For many suburbanites, life without garage door openers is unimaginable. But neighbors of the Marine base here have been reduced to just that after a strong radio signal coming from the facility began neutralizing remote-control openers.

Residents have had to spend hundreds of dollars on new systems. "I feel there should be some kind of compensation," said Queen Carroll, who is in her early 70s and was forced to buy a new receiver and remote. "I am a struggling widow, if you will, and I praise the Lord I'm still here, but I am on a budget. When things like this come up totally unexpected, it is very upsetting."

Repair shops started getting a flurry of calls when the base began using the frequency in late December. Last fall, residents around an Air Force facility in Colorado Springs saw their garage-door remotes stop working when the 21st Space Wing began testing a frequency for use during homeland security emergencies or threats. Two years ago, testing of a similar system in Fort Detrick in Maryland resulted in similar problems.

For decades, the military has held a portion of the radio spectrum, from 138 to 450 megahertz, in reserve. That part was borrowed by remote-control manufacturers, with the understanding that the signal be weak enough to be overridden by the military.

The reserve frequencies became active after the Sept. 11, 2001, attacks, when officials discovered that first responders could not communicate with one another because they were operating radios on different frequencies. The Defense Department is using the mothballed frequencies in a system that eventually will link military and civilian emergency responders. "Consumer wireless devices, such as garage door openers, operate on an unlicensed basis, meaning they are required to accept any interference from licensed spectrum users, including the Department of Defense," said Lt. Brian P. Donnelly, a spokesman for the Quantico base.