LNB or Low Noise Block simply refers to the feature present at the end of a satellite dish which is attached to the coaxial cables feeding the satellite receiver. There are varying types of LNB which all works in their own special way, however a general function they all provide is to serve as the satellite broadcast signal amplifier and oscillate the signal to a lower frequency band which can be contained by the coaxial cable without too much loss of the cable and the greater the frequency the better the cable resistance and the quicker you’ll lose signal as a result of the cable strength. It should, however, be noted that most LNBs (and not all), oscillate the signal down to the satellite intermediate frequency band ranging from 950Mhz to 2150Mhz.
With the availability of a wide range of LNB types, makes and models, picking the right one for your satellite is crucial as the wrong one may imply your satellite will not work. The most common LNB types are single LNBs and Quad LNBs. The major difference between all types is the amount of output possessed by each LNB. This is what allows extra satellite receivers to be added for additional TV points as well as the inclusion of satellite PVRs which features recordable, play, pause and rewind TV services. For example, a single LNB possesses just one LNB connection for a coaxial cable to be attached. This allows you to connect a standard satellite receiver such as Freesat box or Sky. There are also dual or twin LNB, quad LNB and octo LNB which allows for two (or one satellite PVR), four (two PVRs or one PVR and two standard satellite receivers) and eight separate satellite receivers (four PVRs or combination of both) respectively. There are many other LNB types you can choose from with varying features, so it all depends on your requirements.