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

NAME
       splat An RF Signal Propagation, Loss, And Terrain analysis
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  ITM  coverage  analysis
(feet/meters) (float)]
       [-p terrain_profile.ext]
       [-e elevation_profile.ext]
       [-h height_profile.ext]
       [-H normalized_height_profile.ext]
       [-l ITM_profile.ext]
       [-o topographic_map_filename.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  threshold	beyond	which  contours   will	 not   be
displayed]
       [-gc ground clutter height (feet/meters) (float)]
       [-fz Fresnel zone clearance percentage (default = 60)]
       [-ano alphanumeric output file name]
       [-ani alphanumeric input file name]
       [-udt user_defined_terrain_file.dat]
       [-log logfile.ext]
       [-n]
       [-N]
       [-nf]
       [-sc]
       [-dbm]
       [-ngs]
       [-geo]
       [-kml]
       [-gpsav]
       [-metric]
       [-olditm]

DESCRIPTION
       SPLAT!	is   a	 powerful  terrestrial RF propagation and
terrain analysis
       tool for the spectrum between 20 MHz and 20  GHz.   SPLAT!
is free  soft-
       ware,   and  is	designed for operation on Unix and Linux-
based worksta-
       tions.  Redistribution and/or  modification  is	permitted
under the terms
       of   the  GNU  General  Public License, Version 2, as pub-
lished by the Free
       Software Foundation.  Adoption of SPLAT!  source  code  in
proprietary 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 warranty of MER-
CHANTABILITY or
       FITNESS FOR A PARTICULAR PURPOSE.   See	the  GNU  General
Public	License
       for more details.

INTRODUCTION
       Applications  of SPLAT! include the visualization, design,
and link bud-
       get analysis of wireless Wide Area Networks  (WANs),  com-
mercial and ama-
       teur   radio   communication   systems  above  20 MHz, mi-
crowave links, fre-
       quency coordination and interference  studies,	and   the
prediction  of
       analog  and  digital terrestrial radio and television con-
tour regions.

       SPLAT! provides RF site engineering  data  such	as  great
circle distances
       and  bearings between sites, antenna elevation angles (up-
tilt),	depres-
       sion  angles  (downtilt),  antenna height above	mean  sea
level, antenna
       height  above  average  terrain, bearings, distances,  and
elevations  to
       known  obstructions,  Irregular	Terrain  Model	path  at-
tenuation, and
       received signal strength.   In	addition,   the   minimum
antenna  height
       requirements   needed  to clear terrain, the first Fresnel
zone, and any
       user-definable percentage of the first  Fresnel	zone  are
also provided.

       SPLAT!  produces  reports,  graphs,  and  high  resolution
topographic  maps
       that  depict  line-of-sight  paths,   and   regional  path
loss and signal
       strength contours through which expected coverage areas of
transmitters
       and   repeater  systems	can be obtained.  When performing
line-of-sight
       and Irregular Terrain   Model   analyses   in   situations
where  multiple
       transmitter  or repeater sites are employed, SPLAT! deter-
mines individ-
       ual and mutual areas of coverage within the network speci-
fied.

INPUT FILES
       SPLAT! is a  command-line  driven  application  and  reads
input  data
       through	a number of data files.  Some files are mandatory
for success-
       ful  execution  of  the	program,  while  others  are  op-
tional.   Mandatory
       files  include digital elevation topography models in  the
form of SPLAT
       Data  Files  (SDF files), site location files (QTH files),
and  Irregular
       Terrain Model parameter files (LRP files).  Optional files
include city
       location  files,  cartographic  boundary  files,  user-de-
fined  terrain
       files,  path  loss  input  files,  antenna radiation  pat-
tern files, and
       color definition 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.  Geo-
       logical	Survey	Digital Elevation Models (DEMs) using the
postdownload
       and usgs2sdf utilities included with SPLAT!.   USGS  Digi-
tal  Elevation
       Models  compatible  with these utilities may be downloaded
from:

	      http://edcftp.cr.usgs.gov/pub/data/DEM/250/.

       Significantly  better  resolution  and accuracy can be ob-
tained through
       the use of SRTM Version 2 digital  elevation  models,  es-
pecially  when
       supplemented  by USGS-derived SDF data.	These  one-degree
by one-degree
       models  are  the  product  of  the  Space  Shuttle  STS-99
Radar  Topography
       Mission,  and  are  available  for most populated  regions
of the Earth.
       SPLAT Data Files may be generated from 3 arc-second SRTM-3
data  using
       the  included  srtm2sdf	utility.  SRTM-3 Version 2.1 data
may be obtained
       through anonymous FTP from:

	      http://dds.cr.usgs.gov/srtm/version2_1/SRTM3/

       Note that SRTM filenames refer to the latitude  and   lon-
gitude	of  the
       southwest   corner  of  the  topographic dataset contained
within the file.
       Therefore, the region of interest must lie north and  east
of the	lati-
       tude and longitude provided in the SRTM filename.

