Sec.  80.92   Prevention of interference.

   (a) The station operator must determine that the frequency is not in use by
   monitoring the frequency before transmitting, except for transmission of
   signals of distress.

   (b) When a radiocommunication causes interference to a communication which
   is already in progress, the interfering station must cease transmitting at
   the request of either party to the existing communication. As between
   nondistress traffic seeking to commence use of a frequency, the priority is
   established under  Sec. 80.91.

   (c) Except in cases of distress, communications between ship stations or
   between ship and aircraft stations must not interfere with public coast
   stations. The ship or aircraft stations which cause interference must stop
   transmitting or change frequency upon the first request of the affected
   coast station.