Nearly a year into a full-court press to end analog television as we know it, lawmakers finally got around to the subject of how to tell the public. During a Thursday afternoon House subcommittee hearing, a handful of congress members showed up for the testimony from individuals representing senior citizens, Hispanic Americans, the consumer electronics sector and Radio Shack with it's 7,000 outlets.
The two former witnesses cautioned Congress about pulling the plug on analog too abruptly, while the latter two called for establishing a hard date, ASAP.
Lavada DeSalles, who testified on behalf of the 35 million members of the American Association of Retired Persons, urged Congress to embark on an aggressive educational program for a year before kiboshing analog. Manuel Mirabal, founder and co-chair of the Hispanic Technology and Telecommunications Partnership, told the assembled representatives that the Spanish-speaking community would be disproportionately disenfranchised by an analog shutdown.
Leonard Roberts, chairman and CEO of RadioShack Corp., testified that there are 7,000 Radio Shacks just rarin' to sell government-subsidized converter boxes, if only there was a hard date, and Dave Arland, vice president of communications and government affairs for Thomson even brought a small converter box for show-and-tell.
Arland told the lawmakers that Thomson could crank out a $125 converter by fall if a deadline were established soon. Arland also used the opportunity to demonstrate that not all digital TV sets cost as much as a late-model Fiat and have to be moved with a crane.
The Thomson contingent brought two, 27-inch RCA, TruFlat CRT sets -- one digital and one analog, and set them up side-by-side in the hearing room. The digital set, from Chinese setmaker and Thomson partner TTE, cost less than $300, Arland said. At that price level, a comparable analog set would cost about $70 less, he said.
Both sets were tuned to WETA signals, and an impromptu investigation revealed that both were wired to rabbit ears situated in a windowsill behind where the lawmakers were seated. (This arrangement was independently confirmed when the rabbit ears were repositioned and both signals were duly messed up.) The window faced an inner courtyard of the fortress-like Rayburn building, creating a perfect environment for multipath interference.
Arland said the digital set was connected to an off-the-shelf set-top receiver. The digital picture was sharp as a tack, while the analog picture was full of ghosts and snow flurries. Consequently, the digital transmission appeared to be superior to the analog, although the digital dropped much easier during the aforementioned repositioning.
One factor that made the comparison not quite apples-to-apples is that WETA transmits its analog and digital signals from different locations. WETA-TV Channel 26 is transmitted at 2,290 kW from Bethesda, Md., on a tower at a HAAT of 235 meters; WETA-DT Channel 27 is transmitted at 75 kW from a tower in Arlington with a HAAT of 177 meters.
However, based on the available data, the signals behaved in a fairly predictable fashion, according to TV Technology columnist and RF expert Doug Lung, who first addressed the power difference.
"A minimum of 64 dBuV/m is needed to receive a satisfactory analog signal compared to 41 dBuV/m for the threshold level of DTV, which is either perfect or not there, although it can transition between these two states, causing breakup," he said. "Thus, theoretically, a DTV signal can be 20 dB -- a factor of 100 in power -- weaker than the analog signal and still be received."
As for the analog ghosting, which would suggest the type of multipath interference that once overpowered digital reception, Lung said, "any interference, ghosting or noise is going to be visible in the analog signal, even if the amount of interference, ghosts, etc. is minimal. You won't see it at all in the digital signal until it goes away completely. Therefore, if the DTV signal can be received reliably, it will always look better than the analog signal, excluding digital compression artifacts, which is another discussion.
"This ghosting was death to early DTV receivers, but the newer designs can actually use the energy in the ghosts to improve the signal-to-noise level above what it would be on the main signal alone. So the energy that was interference -- ghosts -- to analog becomes something that improves DTV reception!"
Back at the Rayburn Building, the lawmakers were on a vote break while the Thomson contingent scrambled to retrieve the digital signal and corral the nosy reporter who moved the rabbit ears. Arland, no stranger to Capitol Hill hearings, said that reception in the Rayburn Building is far better than it has been during previous OTA demos. The signal was thus restored long before the subcommittee members returned from their break.
