The story goes that Air Force One was over the UK a few years ago and called up a USAF base "Requesting Radar".
"What is you position?" asked ATC
"You got radar you find us" Air Force One replied.
After a few minutes ATC announced "Air Force One we're changing frequency"
"What frequency are you changing to?" asked Air Force One
"You've got 720 channels - you find us!" ATC replied.