Improve your TV signal and troubleshoot problems

Find out how to improve your digital TV signal and troubleshoot problems if you lose signal or experience interference on your TV screen.

Using the menus below you can find out the basic checks to carry out on your TV equipment to make sure you are receiving the best signal to your digital TV. You can also find out the causes of many common issues which affect the picture you receive and find out how to solve them.

Basic checks

• Check your TV signal
• Make sure you have the right aerial
• Check your digital receiver
• Get the right cables

Fix your TV signal problems

• Some of my digital TV channels are missing
• There’s a shadow on my TV picture
• I’m seeing bright bursts of white lines or dots on my TV screen
• My TV picture keeps freezing
• I’m seeing horizontal bands or patterns on the TV screen

Freeview is not available in all areas of the UK. Enter your postcode on the Freeview website to check if your region is covered.

If your region is covered but you are still having problems, it’s a good idea to check the signal . A signal weaker than 50% will often cause reception problems. Most Freeview boxes allow you to test the signal quality – check your user manual to find out how.

On Bravia TVs with a built-in digital tuner, you can check the signal quality by following the procedure detailed in your TV user manual.

Freeview is received through your TV aerial and in most cases, the existing aerial is good enough to receive the signal, provided it is positioned correctly and in good condition .

For the best reception you should use a rooftop aerial rather than an indoor aerial.

In some cases, you may need to upgrade your aerial . This is necessary when your aerial is pointing towards the transmitters for the old analogue channels. Some of these have now been switched off, particularly those in rural areas. If that’s the case, you will need to upgrade to a digital compatible wideband aerial. See more information about aerials on the Freeview website.

Using an indoor aerial
If for any reason you can’t have a rooftop aerial, you should use a high gain wideband loft aerial – these get far better signal than other, smaller indoor aerials. If you are using a loft aerial, the following issues could affect your signal:

• The aerial is pointing through solid walls – it’s always best to have the aerial pointing at tiles in the loft so there are fewer obstacles between it and the air outside
• Foil or lead roofing materials – these provide more obstacles for the signal and can affect strength
• Hills and tall buildings – these can obscure the path between your aerial and the transmitter
• Trees – in high winds and stormy conditions, trees can disrupt the signal from the transmitter to your aerial
• Water tanks – if you’re installing a loft aerial try to keep it away from tanks and water pipes as these can de-tune your signal
• Junk – having a lot of clutter in the loft can create obstacles for the TV signal and affect its strength

Using a signal booster
If you have the right aerial, in good condition and positioned well, but you’re still getting a poor signal, you could try using a signal booster .

Ideally you should use a fully screened mast-head TV amplifier compatible with digital TV – these are the newest type and are the best on the market for boosting your signal. For the best results, you should place your booster near your aerial , and not next to your TV.

If you’re also using a TVI filter, you should make sure this is fitted between the booster and your aerial.

Most modern TVs come with built-in digital receivers. To receive a signal on older TVs you’ll need to connect a receiver – often called a set-top box – to your TV.

These are usually connected to the TV through a SCART cable, with the TV aerial connected to the receiver. If your TV doesn’t have a SCART socket, you’ll need to plug the receiver into a universal modulator and then plug the modulator into your TV. Contact your local electrical retailer to find out more about universal modulators.

If you’re suffering from poor TV reception, your cables could be the cause especially if they are damaged or old.

Your receiver will be connected to your TV with one of the following cables:

Coaxial cable

The best cable to use here is a double screened satellite grade coaxial cable . Older aerials generally use single screened coaxial cables and these tend to pick up more noise and interference, affecting the TV signal. If you’re using older cables it’s a good idea to get them upgraded.

If you have pre-wired TV sockets in your rooms, you should inspect them to make sure all the face plates are correctly wired and use double screened coaxial cable. You should also make sure the cable is securely fitted to both the faceplate and the receiver.

SCART cable

If you use a Freeview box with a SCART connector, make sure that it can output RBG signals , assuming your television supports RGB signals. This will improve the picture on the TV.

TV interference can often be caused by crosstalk on poor quality SCART cables. This results in the faint image of another TV channel shadowing the one you are watching. Switching to a higher quality cable can eliminate this problem.

What’s the problem?

Find out how to solve some of the most common TV signal issues.

The number of channels available on Freeview can vary according to what region you are in. See what channels you should be receiving.

If you’re not receiving all your channels, this could be because your TV is receiving more than one signal and is trying to install channels from more than one region. To solve this, you’ll need to manually tune your digital TV receiver .

First, you should note down the channel numbers for your preferred transmitter. These are referred to as mux channel numbers and you can find a list of them here.

Once you have the channel numbers, you’ll need to re-install each channel manually – check your TV or digital receiver manual to find out how.

When you are watching a TV channel and you can see a shadow of another channel behind it, this is often caused by a poor quality SCART cable .

This is the result of poor screening on the cable and unfortunately many cables supplied with set-top boxes are of a poor standard. To avoid this, you should buy a high quality SCART cable – these have their own foil screen which protects them from picking up other signals.

This problem is often caused by electrical interference and can cause your picture to break up. This usually lasts less than a minute.

Common causes of this are faults in your central heating or boiler thermostat as well as intermittent plugs, switches or sockets around your home. You can check for this by temporarily turning off your central heating or hot water at the time the electrical interference occurs to see if the problem is solved.

It is also possible that a neighbour's property is the source of the electrical interference. Commercial garage premises and MOT Centres can also have equipment such as arc welders which can create high levels of electrical interference.

This problem is more common with loft aerials than rooftop aerials. To avoid electrical interference, you should use a double screened coaxial cable to connect your aerial to your set-top box or TV, making sure the wire is not run too close to electrical wires in your home. Find out more about types of cables and how they affect your TV picture.

This is often caused by impulse interference, which can be generated by vehicle ignitions near your home.

To avoid this, try placing your TV aerial higher up, and make sure you are using a double screened coaxial cable to connect your aerial to your set-top box or TV. Find out more about types of cables and how they affect your TV picture.

This type of problem is known as TETRA interference and is caused by walkie talkie frequencies typically used by Government agencies, the military, emergency services and transport services.

If you are experiencing TETRA interference problems, you should get a high pass filter or a TETRA UHF notch filter. Ask your local electrical retailer for more information.