F*A*B
FAB was from a 60s show called Thunderbirds. It meant 'I got it' or 'I copy.' The guy who made the show, Gerry Anderson, had wild phrases like 'SIG' which meant 'Spectrum Is Green.' It was basically a fancy way of saying 'got it' and 'copy that.'
'Fab!' I yelled back to the radio. 'I got your order, over and out!'
He said 'SIG' and I knew he was ready for the next mission.
Fab was the best way to say 'I heard you.' It was like radio cool.