Yagi go home

I don’t really believe that the FCC, by killing off analog television over the air, is trying to force us into buying cable or satellite service, but this report by Doc Searls doesn’t reassure me:

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.

How does this work out in real life? Not so great from Doc’s place in Santa Barbara:

On my old roof antenna and its rotator, I got just about every analog TV station between Santa Barbara and San Diego. That included both VHF and UHF signals. With that antenna (the top one from Radio Shack) I even got little K35DG, a low-power UHF station at UC San Diego with a signal that puts a deep null in our direction (west-northwest, nearly 200 miles across the Pacific Ocean). I sent them emails reporting reception and they were amazed.

In our new house (next door to the old one with the big roof antenna) I anticipated the digital switchover and installed a very high-gain Winegard HD-9032 UHF antenna. (Here’s a pdf.) It’s an outstanding device that’s even better on UHF than the old all-channel one. For analog reception it got 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 out local TV stations come from) makes them almost impossible to receive. KEYT on Channel 3 was (and for now still is) a powerhouse that we could get with rabbit ears. KEYT’s digital signal on Channel 27 is barely there. In fact it’s so bad that the one time I got it the signal didn’t stay visible long enough for me to shoot a picture of it. Meanwhile we get nothing from anywhere but the only place that provides a fairly clear signal path, even if it’s across the curved ocean. That’s San Diego/Tijuana. All our HD viewing of over-the-air TV is from there. At one time or another we’ve been able to get all the HD signals from there, and add them into the memory of our Dish Network box, which also has an HD receiver. As you see here and here, the reception is either perfect or screwed. It’s the latter most of the time. Fact is, we’re lucky to get anything at all. Such is the nature of the new system.

As a cable subscriber, I presumably will be spared this particular brand of agony. But I worry: if Searls, an experienced broadcast engineer, can’t do much of anything to bring in local television channels, what’s going to happen to John and Mary and their not-so-free DTV converter box and their ten-dollar rabbit ears?

(Explanation of title.)





8 comments

  1. McGehee »

    6 July 2008 · 4:41 pm

    Personally, I think all broadcasters should be doing cybercasts. You can already listen to a lot of radio stations over the internet; why not TV?

  2. CGHill »

    6 July 2008 · 4:44 pm

    Sooner or later, your ISP is going to want to charge you for all that bandwidth.

  3. McGehee »

    6 July 2008 · 10:59 pm

    Let ’em charge the advertisers.

  4. Dan B »

    7 July 2008 · 11:54 am

    Maybe Searls is barking after the wrong conspiracy. Instead of forcing all broadcast off-the-air to cable/satellite, maybe the conspiracy is to get people to buy a new HDTV instead of the converter boxes. My TV on the boxes doesn’t get near the signal the HDTV does, and they’re running off of the same antenna.

  5. CGHill »

    7 July 2008 · 1:37 pm

    If there’s any suggestion of conspiracy here, it’s mine; Doc’s merely reporting his results.

  6. Doc Searls »

    8 July 2008 · 5:06 pm

    There certainly is a purpose, and it’s a conspiracy of a sort, and that is to make HDTV finally happen.

    What the FCC and the TV industry — such as it is — also want is to preserve OTA (over the air) TV in some form. My point is that many OTA watchers won’t get the new signals in any case. This will force them to satellite or cable. I doubt that’s the purpose, but it will be the effect.

    As to Dan’s remarks, it’s true that some HDTV signals will come in better and look better than the old analog ones. But some will come in worse or not at all.

    In the long run it all moves to the Net, supplemented for mobile by cell. Bandwidth demands will be high both upstream and down, but bandwidth isn’t as scarce as the carriers would like you to think. But they’re in the scarcity business, so that’s their game.

    That game will change, of course, but for now that’s where it is.

    Also, for what it’s worth, I’m not a broadcast engineer, but a guy who knew a lot about broadcast engineering, and did some of it in the very old days. Like I said, I look forward to the irrelevance of that know-how.

  7. CGHill »

    8 July 2008 · 9:08 pm

    Perhaps our relatively flat terrain will help OTA viewers here in Oklahoma City, though I have to wonder how fringe viewers will fare when, say, they’re hoping to get Gary England to advise them on the coming storm.

  8. CGHill »

    10 July 2008 · 8:12 pm

    And I notice that, per RabbitEars.info, most of our local stations are using non-directional antennas — while almost all the Los Angeles-market stations are directional, as Doc has noted.

RSS feed for comments on this post