       Even  greater  resolution  and accuracy can be obtained by
using 1 arc-
       second  SRTM-1  Version 2.1 topography data.  This data is
available  for
       the United States and its territories and possessions, and
may be down-
       loaded from:

	      http://dds.cr.usgs.gov/srtm/version2_1/SRTM1/

       High resolution SDF files for use with SPLAT!  HD  may  be
generated  from
       data in this format using the srtm2sdf-hd utility.

       Despite	 the higher accuracy that SRTM data has to offer,
some voids in
       the data sets  exist.   When  voids  are   detected,   the
srtm2sdf  and
       srtm2sdf-hd   utilities	replace  them  with corresponding
data found in
       usgs2sdf generated SDF files.  If USGS-derived SDF data is
not  avail-
       able,  voids  are  handled  through adjacent pixel averag-
ing, 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.  SDF files can be  read	by   SPLAT!   in   either
standard  format
       (.sdf)  as  generated  directly by the usgs2sdf, srtm2sdf,
and srtm2sdf-hd
       utilities, or in bzip2	compressed   format   (.sdf.bz2).
Since  uncom-
       pressed	 files	 can  be  read slightly faster than files
that have been
       compressed, SPLAT! searches for needed SDF data in  uncom-
pressed  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 repre-
sented by Digi-
       tal Elevation Model data.   However,  this   behavior   of
SPLAT!	 under-
       scores  the  importance	of  having  all the SDF files re-
quired for the
       region  being analyzed if meaningful results are to be ex-
pected.

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, or degrees East 0 to  -360
degrees), and
       the  site's  antenna height above ground level (AGL), each
separated by a
       single line-feed character.  The antenna height is assumed
to be speci-
       fied  in  feet  unless  followed  by the letter m  or  the
word meters in
       either upper or lower case.  Latitude and longitude infor-
mation may  be
       expressed   in  either decimal format (74.6864) or degree,
minute, second
       (DMS) format (74 41 11.0).

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

	       WNJT-DT
	       40.2828
	       74.6864
	       990.00

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

IRREGULAR TERRAIN MODEL PARAMETER (LRP) FILES
       Irregular Terrain Model Parameter data files are  required
for  SPLAT!
       to  determine  RF  path	loss, field strength, or received
signal power
       level in either point-to-point or  area	prediction  mode.
Irregular Ter-
       rain   Model  parameter data is read from files having the
same base name
       as the transmitter site QTH file, but with a  .lrp  exten-
sion.	SPLAT!
       LRP files share the following format (wnjt-dt.lrp):

	       15.000  ; Earth Dielectric Constant (Relative per-
mittivity)
	       0.005   ; Earth Conductivity (Siemens per meter)
	       301.000 ; Atmospheric Bending Constant (N-units)
	       647.000 ; Frequency in MHz (20 MHz to 20 GHz)
	       5       ; Radio Climate (5 =  Continental  Temper-
ate)
	       0       ; Polarization (0 = Horizontal, 1 = Verti-
cal)
	       0.50	;  Fraction  of  situations (50% of loca-
tions)
	       0.90    ; Fraction of time (90% of the time)
	       46000.0 ; Effective Radiated Power (ERP) in  Watts
(optional)

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

       Typical Earth dielectric constants and conductivity values
are as	fol-
       lows:

				  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 Temper-
       ate climates.

       The  seventh  and  eighth parameters in the .lrp file cor-
respond to the
       statistical  analysis  provided	by  the  ITM  model.   In
this  example,
       SPLAT! will return the maximum path loss occurring in  50%
of situations
       (fraction  of  situations, or  Location	Variability)  90%
of  the  time
       (fraction  of  time,  or  Time  Variability).  This is of-
ten denoted as
       F(50,90) in Longley-Rice studies.  In the United   States,
an  F(50,90)
       criteria    is	typically  used  for  digital  television
(8-level VSB modula-
       tion), while F(50,50) is  used  for  analog  (VSB-AM+NTSC)
broadcasts.

       For  further information on ITM	propagation  model  para-
meters,  please
       refer						      to:
http://www.its.bldrdoc.gov/resources/radio-propagation-soft-
       ware/itm/itm.aspx				      and
http://www.softwright.com/faq/engineer-
       ing/prop_longley_rice.html

       The  last  parameter  in the .lrp file corresponds to  the
transmitter's
       Effective Radiated Power (ERP), and is optional.  If it is
included  in
       the  .lrp  file,  then SPLAT! will compute received signal
strength levels
       and field strength  level  contours  when  performing  ITM
studies.  If  the
       parameter  is omitted, path loss is computed instead.  The
ERP provided
       in  the .lrp file can be overridden by using SPLAT!'s -erp
command-line
       switch.	 If the .lrp file contains an ERP  parameter  and
the generation
       of  path  loss rather than field strength contours is  de-
sired,	the  ERP
       can  be	assigned  to zero using the -erp  switch  without
having to edit
       the .lrp file to accomplish the same result.

