The last major TV stations that are still broadcasting in analog will turn those signals off Friday and go all digital. And this time, they really mean it.
The original Feb. 17 deadline for the shutdown was delayed by the Obama administration after funding ran out for $40 coupons the government offered to help people buy converter boxes for old TVs.
Now officials say the country is much better prepared than in February, though they still expect some viewers to be confused.
About 3.1 million U.S. homes were unprepared to receive digital signals as of late last month, according to the Nielsen Co. That's half the number that were unprepared in February, and the number will probably decline further by Friday, as procrastinators get around to replacing old TVs or hooking them up to converter boxes or cable or satellite service.
Some people may believe the analog shutdown will be put off once again. But President Barack Obama debunked that with a statement last week: "I want to be clear: There will not be another delay."
Because digital signals are more efficient than the analog TV broadcasts that have been on the air for six decades, the transition will make room in the airwaves for wireless Internet and emergency communications services.
Analog signals cut at many stations
Nearly half of the nation's 1,760 full-power TV stations have already cut their analog signals, though they are mostly in thinly populated areas.
Come Friday, older, non-digital TV sets will lose all major channels unless they have an antenna and a converter box that allows them to accept digital signals, or if they are hooked up to cable or satellite.
A few low-power analog stations and rural relay stations known as "translators" will still be available in some areas. And about 100 stations will keep an analog "night light" on, informing viewers of the need to switch to digital reception.
The Federal Communications Commission has given stations freedom to decide what time of day they will be shutting down analog. Many have opted to do it in the evening, meaning the full impact will not be felt until Saturday.
Groundwork for the analog shutdown has been laid with a massive public information campaign, but getting the whole country to understand what's going on has been a challenge.
Moe Shakkour, manager of an independent electronics store in a largely Hispanic area of New York City, said people have come in with converter box coupons, without knowing what they are for, or that analog TV signals are going away.
Other stores are also reporting antenna shortages, and antenna issues in general could be another problem for the transition. Digital signals travel differently than analog ones, and some viewers may need to get new antennas for optimal reception.
Antennas that produced a poor but watchable picture with an analog broadcast may get nothing at all on digital, or a picture that freezes now and then.
Early public information efforts were focused on getting people to understand the need for a converter box. Thanks to lessons learned from areas where stations shut down analog early, the latest ads also stress the need for a suitable antenna that receives both the UHF and VHF bands.
The ads also point out that viewers need to force converter boxes and digital TV sets to "re-scan" the airwaves to find channels that will move to new frequencies Friday.
Even if a set is correctly hooked up to a converter box and a good antenna, many stations that are already being received digitally will disappear when they move to new channels.
To confuse matters further, many stations will not be broadcasting very strong digital signals on Friday, because those signals are coming from secondary antennas.
The primary antennas, at the top of the broadcast tower, have been used for analog. Until those are taken down and replaced with digital antennas, which can take weeks, outlying areas may get poor or no digital signals.
Where stations have already cut off analog, the shutdown has caused some confusion but hardly the sort of widespread resentment that was originally feared. When hundreds of broadcasters stuck to the original deadline, just 28,000 people called the FCC's help line, though an estimated 12 million households without cable or satellite were affected.
One afternoon this week, a walk-in digital TV help center operated by a Hispanic community association in New York was empty. Roberto Cuesta, who runs a nearby electronics store, said most people were comfortable with their new converter boxes and only about one in 50 customers needed extra help connecting them.
"The good news is that we're in considerably better shape now than we were four months ago," acting FCC Chairman Michael Copps said last week.
"We were nowhere near ready for a nationwide transition in February. Had we flipped the switch back then, we would have faced a debacle that would have made New Coke look like a stroke of marketing genius."