SPLAT!(1)                 KD2BD Software                SPLAT!(1)



NAME
       splat - An RF Signal Propagation, Loss, And Terrain analy-
       sis tool

SYNOPSIS
       splat [-t   transmitter_site.qth]  [-r  receiver_site.qth]
       [-c   rx   antenna   height   for  LOS  coverage  analysis
       (feet/meters) (float)] [-L rx antenna height for  Longley-
       Rice  coverage  analysis  (feet/meters)  (float)] [-p ter-
       rain_profile.ext]    [-e    elevation_profile.ext]     [-h
       height_profile.ext] [-H normalized_height_profile.ext] [-l
       Longley-Rice_profile.ext]    [-o     topographic_map_file-
       name.ppm]   [-b   cartographic_boundary_filename.dat]  [-s
       site/city_database.dat] [-d sdf_directory_path] [-m  earth
       radius multiplier (float)] [-f frequency (MHz) for Fresnel
       zone calculations (float)]  [-R  maximum  coverage  radius
       (miles/kilometers)  (float)] [-dB maximum attenuation con-
       tour to display on path loss maps (80-230 dB)] [-nf do not
       plot  Fresnel  zones in height plots] [-plo path_loss_out-
       put_file.txt]   [-pli   path_loss_input_file.txt]    [-udt
       user_defined_terrain_file.dat]  [-n]  [-N]  [-geo]  [-kml]
       [-metric]

DESCRIPTION
       SPLAT! is a powerful terrestrial RF propagation  and  ter-
       rain  analysis  tool  covering the spectrum between 20 MHz
       and 20 GHz.  SPLAT! is free software, and is designed  for
       operation on Unix and Linux-based workstations.  Redistri-
       bution and/or modification is permitted under the terms of
       the  GNU  General  Public License as published by the Free
       Software Foundation, either version 2 of  the  License  or
       any later version.  Adoption of SPLAT! source code in pro-
       prietary or closed-source applications is a  violation  of
       this license, and is strictly forbidden.

       SPLAT!  is distributed in the hope that it will be useful,
       but WITHOUT ANY WARRANTY, without even  the  implied  war-
       ranty  of MERCHANTABILITY or FITNESS FOR A PARTICULAR PUR-
       POSE. See the GNU General Public License for more details.

INTRODUCTION
       Applications  of SPLAT! include the visualization, design,
       and link budget analysis of wireless  Wide  Area  Networks
       (WANs), commercial and amateur radio communication systems
       above 20 MHz, microwave links, frequency coordination  and
       interference  studies, and the determination of analog and
       digital terrestrial radio and television contour  regions.

       SPLAT!  provides  RF  site  engineering data such as great
       circle distances and bearings between sites, antenna  ele-
       vation  angles  (uptilt),  depression  angles  (downtilt),
       antenna height above mean sea level, antenna height  above
       average  terrain, bearings and distances to known obstruc-
       tions, and Longley-Rice path  attenuation.   In  addition,
       the  minimum  antenna  height requirements needed to clear
       terrain, the first Fresnel zone,  and  60%  of  the  first
       Fresnel zone are also provided.

       SPLAT! produces reports, graphs, and high resolution topo-
       graphic maps that depict line-of-sight paths, and regional
       path  loss  contours through which expected coverage areas
       of transmitters and  repeater  systems  can  be  obtained.
       When performing line-of-sight analysis in situations where
       multiple  transmitter  or  repeater  sites  are  employed,
       SPLAT!  determines individual and mutual areas of coverage
       within the network specified.

       Simply typing splat on the command line will return a sum-
       mary of SPLAT!'s command line options:

                      --==[  SPLAT!  v1.2.0  Available Options...
       ]==--

             -t txsite(s).qth (max of 4)
             -r rxsite.qth
             -c plot coverage of TX(s) with an RX  antenna  at  X
       feet/meters AGL
             -L  plot  path  loss  map  of TX based on an RX at X
       feet/meters AGL
             -s filename(s) of city/site file(s) to  import  (max
       of 5)
             -b  filename(s)  of cartographic boundary file(s) to
       import (5 max)
             -p filename of terrain profile graph to plot
             -e filename of terrain elevation graph to plot
             -h filename of terrain height graph to plot
             -H filename of normalized terrain  height  graph  to
       plot
             -l filename of Longley-Rice graph to plot
             -o filename of topographic map to generate (.ppm)
             -u filename of user-defined terrain file to import
             -d  sdf  file  directory  path  (overrides  path  in
       ~/.splat_path file)
             -n no analysis, brief report
             -N no analysis, no report
             -m earth radius multiplier
             -f frequency for Fresnel zone calculation (MHz)
             -R modify default range for -c or -L  (miles/kilome-
       ters)
            -db maximum loss contour to display on path loss maps
       (80-230 dB)
            -nf do not plot Fresnel zones in height plots
           -plo filename of path-loss output file
           -pli filename of path-loss input file
           -udt filename of user defined terrain input file
           -geo generate a .geo georeference file (with .ppm out-
       put)
           -kml  generate a Google Earth .kml file (for point-to-
       point links)
        -metric employ metric rather than imperial units for  all
       user I/O


INPUT FILES
       SPLAT!  is  a  command-line  driven application, and reads
       input data through a number of data files.  Some files are
       mandatory  for  successful execution of the program, while
       others are optional.  Mandatory files include 3-arc second
       topography  models  in  the  form of SPLAT Data Files (SDF
       files), site location files (QTH files), and  Longley-Rice
       model parameter files (LRP files).  Optional files include
       city location files, cartographic  boundary  files,  user-
       defined  terrain files, path-loss input files, and antenna
       radiation pattern files.

