Sec.  22.159   Computation of average terrain elevation.

   

   Link to an amendment published at  70 FR 19308 , Apr. 13, 2005.

   Average  terrain  elevation  must  be  calculated  by  computer  using
   elevations from a 30 second point or better topographic data file. The
   file  must  be identified. If a 30 second point data file is used, the
   elevation  data  must  be  processed  for  intermediate  points  using
   interpolation techniques; otherwise, the nearest point may be used. In
   cases of dispute, average terrain elevation determinations can also be
   done  manually,  if the results differ significantly from the computer
   derived averages.

   (a)  Radial  average terrain elevation is calculated as the average of
   the  elevation  along  a straight line path from 3 to 16 kilometers (2
   and  10  miles) extending radially from the antenna site. If a portion
   of  the  radial  path  extends  over  foreign territory or water, such
   portion  must  not be included in the computation of average elevation
   unless the radial path again passes over United States land between 16
   and  134  kilometers (10 and 83 miles) away from the station. At least
   50  evenly  spaced  data  points for each radial should be used in the
   computation.

   (b)  Average  terrain  elevation  is  the  average of the eight radial
   average terrain elevations (for the eight cardinal radials).

   (c)  For  locations  in Dade and Broward Counties, Florida, the method
   prescribed  above  may  be  used  or  average terrain elevation may be
   assumed to be 3 meters (10 feet).