WASHINGTON — Problems with old-fashioned television antennas were the most common issue among residents of Wilmington, N.C., a city that volunteered to switch to digital broadcasting more than five months before the rest of the country.

The troubles foreshadow the difficulties that viewers nationwide may face.

Wilmington’s commercial broadcasters turned off their analog signals at noon Monday. The rest of the nation’s full-power television stations won’t be converting until Feb. 17, a date set by Congress.

The Federal Communications Commission hopes the test will provide an early signal on problems with the transformation so it can react to any issues that may arise after the big change in February.

By late Tuesday, the FCC had not released a breakdown of consumer complaints from the Wilmington test. Some results could be drawn from a survey taken by Elon U. students who staffed call lines at local stations from noon Monday until 10 p.m.

It was clear that an ambitious public education campaign had paid off. Of the 172 calls that came in, only a few were from people unaware of the transition, said Connie Book, associate dean of the School of Communications at Elon and the leader of the research project.

“Virtually everyone was aware,” she said. “But being aware and doing something about it are two different things.”

Antenna problems were the No. 1 issue, Book said.

“People were saying, ‘I’m not getting a picture’ and they had a converter box,” she said. “And we had to say, ‘Your antenna is not powerful enough, or you don’t have one, or it’s pointed in the wrong direction, or the height needs to be raised.”‘

In February, Nielsen estimated that there were more than 13 million households in the U.S. with television sets that can receive only analog broadcasts. Just 8% of households in Wilmington are in that category, fewer than the national average.

Viewers who receive programming through an antenna and do not own newer-model digital TV sets by the time of the changeover must buy a converter box. The government is providing two $40 coupons per household to help defray the cost. Viewers who subscribe to a cable or satellite service won’t be affected.

While public education efforts have focused on ensuring that viewers are aware of the transition and the government coupon program, very little has been publicized about the potential need for antennas.

“Many reception issues are generally easy to resolve, but in some cases, in some areas, folks may need a better antenna,” said Andy Combs, general manager of WWAY, one of the stations that turned off its signal. “It’s best to figure all of that out ahead of time.”

A second issue has been that some people haven’t programmed their boxes to tune in the new stations, which actually go by tenths. For example, channel 6 is now channel 6.1.

“That was news to people,” Book said. “They would punch in 6 and not 6.1.”

Viewers who did not have digital-ready televisions were greeted after noon Monday by a screen crawl that included a phone number to call if they had questions. Late yesterday the FCC reported it had received “several hundred” calls.

All four of the city’s network TV affiliates as well as the Trinity Broadcasting Network have gone digital only. The local public television station is broadcasting both a digital and analog signal.