WASHINGTON, DC: Some 2.2 million US households have yet to adapt their television equipment to receive a digital signal, meaning that they could now be facing blank screens following the switch-off of the analogue signal in the country, says the National Association of Broadcasters.

Consumers in the country with analogue-only televisions need to purchase government-subsidised converter units to receive a digital transmission via their existing aerials or a pay-TV cable service.

Nielsen, the research firm, has predicted that 2.8 million Americans were "unready" for the digital switchover on Friday, 12 June, when it became the sole form of transmission available in the US.

However, cable providers have seen little of the predicted surge in new customers, even before the the original February switchover date was delayed by president Barack Obama due to a bottleneck in processing applications for subsidised converters.

Nielsen's research points to African-American, Hispanic and younger audiences being particularly affected by the change, thought to stem from their higher propensity to live in urban apartments reliant on indoor, "rabbit ear" aerials that don't guarantee a clear digital signal on all channels.

But some cable industry observers think the actual switch-off might finally stimulate a pick-up in demand.

Says Bernstein Research cable analyst Craig Moffat:"What I think people are missing is the 'morning-after' problem. I wouldn't be at all surprised if there is a final rush to get converter boxes and this is the trigger to call the cable guys."

Opinion research from Harris Corporation, however, suggests the switchover could be a double-edged sword for premium TV providers, with some current users trading down. Its poll indicated that younger audiences, in particular, might opt for free-to-air services topped up with online viewing.

Data sourced from Financial Times; additional content by WARC staff