CITY LOCATION FILES
       The  names  and	locations  of  cities,	tower  sites,  or
other  points  of
       interest  may  be imported and plotted on topographic maps
generated by
       SPLAT!.	SPLAT! imports the names of cities and	locations
from  ASCII
       files  containing the location of interest's  name,  lati-
tude, and longi-
       tude.  Each field is separated by a comma.  Each record is
separated by
       a   single   line   feed  character.  As was the case with
the .qth files,
       latitude and longitude information may be entered  in  ei-
ther 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 annotations 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!  generated  topo-
graphic  maps,	but
       also  mandates  that important locations be placed  toward
the beginning
       of  the first city data file, and locations less important
be positioned
       further 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   avail-
able  from  the
       U.S.  Census Bureau using the citydecoder utility included
with SPLAT!.
       Such   data   is   available   free  of	charge	via   the
Internet   at:
       http://web.archive.org/web/20130331172800/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 topographic maps  gener-
ated 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://web.ar-
       chive.org/web/20130331144934/http://www.cen-
       sus.gov/geo/www/cob/co2000.html#ascii		      and
http://web.ar-
       chive.org/web/20130507075658/http://www.cen-
       sus.gov/geo/www/cob/pl2000.html#ascii.	A  total  of five
separate carto-
       graphic	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)  operations.   SPLAT!'s  CPU  and  memory
scheduling prior-
       ity  may be modified through the use of the Unix nice com-
mand.

       The  number and type of switches passed to  SPLAT!  deter-
mine its mode of
       operation  and  method  of output data generation.  Nearly
all of SPLAT!'s
       switches may be cascaded in any order on the command  line
when invoking
       the  program.   Simply  typing  splat on the command  line
will  return  a
       summary of SPLAT!'s command line options:

		      --==[ SPLAT!  v1.4.2  Available  Options...
]==--
	    -t	txsite(s).qth  (max  of 4 with -c, max of 30 with
-L)
	    -r rxsite.qth
	    -c plot LOS coverage of TX(s) with 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 (5 max)
	    -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 path loss 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)
	    -m earth radius multiplier
	    -n do not plot LOS paths in .ppm maps
	    -N do not produce unnecessary site or obstruction re-
ports
	    -f frequency for Fresnel zone calculation (MHz)
	    -R	modify	default range for -c or -L (miles/kilome-
ters)
	   -sc display smooth rather than quantized contour  lev-
els
	   -db	threshold  beyond which contours will not be dis-
played
	   -nf do not plot Fresnel zones in height plots
	   -fz Fresnel zone clearance percentage (default = 60)
	   -gc ground clutter height (feet/meters)
	  -ngs display greyscale  topography  as  white  in  .ppm
files
	  -erp override ERP in .lrp file (Watts)
	  -ano name of alphanumeric output file
	  -ani name of alphanumeric input file
	  -udt name of user defined terrain input file
	  -kml generate Google Earth (.kml) compatible output
	  -geo	generate  an  Xastir .geo georeference file (with
.ppm output)
	  -dbm plot signal power level contours rather than field
strength
	  -log copy command line string to this output file
	-gpsav preserve gnuplot  temporary  working  files  after
SPLAT! execution
       -metric	employ	metric rather than imperial units for all
user I/O
       -olditm invoke older ITM propagation model rather than the
newer ITWOM
	 The  command-line  options for splat  and  splat-hd  are
identical.  The
       -log  command  line switch causes all invoked command line
options to  be
       logged to a file of your choosing  (logfile.txt):

       splat -t tx_site -r rx_site -s nj_cities -o topo_map  -log
logfile.txt

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

POINT-TO-POINT ANALYSIS
       SPLAT!  may  be	used  to  perform  line-of-sight  terrain
analysis 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 speci-
       fied  in tx_site.qth and receiver specified in rx_site.qth
using a True
       Earth radius model, and writes  a  SPLAT!  Path	 Analysis
Report	to  the
       current	 working  directory.  The report contains details
of the trans-
       mitter and receiver sites, and identifies the location  of
any  obstruc-
       tions   detected  along the line-of-sight path.	If an ob-
struction can be
       cleared by raising the receive antenna to a  greater   al-
titude,  SPLAT!
       will   indicate	the minimum antenna height required for a
line-of-sight
       path to exist between the transmitter and  receiver  loca-
tions specified.
       Note  that  imperial units (miles, feet) are specified un-
less 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	example,  do  not take Fresnel zone clearance re-
quirements 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! auto-
       matically 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  documentation for de-
tails 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 gener-
       ated by using the -e switch:

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

       The  graph  produced  using this  switch  illustrates  the
elevation  and
       depression  angles  resulting  from  the  terrain  between
the receiver's
       location  and  the  transmitter	site  from  the  perspec-
tive  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
elevation angle
       required  for  a line-of-sight path to exist  between  the
receiver  and
       transmitter  locations.	 If the trace intersects the ele-
vation 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 obstruc-
       tions can be  clearly  identified  on  the  graph  at  the
point(s) of  inter-
       section.

