Jamming (was Confiscation of Sensitive Video)

[Anonymous]

  Speaking of jamming, I've thought for a long time that a
portable jamming device would be very nice to have. Something
that jammed *all* frequencies, or at least everything from 
10 or maybe 6 meters on up, to a range of a mile or so at 
least.
  Anyone have any idea how difficult this would be to do?
And what the power requirements would be?