Do I need a signal booster? | ACMA

Do I need a signal booster?

Signal amplifiers—most commonly masthead and distribution amplifiers—are sometimes used in television systems to increase the level (strength) of signals received at a television set. They should only be used in areas that receive weaker signals from distant broadcast sites or to provide signals to several television receivers.

Digital television in Australia has been planned and implemented to enable adequate reception within the signal coverage areas without using signal boosters. In other words, your TV reception should be good enough in most areas that you don’t need to use boosters to improve your signal.

Signal amplifiers are not an integral part of what technical people call ‘optimised television receiving installations’. They should be installed only if necessary, as they can cause reception difficulties and even interfere with your neighbors’ TV reception, so do your research before using them.

How do I know if my signal is weak?

The mySwitch website helps you to identify the level of TV coverage in your area. If mySwitch predicts that you live in an area with variable poor coverage, you may consider installing a signal booster. This could also be necessary if reception at your location is adversely affected by local obstacles, such as trees or tall buildings, that make signal levels lower than predicted by mySwitch. See What’s wrong with my TV reception? for more information about signal coverage areas.

However, if mySwitch indicates that you live in an area outside terrestrial (land-based) television coverage, you may need to receive digital TV via satellite through the Viewer Access Satellite Television (VAST) service. See Should I consider the VAST service? for more information.

How do I know if I have a masthead amplifier connected?

Image of a masthead amplifier on a roof

A masthead amplifier can usually be seen as a small grey or black plastic box attached to the pole supporting the television antenna. There will be wires running from the antenna into the box and a lead running down into the house to the television set. However, there are other devices that look similar to masthead amplifiers or it may be out of sight in a roof cavity.

Amplifiers usually draw power through the antenna cable from a 240-volt plug pack, which is usually found near or behind the television set. The plug pack is wired to a device known as a power injector attached to the antenna cable going to the antenna. If you have such a device, it’s almost certain to be a masthead amplifier.

Not sure if you have a masthead amplifier? Ask a local expert!

How do I know if I have a distribution amplifier connected?

Image of a distribution amplifier

Distribution amplifiers are generally used where many television outlets are available in the premises—such as a block of flats. They may be located in the roof cavity, or within service ducts or cupboards. Distribution amplifiers are usually physically larger than masthead amplifiers and require a 240-volt power supply to function.

Not sure if you have a distribution amplifier? Ask a local expert!

What are the pros and cons of using signal boosters?

If you have an ‘optimised television receiving installation’, you should be able to get adequate television reception without using masthead and distribution amplifiers within most coverage areas. However, in some cases, they may be a good option to help improve your reception. Their use can depend on certain factors, and installing a high-gain antenna or increasing the height of your antenna may be better options.

If your local expert determines that a masthead or distribution amplifier is necessary to provide enough signal level to your television receivers, we strongly advise that you ask her or him to install an amplifier with a built-in filter or to install a filter in front of the amplifier. This will limit the potential impact of mobile broadband signals on your television reception.

Pros

A masthead amplifier can help to achieve adequate reception if you:

  • live in an area with predicted variable poor coverage
  • are surrounded by tall trees or buildings that block and weaken TV signals.

Distribution amplifiers can help if you have a number of TV outlet in your home and you want to distribute TV signals from one antenna to all of them.

Cons

  • Signal boosters will usually not improve your signal quality and can make television receiving systems susceptible to high-level unwanted signal sources.
  • Incorrect use or faulty amplifiers can also cause interference to television reception, mobile phone systems and two-way radiocommunications systems.

How do signal boosters suffer from or cause interference?

If you use a signal amplifier, your television reception can be adversely affected by:

  • overload of the amplifier (impact on the amplifier by a strong signal)
  • overload of the television receiver by an amplifier (because the amplifier provides a very strong signal to the receiver)
  • a telecommunication base station providing 4G data services. See What’s the link between mobile broadband and TV reception? for more information about the potential impact of 4G data services and how to fix these overload problems.

Your amplifier can also affect your neighbours’ TV reception, or even cause interference to mobile phones and other radiocommunications systems by radiating unwanted signal due to signal mixing or oscillation effects.

Overload of the amplifier occurs when strong unwanted signals in the vicinity cause the amplifier to produce distorted signals that result in disrupted television reception. More commonly, masthead and distribution amplifiers can cause overload of a television receiver when they provide a very high level of signal to the receiver. This can occur when the amplifier is adjusted to provide excessive signal amplification (gain).

A masthead amplifier can pick up signals over a wide frequency range, including unwanted (non-television) signals. If a medium- to high-level unwanted signal is present at the input to the amplifier (for instance, you live close to a mobile base station), a very high-level signal is produced at the output of the amplifier, which is then passed to the television receiver. This high-level unwanted signal causes a response in the television receiver that results in degradation of the wanted television signal and the subsequent pixilation or loss of picture and sound.

When mixing and oscillation occur, the amplifier radiates unintentional signals back through the antenna, as a result of the amplifier design, poor installation or ageing/damage to the amplifier, terminations or associated cabling. These latter two mechanisms mean that the amplifier can cause interference to TV reception of your neighbors, mobile phone systems or two-way radio communication systems in the vicinity of the amplifier.

Who is responsible for any interference?

The person who owns or operates a masthead amplifier or distribution amplifier is responsible for any interfering signals radiated by the amplifier.

The ACMA investigates radio signal interference where it is suspected that the Radiocommunications Act 1992 is being breached. For instances of radio signal interference where the Act is not being breached, it’s appropriate for an antenna installer or technician to resolve the matter.

How can I fix interference problems caused by my signal booster?

Amplifier faults are responsible for a number of television reception problems. Care needs to be taken with installation and maintenance of the antenna, amplifier and cabling. We recommend you seek professional help from an antenna installer to fix amplifier faults.

Common signal booster installation problem

How to fix it

Wrong type of amplifier installed

Choose the correct type for your situation. You may need to consult an antenna installer or supplier of the amplifier

Amplifier gain is set too high

Use the minimum gain required for satisfactory operation

Mounting in close proximity to, or on, the antenna

Locate the amplifier away from the antenna (at least 500 mm) and not between antennas

Input or output cables have been coiled to accommodate excess

Use cables of the correct length and avoid excess cabling

Input and output cables have been tied together or are too close together

Keep the input and output cables separate—don’t tie them together

Poor cable connections

Use masthead amplifiers with ‘F’ type coaxial connectors to ensure good shielding and signal isolation

Poor termination of connectors to the coaxial cable

Follow the manufacturer’s instructions and use the correct tools for terminating cables with connectors, or use a pre-terminated cable

Cable is clamped or tied too tightly, resulting in damaged coaxial cable

Use the minimum tightening required on all cable clamps and ties to prevent cable movement, and avoid over-tightening

Cable kinked or bent too sharply, resulting in damaged coaxial cable

Install without sharp bends or kinks in cables

Amplifier subjected to high temperatures

Don’t put the amplifier in hot locations such as small, unventilated roof spaces

Corrosion of components and boards

Install weather seal correctly, ensuring that any drain holes are unblocked and the unit is mounted correctly to the manufacturer’s specifications

 

 

Last updated: 23 December 2014