       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 fre-
       quency  (in  MHz) at which the Fresnel Zone should be mod-
eled:

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

       Fresnel	Zone  clearances other 60% can be specified using
the -fz switch
       as follows:

       splat  -t  tx_site  -r  rx_site	-f  439.250  -fz  75   -H
height_profile2.png

       A  graph showing ITM 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.   The -gpsav switch in-
structs  SPLAT!  to
       preserve  (rather than delete) the gnuplot  working  files
generated dur-
       ing  SPLAT!  execution,	allowing  the  user to edit these
files and  re-run
       gnuplot if desired.

       When  performing  a  point-to-point  analysis,  a   SPLAT!
Path Analysis
       Report  is  generated  in the form of a text file  with	a
.txt  filename
       extension.   The  report   contains   bearings	and  dis-
tances between the
       transmitter  and  receiver,  as well as the free-space and
ITM  path  loss
       for  the  path being analyzed.  The  mode  of  propagation
for the path is
       given as Line-of-Sight, Single  Horizon,  Double  Horizon,
Diffraction
       Dominant,   or	Troposcatter  Dominant.  Additionally, if
the receiver is
       located at the peak of a single obstruction or at the peak
of a  second
       obstruction,  SPLAT!  will  report  RX	at  Peak  Terrain
Along Path when
       operating under the ITWOM propagation model.

       Distances  and  locations to known obstructions along  the
path  between
       transmitter  and  receiver  are	also  provided.   If  the
transmitter's
       effective radiated power is specified in the transmitter's
correspond-
       ing   .lrp   file,  then predicted signal strength and an-
tenna voltage at
       the receiving location is also provided in the Path Analy-
sis Report.

       To determine the signal-to-noise  (SNR)	ratio  at  remote
location  where
       random  Johnson	(thermal)  noise  is the primary limiting
factor in recep-
       tion:

       SNR=T-NJ-L+G-NF

       where T is the ERP of the transmitter in dBW in	the   di-
rection  of  the
       receiver,   NJ	is Johnson Noise in dBW (-136 dBW for a 6
MHz television
       channel), L is the path loss provided 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 re-
ceiver	is  over
       the horizon).

       To compute how much more signal is available over the min-
imum to neces-
       sary 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-level
       VSB) DTV, 42 dB for analog NTSC television).

       A  topographic  map  may  be  generated by SPLAT! to visu-
alize the path
       between	the transmitter and receiver sites from  yet  an-
other  perspec-
       tive.   Topographic maps generated by SPLAT! display  ele-
vations using a
       logarithmic   grayscale,  with  higher  elevations  repre-
sented	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 lo-
cations of the
       transmitter and receiver sites  specified.   In	addition,
the great  cir-
       cle   path  between the two sites will be drawn over loca-
tions for which
       an unobstructed path exists to the transmitter at  a   re-
ceiving  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 loca-
       tions  of  cities, tower sites, or other  important  loca-
tions.	 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 fol-
       lowing 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  ob-
struction 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  con-
verted	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 topo-
graphic 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.

       The  -ngs  option  assigns all terrain to the color white,
and can be used
       when it is desirable to generate a map that is  devoid  of
terrain:

       splat  -t  tx_site  -r  rx_site	-b  co34_d00.dat  -ngs -o
white_map

       The  resulting  .ppm  image file can be converted to  .png
format with a
       transparent  background	using ImageMagick's convert util-
ity:

       convert	-transparent  "#FFFFFF"  white_map.ppm	transpar-
ent_map.png

REGIONAL COVERAGE ANALYSIS
       SPLAT! can analyze a transmitter or repeater site, or net-
work of sites,
       and  predict  the  regional  coverage for each site speci-
fied.  In this
       mode,  SPLAT!  can  generate a topographic map  displaying
the  geometric
       line-of-sight  coverage area of the sites based on the lo-
cation of each
       site and the height of receive antenna wishing to communi-
cate with  the
       site in question.  A regional analysis may be performed by
SPLAT! using
       the -c switch 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_cover-
       age.ppm	that illustrates the predicted line-of-sight  re-
gional coverage
       of tx_site to receiving	locations  having  antennas  30.0
feet  above
       ground	level  (AGL).  If the -metric switch is used, the
argument fol-
       lowing 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  re-
gional	coverage,
       SPLAT! by default does not account for the effects of  at-
mospheric bend-
       ing.   However, this behavior may be modified by using the
Earth  radius
       multiplier (-m) switch:

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

       An  earth  radius  multiplier of 1.333 instructs SPLAT! to
use the  "four-
       thirds earth" model for line-of-sight  propagation  analy-
sis.  Any appro-
       priate  earth  radius  multiplier  may  be selected by the
user.