SPLAT DATA FILES
       SPLAT! imports topographic data in the form of SPLAT  Data
       Files  (SDFs).  These files may be generated from a number
       of information sources.  In the United States, SPLAT  Data
       Files  can  be  generated  through U.S.  Geological Survey
       Digital Elevation Models (DEMs) using the usgs2sdf utility
       included  with SPLAT!.  USGS Digital Elevation Models com-
       patible  with  this  utility  may  be   downloaded   from:
       http://edcftp.cr.usgs.gov/pub/data/DEM/250/.

       Significantly   better  resolution  and  accuracy  can  be
       obtained through the use of SRTM-3 Version 2 digital  ele-
       vation models.  These models are the product of the STS-99
       Space Shuttle Radar Topography Mission, and are  available
       for most populated regions of the Earth.  SPLAT Data Files
       may  be  generated  from  SRTM  data  using  the  included
       srtm2sdf  utility.   SRTM-3 Version 2 data may be obtained
       through           anonymous           FTP            from:
       ftp://e0srp01u.ecs.nasa.gov:21/srtm/version2/

       Despite  the  higher accuracy that SRTM data has to offer,
       some voids  in  the  data  sets  exist.   When  voids  are
       detected,  the  srtm2sdf utility replaces them with corre-
       sponding data found in existing SDF files (that were  pre-
       sumably   created  from  earlier  USGS  data  through  the
       usgs2sdf utility).  If USGS-derived SDF data is not avail-
       able,  voids are handled through adjacent pixel averaging,
       or direct replacement.

       SPLAT Data Files contain integer value topographic  eleva-
       tions  (in  meters)  referenced  to  mean  sea  level  for
       1-degree by 1-degree regions of the earth with  a  resolu-
       tion  of  3-arc  seconds.  SDF files can be read in either
       standard format (.sdf) as generated by  the  usgs2sdf  and
       srtm2sdf   utilities,   or   in  bzip2  compressed  format
       (.sdf.bz2).  Since uncompressed  files  can  be  processed
       slightly  faster  than  files  that  have been compressed,
       SPLAT! searches for needed SDF data in uncompressed format
       first.   If  uncompressed  data  cannot be located, SPLAT!
       then searches for data in bzip2 compressed format.  If  no
       compressed   SDF   files  can  be  found  for  the  region
       requested, SPLAT! assumes the region is  over  water,  and
       will assign an elevation of sea-level to these areas.

       This  feature  of SPLAT! makes it possible to perform path
       analysis not only over  land,  but  also  between  coastal
       areas  not  represented  by  Digital Elevation Model data.
       However, this behavior of SPLAT!  underscores  the  impor-
       tance  of having all the SDF files required for the region
       being analyzed if meaningful results are to be expected.

SITE LOCATION (QTH) FILES
       SPLAT! imports site location  information  of  transmitter
       and  receiver  sites  analyzed  by  the program from ASCII
       files having a .qth  extension.   QTH  files  contain  the
       site's name, the site's latitude (positive if North of the
       equator, negative if  South),  the  site's  longitude  (in
       degrees  West,  0  to 360 degrees), and the site's antenna
       height above ground level (AGL), each separated by a  sin-
       gle line-feed character.  The antenna height is assumed to
       be specified in feet unless followed by the  letter  m  or
       the  word  meters in either upper or lower case.  Latitude
       and longitude information may be expressed in either deci-
       mal  format (74.6889) or degree, minute, second (DMS) for-
       mat (74 41 20.0).

       For example, a site location  file  describing  television
       station  WNJT,  Trenton,  NJ (wnjt.qth) might read as fol-
       lows:

               WNJT
               40.2833
               74.6889
               990.00

       Each transmitter and receiver site analyzed by SPLAT! must
       be represented by its own site location (QTH) file.

LONGLEY-RICE PARAMETER (LRP) FILES
       Longley-Rice  parameter data files are required for SPLAT!
       to determine RF path loss in either point-to-point or area
       prediction  mode.   Longley-Rice  model  parameter data is
       read from files having the same base name as the transmit-
       ter site QTH file, but with a format (wnjt.lrp):

               15.000  ; Earth Dielectric Constant (Relative per-
       mittivity)
               0.005   ; Earth Conductivity (Siemens per meter)
               301.000 ; Atmospheric Bending Constant (N-units)
               700.000 ; Frequency in MHz (20 MHz to 20 GHz)
               5       ; Radio Climate (5 =  Continental  Temper-
       ate)
               0       ; Polarization (0 = Horizontal, 1 = Verti-
       cal)
               0.5     ; Fraction of  situations  (50%  of  loca-
       tions)
               0.5     ; Fraction of time (50% of the time)

       If  an LRP file corresponding to the tx_site QTH file can-
       not be found, SPLAT! scans the current  working  directory
       for  the  file "splat.lrp".  If this file cannot be found,
       then the default parameters listed above will be  assigned
       by  SPLAT! and a corresponding "splat.lrp" file containing
       this data will be written to the  current  working  direc-
       tory.   "splat.lrp"  can  then  be  edited  by the user as
       needed.

       Typical Earth dielectric constants and conductivity values
       are as follows:

                                  Dielectric Constant  Conductiv-
       ity
               Salt water       :        80                5.000
               Good ground      :        25                0.020
               Fresh water      :        80                0.010
               Marshy land      :        12                0.007
               Farmland, forest :        15                0.005
               Average ground   :        15                0.005
               Mountain, sand   :        13                0.002
               City             :         5                0.001
               Poor ground      :         4                0.001

       Radio climate codes used by SPLAT! are as follows:

               1: Equatorial (Congo)
               2: Continental Subtropical (Sudan)
               3: Maritime Subtropical (West coast of Africa)
               4: Desert (Sahara)
               5: Continental Temperate
               6: Maritime Temperate,  over  land  (UK  and  west
       coasts of US & EU)
               7: Maritime Temperate, over sea

       The  Continental Temperate climate is common to large land
       masses in the temperate zone, such as the  United  States.
       For  paths shorter than 100 km, there is little difference
       between Continental and Maritime Temperate climates.

