Sec.  97.121   Restricted operation.

   (a) If the operation of an amateur station causes general interference to
   the reception of transmissions from stations operating in the domestic
   broadcast service when receivers of good engineering design, including
   adequate   selectivity  characteristics,  are  used  to  receive  such
   transmissions, and this fact is made known to the amateur station licensee,
   the amateur station shall not be operated during the hours from 8 p.m. to
   10:30 p.m., local time, and on Sunday for the additional period from 10:30
   a.m. until 1 p.m., local time, upon the frequency or frequencies used when
   the interference is created.

   (b) In general, such steps as may be necessary to minimize interference to
   stations operating in other services may be required after investigation by
   the FCC.

Subpart C—Special Operations