Low Noise Block downconverter – or more commonly known as LNBs, are the “eyes” of the satellite dish.
These LNBs are the box of tricks that site at the end of the support arms facing the dish.

Basically they collect the signals and send them to the satellite receivers via the satellite coax cable.

More complex, they actually convert the relatively high frequencies received by the satellite dish into similar signals carried at a much lower frequency, with less attenuation, so that there is more signal available for use by satellite receivers.

There are various types of LNB, which are determined by the satellite dish you have and the type of signals that you want to receive.

A single output LNB has one cable feed, for use with one satellite tuner.
A twin output LNB has two cable feeds, for use with two satellite tuners.
A quad output LNB has four cable feeds, for use with four satellite tuner.
An octo output LNB has eight cable feeds, for use with eight satellite tuner.

However, do not confuse a QUAD LNB with a QUATRO LNB.

A QUATRO LNB is a special type of LNB, with four individual outputs for the four “groups” of signals used in satellite TV. These signal groups are the four types of signal polarisations used – vertical high, vertical low, horizontal high, horizontal low.

The main use of QUATRO LNBs is to feed a multiswitching unit. These are generally used where more than 4 or 8 feeds are required, such as in community systems. The QUATRO LNB feeds the four polarisations groups to the multiswitching unit.

The multiswitching unit can have a large number of outputs and can be “daisy chained” together allowing more satellite tuners / receivers can be fed from a single dish with a normal single, twin, quad, or octo LNB.

3 Responses to “LNBs. Low Noise Block downconverter”

  1. Alan Bird says:

    Hi there,
    THere appears to be another variety of LNB: my minidish (supplied by Sky for connection to a sky+ box) has 2 coax leads going to the box. At the box end the 2 skts are labelled input 1 and input 2. One or both appears to be powered, as the label (“13/18v 350mA max combined”) is squarely between them.
    Can you help me with a problem: can I use a single in-line meter (eg Philex 28202HS) with this rig? Does it matter which lead I use? Do I leave the other lead connected or not?
    Alan B.

  2. satandpcguy says:

    Alan Bird: Sky will have set you up with a minimum of a twin output LNB, that has two outputs, one for each input on the Sky+ box.

    Both sockets on the Sky+ box are powered.

    The meter needs to be connected to the line that is being used..normally input 1 is the cable being used for the channel on the TV.
    Yes you can leave the other cable alone.

  3. Alan Bird says:

    Many thanks for your help.