       The final two parameters in the .lrp  file  correspond  to
       the  statistical  analysis  provided  by  the Longley-Rice
       model.  In this example, SPLAT!  will return  the  maximum
       path  loss occurring 50% of the time (fraction of time) in
       50% of situations (fraction of situations).  In the United
       States, use a fraction of time parameter of 0.97 for digi-
       tal television (8VSB modulation), or 0.50 for analog (VSB-
       AM+NTSC) transmissions.

       For   further   information   on  these  parameters,  see:
       http://flattop.its.bldrdoc.gov/itm.html                and
       http://www.softwright.com/faq/engineering/prop_long-
       ley_rice.html

CITY LOCATION FILES
       The names and locations of cities, tower sites,  or  other
       points  of  interest  may be imported and plotted on topo-
       graphic maps generated  by  SPLAT!.   SPLAT!  imports  the
       names  of cities and locations from ASCII files containing
       the location of interest's name, latitude, and  longitude.
       Each  field is separated by a comma.  Each record is sepa-
       rated by a single line feed character.  As  was  the  case
       with  the  .qth  files, latitude and longitude information
       may be entered in either decimal or degree, minute, second
       (DMS) format.

       For example (cities.dat):

               Teaneck, 40.891973, 74.014506
               Tenafly, 40.919212, 73.955892
               Teterboro, 40.859511, 74.058908
               Tinton Falls, 40.279966, 74.093924
               Toms River, 39.977777, 74.183580
               Totowa, 40.906160, 74.223310
               Trenton, 40.219922, 74.754665

       A  total  of five separate city data files may be imported
       at a time, and there is no limit  to  the  size  of  these
       files.   SPLAT!  reads  city  data  on a "first come/first
       served" basis, and plots only those locations whose  anno-
       tations do not conflict with annotations of locations read
       earlier in the current city  data  file,  or  in  previous
       files.   This  behavior minimizes clutter in SPLAT! gener-
       ated topographic maps, but also  mandates  that  important
       locations be placed toward the beginning of the first city
       data file, and locations less important be positioned fur-
       ther down the list or in subsequent data files.

       City  data  files may be generated manually using any text
       editor, imported from other sources, or derived from  data
       available  from  the  U.S. Census Bureau using the cityde-
       coder utility included with SPLAT!.  Such data  is  avail-
       able  free  of charge via the Internet at: http://www.cen-
       sus.gov/geo/www/cob/bdy_files.html, and must be  in  ASCII
       format.

CARTOGRAPHIC BOUNDARY DATA FILES
       Cartographic  boundary  data  may also be imported to plot
       the boundaries of cities, counties,  or  states  on  topo-
       graphic  maps  generated  by SPLAT!.  Such data must be of
       the form of ARC/INFO Ungenerate  (ASCII  Format)  Metadata
       Cartographic  Boundary  Files,  and are available from the
       U.S.     Census    Bureau    via    the    Internet    at:
       http://www.census.gov/geo/www/cob/co2000.html#ascii    and
       http://www.census.gov/geo/www/cob/pl2000.html#ascii.     A
       total  of five separate cartographic boundary files may be
       imported at a time.  It is not necessary to  import  state
       boundaries   if   county   boundaries  have  already  been
       imported.

PROGRAM OPERATION
       SPLAT! is invoked via the command-line using a  series  of
       switches  and arguments.  Since SPLAT! is a CPU and memory
       intensive application, this type  of  interface  minimizes
       overhead  and lends itself well to scripted (batch) opera-
       tions.  SPLAT!'s CPU and memory scheduling priority may be
       modified through the use of the Unix nice command.

       The number and type of switches passed to SPLAT! determine
       its mode of operation and method of  output  data  genera-
       tion.   Nearly all of SPLAT!'s switches may be cascaded in
       any order on the command line when invoking the program.

       SPLAT! operates  in  two  distinct  modes:  point-to-point
       mode,  and  area  prediction mode.  Either a line-of-sight
       (LOS) or Longley-Rice Irregular Terrain (ITM)  propagation
       model may be invoked by the user.  True Earth, four-thirds
       Earth, or any other user-defined Earth radius may be spec-
       ified when performing line-of-sight analysis.

POINT-TO-POINT ANALYSIS
       SPLAT! may be used to perform line-of-sight terrain analy-
       sis between two specified site locations.  For example:

       splat -t tx_site.qth -r rx_site.qth

       invokes  a  line-of-sight  terrain  analysis  between  the
       transmitter  specified  in tx_site.qth and receiver speci-
       fied in rx_site.qth using a True Earth radius  model,  and
       writes  a SPLAT! Obstruction Report to the current working
       directory.  The report contains details of the transmitter
       and  receiver  sites,  and  identifies the location of any
       obstructions detected along the line-of-sight path.  If an
       obstruction  can be cleared by raising the receive antenna
       to a greater altitude, SPLAT! will  indicate  the  minimum
       antenna  height required for a line-of-sight path to exist
       between the transmitter and receiver locations  specified.
       Note  that  imperial  units  (miles,  feet)  are specified
       unless the -metric switch is  added  to  SPLAT!'s  command
       line options:

       splat -t tx_site.qth -r rx_site.qth -metric

       If  the  antenna must be raised a significant amount, this
       determination may take  a  few  moments.   Note  that  the
       results  provided are the minimum necessary for a line-of-
       sight path to exist, and in the case of this simple  exam-
       ple,  do not take Fresnel zone clearance requirements into
       consideration.

       qth extensions are assumed by SPLAT! for  QTH  files,  and
       are  optional  when  specifying -t and -r arguments on the
       command-line.  SPLAT! automatically reads all  SPLAT  Data
       Files  necessary  to  conduct the terrain analysis between
       the sites specified.  SPLAT!  searches  for  the  required
       SDF  files in the current working directory first.  If the
       needed files are not found, SPLAT! then  searches  in  the
       path specified by the -d command-line switch:

       splat -t tx_site -r rx_site -d /cdrom/sdf/

       An  external  directory path may be specified by placing a
       ".splat_path" file under the user's home directory.   This
       file  must  contain the full directory path of last resort
       to all the SDF files.  The path in  the  $HOME/.splat_path
       file must be of the form of a single line of ASCII text:

       /opt/splat/sdf/

       and can be generated using any text editor.

