A week before the Federal Communications Commission officially signed off on a plan for Ligado Networks to use L-Band spectrum, Rep. Peter DeFazio, D-Oregon, the chairman of the House Transportation and Infrastructure committee, sent a letter to Secretary of Transportation Elaine Chao, warning the plan could harm the Global Positioning System. The April missive was the first sign some members of Congress were unhappy with the plan, but it would not be the last, as officials from the departments of defense, transportation and other government agencies raised alarms about how Ligado’s system could damage GPS capability for the military and...