To access digital terrestrial television you need an aerial. It can be built-in, indoor or external and vary with platform.
This guide gives a simple overview of the different aerials available.
There are three main factors to consider when discussing television aerials - polarity, group and location.
This is not as complex as it sounds. Television services are broadcast either horizontally-polarised or vertically-polarised. Your aerial needs to be mounted flat (horizontal), or on its side (vertical), depending on the transmitter it is pointing towards and the polarity of the services broadcast.
To help boost reception, an aerial can be manufactured to receive a specific range of frequencies. This is known as a grouped aerial. For example, Group A aerials are better at receiving services between channel 21 and channel 37. This worked well for many years, but since we had to clear some broadcast channels for 4G and 5G services, we have had to squeeze more television services into fewer channels.
This has meant that some transmitters are using frequencies different from those that have been used for many years. This can mean some households may have a grouped antenna that isn’t suitable, or is less effective, for the frequencies now being used. The solution is to install a wide band aerial that covers all frequency ranges.
It is difficult to determine which group aerial you have, or even if it is wide-band. You may need to seek advice from a professional aerial installer.
The best place for an aerial is at a height of ten metres, mounted outside without anything between the aerial and the transmitter. All the coverage predictions used in our tools assume you have an external aerial at 10m.
If you are in an area that has very good coverage, you can use loft or indoor aerials. However, some of the signal strength will always be lost when using indoor aerials. This is becoming more prevalent with new properties as many have foil-backed insulation in roofs and walls. This sort of insulation blocks television and radio signals.
Indoor portable aerials tend to come in two varieties, mini replicas of external aerials and wire loops. The looped aerial will perform the worst and is unlikely to give you good reception.