       A  graph  of  the terrain profile between the receiver and
       transmitter locations as a function of distance  from  the
       receiver can be generated by adding the -p switch:

       splat -t tx_site -r rx_site -p terrain_profile.png

       SPLAT!  invokes gnuplot when generating graphs.  The file-
       name extension specified to SPLAT! determines  the  format
       of  the graph produced.  .png will produce a 640x480 color
       PNG graphic file, while .ps or  .postscript  will  produce
       postscript  output.   Output in formats such as GIF, Adobe
       Illustrator, AutoCAD  dxf,  LaTeX,  and  many  others  are
       available.  Please consult gnuplot, and gnuplot's documen-
       tation for details on all the supported output formats.

       A graph of elevations subtended by the terrain between the
       receiver  and  transmitter  as a function of distance from
       the receiver can be generated by using the -e switch:

       splat -t tx_site -r rx_site -e elevation_profile.png

       The graph produced using this switch illustrates the  ele-
       vation  and  depression  angles resulting from the terrain
       between the receiver's location and the  transmitter  site
       from the perspective of the receiver's location.  A second
       trace is plotted  between  the  left  side  of  the  graph
       (receiver's location) and the location of the transmitting
       antenna on the right.  This trace illustrates  the  eleva-
       tion  angle  required  for  a  line-of-sight path to exist
       between the receiver and transmitter  locations.   If  the
       trace intersects the elevation profile at any point on the
       graph, then this is an  indication  that  a  line-of-sight
       path  does  not  exist under the conditions given, and the
       obstructions can be clearly identified on the graph at the
       point(s) of intersection.

       A  graph illustrating terrain height referenced to a line-
       of-sight path between the transmitter and receiver may  be
       generated using the -h switch:

       splat -t tx_site -r rx_site -h height_profile.png

       A  terrain  height  plot normalized to the transmitter and
       receiver antenna heights can  be  obtained  using  the  -H
       switch:

       splat  -t  tx_site  -r  rx_site  -H normalized_height_pro-
       file.png

       A contour of the Earth's curvature is also plotted in this
       mode.

       The  first Fresnel Zone, and 60% of the first Fresnel Zone
       can be added to height profile graphs  by  adding  the  -f
       switch,  and  specifying a frequency (in MHz) at which the
       Fresnel Zone should be modeled:

       splat  -t  tx_site  -r  rx_site  -f  439.250  -H   normal-
       ized_height_profile.png

       A  graph  showing  Longley-Rice  path  loss may be plotted
       using the -l switch:

       splat -t tx_site -r rx_site -l path_loss_profile.png

       As before, adding the -metric switch forces the graphs  to
       be plotted using metric units of measure.

       When  performing  path loss profiles, a Longley-Rice Model
       Path Loss Report is generated by SPLAT! in the form  of  a
       text file with a .lro filename extension.  The report con-
       tains bearings and distances between the  transmitter  and
       receiver,  as well as the Longley-Rice path loss for vari-
       ous distances between the transmitter and  receiver  loca-
       tions.   The mode of propagation for points along the path
       are given as Line-of-Sight, Single Horizon,  Double  Hori-
       zon, Diffraction Dominant, and Troposcatter Dominant.

       To  determine  the  signal-to-noise  (SNR) ratio at remote
       location where random Johnson (thermal) noise is the  pri-
       mary limiting factor in reception:

       SNR=T-NJ-L+G-NF

       where T is the ERP of the transmitter in dBW in the direc-
       tion of the receiver, NJ is Johnson Noise in dBW (-136 dBW
       for  a  6 MHz television channel), L is the path loss pro-
       vided by SPLAT!  in dB (as a positive number),  G  is  the
       receive  antenna  gain in dB over isotropic, and NF is the
       receiver noise figure in dB.

       T may be computed as follows:

       T=TI+GT

       where TI is actual amount of RF  power  delivered  to  the
       transmitting  antenna  in  dBW,  GT  is  the  transmitting
       antenna gain (over isotropic)  in  the  direction  of  the
       receiver (or the horizon if the receiver is over the hori-
       zon).

       To compute how much more signal is available over the min-
       imum  to  necessary  to achieve a specific signal-to-noise
       ratio:

       Signal_Margin=SNR-S

       where S is the minimum required SNR  ratio  (15.5  dB  for
       ATSC (8-VSB) DTV, 42 dB for analog NTSC television).

       A  topographic map may be generated by SPLAT! to visualize
       the path between the transmitter and receiver  sites  from
       yet  another  perspective.   Topographic maps generated by
       SPLAT! display elevations using a  logarithmic  grayscale,
       with higher elevations represented through brighter shades
       of gray.  The dynamic range of the image is scaled between
       the highest and lowest elevations present in the map.  The
       only exception to this is sea-level, which is  represented
       using the color blue.

       Topographic output is invoked using the -o switch:

       splat -t tx_site -r rx_site -o topo_map.ppm

       The  .ppm  extension  on the output filename is assumed by
       SPLAT!, and is optional.

