YOKOSUKA NAVAL BASE, Japan — The culprit this time was an American-made baby monitor.

The 900-megahertz cordless device interrupted a Japanese emergency frequency and prompted a call this month to Yokosuka Naval Base after Japanese officials pinpointed the monitor’s location at the Negishi Housing area.

The base catches static every so often as new military families move to Japan and switch on cordless devices they brought from home, said Yokosuka chief staff officer Cmdr. Jon Lundquist.

The problem is that 900-megahertz devices — commonly used stateside for cordless phones, baby monitors and walkie talkies — break into a frequency reserved in Japan for cellular phone communication and disaster prevention.

“We’ve received several calls reporting the interference on the emergency management frequency,” Lundquist said. “It’s a civilian frequency in CONUS, but here, it’s a much bigger issue.”

Even remote-controlled model aircraft, boats and cars brought from home can be problematic, said base safety director Lucky Hawkins, adding that a new instruction was written this past spring outlining where they can be used and at what frequencies.

Baby monitors interrupted cellular phone coverage twice in Sasebo’s Hario housing area last summer. The Japanese Ministry of Internal Affairs and Communications also pointedly gave U.S. Forces Japan a list of frequencies to avoid after two 2005 interruptions at Haneda airport coming from the general direction of Yokosuka Naval Base.

USFJ has a policy restricting frequencies, but is also working on a general order that will strengthen the enforcement of the issue throughout Japan and Okinawa, said USFJ spokesman Maj. Neil Murphy. It is taking time to draft as all of USFJ’s component commands are weighing in, he said.

The Navy Exchange has made it a point not to sell 900-megahertz devices in Japan and offers a selection of Japan-safe cordless appliances, Navy Exchange retail manager Rusti Rausch told residents at recent town hall meetings in the housing areas.

The issue also has been added to the base’s area orientation brief, Lundquist said, but — with new military families moving to Japan all the time — there will always be the need for reminders.

If there’s one thing to remember, it’s this, said Lundquist and base commanding officer Capt. Daniel Weed during recent town hall meetings: “If it’s cordless and made in the States, don’t use it.”

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