sign off

from WordNet (r) 3.0 (2006)

sign off
    v 1: cease broadcasting; get off the air; as of radio stations

from The Collaborative International Dictionary of English v.0.48

sign off \sign` off"\ (s[imac]n` [add]f"), v. i.
   To terminate a communication, especially one conducted by
   radio waves; to terminate a broadcast over radio or
   television; as, this is your reporter in Cairo, signing off.
   [PJC]

from Moby Thesaurus II by Grady Ward, 1.0

20 Moby Thesaurus words for "sign off":
      Teletype, beam, broadcast, cable, flash, newscast, radiate, radio,
      radiobroadcast, send, send a wire, shortwave, sign on, sportscast,
      telegram, telegraph, telex, transmit, wire, wireless

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