       When performing a regional analysis,  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 aver-
       age  terrain, and the height of the average  terrain  cal-
culated  toward
       the bearings of 0, 45, 90, 135, 180, 225, 270, and 315 de-
grees 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 exam-
       ple:

       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 coverage area of the transmitters are  plot-
ted as	follows
       in   the  colors indicated (along with their corresponding
RGB values 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  loca-
       tions on a single tower may be generated by SPLAT!.

PATH LOSS ANALYSIS
       If   the   -c   switch  is replaced by a -L switch, an ITM
path loss map, a
       field strength map, or a received power map for the trans-
mitter site(s)
       specified  may be generated.  The type of analysis  gener-
ated depends on
       the  presence  or  absence of an -erp switch followed by a
positive valued
       argument (or equivalent ERP entry in the appropriate  .lrp
file), or the
       presence  or  absence  of the -dBm switch.  The	following
example  would
       generate an ITM path loss map:

       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 in areas surrounding the  transmitter  site.
A  legend  at
       the   bottom  of the map correlates each color with a spe-
cific path loss
       range in decibels.

       The -db switch allows a threshold to be set  beyond  which
contours  will
       not   be  plotted on the map.  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 at-
tenuation con-
       tour as follows:

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

       The  path  loss contour threshold may be expressed as  ei-
ther a positive
       or negative quantity.

       The  path loss analysis range may be modified to  a  user-
specific  dis-
       tance  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 ITM path
       loss calculations between all four  corners  of	the  area
prediction map.

       The  colors  used  to illustrate contour regions in SPLAT!
generated  cov-
       erage  maps  may  be  tailored  by  the	user  by creating
or modifying
       SPLAT!'s color definition files.  SPLAT! color  definition
files  have
       the  same  base	name  as  the  transmitter's  .qth  file,
but carry .lcf,
       .scf, and .dcf extensions.  If the necessary file does not
exist in the
       current	 working  when	SPLAT!	is run, a file containing
default color
       definition parameters that is suitable for manual  editing
by  the  user
       is written into the current directory.

       When   a regional ITM analysis is performed and the trans-
mitter's ERP is
       not specified or is zero, a .lcf path loss  color  defini-
tion file corre-
       sponding  to the transmitter site (.qth) is read by SPLAT!
from the cur-
       rent working directory.	If a .lcf file	corresponding  to
the  transmit-
       ter   site  is not found, then a default file suitable for
manual editing
       by the user is automatically generated by SPLAT!.

       A path loss color definition file  possesses  the  follow-
ing  structure
       (wnjt-dt.lcf):

	;  SPLAT!  Auto-generated   Path-Loss	Color  Definition
("wnjt-dt.lcf")
       File
	;
	;  Format for the parameters held in this file is as fol-
lows:
	;
	;    dB: red, green, blue
	;
	; ...where "dB" is the path loss (in dB) and
	; "red", "green", and "blue" are  the  corresponding  RGB
color
	; definitions ranging from 0 to 255 for the region speci-
fied.
	;
	; The following parameters may be edited and/or expanded
	;  for	future	runs of SPLAT!	A total of 32 contour re-
gions
	; may be defined in this file.
	;
	;
	 80: 255,   0,	 0
	 90: 255, 128,	 0
	100: 255, 165,	 0
	110: 255, 206,	 0
	120: 255, 255,	 0
	130: 184, 255,	 0
	140:   0, 255,	 0
	150:   0, 208,	 0
	160:   0, 196, 196
	170:   0, 148, 255
	180:  80,  80, 255
	190:   0,  38, 255
	200: 142,  63, 255
	210: 196,  54, 255
	220: 255,   0, 255
	230: 255, 194, 204

       If the path loss is less than 80 dB, the color Red (RGB	=
255, 0, 0) is
       assigned   to   the  region.   If the path loss is greater
than or equal to
       80 dB, but less than 90 db, then Dark Orange (255, 128, 0)
is  assigned
       to  the	region.   Orange (255, 165, 0) is assigned to re-
gions having a
       path loss greater than or equal to 90 dB,  but  less  than
100 dB, and  so
       on.    Greyscale   terrain  is displayed beyond the 230 dB
path loss con-
       tour. Adding the -sc switch will smooth	the   transitions
between  the
       specified quantized contour levels.

FIELD STRENGTH ANALYSIS
       If  the	transmitter's  effective  radiated power (ERP) is
specified in the
       transmitter's .lrp file, or expressed  on   the	 command-
line  using  the
       -erp   switch,	field	strength  contours  referenced to
decibels over one
       microvolt per meter (dBuV/m) rather  than  path	loss  are
produced:

       splat -t wnjt-dt -L 30.0 -erp 46000 -db 30 -o plot.ppm

       The -db switch can be used in this mode as before to limit
the  extent
       to   which   field  strength  contours  are plotted.  When
plotting field
       strength contours, however, the argument given  is  inter-
preted as  being
       expressed in dBuV/m.

