What is an LNB? The acronym LNB stands for low-noise block down converter. An LNB is the receiving device mounted on satellite dishes used for satellite TV reception. An LNB is usually placed at the focal point of a satellite dish where the signals received are concentrated. It is called a down converter because it amplifies the signals received and then down converts them to IF (Intermediate Frequencies) which the satellite receiver or decoder can interpret easily.
These are tips that will help you to buy a good LNB. The first question to ask yourself is what type of TV reception you will be getting? Is it Pay TV or Free to Air TV? If the answer is Pay TV, then I will advise you to buy the equipment that the Pay TV firm is selling you. Pay TV operators like Dstv and Zuku usually sell the best quality equipment because their reputation is on the line and also to give their consumers pleasant viewing. Most free to air satellite TV installers like me will tell you without a doubt that the LNBs Pay TV firms offer actually perform better. You however cannot buy such an LNB as a single unit; if you want their LNB then you have to buy everything from the Pay TV Company including the subscription. That’s why there are some unscrupulous distributors and traders in downtown Nairobi and other towns as well that hide these type of LNBs. What they do with the LNBs is a mystery. But I think you have an idea if you are reading this.
If you want an LNB for Free to Air Installation then continue reading.
The second thing to check is the type of LNB you want; is it a Ku band or C band LNB you want? This will be dictated by the type of satellite dish you have or will buy. Is it a Prime focus or an Offset dish? You can differenciate between the two simply by reading the label on the LNB and its packaging.
How many receivers will you be using? With only one decoder, you require a single output LNB. With two decoders, you will require a twin LNB like the one pictured above. For 3 or 4 decoders you will need a Quad LNB. One decoder can use a twin or Quad LNB, it does not matter the number of unused ports and there is a reason why and you will find out at the bottom. Well if you have more than 4 decoders then you will need to import an LNB with 8 ports as they are not so common in Electronics shops.
There is a reason why some decoders like Zuku or even Dstv use a twin LNB connected to the receiver using two separate cables. The reason is simple, it is for watching two different channels at the same time or watching one channel while recording the other. In order for this to happen the decoder itself must be a twin tuner decoder. Each tuner usually receive's its own channel even if from two different Polarities. So if you have a twin decoder then you must have a twin LNB.
Another thing to check is the strength of the beam you want to receive. It’s no use buying an expensive high gain LNB for a satellite footprint that is easily receivable using a low cost standard LNB. Examples of Ku band satellites that can be received in Sub-Saharan Africa using low cost standard LNBs are Intelsat 20, NSS 12, Amos 5, Eutelsat 7A, SES 5 and SES 4. The signals from these satellites are so strong that they are receivable using a 65cm offset dish and a standard LNB. Examples of standard LNBs are Eurostar Gold+, Eurostar P8 – II and Stargold SG 100 – I. These LNBs cost around Ksh300 to Ksh350 (roughly 3 to 5 US Dollars) in Nairobi’s Luthuli Avenue.
Now if the type of satellite footprint you want to receive is weaker, then it’s advisable to buy a bigger dish in combination with a better performing LNB. The type of dish will also matter what type of LNB you need to buy. For good Ku Band reception, you can either buy a bigger offset dish (1.2 meters and above) or a prime focus dish (the smallest size being 1.8 meters).
With an offset dish an ordinary Ku band LNB is required but with a prime focus dish you might require a Ku band LNB specifically made for use on a prime focus satellite dish.
There are Ku band LNBs for use on offset dishes that are actually better because of the high gain and low noise figure they have. These are called high performance LNBs and usually amplify and stabilize signals even in heavy rain. That’s right you can enjoy your TV in heavy downpour without any signal loss or even the slightest pixilation.
You can get a high performance (high gain low noise figure) LNB by buying a single output LNB or a multiple output LNB. A single output high performance LNB costs around Ksh1200 to Ksh2000 (roughly 8 to 20 US Dollars) in Nairobi’s Luthuli Avenue. Examples of such type of LNBs are Lazer Gold V12 and Inverto Black Ultra.
The other method of achieving high gain as mentioned earlier is buying a multiple output LNB. Multiple output LNBs offer more gain because they are meant to serve more than one receiver. It does not matter the number of unused ports, they can work well with only one decoder. An example of such an LNB is the Eurostar quad QP4 that has four outputs.
With a bigger dish and a high performance LNB, you can receive stabilized signals from Nilesat 201’s Middle East beam and Eutelsat 7A’s Europe B footprints.
I will tackle Ku band LNBs for use on prime focus dishes very soon.
Written by Gichane
Wednesday, April 30, 2014