What's behind a SKY Q Hybrid LNB or FreeSat LNB

What's behind a SKY Q Hybrid LNB or FreeSat LNB

LNB – namely a Low-Noise Block is a receiving device mounted on satellite dishes used for satellite TV reception, which collects the radio waves from the dish and converts them to a signal which is sent through a cable to the receiver inside the building.

The LNB utilises a combination of low-noise amplifier, local oscillator, frequency mixer, and intermediate frequency amplifier. It serves as the Radio Frequency front end of the satellite receiver, managing and amplifying the microwave signal from the satellite collected by the dish and down converting the block of frequencies to a lower block of intermediate frequencies.

This conversion process allows the signal to be transported to the indoor satellite TV receiver using coaxial cable.

The LNB is usually a small box suspended on one or more short arms, in front of the dish reflector. The microwave signal from the dish is collected by a feedhorn on the LNB and is passed to a section of waveguide. Internal antennas feed the signal to a motherboard for processing. The output signal emerges from an output socket on the box to which the coaxial cable is connected.

A component called a block upconverter (BUC), is used at the satellite earth station (uplink) dish to convert the band of television channels to the microwave uplink frequency.

Multi-output LNBs

An eight-output or octo, hybrid quad or 6 port, standard dual or twin and quad LNBs are some of the current market offerings.

Sporting a single LNB with a single feedhorn but multiple coax outputs for enabling connection to multiple satellite boxes.

Typically, two, four, six or eight outputs are provided. Each output responds to the tuner's band and polarization selection signals independently of the other outputs and mimics to the tuner to be a separate LNB.

The LNB will usually derive its power from a receiver connected to any of the outputs. Unused outputs may be left unconnected (these are best kept covered to keep the LNB waterproof).

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 an upgrade is typically required.

There are hybrid models of the LNB with multiple connections, such as the SKY Q Hybrid LNB EL027 Quad and EL028 6 Way Hybrid for running Sky Q and legacy systems such as FreeSat LNB and SKY HD LNB.

In cases where only a single cable is present, such as blocks of flats, Sky Q compatible multiswitches can be used, which instead use an dSCR namely a Digital Satellite Cable Router.