Well, on the TV side, 2006. Not certain about radio. Nice to know many of our wonderful TV Sets with rabbit ears won't work anymore. But then again, it seems most people are on cable or satelite these days.
As a broadcast engineer, I've been aware of the 2006 deadline for over the air analog television since it was set in 1996.
I can assure you that it's not going to happen. No one has set the deadline back. The FCC hasn't said, "So sorry, big mistake." But it's still not going to happen.
This is why: In the United States media corporations can take away people's fair use of copyrighted material in the name of profits. A faceless federal task force made up of hand picked tree huggers can declare property owners land "pristine beach front " and render it valueless by forbidding the property owners to ever build a home on it. The state of California can force people to surrender certain guns without any payment because the state decided they were illegal. Disciplinary committees may sanction students in public universities for telling an offensive joke.
All of these things the majority of the American people will tolerate to one extent or another. Some folks will even applaud one or more of these actions.
But if broadcasters shut off the analog over the air broadcast signal in 2006, we will witness the closest thing to a revolution to come along since 1776. The telephone exchanges to the house and senate office buildings will overload. Their E-mail servers will choke, melt and die. Snail mail will be delivered to each representative's office with a forklift. Democrats will begin proposing bills to fund digital set top converters for the under the privileged.
Kind of sad isn't it?
There are other reasons why I don't think the deadline will be met, but it's a bit off topic for this thread.