In discussing his paper on improved FM HD-R coverage prediction given Sunday here in Las Vegas, John Kean of NPR Labs said he will continue to test consumer radios and conduct field measurements of mobile and indoor reception.
The more measurements we collect, the more we’ll know about how the next generation of HD-R receivers will behave, he said. At this time, however, he reported that the NPR Labs coverage prediction model is providing remarkably accurate predictions of IBOC DAB coverage, based on thousands of miles of drive-test data as well as indoor testing.
In a draft report to CPB, he said, he predicted there will be little near-term improvement in HD-R receiver performance and it’s likely the performance may actually decrease with engineering pressures from price competition.
The labs has completed a series of major studies related to coverage and are still completing studies on the impact of IBOC on FM translators, using prediction models of field strength from first-, second- and third-adjacent channels. All this information (and more) will be helpful to know as the industry debates the issue of elevated FM IBOC power, he said.
Something to consider with elevated FM digital power comes the potential for increased interference to adjacent stations. This includes the effect the higher digital power levels would have on FM subcarriers, something the International Association of Audio Information Services will look at soon, Kean said.
He had the best joke at the Public Radio Engineering Conference regarding the question of whether a glass is half-full or half-empty: “An engineer will tell you the glass was improperly sized.”