LNB 101: What It Is and How to Choose The Right One | Aerialforce
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LNB 101: What It Is and How to Choose The Right One

Satellite TV
Apr-2020 / 4 min read

Reading Time: 4 minutes

In the past decades, satellite dishes have started replacing weaker antennas on rooftops, allowing higher signal delivery and more information reception. This translates to clear, crisps images and sounds onscreen and less room for glitches. While they will need replacing, these small satellite dishes are designed to withstand elements, including time. In moments that you want to want to upgrade its capabilities, you will need to replace the LNB.

What Is an LNB and how does it work

If you’ve seen a satellite dish mounted on roofs, you will know that it is composed of two parts. Most of it will be the concave metal that gives this machine its distinct look. The electric part attached to the metal arm is called Low Noise Block downconverter; generally referred to as the LNB or LNBF. It is also called LNB satellite or satellite LNB

As these dishes are sitting around 22,000 miles from satellites orbiting around the planet, the signal gets weaker as they travel to your home. The round plate focuses this weakened signal onto the LNB. It then does two things: amplify and downconvert. First, this object is a low-noise amplifier. As the name suggests, it gathers weak satellite signals and amplifies it. Second, it is also a block downconverter. After increasing super-high satellite frequencies on the dish, the LNB converts them to frequencies your TV cable can digest. The LNB consists of the following parts:

Low Noise Amplifier
Frequency Mixer
Local Oscillator
Intermediate Frequencies Amplifier

All of these parts help the LNB function properly. When talking about its common types, their main difference lies in the number of outputs. As this allows more satellite receivers to be added, your TV will get extra points and will enable you to connect your PVR (personal video recorder).


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Single LNB

Only one cable can be connected to this LNB, allowing a standard satellite receiver like a Sky or Freesat box connection. While you can join a Sky+ or Sky+HSD, you will not have to be capable of recording one programme while you watch another.

Twin or Dual LNB

While these types are not that common in the market, it has two outputs. You may opt to either connect two separate satellite receivers or connect a PVR on the other. This works well as your first LNB purchase. However, if this is not your first time buying, we recommend installing a Quad LNB instead as a more affordable investment. The price of a Quad LNB may be steep as compared to other alternatives, but its utility is also better.

If you have upgraded to a Sky Q, you might be confused that its LNB comes with two outputs. This is a Sky Q wideband LNB and works differently. This type has two outputs: vertical and horizontal. These cables carry different services without needing to polarise the signals. While you use a Sky Q wideband LNB, your Sky Q box needs to be connected to both cables to watch all the channels and avail of Sky Q’s services. This has a higher frequency range than universal LNBs, using 300Mhz to 2340Mhz. However, this means that your Sky Q box cannot be used on a communal IRS system.


Being the most favoured type of LNB installed, they are produced in larger volumes and priced lower than the rest. As it has four outputs, you may choose to connect four satellite receivers, or two PVRs and receivers, or only one PVR. If you want a more powerful connection, you will need to have it upgraded to an Octo LNB.


As the name suggests, Octo LNBs allows you to connect up to eight separate satellite receivers or a combination of receivers and PVRs.


One of the more common hybrids, a Quattro LNB is a practical choice for those who have multiple TVs in their home. Traditional LNBs are not the best choice for a communal IRS TV system. While this also has four outputs like the quad, a Quattro’s outputs can be used with multi-switches.

A multi-switch amplifier has separate inputs for VL (Vertical Low), VH (Vertical High), HL (Horizontal Low), and HH (Horizontal High). These are dedicated to a specific cable, polarising the signals at horizontal and vertical planes. This helps the satellite reuse the same frequency for more than one signal and transmit the same image and quality to different televisions.

Aside from these universal LNBs and Quattro, here are more LNB types: high gain, monoblock, dSCR or dCSS, etc. Though the options may be confusing, it’s essential to choose the right one for your home. There are also digital systems that come with a Sky or Freesat LNB already. However, if you want to look for your own, here are a few factors to consider:

How to pick the right one

1. Take note of the noise figure: To define some terms, the noise figure measures how much noise the LNB might add to the signal that you want to receive. The lower the number, the better your LNB will receive the weaker signals. This is often expressed in K or Kelvin.

2. Choose the LNB with the right gain level: The gain tells you how high the LNB will amplify your signal. The required LNB gain for most digital systems would be between 55sB to 65dB. It’s essential that these numbers are not affected by temperature changes, as well. Anything higher than this can cause the signals to get distorted when the LNB amplifies it, causing low-quality performance.

3. Check the stability of your local oscillator frequency: When choosing an LNB, make sure to check the frequency conversion oscillator.

Dielectric Resonant Oscillator (DRO) Types – This has a free-running oscillator that uses a small metal to determine the frequency.

Phase-Locked Loop (PLL) Types – For this type, a crystal oscillator and a digital phase circuit are used to determine the conversion oscillator frequency.

External Referenced Phase Locked Types – The satellite receiver is responsible for providing the reference signal for this type. Therefore, it is found outside of the LNB.

Choosing the right one is crucial not only for your satellite receiver but also, ultimately, for you and your family’s home entertainment. If you need more guidance choosing the right LNB upgrade for your system, make sure to contact us now!

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