Sec.  101.117   Antenna polarization.

   Except  as  set forth herein, stations operating in the radio services
   included in this part are not limited as to the type of polarization of the
   radiated signal that may be employed. However, in the event interference in
   excess of permissible levels is caused to the operation of other stations as
   a result of employing other than linear polarization, the Commission may
   order  a  licensee  to  change its system polarization to mitigate the
   interference.  No  change  in  polarization  may be made without prior
   authorization from the Commission. Unless otherwise allowed, only linear
   polarization (horizontal and vertical) shall be used. For LMDS systems,
   unless otherwise authorized, system operators are permitted to use any
   polarization within its service area, but only vertical and/or horizontal
   polarization for antennas located within 20 kilometers of the outermost edge
   of their service area.

   [ 68 FR 4957 , Jan. 31, 2003]