       In this example, topo_map.ppm will  illustrate  the  loca-
       tions of the transmitter and receiver sites specified.  In
       addition, the great circle path between the two sites will
       be  drawn  over  locations  for which an unobstructed path
       exists to the transmitter at a  receiving  antenna  height
       equal   to   that  of  the  receiver  site  (specified  in
       rx_site.qth).

       It may desirable to  populate  the  topographic  map  with
       names  and  locations  of  cities,  tower  sites, or other
       important locations.  A city file may be passed to  SPLAT!
       using the -s switch:

       splat -t tx_site -r rx_site -s cities.dat -o topo_map

       Up  to five separate city files may be passed to SPLAT! at
       a time following the -s switch.

       County and state boundaries may be added  to  the  map  by
       specifying  up  to  five  U.S.  Census Bureau cartographic
       boundary files using the -b switch:

       splat -t tx_site -r rx_site -b co34_d00.dat -o topo_map

       In situations where multiple transmitter sites are in use,
       as  many as four site locations may be passed to SPLAT! at
       a time for analysis:

       splat -t tx_site1 tx_site2 tx_site3 tx_site4 -r rx_site -p
       profile.png

       In  this  example,  four  separate  terrain  profiles  and
       obstruction reports will be generated by SPLAT!.  A single
       topographic  map can be specified using the -o switch, and
       line-of-sight  paths  between  each  transmitter  and  the
       receiver  site indicated will be produced on the map, each
       in its own color.  The path between the first  transmitter
       specified  to  the  receiver  will  be  in green, the path
       between the second transmitter and the receiver will be in
       cyan,  the  path  between  the  third  transmitter and the
       receiver will be in  violet,  and  the  path  between  the
       fourth transmitter and the receiver will be in sienna.

       SPLAT!  generated  topographic  maps  are 24-bit TrueColor
       Portable PixMap (PPM) images.  They may be viewed, edited,
       or  converted  to  other  graphic formats by popular image
       viewing applications such as xv,  The  GIMP,  ImageMagick,
       and XPaint.  PNG format is highly recommended for lossless
       compressed storage of SPLAT!  generated topographic output
       files.  ImageMagick's command-line utility easily converts
       SPLAT!'s PPM files to PNG format:

       convert splat_map.ppm splat_map.png

       Another excellent  PPM  to  PNG  command-line  utility  is
       available                                              at:
       http://www.libpng.org/pub/png/book/sources.html.    As   a
       last  resort,  PPM files may be compressed using the bzip2
       utility, and read directly by The GIMP in this format.

REGIONAL COVERAGE ANALYSIS
       SPLAT! can analyze a transmitter or repeater site, or net-
       work  of sites, and predict the regional coverage for each
       site specified.  In this mode, SPLAT! can generate a topo-
       graphic  map displaying the geometric line-of-sight cover-
       age area of the sites based on the location of  each  site
       and  the  height of receive antenna wishing to communicate
       with the site in question.  SPLAT! switches from point-to-
       point  analysis  mode  to area prediction mode when the -c
       switch is invoked as follows:

       splat -t tx_site -c 30.0 -s cities.dat -b co34_d00.dat  -o
       tx_coverage

       In this example, SPLAT! generates a topographic map called
       tx_coverage.ppm that illustrates  the  predicted  line-of-
       sight  regional coverage of tx_site to receiving locations
       having antennas 30.0 feet above ground  level  (AGL).   If
       the  -metric switch is used, the argument following the -c
       switch is interpreted as being in meters, rather  than  in
       feet.   The contents of cities.dat are plotted on the map,
       as are the cartographic boundaries contained in  the  file
       co34_d00.dat.

       When  plotting  line-of-sight  paths and areas of regional
       coverage, SPLAT! by  default  does  not  account  for  the
       effects  of  atmospheric  bending.  However, this behavior
       may be modified by using the Earth radius multiplier  (-m)
       switch:

       splat  -t  wnjt  -c  30.0  -m 1.333 -s cities.dat -b coun-
       ties.dat -o map.ppm

       An earth radius multiplier of 1.333  instructs  SPLAT!  to
       use the "four-thirds earth" model for line-of-sight propa-
       gation analysis.  Any appropriate earth radius  multiplier
       may be selected by the user.

       When  invoked  in area prediction mode, SPLAT! generates a
       site  report  for  each  station  analyzed.   SPLAT!  site
       reports contain details of the site's geographic location,
       its height above mean  sea  level,  the  antenna's  height
       above  mean  sea level, the antenna's height above average
       terrain, and the height of the average terrain  calculated
       in  the  directions  of 0, 45, 90, 135, 180, 225, 270, and
       315 degrees azimuth.

DETERMINING MULTIPLE REGIONS OF LOS COVERAGE
       SPLAT! can also display line-of-sight coverage  areas  for
       as  many  as  four  separate transmitter sites on a common
       topographic map.  For example:

       splat -t site1 site2 site3 site4 -c 10.0 -metric  -o  net-
       work.ppm

       plots the regional line-of-sight coverage of site1, site2,
       site3, and site4 based on a receive antenna  located  10.0
       meters  above  ground  level.   A  topographic map is then
       written to the file network.ppm.  The line-of-sight cover-
       age area of the transmitters are plotted as follows in the
       colors indicated (along with their corresponding RGB  val-
       ues in decimal):

           site1: Green (0,255,0)
           site2: Cyan (0,255,255)
           site3: Medium Violet (147,112,219)
           site4: Sienna 1 (255,130,71)

           site1 + site2: Yellow (255,255,0)
           site1 + site3: Pink (255,192,203)
           site1 + site4: Green Yellow (173,255,47)
           site2 + site3: Orange (255,165,0)
           site2 + site4: Dark Sea Green 1 (193,255,193)
           site3 + site4: Dark Turquoise (0,206,209)

           site1 + site2 + site3: Dark Green (0,100,0)
           site1 + site2 + site4: Blanched Almond (255,235,205)
           site1 + site3 + site4: Medium Spring Green (0,250,154)
           site2 + site3 + site4: Tan (210,180,140)

           site1 + site2 + site3 + site4: Gold2 (238,201,0)

       If separate .qth files are generated, each representing  a
       common  site  location  but  a different antenna height, a
       single topographic map illustrating the regional  coverage
       from  as many as four separate locations on a single tower
       may be generated by SPLAT!.

