Scrambler
WordNet
noun
(1) Electronic equipment that makes speech unintelligible during transmission and restores it at reception
(2) A lightweight motorcycle equipped with rugged tires and suspension; an off-road motorcycle designed for riding cross country or over unpaved ground
(3) A rapid mover; someone who scrambles
"Their quarterback was a good scrambler"
"Scramblers can often unnerve a better tennis player"