A television signal amplifier can help improve a weak signal, especially in areas that do not have good television coverage. It is also useful for distributing a signal to many televisions. In contrast, an attenuator can reduce a signal if it is too strong.
Both these devices should only be used when necessary. In many cases a good aerial installation with good quality cables can be enough to receive good reception.
When to use an amplifier
A signal amplifier should only be used as a last resort when the television signal is weak. Even the best amplifier will still add some noise to the television signal it is amplifying/boosting that could result in picture break up. A good amplifier should have a filter built in that only allows the signal you want to be boosted and not any unwanted signals. Otherwise, all the unwanted signals will also be boosted, which can cause pictures to break up.
Problems using amplifiers
Amplifiers themselves are a common source of reception problems. For example, if water were to get into a masthead type, they can start to boost the result of the fault. This could be unwanted signals and result in picture loss on your own television and, maybe, those living nearby. To check, remove the power from the amplifier and see whether the problem goes away.
There are three types of amplifier – masthead, set-back and distribution. All these need a power supply to work.
These fit directly under an outside aerial and usually the best type of amplifier to fix weak signals.
These fit between the aerial socket in the wall and your television.
These split the TV signal from a single aerial and allow the signal to be sent to several different televisions in the building.
Some amplifiers are a mix of the above. For example, some masthead amplifiers are also distribution amplifiers. Some can also combine television and FM radio signals.
When to use an Attenuator
If you are experiencing pixellation or picture break up, it may be that your signal is too strong as this often presents itself similarly to a weak signal. This is likely to happen if you live close to a transmitter.
Attenuators can be used to decrease the incoming signal if it is too strong without distorting it. It is effectively the opposite of an amplifier, though the two work by different methods. While an amplifier provides gain, boosts the signal, an attenuator provides loss, reduces the signal. Attenuators are always a compromise and should only be used if absolutely necessary.
They come in a variety of powers; in most cases a small reduction is all that is needed. It may take a little trial and error to find the most suitable one for your installation, and it is worth taking the advice of a local aerial contractor to select the correct one for the installation.