Yesterday, the Federal Communications Commission gave a big boost to HD Radio, the digital technology that permits an FM station to broadcast multiple channels and allows AM stations to sound like FM.
The FCC ruling (109 kb PDF) leads off by eliminating filing requirements for FM stations that want to offer secondary, digital-only channels. The important part, however, comes farther down, and covers the so-far neglected area of digital AM: Stations can now broadcast digitally at night, not just during the daytime.
That's good news in a purely selfish sense; I'm looking forward to hearing Rich Chvotkin call a Georgetown game without the usual static and hiss. The vastly superior sound quality of HD AM could also allow broadcasters to offer music programming as well as the usual talk/news/sports mix.
(Would-be merger partners XM and Sirius seized on this angle in a press release today, arguing that a single satellite radio firm would still have plenty of competition: "The FCC decision underlines that HD radio on the AM/FM bands provide a real alternative to satellite.")
But HD Radio AM broadcasts may also obstruct one of AM radio's oldest attractions--so-called skywave reception, in which AM signals bounce off the ionosphere after sunset and allow listeners to tune in from hundreds of miles away. For example, two years ago, a Cleveland station's broadcast of an Indians game kept me entertained on the New Jersey Turnpike; a couple of nights later, I tuned into WTWP-AM's coverage of a Nationals game in north Jersey.