Too bad you blocked my posts. You might find this useful:

CG To Mariners: No GPS June 11-20
Boaters will be unable to rely on Global Positioning System (GPS) equipment
and possibly cell phones, because of scheduled disruptions from Friday, June
11 to Sunday, June 20 that will affect mariners transiting the waters of
North Carolina and parts of Florida.

GPS interference-testing conducted during an exercise by Department of
Defense will make the GPS signal unreliable and may affect cell phone
signals from about 50 to 60 miles off the coast of Cape Hatteras, N.C. and
approximately 80 miles out between Jacksonville and Melbourne, Fla.
Disruptions along the North Carolina coast will affect Albemarle Sound,
Pamlico Sound and the coastal North Carolina area from Currituck Beach Light
to Cape Lookout and the Intracoastal Waterways of North Carolina.

"The Coast Guard fully supports the efforts of the Department of Defense
during this important exercise," said Rear Admiral Sally Brice -O'Hara,
Commander of the Fifth Coast Guard District. "But, we must get the word out
to impacted mariners so they can take the necessary precautions to keep
themselves safe during this busy boating season."

Mariners should not rely on GPS or cell phones from June 11th to the 20th.
Plan ahead and use VHF radios to communicate on the water. A cell phone is a
good backup communications device, but out on the open water, it is no
substitute for a VHF marine radio.

Questions regarding the GPS testing should be directed to Major Sandra Burr
at (703) 697-5131.