Commentary: HD Radio in TV1 Band? (Feb 2, 2008)

If you own a radio with TV sound, you're familiar with the TV1 band, which is the band containing the audio of channels 2-6, broadcasting from 54 Mhz to 72Mhz for channels 2-4, and from 76MHz to 88MHz. If you add up the two ranges, you get 30MHz, which is 150 percent as large as the FM band.

The TV2 band is the audio for channels 7-13.

When the digital switchover happens on February 18, 2009, the analog channels originally in the U.S. will be shut down. Most of the broadcasters have selected a channel outside of the TV1 band range to broadcast their DTV signal on by now.

The exceptions may be low-powered translator stations, which may be allowed to broadcast analog until they can afford to make the digital switch to DTV.

In Mexico, the digital switchover will happen over a decade later, probably in 2020, so in Tijuana, channels 3 and 6 will still be in use, in Mexicali, it's channels 3 and 5, and so on for other border Mexican cities where you can still pick up an analog Mexican television station from up to 200 miles north of the Mexican-U.S. border. For people living withing the range of the border, an analog TV is still useful for watching the Mexican telenovelas and their version of "football".

But with most of the U.S. broadcasters vacating the TV1 band, a use for that band will be better served by allowing the radio broadcasters to use the TV1 band for high-powered digital radio transmissions without an analog signal. Radio stations could broadcast their digital stations in HD1, HD2, HD3, and possibly up to HD8, using a power range from 25kW to 50kW, and maybe 100kW, instead of the subpar wattage for their digital signals that they're using in the FM band. This will help the cause for HD radio's existance as radios will be more likely to pick up a stronger digital signal than a weak one that's easily wiped out by an obstruction or long distance.

The local broadcasters could use the new TV1 band for digital-only broadcasts and turn off the digital signals in the FM band. The simulcast of the analog and digital channels will last until at least 80 percent of the population has a radio that can get the new HD radio on the TV1 band. After that date, stations can choose to broadcast either analog or digital on the FM band or digital on the TV1 band. Most of the radio stations restricted to low-wattage could move over to the TV1 band and broadcast digitally in higher power. Imagine Indie 103.1 in Santa Monica moving over to the TV1 band as, say, Indie 82.1 digital in 25kw of power to gain more coverage. The legacy full-power FM radio stations can choose to switch over to digital on the same frequency with the same power, which most would do anyway, or move to the TV1 band, which wouldn't make sense to stations such as KBIG 104.3 or KRTH 101.1.

In any case, opening up the TV1 band to full-power HD radio stations could be what HD radio, as well as radio broadcasting in general, needs to increase its chances of survival in a competetion pool that now includes satellite radio, portable wi-fi Internet radio, and portable 10,000 song mp3 players.