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© 2004 Door & Access Systems
Publish Date: Summer 2004
Author: Tom Wadsworth
Page 44


GDOs vs. Military Radios

A new U.S. military radio communications system may cause widespread garage door opener problems in areas near military bases.

In May, at Eglin Air Force Base in the Florida panhandle, a test of a new system resulted in dozens of complaints from homeowners whose remote controls failed to open their garage doors. The problem apparently affected garage door openers as far as 10 miles from Eglin.

The $5.5 million Land Mobile Radio (LMR) system, used by military police, fire, and medical users at Eglin, is being installed by Motorola. Colonel Russell Miller, Commander of the 96th Communications Group at Eglin, says Congress mandated the Department of Defense to change its land-based two-way radios from a wide-band system to a more efficient narrow-band system.

A Clash of Frequencies

Miller told Door & Access Systems that the new system is licensed to operate anywhere between 380 and 399.9 megahertz (MHz). For the first test at Eglin, conducted around May 10, Motorola broadcast a steady test signal at 390 MHz. However, that test attracted 60-70 telephone complaints to Eglin's Public Affairs office and possibly many more calls to other Eglin offices.

As Motorola soon discovered, 390 MHz is the same frequency commonly used by Chamberlain and Genie openers, according to Miller. For the next test, Motorola moved down to 387 MHz, and that decreased the problem significantly. Many other garage door opener remote controls, operating between 310 and 320 MHz, were unaffected.

"I have a LiftMaster opener with a frequency around 390 MHz. In our first test, it would work only if I was very close to it," says Col. Miller. "I was affected like everyone else."

Col. Miller explains, "If we can do something to lessen the problem so that we can all co-exist, that's the best solution." He adds, however, that when Eglin's system goes operational in July, "There's a possibility for this to intermittently interfere with garage door openers."

Who Must Move?

Technically, the federal government controls all frequencies between 225-399.9 MHz. The Federal Communications Commission (FCC) requires garage door openers to carry a disclaimer that says, "This device must accept any interference received, including interference that may cause undesired operation."

The FCC Web site explains that garage door remote control devices (also known as Part 15 devices) "are unlicensed and do not get protection from interference."

"If you're interfering with us, you have to cease and desist," says Col. Miller. "It's not like the government can move."

Colin Willmott, Chamberlain's director of engineering, international liaison, traveled to Eglin in May to monitor the testing of the system. "If we are forced to move because of excessive interference, we will, because we have no choice," says Willmott.

Col. Miller recognizes the potential inconvenience to our industry and to homeowners with GDO remote controls. "As a practical matter, (moving the frequency) is not something that's easy to do. It means replacing the logic boards, the receiver, and the transmitter," says Miller. "The homeowner would bear the cost of that."

New communications systems have the potential to affect many more areas than just Eglin. Col. Miller says the narrow-band mandate is from the Department of Defense and applies to all the military. Army, Navy, Air Force, and Marine bases are located all over the country.

Miller says the Naval Air Station in Pensacola will soon use the same band. It is believed that Puget Sound in Washington may also be in line for a new system.

It Could Be Worse

Stories of the garage door opener problems near Eglin were widely publicized. Reports were published by the Associated Press, USA Today, and internationally. One United Kingdom news outlet (the Inquirer), entitled their story, "Weapons of Mass Irritation."

The problems at Eglin may appear to be an annoyance, but Miller says the new communications system is "a good thing for the country."

"It would be a much worse problem if we had garage doors opening," he adds. That would leave homes open to intruders and theft. "But the very worst thing for a homeowner is that they cannot open their door."

To respond to this story, send an E-mail to daseditor@dasma.com.

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