LONGLEY-RICE PATH LOSS ANALYSIS
       If the -c switch is replaced by a -L  switch,  a  Longley-
       Rice  path  loss  map for a transmitter site may be gener-
       ated:

       splat -t wnjt -L 30.0 -s  cities.dat  -b  co34_d00.dat  -o
       path_loss_map

       In  this  mode,  SPLAT! generates a multi-color map illus-
       trating expected signal levels (path loss) in  areas  sur-
       rounding  the transmitter site.  A legend at the bottom of
       the map correlates each color with a  specific  path  loss
       range in decibels.

       The Longley-Rice analysis range may be modified to a user-
       specific value using the -R switch.  The argument must  be
       given  in  miles  (or  kilometers if the -metric switch is
       used).  If a range wider than  the  generated  topographic
       map  is  specified,  SPLAT! will perform Longley-Rice path
       loss calculations between all four  corners  of  the  area
       prediction map.

       The  -db  switch  allows  a constraint to be placed on the
       maximum path loss region plotted on the  map.   A  maximum
       path  loss  between  80  and 230 dB may be specified using
       this switch.  For example, if a path loss beyond  -140  dB
       is irrelevant to the survey being conducted, SPLAT!'s path
       loss plot can be constrained to the region bounded by  the
       140 dB attenuation contour as follows:

       splat  -t  wnjt  -L 30.0 -s cities.dat -b co34_d00.dat -db
       140 -o plot.ppm


ANTENNA RADIATION PATTERN PARAMETERS
       Normalized  field  voltage  patterns  for  a  transmitting
       antenna's  horizontal  and  vertical  planes  are imported
       automatically into SPLAT!  when  a  Longley-Rice  coverage
       analysis  is performed.  Antenna pattern data is read from
       a pair of files having the same base name as the transmit-
       ter  and  LRP  files,  but with .az and .el extensions for
       azimuth and elevation pattern files, respectively.  Speci-
       fications   regarding   pattern   rotation  (if  any)  and
       mechanical beam tilt and tilt direction (if any) are  also
       contained within SPLAT! antenna pattern files.

       For  example, the first few lines of a SPLAT! azimuth pat-
       tern file might appear as follows (kvea.az):

               183.0
               0       0.8950590
               1       0.8966406
               2       0.8981447
               3       0.8995795
               4       0.9009535
               5       0.9022749
               6       0.9035517
               7       0.9047923
               8       0.9060051

       The first line of the .az file  specifies  the  amount  of
       azimuthal  pattern rotation (measured clockwise in degrees
       from True North) to be applied by SPLAT! to the data  con-
       tained in the .az file.  This is followed by azimuth head-
       ings (0 to 360 degrees) and  their  associated  normalized
       field patterns (0.000 to 1.000) separated by whitespace.

       The   structure  of  SPLAT!  elevation  pattern  files  is
       slightly different.  The first line of the .el file speci-
       fies  the  amount  of  mechanical beam tilt applied to the
       antenna.  Note that a downward tilt (below the horizon) is
       expressed as a positive angle, while an upward tilt (above
       the horizon) is expressed as a negative angle.  This  data
       is  followed by the azimuthal direction of the tilt, sepa-
       rated by whitespace.

       The remainder of the file consists of elevation angles and
       their  corresponding  normalized voltage radiation pattern
       (0.000 to 1.000) values separated by  whitespace.   Eleva-
       tion angles must be specified over a -10.0 to +90.0 degree
       range.  As was the convention  with  mechanical  beamtilt,
       negative elevation angles are used to represent elevations
       above the horizon, while positive angles represents eleva-
       tions below the horizon.

       For  example,  the first few lines a SPLAT! elevation pat-
       tern file might appear as follows (kvea.el):

               1.1    130.0
              -10.0   0.172
              -9.5    0.109
              -9.0    0.115
              -8.5    0.155
              -8.0    0.157
              -7.5    0.104
              -7.0    0.029
              -6.5    0.109
              -6.0    0.185

       In this example, the antenna is mechanically tilted  down-
       ward 1.1 degrees towards an azimuth of 130.0 degrees.

       For  best  results, the resolution of azimuth pattern data
       should be specified to the  nearest  degree  azimuth,  and
       elevation  pattern  data resolution should be specified to
       the nearest 0.01 degrees.  If the pattern  data  specified
       does  not  reach  this  level  of  resolution, SPLAT! will
       interpolate the values provided to determine the  data  at
       the  required  resolution,  although  this may result in a
       loss in accuracy.


IMPORTING AND EXPORTING REGIONAL PATH LOSS CONTOUR DATA
       Performing a Longley-Rice coverage analysis can be a  very
       time  consuming  process,  especially  if  the analysis is
       repeated repeatedly to discover what  effects  changes  to
       the  antenna radiation patterns make to the predicted cov-
       erage area.

       This process can be expedited by  exporting  the  Longley-
       Rice  regional  path  loss contour data to an output file,
       modifying the path loss  data  externally  to  incorporate
       antenna  pattern  effects, and then importing the modified
       path loss data back into  SPLAT!   to  rapidly  produce  a
       revised path loss map.