       SPLAT!  field  strength	color  definition  files  share a
very similar
       structure to .lcf files used for plotting path loss:

	;  SPLAT!  Auto-generated Signal Color Definition ("wnjt-
dt.scf") File
	;
	; Format for the parameters held in this file is as  fol-
lows:
	;
	;    dBuV/m: red, green, blue
	;
	;  ...where  "dBuV/m"  is the signal strength (in dBuV/m)
and
	; "red", "green", and "blue" are  the  corresponding  RGB
color
	; definitions ranging from 0 to 255 for the region speci-
fied.
	;
	; The following parameters may be edited and/or expanded
	;  for	future	runs of SPLAT!	A total of 32 contour re-
gions
	; may be defined in this file.
	;
	;
	128: 255,   0,	 0
	118: 255, 165,	 0
	108: 255, 206,	 0
	 98: 255, 255,	 0
	 88: 184, 255,	 0
	 78:   0, 255,	 0
	 68:   0, 208,	 0
	 58:   0, 196, 196
	 48:   0, 148, 255
	 38:  80,  80, 255
	 28:   0,  38, 255
	 18: 142,  63, 255
	  8: 140,   0, 128

       If the signal strength is greater than or equal to 128  dB
over 1 micro-
       volt per meter (dBuV/m), the color Red (255, 0, 0) is dis-
played for the
       region.	 If  the signal strength is greater than or equal
to 118 dBuV/m,
       but  less  than 128 dBuV/m, then the  color  Orange  (255,
165, 0) is dis-
       played,	and  so on.  Greyscale terrain is  displayed  for
regions  with
       signal strengths less than 8 dBuV/m.

       Signal  strength contours for  some  common  VHF  and  UHF
broadcasting ser-
       vices in the United States are as follows:

	      Analog Television Broadcasting
	      ------------------------------
	      Channels 2-6:	  City Grade: >= 74 dBuV/m
				     Grade A: >= 68 dBuV/m
				     Grade B: >= 47 dBuV/m
	      --------------------------------------------
	      Channels 7-13:	  City Grade: >= 77 dBuV/m
				     Grade A: >= 71 dBuV/m
				     Grade B: >= 56 dBuV/m
	      --------------------------------------------
	      Channels 14-69:	Indoor Grade: >= 94 dBuV/m
				  City Grade: >= 80 dBuV/m
				     Grade A: >= 74 dBuV/m
				     Grade B: >= 64 dBuV/m
	      Digital Television Broadcasting
	      -------------------------------
	      Channels 2-6:	  City Grade: >= 35 dBuV/m
			   Service Threshold: >= 28 dBuV/m
	      --------------------------------------------
	      Channels 7-13:	  City Grade: >= 43 dBuV/m
			   Service Threshold: >= 36 dBuV/m
	      --------------------------------------------
	      Channels 14-69:	  City Grade: >= 48 dBuV/m
			   Service Threshold: >= 41 dBuV/m
	      NOAA Weather Radio (162.400 - 162.550 MHz)
	      ------------------------------------------
			 Reliable: >= 18 dBuV/m
		     Not reliable: <  18 dBuV/m
	      Unlikely to receive: <  0 dBuV/m
	      FM Radio Broadcasting (88.1 - 107.9 MHz)
	      ----------------------------------------
	      Analog Service Contour:  60 dBuV/m
	      Digital Service Contour: 65 dBuV/m

RECEIVED POWER LEVEL ANALYSIS
       If  the	transmitter's  effective  radiated power (ERP) is
specified in the
       transmitter's  .lrp  file,  or  expressed on the  command-
line using the
       -erp  switch,  and  the	-dbm  switch is invoked, received
power level  con-
       tours referenced to decibels over one milliwatt (dBm)  are
produced:

       splat  -t  wnjt-dt  -L  30.0  -erp  46000 -dbm -db -100 -o
plot.ppm

       The  -db switch can be used to limit the extent	to  which
received power
       level  contours	are  plotted.  When plotting power  level
contours,  the
       argument given is interpreted as being expressed in dBm.

       SPLAT! received power level color definition files share a
very similar
       structure to the color definition files described earlier,
except	that
       the  power  levels  in  dBm may be either positive or neg-
ative, and are
       limited to a range between +40 dBm and -200 dBm:

	; SPLAT! Auto-generated DBM  Signal  Level  Color  Defin-
ition  ("wnjt-
       dt.dcf") File
	;
	; Format for the parameters held in this file is as  fol-
lows:
	;
	;    dBm: red, green, blue
	;
	;  ...where  "dBm" is the received signal power level be-
tween +40 dBm
	; and -200 dBm, and "red", "green", and  "blue"  are  the
corresponding
	;   RGB  color	definitions ranging from 0 to 255 for the
region speci-
       fied.
	;
	; The following parameters may be edited and/or expanded
	; for future runs of SPLAT!  A total of  32  contour  re-
gions
	; may be defined in this file.
	;
	;
	  +0: 255,   0,   0
	 -10: 255, 128,   0
	 -20: 255, 165,   0
	 -30: 255, 206,   0
	 -40: 255, 255,   0
	 -50: 184, 255,   0
	 -60:	0, 255,   0
	 -70:	0, 208,   0
	 -80:	0, 196, 196
	 -90:	0, 148, 255
	-100:  80,  80, 255
	-110:	0,  38, 255
	-120: 142,  63, 255
	-130: 196,  54, 255
	-140: 255,   0, 255
	-150: 255, 194, 204

