You may have noticed this week's RF Report is early due to Thanksgiving. With less news to report, it gives me an opportunity to discuss what I see as a major problem with the DTV conversion unrelated to the Feb. 17, 2000 analog shutoff. This problem only affects cable TV viewers and I don't see it getting the attention it deserves.
In the past, if you purchased a “cable-ready” analog TV set and hooked it up to any cable outlet in your house, local TV stations and other “basic” or “standard” cable channels could be received on the channels listed in the printed service guide. You might even have a channel listing the programming on all the channels for the next few hours.
Today, if you purchase a new DTV set and hook it up to an off-air antenna, the local stations will appear on known channels and, depending on the set, you may even be able to see a program guide on each channel. Take the same DTV receiver and hook it up to a cable outlet, then do a channel scan on the cable channels. Don't be surprised if your scan returns 100 channels or more!
If you've done this at home you know what happens next. Tuning through the channels, many will display black or are perhaps “scrambled.” Most cable systems carry local broadcast DTV channels and some other basic programming unencrypted, and eventually you will find them. Write down the channel number, as I doubt you will find it published anywhere except perhaps on an Internet forum. Don't be surprised if it stops working in a month or two, as the cable system changes the channel or PSIP data, requiring a new scan and search through the scrambled channels. Of course, the analog channels will be displayed as before.
I hope the cable companies are not doing this just to frustrate subscribers and force them to rent a digital converter box for every TV set in their house. More subscribers watching digital channels means that fewer viewers are depending on the spectrum-hogging analog cable signals. The FCC attempted to make it easier for viewers to watch digital cable without set-top boxes, instead using “CableCards,” which had to be rented from the cable company. Understandably, there wasn't a lot of interest in them and few DTV sets now offer this feature.
A new technology, tru2way, promises to offer interactivity and eliminates the need for DTV cable boxes. It’s being deployed by Comcast in Denver and Chicago. If the technology is successful, it should spread to other markets. This, of course, doesn't help the millions of viewers who already own DTV sets with QAM tuners.
In my opinion, cable companies should be required to pass along or, if necessary, repackage at least some of the critical PSIP information transmitted by broadcasters over-the-air.
This should include the station's major and minor channel numbers and the station name, as well as EIT/ETT data for the current program and, ideally, programming for at least the next 12 hours. Each station's major and minor cable channel number should also be published in cable channel listings, and subscribers notified when the channel or service number is changed. The FCC or Congress should require the transmission of accurate and complete PSIP data for “ClearQAM” sets before cable operators are allowed to shut off unscrambled basic or standard service analog channels and perhaps make it easier for them to reclaim analog channel spectrum if they do this.
While I'm not confident cable operators will do this without it being a legal requirement, I was encouraged by Rich Chernock's answer to a question about cable PSIP at the recent IEEE Broadcast Technology Symposium. Rich's company, Triveni Digital, is possibly the largest manufacturer of PSIP equipment. Rich said that Triveni Digital was starting to get calls from cable operators asking how they could implement PSIP, probably after receiving calls from subscribers frustrated with trying to find local DTV stations on their new DTV sets. I've also heard some stations have been able to get cable companies to carry their PSIP.
Are any readers using ClearQAM DTV receivers getting station PSIP data from their cable companies? Has your station been able to get the local cable company to carry its PSIP? Please share your experiences. It may help other TV stations and their digital cable viewers.
Doug Lung is one of America's foremost authorities on broadcast RF technology. He has been with NBC since 1985 and is currently vice president of broadcast technology for NBC/Telemundo stations.
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