Teletext assists aerial strength test

Analogue teletext is being used to determine whether homes will need new aerials after digital switchover.

According to the BBC, around 10% of domestic aerials will need attention in order to receive digital transmissions. The
difficulty has been developing a reliable way of letting viewers know they will need a new aerial.

As the BBC Innovation and Research's 2007 review explains, a test pattern was designed which became less apparent as signal quality fell. But while that technique showed the correct trend, "there was too much spread on individual
results to give a reliable indication".

Instead, BBC engineers working within the Digital Reception Prediction Group at Digital UK, the industry-funded body charged with coordinating digital switchover, came up with a test pattern using analogue teletext.

The test pattern, broadcast on page 284 on BBC One, BBC Two, ITV1 and Channel 4 and S4C, provides a more accurate and objective result. "Tests have been successsful, with errors starting to show just at the point where an aerial
installation ought to be checked," says the annual review.

A Digital UK spokesman told Lovelace Consulting that the teletext innovation is being used in Whitehaven to determine aerial strength ahead of the area's switchover - the UK's first - on October 17.

"We've produced a leaflet on how to test aerials, explaining the teletext page and also providing a reference 'snowy' picture for people to compare their reception to (if it's as or more snowy, they will probably need a new aerial)," said the spokesman.

"The other method explained in the leaflet is to hire a Handheld Aerial Checker from local retailers which you take home and plug in to test."

Lovelace Consulting - 25.05.2007
from: http://www.dtg.org.uk/news/news.php?class=countries&subclass=0&id=2452