Interpreting the trade view of the Postcode Database

The Trade view provides comprehensive details of television reception options for an address or postcode based on the nearest prediction point to either the address or postcode centroid. The DTT predictions are those which are being used to plan the DTT network, and the prediction is based on the assumption of a representative receiving system in good condition at 10 metres above ground level. Predictions can vary significantly over a short distance due to the effects of terrain and interference, so they should be treated as a guide to the likely situation on the ground.

The checker does not currently include information about self-help transmitters.

Analogue transmitters

Information relating to the analogue transmitters which could potentially be in use at the address include:

• The 'most likely' transmitter to be in use, derived from a complex algorithm. Note that this may not be the actual transmitter in use, and it is not always possible to identify a most likely transmitter; however research has shown it is correct in over 80% of cases.
• The distance to and bearing of the transmitter from the address.
• The transmission channels, listed in the order BBC One, BBC Two, ITV1, C4/S4C and C5.
• The analogue aerial group and polarisation.

Digital transmitters

Information relating to the digital transmitters which are predicted to be receivable at the search address:

• The 'most likely' transmitter to be in use. This will be the same as the 'most likely' analogue transmitter, providing that transmitter provides coverage after switchover.
• The distance to and bearing of the transmitter from the address.
• The published switchover date.
• The digital aerial group and polarisation a) now b) after switchover (in the event there is a change in aerial group).
  

Prediction

The Prediction section details the transmission channels and a multiplex-by-multiplex coverage prediction for each transmitter that is predicted to provide a usable signal (i.e. a prediction of at least 50) on at least one multiplex at the address or postcode centroid at any time during the switchover process. The prediction is repeated for each step where there is a change in either coverage, or transmission channels.

Two predictions are provided:

1. where the signal meets the planning standard
2. where the signal may be subject to periodic interference, but may still be usable

The higher the prediction figure, the better the reception margin.

Planning standard

The prediction is made at the centre of a 100m x 100m tile. Based on the use of an antenna of the correct type at 10m above ground level, the signal is predicted to be receivable without interference from co-channel transmissions for at least 99% of the time to the proportion of the tile indicated, measured in %. The UK planning standard is met where at least 70% of the tile is served in this way, i.e. for values between 70 and 100.

Periodic interference

The prediction is made at the centre of a 100m x 100m tile. Based on the use of an antenna of the correct type at 10m above ground level, the signal is predicted to be receivable without interference from co-channel transmissions for between 50% and 99% of the time to the proportion of the tile indicated, measured in %. While this does not meet the UK planning standard for service reliability, the level signal may be usable and the level of service acceptable to a consumer.

Other platforms

Information relating to the current availability of other digital television platforms in the postcode, as provided to Digital UK by the relevant platform provider. Note that in general, predictions of future coverage are not available. The limitations of cable and DSL network coverage means that availability to a specific address needs to be confirmed with the relevant platform provider.