BANGOR -- Because of Maine's topography, some TV viewers will be out of luck when the switch is made from analog to digital signals next month.

Even if they bought converter boxes, some TV viewers in remote areas won't be able to get digital television signals. The problem has to do with signal strength, not the converter boxes required for the long-awaited switch to digital television, scheduled for Feb. 17.

"The way a signal travels across a terrain, with analog, it fades gradually, but you can still get a picture," said Suzanne Goucher of the Maine Association of Broadcasters. "With digital, it's all or nothing."

This "cliff effect" means that people on the fringes of analog coverage areas who currently get fuzzy reception will lose that reception entirely.

Even the converter box issue has become problematic for some. In Maine, and all over the country, consumers who rely on free over-the-air TV channels are finding it hard to get coupons for the necessary digital converter boxes.

Last week, the Commerce Department ran out of money for coupons to subsidize digital converter boxes.

The coupon program funding shortfall was a key reason behind the Obama transition team's call for Congress to delay the Feb. 17 analog shutoff.

The latest data from a year ago indicated about 87,000 households in Maine relied on over-the-air analog TV signals, Goucher said.

To continue receiving signals after the switch to digital television, some of those TV viewers will need to upgrade antennas at a significant cost, in addition to getting converter boxes, said Wayne Jortner of the state public advocate's office.

"I'm sure some people might be upset by that," said Jortner. "A good antenna could cost $50-$100 plus installation."