Perhaps worried US, pay-TV suppliers should not just be looking at OTT but also OTA the number of those relying solely on over the air services has risen sharply over the last twelve months.

According to data from Knowledge Networks, as part of its The 2011 Ownership Survey and Trend Report, itself a segment of The Home Technology Monitor, the number of Americans now relying exclusively on over-the-air (OTA) television broadcasting in their home increased to 45.6 million, up from 42 million just a year ago.

In addition the number of US households with TVs that rely solely on over-the-air signals to watch TV programming rose by a single point to 15% or just more than 17 million homes. Over the last three years this figure had remained at 14%.

As one may expect, the demographics of broadcast-only households included a large number of lower-income families. Yet, worryingly for pay-TV providers looking for tomorrow’s customers, it also included a high proportion of younger adults. A fifth of homes with a head of household age 18-34 are broadcast only, compared with 15% of homes in which the head of household is 35-54, or 13% of homes with someone 55 or older.

Even more worryingly for providers, the survey also found that a small but notable number of homes that have cancelled pay-TV services at their current home. According to the study, 4% of TV households, 5 million TV households, pulled the plug on their pay-TV service in their current home at some point in the past and now rely only on over-the-air reception. Of these homes, most report overall cost-cutting (71%) or not enough value for cost (30%) as the reason for doing so (respondents could give more than one reason).

"As we've seen for the past few years, over-the-air households continue to make up a sizeable portion of the television viewing landscape," said David Tice, Vice President and Groups Account Director of KN's Media practice. "Our research reveals that over-the-air broadcasting remains an important distribution platform of TV programming, and that the estimated number of broadcast TV households in the US has grown.