Earlier, Patrick posted the news about the House voting to postpone the planned transition from analog to digital television broadcasting from Feb. 17 to June 12. The news sent me back searching for Doc Searls‘ fascinating rumination in Linux Journal on what happens after TV’s mainframe era ends.

He means the digital switchover. And he sees trouble ahead:

1. For many viewers, the digital signals aren’t going to be there, no matter what the viewer does (other than hunt them down on cable or satellite).
2. The stations themselves in most cases are giving up viewers, including (as in WECT’s case — see below) whole regional markets.

It’s all a big new game of hard-to-get.

The implications of that game are far reaching. Technical but still accessible, Searls begins explaining:

On February 17, 2009, all U.S. television stations will be required to switch off their analog transmitters and use digital transmission exclusively. Nearly all of that will happen on what’s left of the UHF band. Most stations will maintain their old channel branding, and still be known as “Channel 2” or “Channel 12”, but their signals will in nearly all cases be coming in on a new UHF channel. For example, WNBC-TV in New York will move from Channel 4 to Channel 28. WABC-TV will move from Channel 7 to Channel 45. Both are already broadcasting on those channels in digital form. Come next February, all of them will, even if all they’re doing is putting out low-def pictures over a high-def signal. In the Boston area, where I live most of the year, only one of the four major commercial networks broadcast their evening news in HD. The rest put SD (standard def) pictures on an HD signal.

If you have an HDTV and live within sight of New York TV station transmitters on the Empire State Building, you can probably pick them up over an antenna on your set or your roof. In fact, a loop or bowtie antenna will do. So will length of wire about 5 inches long, attached to the center conductor of your coaxial connection on the back of your set.

But if you live farther away, good luck. Your old VHF TV station not only won’t have the range it did on VHF, but will probably not have the same range as an old analog signal on the same UHF frequency. It certainly won’t have the same behavior. The signals tend to be either there or not-there. They don’t degrade gracefully with increasing “snow”, as analog signals did. They break up into a plaid-like pattern, or disappear entirely. Read through the photo essays here and here for more about how that works, and what a confusing mess this move is making out of the familiar old local channel rosters. […]

For a variety of arcane technical reasons, many (perhaps most) digital signals are directional. That is, they operate at their full licensed power in only a few (or perhaps only one) direction, and have big dents or “nulls” in other directions. In the old analog days directionality was the exception rather than the rule, and was usually intentional, to protect other signals on the same or adjacent frequencies, or to pull back on the signal in the direction of a mountain that might cause unwanted reflections or places (such as the sea) where nobody lived anyway. Not the case with DTV. Lots of new DTV signals are directional just anyway.

This is how it played out in Santa Barbara, where he wrote the piece:

In our new house (next door to the old one that had the big roof antenna) I anticipated the digital switchover and installed a high-gain Winegard HD-9022 UHF antenna. For analog reception it gets every UHF in Santa Barbara, Los Angeles and San Diego/Tijuana — in nearly all weather, at nearly all times of year. But that’s analog. What about digital?

For DTV, the Winegard does the best it can, but it’s not enough. The slight terrain shadowing between here and Broadcast Peak (where most our local TV stations radiate from) makes the two digital signals from there — KPMR and KEYT — almost impossible to receive. I haven’t seen KPMR at all (could be it’s not on the air yet), and KEYT’s signal on Channel 27 is barely there. In fact the signal is so bad that I can’t keep it visible long enough for me to shoot a picture of it. That’s a far cry from KEYT’s old analog signal on Channel 3, which was crystalline on our old roof antenna and is still okay with rabbit ears on our old Trinitron in the basement.

As it happens, the only clear DTV pictures we get are from 200+ miles away: from San Diego/Tijuana. That’s because there’s a clear signal path across the ocean between those transmitters and our house. While signals on UHF frequencies are characterized as “line of sight” (clearly the case with our local KEYT signal), they do bend slightly. Across the gently curved ocean between San Diego and Santa Barbara, UHF TV signals bend just enough to make it most of the time with a watchable signal — in analog. Not so with digital, which is much more demanding of the receiver. (Specifically, it demands a high signal/noise ratio.) As you see here and here, reception is either perfect or gone. In fact it’s gone most of the time. Setting up the DVR ro record programs is almost pointless, given the crap-shoot nature of reception.

His conclusion suggests that what we’ve been watching happen in the newspaper industry, we will soon see happen to TV.  And he’s looking forward to it:

Because the failures of the DTV switchover will bring into sharp relief the obsolescence of official notions about What TV Is.

What we called TV has already become nothing more than a form of data that can be carried over the Net at nearly zero cost, and stored anywhere for about the same. Live transmission is a demanding thing, but not once the pipes get fat enough. Where they aren’t, we have podcasting and variations in file size to avoid bandwidth hoggery.

Already anybody can produce high-def TV. As devices such as the Red camera come down in price, along with processing, data storage and render farming, Hollywood-grade video production quality will no longer be exclusive to Hollywood. Collaboration and distribution over the Net will inevitably follow.

As it does, it will become ever more clear that “TV stations” will be repositioned as doomed mainframes.

There will always be a need for local and regional news, and coverage of events by organizations and individuals whose interest and expertise is also local and regional. But “range” will be determined by interest, not by transmission medium. The lack of capacity for new program sources on one-way cable and satellite systems will expose the antique natures of those systems as well.

The digital switchover may be moved to June, but the rest is inevitable.