ANTENNA RADIATION PATTERN PARAMETERS
       Normalized  field  voltage patterns for a transmitting an-
tenna's horizon-
       tal  and  vertical planes are imported automatically  into
SPLAT! when a
       path  loss, field strength, or received power level cover-
age analysis is
       performed.   Antenna  pattern  data is read from a pair of
files having
       the same base name as the transmitter and LRP  files,  but
with  .az  and
       .el   extensions  for azimuth and elevation pattern files,
respectively.
       Specifications regarding pattern rotation (if any) and me-
chanical  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 pat-
       tern  rotation  (measured  clockwise in degrees from  True
North)	to  be
       applied	by SPLAT! to the data contained in the .az  file.
This is fol-
       lowed by azimuth headings (0 to 360 degrees) and their as-
sociated  nor-
       malized	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 specifies the amount of me-
chanical  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, separated by
whitespace.

       The remainder of the file consists of elevation angles and
their corre-
       sponding  normalized  voltage radiation pattern (0.000  to
1.000) values
       separated by whitespace.  Elevation angles must	be  spec-
ified  over  a
       -10.0   to   +90.0   degree  range.  As was the convention
with mechanical
       beamtilt, negative elevation angles are used   to   repre-
sent  elevations
       above  the  horizon,  while positive angles represents el-
evations 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
downward 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  de-
grees.	 If  the
       pattern	data specified does not reach this level of reso-
lution, SPLAT!
       will interpolate the values provided  to   determine   the
data  at  the
       required resolution, although this may result in a loss in
accuracy.

EXPORTING AND IMPORTING REGIONAL CONTOUR DATA
       Performing   a  regional coverage analysis based on an ITM
path analysis
       can be a very time consuming process, especially  if   the
analysis  is
       performed   repeatedly	to  discover what effects changes
to a transmit-
       ter's antenna radiation pattern make to the predicted cov-
erage area.

       This process can be expedited  by  exporting  the  contour
data produced by
       SPLAT!  to  an  alphanumeric output (.ano) file.  The data
contained in
       this file can then be modified to incorporate antenna pat-
tern  effects,
       and imported back into SPLAT! to quickly produce a revised
contour map.
       Depending  on  the  way	in which SPLAT! is  invoked,  al-
phanumeric  output
       files   can   describe	regional    path   loss,   signal
strength, or received
       signal power levels.

       For  example,  an alphanumeric output file containing path
loss  informa-
       tion 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 maximum
       path loss of 140 dB (assuming ERP is not specified in  the
transmitter's
       .lrp file) using the following syntax:

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

       If  ERP	is  specified  in the .lrp file or on the command
line through the
       -erp  switch,  the  alphanumeric  output file will instead
contain pre-
       dicted field values in  dBuV/m.	 If  the   -dBm   command
line  switch  is
       used,   then   the  alphanumeric  output file will contain
receive signal
       power levels in dBm.

       SPLAT! alphanumeric output files can exceed many  hundreds
of  megabytes
       in   size.    They   contain  information  relating to the
boundaries of the
       region  they  describe  followed  by  latitudes	 (degrees
North),  longitudes
       (degrees  West), azimuths (referenced to True North), ele-
vations (to the
       first obstruction), followed by either	path   loss   (in
dB),  received
       field   strength   (in  dBuV/m),  or received signal power
level (in dBm)
       without regard to  the  transmitting  antenna's	radiation
pattern.

       The  first  few lines of a SPLAT! alphanumeric output file
could take  on
       the following appearance (pathloss.dat):

	       119, 117    ; max_west, min_west
	       35, 34	   ; max_north, min_north
	       34.2265424, 118.0631096, 48.199, -32.747, 67.70
	       34.2270358, 118.0624421, 48.199, -19.161, 73.72
	       34.2275292, 118.0617747, 48.199, -13.714, 77.24
	       34.2280226, 118.0611072, 48.199, -10.508, 79.74
	       34.2290094, 118.0597723, 48.199, -11.806, 83.26 *
	       34.2295028, 118.0591048, 48.199, -11.806, 135.47 *
	       34.2299962, 118.0584373, 48.199, -15.358, 137.06 *
	       34.2304896, 118.0577698, 48.199, -15.358, 149.87 *
	       34.2314763, 118.0564348, 48.199, -15.358, 154.16 *
	       34.2319697, 118.0557673, 48.199, -11.806, 153.42 *
	       34.2324631, 118.0550997, 48.199, -11.806, 137.63 *
	       34.2329564, 118.0544322, 48.199, -11.806, 139.23 *
	       34.2339432, 118.0530971, 48.199, -11.806, 139.75 *
	       34.2344365, 118.0524295, 48.199, -11.806, 151.01 *
	       34.2349299, 118.0517620, 48.199, -11.806, 147.71 *
	       34.2354232, 118.0510944, 48.199, -15.358, 159.49 *
	       34.2364099, 118.0497592, 48.199, -15.358, 151.67 *

