Sec.  90.1209   Policies governing the use of the 4940–4990 MHz band.

   (a) Channels in this band are available on a shared basis only and will not
   be assigned for the exclusive use of any licensee.

   (b) All licensees shall cooperate in the selection and use of channels in
   order  to  reduce  interference and make the most effective use of the
   authorized facilities. Licensees of stations suffering or causing harmful
   interference are expected to cooperate and resolve this problem by mutually
   satisfactory arrangements. If licensees are unable to do so, the Commission
   may impose restrictions including specifying the transmitter power, antenna
   height, or area or hours of operation of the stations concerned. Further,
   the Commission may prohibit the use of any 4.9 GHz channel under a system
   license  at a given geographical location when, in the judgment of the
   Commission, its use in that location is not in the public interest.

   (c) Licensees will make every practical effort to protect radio astronomy
   operations as specified in  Sec. 2.106, footnote US311 of this chapter.

   (d) There is no time limit for which base and temporary fixed stations
   authorized under a 4940–4990 MHz band license must be placed in operation.
   Fixed point-to-point stations which are licensed on a site-by-site basis
   must  be placed in operation within 18 months of the grant date or the
   authorization for that station cancels automatically.