WATERLOO - When KWWL television made the switch to digital more than a month ago, some viewers who thought they were prepared for the switch learned they weren't.

On Feb. 18, the day after the switch, the Waterloo television station was flooded with hundreds of calls. Many people said they received the NBC-affiliate's digital signal fine before the change over but couldn't get a signal afterwards.

Some people still report problems with receiving the signal, a problem station officials hope a new, higher-powered transmitter solves. The new signal will go up next month and be six times as powerful as the current transmission, station officials said.

"We're hoping that's going to help people who have indoor antennas," said station manager Kim Leer.

The station switched from the UHF bandwidth to VHF when it made the digital transition. Many digital television antennas are UHF receivers, and unpowered VHF "rabbit ear" antennas haven't been much help for most viewers, said Jarrett Liddicoat, KWWL chief engineer.

The station will replace its 5-kilowatt digital transmitter with a 30-kilowatt transmitter in early May. Liddicoat said that may help some people pull in a signal, but added that having the right antenna is key.

"It's not so much the signal as it is the thing used to get it," he said.

For best reception station officials recommend a VHF antenna -bigger than a UHF antenna - or getting an outdoor antenna and aiming the antenna at the station's transmitter tower in Rowley.

In Liddicoat's second-floor workshop in the KWWL building, he has a television with a regular "rabbit ear" antenna. In the middle of the room, he can't get a signal. By placing the antenna up against the window, however, he now uses the antenna and television as one of his testers to see that the over-the-air signal from Rowley is good.

"Television is a line-of-sight technology," he said.

The problems with the switch to the VHF band go against some conventional wisdom.

Edie Herman, spokeswoman for the Federal Communications Commission, said it is unusual for a station to have problems going from UHF to VHF. The FCC has handled more problems and complaints from people unable to receive stations that switched from VHF to UHF.

Some viewers further away from the KWWL transmitter in Rowley may have an easier time picking up the signal than people closer to the tower.

Signals in the UHF band don't travel well over hills compared with the VHF band, according to engineering officials at the FCC. That means VHF signals may reach places UHF signals don't.

"We have people getting us in Wisconsin who were never getting us before," Liddicoat said.

KCRG in Cedar Rapids will be making a similar switch when that station goes to broadcasting exclusively in digital June 12. The current digital signal is on the UHF band and will move to VHF. Other stations in the market will remain on UHF.

Contact John Molseed at (319) 291-1418 or john.molseed@wcfcourier.com.