       Comments  can  be  placed  in the file if  they	are  pre-
ceeded by a semi-
       colon.	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
transmitter and
       receiver  is  unobstructed.   If  the   path  between  the
transmitter  and
       receiver  is  obstructed,  an  asterisk (*) is  placed  on
the end of the
       line,  and  the	elevation angle returned by SPLAT! refers
the  elevation
       angle  to  the  first  obstruction  rather than	the  geo-
graphic location
       specified  on  the  line.  This is done in response to the
fact  that  the
       ITM  model  considers  the  energy  reaching   a   distant
point over an
       obstructed  path  to be the result of the energy scattered
over  the  top
       of the first obstruction along  the  path.   Since  energy
cannot reach the
       obstructed  location  directly, the actual elevation angle
to the	desti-
       nation over such a path becomes irrelevant.

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

       Modified  alphanumeric  output	files	can  be  imported
back into SPLAT!
       for  generating	revised  coverage maps provided that  the
ERP  and  -dBm
       options	are  used  as  they were  when	the  alphanumeric
output file was
       originally generated:

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

       Note that alphanumeric output  files  generated	by  splat
cannot	be  used
       with   splat-hd,   or   vice-versa  due	to the resolution
incompatibility
       between the two versions of the program.   Also,  each  of
the three types
       of   alphanumeric  output  files are incompatible with one
another, so a
       file containing path loss data  cannot  be  imported  into
SPLAT!	to  pro-
       duce  signal  strength  or  received power level contours,
etc.

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  ter-
       rain features believed to be of importance to  the  SPLAT!
analysis being
       conducted, but noticeably absent from the  SDF  files  be-
ing  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 inter-
       preted  as being 3-arc seconds in both latitude and longi-
tude  in  splat
       and  1  arc-second  in  latitude  and  longitude in splat-
hd.  Features
       described in the user-defined  terrain  file  that   over-
lap  previously
       defined	features  in  the  file  are ignored by SPLAT! to
avoid ambiguity.

GROUND CLUTTER
       The height of ground clutter can be  specified  using  the
-gc switch:

	     splat   -t  wnjt-dt  -r  kd2bd  -gc  30.0	-H  wnjt-
dt_path.png

       The  -gc  switch  as  the  effect of raising  the  overall
terrain by the
       specified  amount in feet (or meters if the -metric switch
is  invoked),
       except  over  areas  at sea-level and at the  transmitting
and receiving
       antenna locations.

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 follows:

       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  kilome-
       ters   if   the	 -metric  switch is used).  Note that the
tx_site name and
       location are not displayed in this example.  If display of
this  infor-
       mation  is  desired,  simply  create a  SPLAT!  city  file
(-s option) and
       append  it to the list of command-line options illustrated
above.

       If the -o switch and output filename are omitted in  these
operations,
       topographic   output   is  written   to	 a   file   named
tx_site.ppm in the cur-
       rent 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) software by generating a	georefer-
ence 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 interpre-
       tation  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 gen-
       erated  by  SPLAT! when performing point-to-point  or  re-
gional	coverage
       analyses by invoking the -kml switch:

       splat -t wnjt-dt -r kd2bd -kml

       The  KML file generated will have the same filename struc-
ture as a Path
       Analysis 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 anno-
       tate 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  dis-
played 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 con-
tent.

       When performing regional coverage analysis, the	.kml file
generated by
       SPLAT!  will permit path loss or signal strength  contours
to be layered
       on  top of Google Earth's display along with a correspond-
ing  color  key
       in  the	upper left-hand corner.  The generated .kml  file
will have the
       same basename as that of the .ppm file normally generated.

DETERMINATION OF ANTENNA HEIGHT ABOVE AVERAGE TERRAIN
       SPLAT!  determines  antenna  height  above average terrain
(HAAT) according
       to  the	procedure  defined   by   Federal  Communications
Commission Part
       73.313(d).  According to  this  definition,  terrain  ele-
vations  along
       eight  radials  between	2  and 10 miles (3 and 16 kilome-
ters) 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 available), then those radials are
omitted from
       the calculation of average terrain.

       Note that SRTM-3 elevation data, unlike older  USGS  data,
extends beyond
       the   borders   of the United States.  Therefore, HAAT re-
sults may not be
       in full compliance 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  ques-
       tion  does  not	lie  within 10 miles of the  boundary  of
the topography
       data in memory.

       When  performing area prediction analysis,  enough  topog-
raphy  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 de-
grees, 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.

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>
	      Original Longley-Rice ITM Model integration

       Ron Bentley <ronbentley@embarqmail.com>
	      Fresnel Zone plotting and clearance determination

KD2BD	   Software			   27	   June      2014
SPLAT!(1)


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