It’s hard to avoid Digital TV Transition ads these days. With less than two months till the nation’s TV stations switch to a new, all-digital transmission scheme, broadcasters and government officials are running thousands of public service advertisements warning viewers that unless they take action, millions of sets may turn into doorstops on Feb. 17.

Some stations are even running half-hour shows discussing the DTV transition and telling viewers how to buy and install converter boxes for their existing analog sets. Others are telling people how to find new digital TVs with tuners that can receive the new signals on their own.

All these ads make the process look deceptively easy, but unfortunately, it won’t be easy for everyone. In fact, after Feb. 17, a small but significant minority of viewers will never again be able to get the same variety of programming they get now. Some will have to spend hundreds of dollars for rotating outdoor antennas to match the reception they get today from the $3 rabbit ears that came with their old analog TV sets. Even then, the dirty little secret of digital broadcasting is that it won’t reach as many TV sets as the analog system we’ve used for the better part of seven decades.

First things first: if a set is hooked to a cable, satellite TV or fiber optic service, it won’t be affected by the switchover. These providers will continue to offer analog signals to their customers for a several years at least. But up to 20 million homes rely strictly on over-the-air broadcasts — and they’re disproportionately occupied by the poor and elderly. Even more may have cable service, but not in every room. Millions of these homes have secondary sets with antennas in bedrooms, kitchens, dens and rec rooms.

My 89-year-old mother-in-law inhabits one of those homes - or more precisely, an apartment on the 11th floor of a building in Chevy Chase, Md., just outside the District of Columbia line. I’m being specific here so you’ll understand that Jenny doesn’t live in a “fringe” reception area, but smack in the middle of metropolitan Washington.

Like many apartment houses, this one does not provide a cable feed in every room - just in the formal living area, where Jenny doesn’t have a TV set, and in the adjacent bedroom, which she uses as a den and where she watches most of her shows.

The problem arises because she likes to watch the news at night while she’s eating at the kitchen table — a habit shared by millions of Americans. For years she has used a 13-inch portable set with rabbit ears. Since the kitchen is smack in the middle of a well-constructed apartment house, the reception there was never perfect, but Jenny could get every Washington channel well enough to see the picture and hear the newscast without straining. That was okay: because of the apartment’s floor plan and construction, it would be prohibitively expensive to run cable into the kitchen.

Because I worry about these things, I decided to see how Jenny would fare under the new digital regime. So I bought a digital converter box from Best Buy and hooked it up to her old TV. Instead of using the rabbit ears that came with the set, I attached a new, powered RCA rabbit ears antenna advertised as being HDTV-compatible.

Bottom line: after a couple of hours of finagling the antenna, I could never receive digital broadcasts from more than 5 of the 8 major stations, and often fewer. I couldn’t get the digital broadcast from Maryland Public Television at all, although the DC public stations were usually available.

On the old analog set, the stations were all available, even if the pictures were snowy. But digital TV is subject to the “fall-off-a-cliff” effect. Unlike analog tuners, which will display the best picture they can, a digital tuner won’t display an image if it doesn’t think the signal is good enough. So you’ll get a great picture — or none at all. I’m sure my mother-in-law will enjoy this improvement when she can’t watch her favorite anchor on Channel 4.

Nor will it help to fiddle with the rabbit ears till you get something watchable. To get a digital tuner to recognize a station at all, you have to put it through a scan of the entire spectrum - a process that can take 5 to 10 minutes. If a station doesn’t show up, you have to adjust the antenna, run another scan to see if it works, then check all the other stations to see if any of them dropped out because you’d moved the antenna to get the first missing station. Then, if you do lose another station, you have to position the antenna again and run yet another scan to see if you can get the other station back, and so on, ad nauseum. It’s infuriating.

Being a troubleshooter by nature, I figured Jenny’s problem might lie with the converter box. I mean, how much can you expect for $40? Since the picture on the old TV was a bit faded anyway, I bought a nice new flat panel set, which would also occupy less real estate in her cramped kitchen. I brought the 15-inch LCD model at Best Buy, hooked it to the antenna and guess what? Even with its new, and presumably better, built-in tuner, I had the same problem. The new digital TV displayed a great image when it found a digital station, but it couldn’t ever find them all.

Since the set also has an analog tuner that does bring in every channel, Jenny has been only marginally inconvenienced so far. But she asked me what would happen after Feb. 17, and I told her she was likely to lose two or three channels in the kitchen. The problem is that it’s impossible to tell which ones. That’s because half of Washington’s stations are broadcasting digitally on temporary frequencies. They won’t change to their permanent frequencies until the day of the switchover.

Because digital signals are more subject to physical interference than analog transmissions, there’s no way of knowing just how bad things will get. Also, because many stations are still broadcasting digitally at half power to save money on electricity, some of the problems I found may go away on Feb. 17. Or not.

Homeowners may be forced to spend hundreds of dollars on external antennas to get the same stations they get today for nothing — but at least there’s a good chance that will solve the problem. In millions of apartments like my mother-in-law’s, where external antennas aren’t an option, viewers are just out of luck.

If you think this is a rotten state of affairs, you’re right.  It’s the result of an unholy alliance between broadcasters, government and TV manufacturers who decided to fix something that wasn’t broken and get you and me to pay for it. Read more about the transition on my DTV Q&A page.