       For  example,  a path loss output file can be generated by
       SPLAT!  for a receive site 30 feet above ground level over
       a 50 mile radius surrounding a transmitter site to a maxi-
       mum path loss of 140 dB using the following syntax:

       splat -t kvea -L 30.0 -R 50.0 -db 140 -plo pathloss.dat

       SPLAT! path loss output files often exceed  100  megabytes
       in  size.  They contain information relating to the bound-
       aries  of  region  they  describe  followed  by  latitudes
       (degrees North), longitudes (degrees West), azimuths, ele-
       vations (to the first obstruction), and path loss  figures
       (dB)  for  a  series  of specific points that comprise the
       region surrounding the transmitter site.   The  first  few
       lines  of  a SPLAT! path loss output file take on the fol-
       lowing appearance (pathloss.dat):

               119, 117    ; max_west, min_west
               35, 33      ; max_north, min_north
               34.2265434, 118.0631104, 48.171, -37.461, 67.70
               34.2270355, 118.0624390, 48.262, -26.212, 73.72
               34.2280197, 118.0611038, 48.269, -14.951, 79.74
               34.2285156, 118.0604401, 48.207, -11.351, 81.68
               34.2290077, 118.0597687, 48.240, -10.518, 83.26
               34.2294998, 118.0591049, 48.225, 23.201, 84.60
               34.2304878, 118.0577698, 48.213, 15.769, 137.84
               34.2309799, 118.0570984, 48.234, 15.965, 151.54
               34.2314720, 118.0564346, 48.224, 16.520, 149.45
               34.2319679, 118.0557632, 48.223, 15.588, 151.61
               34.2329521, 118.0544281, 48.230, 13.889, 135.45
               34.2334442, 118.0537643, 48.223, 11.693, 137.37
               34.2339401, 118.0530930, 48.222, 14.050, 126.32
               34.2344322, 118.0524292, 48.216, 16.274, 156.28
               34.2354164, 118.0510941, 48.222, 15.058, 152.65
               34.2359123, 118.0504227, 48.221, 16.215, 158.57
               34.2364044, 118.0497589, 48.216, 15.024, 157.30
               34.2368965, 118.0490875, 48.225, 17.184, 156.36

       It is not uncommon for SPLAT! path loss files  to  contain
       as  many as 3 million or more lines of data.  Comments can
       be placed in the file if they are proceeded by a semicolon
       character.   The  vim  text  editor  has proven capable of
       editing files of this size.

       Note as was the case in the antenna pattern  files,  nega-
       tive  elevation  angles  refer  to  upward tilt (above the
       horizon), while positive angles  refer  to  downward  tilt
       (below  the horizon).  These angles refer to the elevation
       to the receiving antenna at the height above ground  level
       specified  using  the -L switch if the path between trans-
       mitter and receiver is unobstructed.  If the path  between
       the  transmitter and receiver is obstructed, then the ele-
       vation angle to  the  first  obstruction  is  returned  by
       SPLAT!.   This is because the Longley-Rice model considers
       the energy reaching a distant  point  over  an  obstructed
       path  as a derivative of the energy scattered from the top
       of the first obstruction, only.  Since energy cannot reach
       the  obstructed  location  directly,  the actual elevation
       angle to that point is irrelevant.

       When modifying SPLAT! path loss files to  reflect  antenna
       pattern  data,  only the last column (path loss) should be
       amended to reflect the antenna's normalized  gain  at  the
       azimuth  and  elevation angles specified in the file.  (At
       this time, programs and scripts capable of performing this
       operation are left as an exercise for the user.)

       Modified  path  loss maps can be imported back into SPLAT!
       for generating revised coverage maps:

       splat -t kvea -pli pathloss.dat -s city.dat -b  county.dat
       -o map.ppm

       SPLAT!  path  loss  files  can also be used for conducting
       coverage or interference studies outside of SPLAT!.

USER-DEFINED TERRAIN INPUT FILES
       A user-defined terrain file is a user-generated text  file
       containing latitudes, longitudes, and heights above ground
       level of specific  terrain  features  believed  to  be  of
       importance  to  the  SPLAT!  analysis being conducted, but
       noticeably absent from the SDF files being used.  A  user-
       defined  terrain  file  is imported into a SPLAT! analysis
       using the -udt switch:

        splat -t tx_site -r rx_site -udt udt_file.txt -o map.ppm

       A user-defined terrain file has the  following  appearance
       and structure:

              40.32180556, 74.1325, 100.0 meters
              40.321805, 74.1315, 300.0
              40.3218055, 74.1305, 100.0 meters

       Terrain  height  is interpreted as being described in feet
       above ground level unless followed by the word meters, and
       is  added  on top of the terrain specified in the SDF data
       for the locations specified.  Be  aware  that  each  user-
       defined  terrain  feature specified will be interpreted as
       being 3-arc seconds in both latitude and longitude.   Fea-
       tures  described  in  the  user-defined  terrain file that
       overlap  previously  defined  features  in  the  file  are
       ignored by SPLAT!.

SIMPLE TOPOGRAPHIC MAP GENERATION
       In  certain  situations  it may be desirable to generate a
       topographic map of  a  region  without  plotting  coverage
       areas,  line-of-sight  paths,  or  generating  obstruction
       reports.  There are several ways of doing  this.   If  one
       wishes  to  generate  a  topographic  map illustrating the
       location of a transmitter and receiver site along  with  a
       brief  text  report describing the locations and distances
       between the sites, the -n switch should be invoked as fol-
       lows:

       splat -t tx_site -r rx_site -n -o topo_map.ppm

       If no text report is desired, then the -N switch is used:

       splat -t tx_site -r rx_site -N -o topo_map.ppm

       If a topographic map centered about a single site out to a
       minimum specified radius is  desired  instead,  a  command
       similar to the following can be used:

       splat  -t  tx_site  -R 50.0 -s NJ_Cities -b NJ_Counties -o
       topo_map.ppm

       where -R specifies the minimum radius of the map in  miles
       (or kilometers if the -metric switch is used).

