The Magic Instant

This much is known about February 17, 2009. It will be the 51st anniversary of Pope Pius XII’s naming St. Clare of Assisi the patron saint of television. Whether it will be the last day certain Americans get to watch the full-power analog-broadcast version of St. Clare’s technology remains to be seen.

According to an act of Congress signed by the President, that date will be the last for such transmissions. There is a challenge to the act based on differing language in the House and Senate versions (in a section unrelated to television broadcasting), and Congress has already changed the previous analog cutoff date of Dec. 31 of last year, so it’s by no means certain the law will remain in place. But, if it does, what happens?

For many viewers, the answer should be “nothing.” Low-power analog television transmitters are permitted to continue to broadcast even under the act. Anyone currently getting terrestrial broadcasts via satellite or digital cable will be able continue to do so. It’s somewhat less clear that those getting TV broadcasts via analog cable will continue to get them, but, as this is being written, work is in progress on assuring that, too.

That leaves only the shrinking percentage of U.S. households that don’t get TV broadcasts via cable, satellite, or other retransmission systems, or do but also have at least one over-the-air-only set. As of March 1 of this year, all TV tuners imported or shipped interstate in the U.S. had to include digital-reception circuitry, so even hardcore terrestrial-antenna-only viewers should soon enter the digital age.

As for full-power TV broadcasters, the first U.S. digital terrestrial television (DTT) stations went on the air in mid-1996; all were required to be on the air as of May 2003 (the commercial-station deadline was a year earlier), and, as this is being written, 1,603 are transmitting DTT. So there isn’t much of a transmission transition left to happen—or is there?

On the website of the Association for Maximum Service Television (, you can find a countdown clock ticking off the seconds until the analog shutdown. You can also find a link to the slides of “DTV: The Rubber Meets the Road,” a webcast conducted in March. Slides 1 & 2 introduce the presenters from APTS, the FCC, MSTV and NAB. Slide 5 covers the big issue. “Full service analog TV stops: February 17, 2009, at 11:59PM and 59 seconds.” But then there’s slide 16.

“Significant channel movement on February 17, 2009 (35%) (600 stations).” Due to spectrum repacking after analog cutoff, some 600 U.S. full-power TV stations, about 35% of the total, will have to change their DTT channel at the cutoff.

What does that mean? Slide 17: “181 will cause interference....” “300 stations will receive interference....”

There’s more. According to slide 24, “Nearly 50% of stations plan modification prior to February 2009.” According to slide 26, some of those believe the modifications will take 36 months, a time period extending well beyond February 17, 2009.

If that seems too scary, avoid the right column of slide 29. It provides a simple calculation. The numbers of transmitters, masks/filters, antennas and tower installations required are divided by the suppliers and multiplied by a two-week manufacturing or installation schedule (the previous column does it for a one-week schedule).

The smallest number in the column is 122. That’s the number of weeks it would take tower crews to do the necessary antenna or transmission-line work. As a reminder, two years is 104 weeks.

The largest number, 383, is for transmitters. If dated from the March 12, 2007 webcast, the end of that number of weeks would be July 24, 2014. Unfortunately, the analog cutoff date is more than five years earlier.

It’s possible that some stations were laggards, but some didn’t find out about their new allocations until recently. No one’s allocation is yet set in stone. But channel changes, in theory at least, need to occur not over the course of more than seven years but between 11:59:59 p.m. on February 17, 2009 and the start of February 18.

Stations not broadcasting can still feed cable, satellite and telephone company IPTV directly with video and audio. But, if not broadcasting, will they still be “broadcasters” with regard to must-carry? It’s going to be one heck of a second!

Mark Schubin is an engineering consultant with a diverse range of clients, from the Metropolitan Opera to Sesame Workshop.