Cumulus Tests Improving Analog FM Reception; May Eventually Help HD

The single sideband technology, long available but never tested before by stations, could help eliminate multipath -- which listeners experience in terrain that’s not flat and can make it hard to hear radio, supporters said in interviews. The FCC Aug. 19 and on Friday approved Cumulus Media’s requests for experimental authorization for one year to test SSB at two Atlanta FM translators and at KHJK La Porte, Texas. “This authority is specifically conditioned on a lack of objectionable interference,” said a grant to a Cumulus translator in Atlanta. A report on the “methodology employed and the results obtained” is due to the commission 90 days after the experimental authority expires Sept. 9, 2012, wrote Jerome Manarchuck of the Media Bureau’s audio division. Cumulus separately is poised to get bureau approval to buy Citadel Broadcasting in a $2.4 billion deal (CD Sept 13 p4).

SSB won’t necessitate CE makers making changes to existing radios, since it seems to be “backwards compatible” with most of them, said President Frank Foti of Omnia Audio. One of the company’s audio processors, with a list price of about $15,000, can be upgraded for free to use the technology, which also improves audio quality, he said. Foti hopes to test the technology in about six locations to see if it works in the field, he said. “If there’s a way that we can reduce the annoying effect of multipath in a receiver, everybody wins.” Multipath interference occurs in areas where the FM radio signal bounces off buildings or terrain features causing the receiver to try to lock onto both the original signal and the reflection. The distortion is sometimes referred to as flutter or picket-fencing.

No other companies have sought to join in, said executives at Emmis and Greater Media, which both have several dozen HD Radio stations. Foti said CE companies haven’t become engaged on SSB, either. “It’s understandable that they are going to take a wait-and-see approach,” he said: “I'm willing to put a few years into this, easily” for tests. Eliminating the upper stereo sideband with the technology could help provide “the conventional signal with more protection” from HD Radio signals that are transmitting at higher power levels, Foti said. The FCC last year allowed most FM stations to boost digital power by 300 percent. An executive at iBiquity Digital, which licenses HD Radio technology to stations and CE manufacturers, had no comment. Executives have said that not enough receivers have HD Radio chips in them for digital broadcasts to catch on more with U.S. listeners.

Testing new ways to transmit analog radio is looking backwards when the industry needs to focus on digital, said Emmis Chief Technology Officer Paul Brenner. “One litmus test that does not pass for me is does this solution solve a relevant business or revenue impacting technical challenge for our industry? Or, is this a cure looking for an illness?” Cumulus’ tests may “answer those questions,” he continued. To continue coordinating efforts with makers of CE devices like smartphones and with automakers who control what radios go into cars, radio needs “a full and complete focus on conversion to digital radio,” Brenner said. “The results of the test will be interesting -- perhaps we learn something that makes us think differently."

Cumulus is in the early stages of the tests, and so far has found that the technology works well by making signals clearer in areas where multipath had been experienced including parking garage structures, said Gary Kline, Cumulus head of engineering. “If it becomes a technology that is something we can put our hands on, and actually install at our transmission facility, and actually test it without damaging our current signal or our operation, we're interested,” he said. “We applied to the FCC aboveboard for authorization to do this. So we're not in a dark dungeon somewhere wanting to play around with the airwaves.” Better electronics make it possible to use SSB, a concept available for decades, said Kline and Foti. Kline is co-chairman of the National Radio Systems Committee’s AM and FM analog broadcasting subcommittee.

That the NRSC subcommittee is looking at SSB’s pros and cons shows testing is a worthy endeavor, said Milford Smith, Greater Media engineering vice president. Radio receivers that 20 years ago wouldn’t have worked with the technology aren’t in wide use anymore, he said. “The hope is that SSB operation may result in less multipath, provide somewhat better protection to the HD Radio carriers and, in new receiver design, result in an improved FM signal-to-noise ratio. The initial as well as any follow-up testing will better define the possible upsides of the concept or may determine that any upside is minimal.” Smith said he views the work as a way to improve analog FM, “still far and away the dominant over the air transmission mode, and not in any way detracting from any and all efforts to further promote and develop HD Radio.”