The signal is part of the Enterprise Land Mobile Radio system, which is used by the military to coordinate responses with civil emergency workers, said Chris Zendan, a spokesman for submarine base in Groton.
The problem, first reported by The Day of New London, is that the same frequency is used at very low levels by the manufacturers of garage door openers. The signals from remote controls to open or close the doors are blocked by the signal from the base.
Overhead Door Co. of Norwich Inc. told the newspaper it has been receiving complaints from several towns near the base and has found no problem with its equipment. The Associated Press left messages with the company Monday.
Sondra Tuchman, of Montville, told the newspaper she has to get out of her car, stand in front of the door and press the remote for the opener to work. She said an installation company told her she would have to pay about $300 to change her system to another frequency.
The garage-door companies do not need to be licensed to use the frequency because the remote controls transmit at such low levels, Zendan said. But the homeland security needs for the signal take precedence, he said.
“Because garage door openers are unlicensed devices, they are not offered any protection from interference by licensed users in the same frequency band, and in fact are required by federal law to accept interference from licensed users,” Zendan said. “Base commanding officers do not have the authority to change those systems, and unfortunately we cannot offer compensation to the unlicensed users.”
For decades, the military has held a portion of the radio spectrum, from 138 to 450 megahertz, in reserve. But that range came back into use after the Sept. 11, 2001, terrorist attacks, when officials discovered they needed a new system to allow civil and military first responders to communicate.
The ELMR system, which uses radio frequencies between 380 and 399.9 megahertz, was developed. It began operating at the sub base last summer but is not unique to the state.
In 2006, residents around an Air Force facility in Colorado Springs, Colo., saw their garage-door remotes stop working when the 21st Space Wing began testing a frequency for use during homeland security emergencies or threats. In 2005, testing of a similar system in Fort Detrick in Maryland resulted in similar problems.
In May, Overhead Door Co. said it would offer free installation and parts to change the signal on remote garage door openers near a naval base in Newport, R.I.