Sec.  101.517   Antennas.

   (a) Transmitting antennas may be omnidirectional or directional, consistent
   with coverage and interference requirements.

   (b) The use of horizontal or vertical plane wave polarization, or right hand
   or left hand rotating elliptical polarization must be used to minimize
   harmful interference between stations.

   (c) Directive antennas must be used at all DEMS User Stations and may be
   elevated no higher than necessary to assure adequate service. Antenna
   structures requiring FAA notification under part 17 of this chapter must be
   registered with the Commission. The structure owner is responsible for
   registering, painting, and lighting the structure if applicable. Requests
   for such authorization must show the inclusive dates of the proposed
   operation.