See also:

Global Positioning System (GPS)
○ Obstruction of the GPS can occur in a large city with tall buildings; in parking garages; around airports; in tunnels, underpasses, or parking garages; or in an area with very dense trees. ...

Tips and Troubleshooting Chart
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DVD Distortion
Video distortion can occur when operating cellular phones, scanners, CB radios, Global Position Systems (GPS)*, two-way radios, mobile faxes, or walkie talkies. It might be necessary to turn off the ...