Aerial Considerations for Digital TV

You may not need to update or buy new aerial equipment to receive a digital signal. There is no such thing as a ‘digital aerial’ so the installation you currently have may well be sufficient. It may even perform better as the digital signal is being transmitted more powerfully than the old analogue one.

The Transmitter

This is the starting point for ascertaining whether your present aerial installation is suitable for digital. If you have a ‘grouped frequency’ aerial as opposed to a wideband one, then you may need to change ONLY IF your transmitter has changed its frequency groupings as part of turning digital.

Each transmitter transmits using a portion of the overall frequency range for TV broadcasts. If you have a grouped frequency aerial, it will match the transmitter’s frequency groups. If your transmitter has changed groupings, then your aerial will no longer be compatible so you will require one matching the transmitter’s new frequency groupings.

How To Find Out If Your Transmitter Has Changed Frequency Groupings

Go to the Ofcom website and look up your region. A document containing details of all the transmitters in your region is available for free download. This will show whether transmitters in your region have, or are about to, change frequency groupings. If so, the new grouping will be shown expressed as a letter. You would need a new aerial matching this letter code.

If you have a wideband aerial, then it is unlikely to matter what frequency changes your transmitter may be making. A wideband aerial is designed to receive a signal across the entire frequency range used for TV broadcast, so you will continue to be able to receive a signal.

The ‘Digital Cliff Edge’

This is where the digital picture literally ‘falls off a cliff’ and fails completely and suddenly. An analogue signal gradually tapers off as quality reduces, so even when conditions are poor something will appear on the TV screen. With digital, the signal is either there or it is not: the picture might be fine, then at the point of degradation you will experience blocking and freezing followed abruptly by no picture at all. A graph displaying this would resemble a horizontal and vertical line meeting and forming a right angle (the ‘cliff edge’).

To keep your signal on the ‘right side’ of this digital cliff edge, the use of a higher quality (of construction) aerial and cabling MAY POSSIBLY be required. This is something to consider perhaps once you are using digital and can ascertain the level of signal reliability you are experiencing. There is no need to spend money unnecessarily – upgrading can be done retrospectively.

A Reliable Digital Aerial Installation

Simply put, it is any installation receiving a digital signal well enough to afford reliable viewing. ‘Reliable’ is the operative word: in order to minimise or (ideally) eradicate the effects of the ‘digital cliff edge’ as described above. Therefore, your present set up may well be all you require.