.

Wideband LNB signals can be accepted by new wideband tuners, and by new SCR systems (e.g., Inverto/Fuba,<ref>{{Cite web
 | url=http://www.inverto.tv/products/product.php?section=49&id=328&cat=124
 | title=Inverto - IDLU-UWT110-CUO1O-32P -
 | website=www.inverto.tv
 | access-date=2016-07-01
 | archive-date=2016-08-20
 | archive-url=https://web.archive.org/web/20160820180050/http://www.inverto.tv/products/product.php?section=49&id=328&cat=124
 | url-status=dead
 }}</ref> Unitron,<ref>{{Cite web
 | url=http://www.unitrongroup.com/upl/document/Catalogue%202016-2017-ENG.pdf
 | title=Unitron catalog
 | access-date=2016-07-01
 | archive-date=2016-09-19
 | archive-url=https://web.archive.org/web/20160919040740/http://www.unitrongroup.com/upl/document/Catalogue%202016-2017-ENG.pdf
 | url-status=live
 }}</ref> Optel,<ref>{{Cite web
 | url=http://www.optelit.com/satellite&terrestrial.asp
 | title=Optel
 | website=www.optelit.com
 | access-date=2016-07-01
 | archive-date=2016-08-06
 | archive-url=https://web.archive.org/web/20160806000529/http://www.optelit.com/satellite%26terrestrial.asp
 | url-status=live
 }}</ref> GT-Sat/Astro), with or without optical transmission. Wideband signals can be converted to conventional quattro signals<ref>{{Cite web
 | url=http://www.unitrongroup.com/en/products/CAT/WSD/WQC/9646.html
 | title=Wideband to Quattro {{sic|Convertor|nolink=y}} - Unitron Group
 | last=popcom.be
 | website=Unitron Group
 | language=en
 | access-date=2016-07-01
 | archive-date=2016-06-23
 | archive-url=https://web.archive.org/web/20160623045542/http://www.unitrongroup.com/en/products/CAT/WSD/WQC/9646.html
 | url-status=live
 }}</ref> and vice versa.<ref>
{{Cite web
 |url   = http://www.solutionsgroup-plc.com/app/uploads/page_files/Sky_SG_pdf_package.pdf
 |archive-url = https://web.archive.org/web/20160705104030/http://www.solutionsgroup-plc.com/app/uploads/page_files/Sky_SG_pdf_package.pdf
 |url-status = dead
 |archive-date = 2016-07-05
 |title = Sky Q Installation
}}</ref>

In February 2016, Sky (UK) launched a new LNB only compatible with their new wideband tuner.<ref>{{Cite web |url=https://corporate.sky.com/documents/sky-q-2015/fact-sheet-sky-q.pdf |title=Archived copy |access-date=2016-05-14 |archive-date=2015-12-23 |archive-url=https://web.archive.org/web/20151223013545/https://corporate.sky.com/documents/sky-q-2015/fact-sheet-sky-q.pdf |url-status=live }}</ref> This LNB has one port for all vertical polarised channels both low and high band, and another port for all low and high band horizontal channels. The basic model has only 2 connections and presumably has a local oscillator of 10.41&nbsp;GHz with an intermediate frequency of 290–2340&nbsp;MHz from an input of 10.7–12.75&nbsp;GHz. This LNB seems to be the same as Unitron's ASTRA Universal Wideband LNB.<ref>LNB http://www.unitrongroup.com/en/news-events/unitrongroup-introduces-wideband-satellite-product-family.html {{Webarchive|url=https://web.archive.org/web/20200806215452/https://unitrongroup.com/en/news-events/unitrongroup-introduces-wideband-satellite-product-family.html |date=2020-08-06 }}</ref> Two cables minimum are needed to access all channels. In the Sky Q box, multiple tuners can select multiple channels, more than the usual two for dual coax systems. This type of LNB is incompatible with the more common Astra Universal LNB used in the UK meaning the LNB is changed during upgrade. There is a model of the LNB with 6 connections, 2 for Sky Q and 4 Astra Universal LNB for users with multiple legacy systems such as Freesat in addition to Sky Q. In cases where only a single cable is possible, such as apartment blocks, Sky Q compatible multiswitches can be used, which instead use BSkyB SCR.<ref>{{Cite web |url=http://www.unitrongroup.com/download.php?lang=en&id=657 |title=Unitron Group • Your dedicated partner for customize IP and RF solutions |access-date=2016-05-14 |archive-date=2016-08-10 |archive-url=https://web.archive.org/web/20160810170148/http://www.unitrongroup.com/download.php?lang=en&id=657 |url-status=live }}</ref>