Help File

QI've set up a digital TV converter, and I get most of my local stations' digital broadcasts but not all of them. Do any of these broadcasters have upgrades in store for their signals?

AWith few exceptions -- low-power stations that relay or carry translated versions of other stations' programming -- broadcasters should have brought their digital signals up to full strength months ago. That doesn't mean that they won't continue to fine-tune their digital operations before the Feb. 17 shutoff of their analog broadcasts.

Some stations, however, will also change frequencies overnight on that date. They will move their digital broadcasts from UHF, or ultra-high-frequency, airwaves (channel 14 and up) to VHF, or very-high-frequency, channels (2 to 13) that their analog signals once occupied. Viewers won't have to learn new numbers because tuners already ignore these frequency assignments to label digital signals as if they were only a decimal point away from a station's original analog channel number.

The different characteristics of VHF signals may, however, yield a notable improvement in reception.

You can look up these moves at http://antennaweb.org, a site run by the Consumer Electronics Association and the National Association of Broadcasters to help viewers pick out antennas. Enter your address or just your Zip code, let the site map out your reception, then click the "Show Digital Stations Only" button above its list of stations. Some will show up a second time, with "Feb 17, 2009 (post-transition)" under the "Live Date" heading and a channel from 2 to 13 in the "Frequency Assignment" column.

In the Washington area, these stations include WJLA and WUSA. This list also indicates that other stations will make smaller adjustments, such as moving digital broadcasts to a different antenna.

Rob Pegoraro attempts to untangle computing conundrums and errant electronics each week. Send questions to The Washington Post, 1150 15th St. NW, Washington, D.C. 20071 or robp@washpost.com. Turn to Thursday's Business section or visit washingtonpost.com anytime for his Fast Forward column.