The following information comes from the JPL DSN website
     (http://deepspace.jpl.nasa.gov/dsn/antennas/34m.html)
 
      The DSS-25 antenna is located at the Apollo site of the
      Goldstone Deep Space Communications Complex in Fort Irwin,
      California, USA. The 34-meter Beam Waveguide (BWG) antenna is
      based on that of the 34-meter High-Efficiency antenna, and
      provides the same basic performance parameters. The mount is an
      azimuth-elevation type and operates in both axes at 0.40
      degree/second.
 
      A major change in the design is the addition of five precision
      radio frequency mirrors that reflect radio signals along a
      beam-waveguide tube from the vertex of the antenna to the
      below-ground pedestal equipment room. This design allows:
        - The relocation of sensitive electronics from a feed cone in
          the center of the main reflector to the pedestal equipment
          room.
        - Easier access for maintenance and modification (such as
          adding new electronics for transmitting and receiving at
          additional radio frequency bands when needed to support
          future deep space missions.