Digital Dilemma

When the U.S. Congress voted in 2006 to stop over-the-air broadcasts of analog television on 17 February 2009, it assured the public that going digital would be cheap and painless. It allocated US $1.5 billion to help fund the purchase of converter boxes for what was supposedly the tiny minority of U.S. households that don’t subscribe to a cable or satellite television service. But if my experience is typical, the coupons are just the first step in a conversion that will be neither painless nor, in the long run, cheap.

I ordered two coupon cards back in January. They arrived in April, and in June I purchased a $50 RCA converter box at Wal-Mart. A different brand at Radio Shack was sold out.

The television’s built-in analog tuner had gotten great reception on all the major networks, a local nonaffiliated television station, and a Spanish-language channel—all in the VHF band—and six fuzzy but watchable UHF channels.

Using the RCA converter box, I got great reception on one PBS-affiliate channel. This gave me four choices of programming, because the affiliate broadcasts multiple standard-definition programs instead of one high-definition program. Unfortunately, the PBS station was KTEH, out of San Jose, Calif., instead of San Francisco’s award-winning KQED. In addition, I got reasonable reception on four Spanish- and Chinese-language channels. But ABC and NBC, two of the three major U.S.w networks, broke up constantly and were unwatchable, while CBS went missing entirely.

I went back to Radio Shack with my remaining coupon and ended up with a $60 Digital Stream converter. The connection process was the same as for the RCA box. The on-screen graphics are a little nicer, but I never found a comprehensive program guide, which made channel selection difficult. And the digital reception? No better.

Like most people who watch broadcast television, I get my signals through an ancient antenna on my roof—a bent, cobwebbed, aluminum monstrosity that is, it turns out, optimized for VHF signals. Most digital channels come in on the UHF band. So I next installed a $60 indoor RCA Flat Antenna. No improvement.

I convinced my husband to climb up on the roof and replace the VHF antenna with an $80 C2 UHF antenna from Antennas Direct, in Eureka, Mo. This improved reception on my second-floor Sony television. It now gets most of the broadcasts I got with analog reception, along with CW and Ion (two secondary U.S. networks), plus the Spanish and Chinese stations.

The new antenna didn’t do as much for the TV in the family room; I am picking up NBC now, but I still can’t get most local network affiliates. The local terrain may be responsible, says Ernest Neumann, KQED’s director of broadcast operations; UHF doesn’t propagate through hills and other obstacles. Or my problem might stem from multipath interference. In urban environments, a strong digital signal can bounce around, and many tuners can’t sort out the information.

But, given that I have better reception upstairs, a more likely culprit is the cable from the antenna to the television. Richard Schneider, president of Antennas Direct, says, ”Eighty percent of the calls we get about reception problems turn out to be in the signal distribution between the antenna and the tuner.”

Our antenna cables were installed before we lived in this house. I try to imagine what’s going on inside the walls. A splitter probably sends a line into the bedroom—giving the upstairs TV half the original signal—before continuing down the wall, dropping under the house, and splitting into three to five other lines. If that’s the case, the family room gets 10 to 15 percent of the original signal.

Yet that was fine for analog VHF television. ”The lower VHF frequencies,” Schneider says, ”tend to be more forgiving of long cable runs and splitters. UHF signals are more prone to loss.” With 30 meters of typical coaxial cable, a 50-megahertz VHF signal loses about 2.8 decibels; a 500-mHz UHF signal loses about 8.5 dB. A couple of bites from a mouse along the way can increase that loss dramatically.

If I can find one of the splitters, I can put a preamp on it for about $60. Alternatively, I can rewire. And I’m not alone. ”People living more than 10 miles [16 kilometers] away from the transmitter are mainly going to have to start over,” Neumann says. Or I can spend about $60 a month for cable or satellite service—just the thing the digital television converters are supposed to help me do without.

A version of this column appeared in IEEE Spectrum Online’s Tech Talk blog on 16 July.