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My DTV Debacle

Kim Hart

Two months ago, my husband and I got rid of our subscription to satellite television service. We weren't watching it enough to justify the $75 a month fee, and it was a good way to cut down on our monthly expenses.

So instead we took advantage of a sale and got a new flat-screen plasma TV set to replace the 12-year-old CRT set that was on the fritz. With the major stations in the Washington area already airing digital signals, we were excited about getting the great digital picture on our gleaming new TV.

But when we set it all up and scanned for the stations, we only picked up a few. And the reception wasn't great. So we bought a $50 table-top antenna that a salesman at the electronic store said should be strong enough to pick up the stations. It turns out that it can pick up the stations, but only when the antenna is facing the precise direction of each station's tower.

So if I want to switch between a program on NBC and ABC, I have to get up each time and slightly adjust the antenna so the picture will come in clearly.

Many analog TV viewers have the same problem. But with analog TV, you can see the picture and hear the sound even if there's a bit of snow bleeding through. With digital TV, however, any disturbance causes the picture to freeze and the sound to cut out, making it nearly impossible to watch the show. The tendency of digital signals to dissolve due to any disruption is known as the "cliff effect."

It looks like we'll have to get a stronger rooftop antenna to pick up all the signals in our area without so much fuss. But I decided to fiddle around with the table-top antenna to be sure I couldn't find a way to make it work.

I extended the antennas. Pointed them in every direction. Put the antenna on the floor, then on top of a bookshelf. Finally I found a position on a nearby table pointing north. I rescanned the channels and they seemed to come in fairly clearly.

Relieved, I sat back down on the couch and started watching. Then the cat walked in front of the antenna -- and the picture froze. My husband sat on the love seat -- and the picture disappeared completely. I've resigned to having to install a big, awkward, not-so-pretty antenna on our roof.

We've written many times about the trouble some people will have receiving digital reception when the transition to digital TV happens June 12. (That's only 10 days away.)
If you have an ill-placed tree in your yard, you could lose a channel. If you live near tall buildings, several stations' signals may not be able to reach your TV. If you live more than 20 miles away from the towers (most of which are in Northwest Washington), you may not be able to pick up anything. Even with a new digital TV, you'll likely need to upgrade your antenna.

My advice: experiment with your set-up to make sure you can receive the signals. All the major stations in Washington are airing digital signals, so you should be able to receive them. Remember to use the "scan" function on your TV or converter box every time you make a change to your set-up.

And get your converter box and/or new antenna before June 12. Stores have limited supplies of this equipment and you should try to beat the rush. If you still haven't ordered a $40 converter box coupon from the Commerce Department, do so immediately. You already may be too late to receive it before midnight on June 12.

How are your set-ups working out? Stay tuned for more coverage as the transition draws closer.

For more resources and information about the switch, as well as stories we've published on the topic for the past two years, check out our DTV page.

By Kim Hart  |  June 2, 2009; 2:00 PM ET  | Category:  Kim Hart
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Please let us know if your reception and "digital freezes" improve after the June 12th date, when the stations should go to broadcasting with full power. That might make a difference. Currently many stations are not using their full power signal- and won't until the switch over.

Posted by: moonwatcher2001 | June 4, 2009 11:16 AM

Don't do anything too drastic until after the 12th. Many many stations will switch channels, some listed as 2-13 actually are now broadcasting digital on channels 14-60.

Some will stay where they are, others will come back to their analog channels. Here channels 8 and 12 are broadcasting on UHF in digital. After 9 am on the 12th, they will broadcast digital on channels 8 and 12, and the antennas for these stations may not be in the same place.

antennaweb.org gives the information on where the stations are now and where they will be after the 12th.

Posted by: eteonline | June 4, 2009 12:32 PM

Dear Kim,

So sorry to hear of your DTV problems. What you, and others, have described is a classic case of signal "quality" versus signal "quantity". I'll explain.

It turns out that DTV receivers are remarkably sensitive to both the channel's incident signal power as well as when the same incident signal also arrives at the receiver as an interfering signal, called "multipath". Multipath is when the incident signal is reflected off a building or other structure and arrives a short time period later and causes an interference with the incident signal. More multipath, more problems.

Unfortunately, DTV receivers are most times outfitted with signal strength meters (quantity) rather than the more important multipath meters (quality). Raising the power does not solve the problem since that also increases the power level of the multipath interference. Since they are both at the same frequency of interest (the channel you tune in), the receiver has difficulty sorting out which one is more important, the incident signal or the multipath signal. Sometimes the multipath signal only serves to inhibit decoding the signal properly. Whoops.

To prove this, an experiment was conducted in the suburbs of New Jersey during the DTV trials. A receiving antenna was mounted in a closet (no kidding) in the farthest position away from the TV station's antenna. It was demonstrated that more signal power to the receiver was not needed. Indeed, careful pointing of the antenna to discriminate *against* multipath signals that were overwhelming the incident signal was the acceptable and simple solution. This was a case where the "carrier to interference" ratio ("C/I") was maximized for proper decoding.

Regrettably, none of the DTV receiver manufacturers saw fit to use this more important modality as the means to correctly orient the antenna for maximum signal decoding reliability. They left it to the over the air viewer to resolve this. It is a shame because had they included or substituted this simple addition to the DTV receivers, it would have produced a much more satisfactory experience for DTV viewers.

Sorry, but over the air users have been hosed. Again.

In retrospect, it is an interesting way to get people to sign up for cable when they get too frustrated to deal with their antenna.

Posted by: HoofHearted | June 8, 2009 10:42 PM

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