Buying Guide to Single LNBs

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Buying Guide to Single LNBs

TV viewing is literally brighter these days. The switch from analogue to digital TV has provided clearer picture and richer colour to TV sets. In addition, digital technology in TV made it possible for networks to create more channels, from two to even four channels in a space of a single analogue channel. With the new age of television technology started, satellite dishes for homes are becoming even more popular amongst home users.

And what is a satellite dish without a low-noise block down converter or LNB. A single LNB sits at the centre of a dish to enhance the received satellite signals, converting them from high frequency to low frequency signals. Such type of LNB plays an important role in funnelling the satellite signals to the TV set in order to view sharper pictures and hear better sound quality. A better understanding of the functions and specifications of a single LNB leads to information-driven purchase decision.

Overview of Single LNBs

As the receiving device of a satellite dish antenna, a single low-noise block down converter is composed of different parts, such as a local oscillator, a frequency meter, a low-noise amplifier, and an IF amplifier. As mentioned, an LNB receives the satellite signals, amplifies it, and converts the signal to a format that can be delivered to an indoor satellite TV receiver through a coaxial cable. A single LNB is an essential part of a satellite dish because without it, a satellite signal can only be funnelled into the TV with a very expensive and cost-inhibitive device called waveguide.

In the U.K., a universal single LNB is a standard among satellite dishes, and it funnels signal with vertical or horizontal polarisation and handle frequency ranging from 10.7 to 12.75 GHz in the satellite Ku or C band. A common type of single LNB has an inbuilt feedhorn that collects the signal and routes it to the LNB, and a polariser that selects between a horizontal and a vertical polarisation. Such type of LNB is a vital component in mini-dish for Sky Digital and Freesat.

Considerations in Single LNBs

There are several considerations when choosing a single LNB for a satellite dish. The amount of amplified signal, the skew, the noise reduction and the increase of a weak signal are important factors.

Amount of Amplified Signal

An LNB gain provides the amount of amplified signal routed to the receiver through the coaxial cable. An amplified signal can range from 40 or 70 dB, which is 10,000 to 4,000,000 times the original signal power before an LNB amplifies it. When considering the gain capability of an LNB, users may think that going for the highest range may seem a logical decision, but it is not wholly so. A large dish looking at high power satellites, such as Astra 2A and Astra 2B, can gain too high a signal that a receiver becomes overloaded, leading to swamping of powered satellite signals. Even if a receiver is capable of holding an immense amount of signal, its LNB may not keep up, which can lead to distortion and spurious signals that create a problem in reception. A well-constructed LNB is able to gain the same amount of signal at all frequencies.

Skew of LNB

The skew or angle of single LNBs in relation to the dish determines if there is a good or bad signal. Because geostationary satellites, which are located above the equator or the Clark Belt to match the rotation of the earth, are tilted from the view of the earth, so an LNB should also tilt to a similar angle. Now, it is all a question of where to angle a single LNB. It really depends on two factors: what satellite the signals come from and the location of the satellite dish.

The tilt is around 22 degrees in the southwest of England and around 15 degrees in the north of Scotland. Remember to always rotate clockwise as viewed facing the front of the dish. To angle a single LNB accordingly, just loosen the screw that keeps it in place on the dish. Although an LNB skew is not crucial inside a satellite’s footprint, it becomes so when approaching the edges of the signal footprint.

Noise Reduction

A single LNB that minimises the noise level is worth buying. With less noise, the receiver gets a higher signal, slightly helping in getting good reception. Modern LNBs employ high electron mobility transistor and gallium arsenide technologies to minimise its noise level. There are people who modify their LNBs with smoothing circuits to deter any further noise from the power supply. Although an LNB helps improve reception, only a dish (and a large one for that matter) can directly enhance reception.

Increase of a Weak Signal

Other people believe that inline amplifiers are a solution to weak signals, but these devices only reduce a signal more. An inline amplifier is useful when the length of a cable from a single LNB to a receiver is more than 75 feet. Installing an inline amplifier between an LNB and a satellite receiver or a multiswitch does not correct a weak signal. A more apt solution is to increase the dish size and use a good receiver with a low threshold.

Summary of Considerations

The table below shows the following considerations when choosing a single LNB. This is especially important when correcting a signal or reception problem.

What to Consider

What to Do

Amount of amplified signal

Have a well-constructed LNB that is able to gain the same amount of signal at all frequencies

Noise reduction

Modern LNBs with high electron mobility transistor and gallium arsenide technologies; modify LNBs with smoothing circuits to deter any further noise from the power supply

Skew

Tilt an LNB depending on the type of satellite where signal is received and the dish location

Increase of a weak signal

Inline amplifier of an LNB is not the solution; instead, increase the dish size and use a good receiver with a low threshold

Correcting different problems in signal can or cannot be a function of a single LNB. In some cases, problems are resolved by getting a larger dish, fixing a cable, or removing local interferences.

Testing a Single LNB

The only way to check if an LNB is in tip-top condition is to use it. Once attached to the dish, a single LNB should allow viewing of all channels on TV despite change in outside temperature. When sure that an LNB is of good condition and there are still channels missing, the problem may come from a faulty cable or a local interference, such as a car radar or even a malfunctioning laptop battery. It is possible that the dish or the receiver is at fault. Although a durable device, a single LNB does fail at a certain point due to frequent exposure to heat and water, so a replacement is necessary.

Buying Single LNB's on eBay

The great thing about buying online, especially for small items, is that you do not need to get dressed and drive to a physical shop just to buy a small item. Of course a single LNB, although small, is an essential item when maximising TV viewing experience, but still, it is immensely convenient to just order it online. On eBay, you can find different models of single LNBs. All you need to do is do a direct search by inputting the keywords, such as "single LNB" into the search bar.

When buying on eBay, it is wise to check the seller's page to see if he or she has a great reputation on the site. The number of positive feedbacks and the percentage of user ratings give you a good idea on what kind of seller you are dealing with. Also, make sure to read the product and shipping details carefully before you make a purchase. eBay is a great site to search single LNBs, and if you are prudent and patient enough, you are going to find a great deal.

Conclusion

Single LNBs are an essential part of a satellite dish. Without them, it is only possible to amplify signals and convert them to a format that can be used by the TV set with an expensive and impractical waveguide for the dish. An LNB not only amplifies a signal but also helps in reducing noise to allow signal to flow more through the dish.

It is important to note that skewing a single LNB in relation to the satellite must also depend on the location of the home. An LNB is susceptible to wear and tear because it is always exposed to heat, water, and other outside factors, so it is a part of a dish that may need replacement at a certain point. A single LNB, despite its simplicity and susceptibility, is truly a powerful device that allows home users to get good signal, more channels, and satisfaction from watching TV.

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