       If  the -o switch and output filename are omitted in these
       operations, topographic output is written to a file  named
       map.ppm in the current working directory by default.

GEOREFERENCE FILE GENERATION
       Topographic,  coverage  (-c),  and  path loss contour (-L)
       maps generated by SPLAT! may be imported  into  Xastir  (X
       Amateur  Station Tracking and Information Reporting) soft-
       ware by generating a georeference file using SPLAT!'s -geo
       switch:

       splat -t kd2bd -R 50.0 -s NJ_Cities -b NJ_Counties -geo -o
       map.ppm

       The georeference file generated will have  the  same  base
       name as the -o file specified, but have a  .geo extension,
       and permit proper interpretation and display  of  SPLAT!'s
       .ppm graphics in Xastir software.

GOOGLE MAP KML FILE GENERATION
       Keyhole Markup Language files compatible with Google Earth
       may be generated by SPLAT! when performing  point-to-point
       analyses by invoking the -kml switch:

       splat -t wnjt -r kd2bd -kml

       The  KML file generated will have the same filename struc-
       ture as an Obstruction  Report  for  the  transmitter  and
       receiver  site  names  given, except it will carry a  .kml
       extension.

       Once loaded into Google Earth (File  -->  Open),  the  KML
       file  will  annotate the map display with the names of the
       transmitter and receiver site locations.  The viewpoint of
       the  image  will  be  from the position of the transmitter
       site looking towards the location of  the  receiver.   The
       point-to-point path between the sites will be displayed as
       a white line while the RF line-of-sight path will be  dis-
       played  in  green.   Google Earth's navigation tools allow
       the user to "fly" around  the  path,  identify  landmarks,
       roads, and other featured content.

DETERMINATION OF ANTENNA HEIGHT ABOVE AVERAGE TERRAIN
       SPLAT!  determines  antenna  height  above average terrain
       (HAAT) according to the procedure defined by Federal  Com-
       munications  Commission Part 73.313(d).  According to this
       definition, terrain elevations along eight radials between
       2  and  10 miles (3 and 16 kilometers) from the site being
       analyzed are sampled and averaged for each 45  degrees  of
       azimuth  starting with True North.  If one or more radials
       lie entirely over water or over land  outside  the  United
       States  (areas for which no USGS topography data is avail-
       able), then those radials are omitted from the calculation
       of average terrain.

       Note  that  SRTM elevation data, unlike older 3-arc second
       USGS data,  extends  beyond  the  borders  of  the  United
       States.   Therefore,  HAAT results may not be in full com-
       pliance with FCC Part 73.313(d) in areas along the borders
       of  the  United States if the SDF files used by SPLAT! are
       SRTM-derived.

       When performing point-to-point  terrain  analysis,  SPLAT!
       determines  the  antenna height above average terrain only
       if enough topographic data has already been loaded by  the
       program  to  perform the point-to-point analysis.  In most
       cases, this will be true, unless the site in question does
       not  lie within 10 miles of the boundary of the topography
       data in memory.

       When performing area prediction analysis, enough  topogra-
       phy  data  is normally loaded by SPLAT! to perform average
       terrain calculations.  Under such conditions, SPLAT!  will
       provide  the  antenna height above average terrain as well
       as the average terrain above mean sea level  for  azimuths
       of  0,  45,  90,  135, 180, 225, 270, and 315 degrees, and
       include such information in the generated site report.  If
       one or more of the eight radials surveyed fall over water,
       or over regions for which no SDF data is available, SPLAT!
       reports No Terrain for the radial paths affected.

RESTRICTING THE MAXIMUM SIZE OF AN ANALYSIS REGION
       SPLAT!  reads  SDF files as needed into a series of memory
       pages or "slots" within  the  structure  of  the  program.
       Each  "slot"  holds one SDF file representing a one degree
       by one degree  region  of  terrain.   A  #define  MAXSLOTS
       statement in the first several lines of splat.cpp sets the
       maximum number of "slots" available for holding topography
       data.   It  also  sets the maximum size of the topographic
       maps generated  by  SPLAT!.   MAXSLOTS  is  set  to  9  by
       default.   If  SPLAT!   produces  a  segmentation fault on
       start-up with this default, it is an indication  that  not
       enough RAM and/or virtual memory (swap space) is available
       to run SPLAT! with the number of MAXSLOTS  specified.   In
       situations  where available memory is low, MAXSLOTS may be
       reduced to 4 with the understanding that this will greatly
       limit  the  maximum region SPLAT! will be able to analyze.
       If 118 megabytes or more of total memory (swap space  plus
       RAM)  is  available, then MAXSLOTS may be increased to 16.
       This will permit operation over  a  4-degree  by  4-degree
       region,  which is sufficient for single antenna heights in
       excess of 10,000 feet above mean sea level,  or  point-to-
       point distances of over 1000 miles.

ADDITIONAL INFORMATION
       The  latest news and information regarding SPLAT! software
       is available through the official SPLAT! software web page
       located at: http://www.qsl.net/kd2bd/splat.html.

AUTHORS
       John A. Magliacane, KD2BD <kd2bd@amsat.org>
              Creator, Lead Developer

       Doug McDonald <mcdonald@scs.uiuc.edu>
              Longley-Rice Model integration

       Ron Bentley <ronbentley@earthlink.net>
              Fresnel Zone plotting and clearance determination




KD2BD Software           20 December 2006               SPLAT!(1)
