The issue of elevated power levels for FM stations using IBOC technology is being discussed at the 2008 NAB Show.
NAB has not yet filed anything with the commission, yet sources believe a request will soon be filed asking the agency to grant broadcasters who so choose permission to increase their FM digital power levels by up to 10 dB. Those who favor the increase say it will improve a station’s digital coverage to better match the analog coverage and improve receiver reception.
I’ve reported that elevated power levels were tested on stations for several radio groups, including CBS Radio.
Some of that material will be discussed at the Broadcast Engineering Conference later this week.
On Wednesday afternoon, CBS Radio’s Glynn Walden plans to present the results of a building penetration receiver study at elevated power levels. Sources say his paper will show the results of tests using KROQ(FM), Los Angeles, using measurements made with the IBOC sidebands at –20 dB and –10 dB.
A receiver by a second-floor window got good reception at –20 dB, but when it was moved 30 feet into the core of the building, the receiver showed no analog or digital reception, according to this source. After increasing the digital power, at –10 dB, 30 feet into the core of the building, the receiver had good digital reception.