--- /dev/null
+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)] [-fz Fres-
+ nel zone clearance percentage (default = 60)] [-plo
+ path_loss_output_file.txt] [-pli path_loss_input_file.txt]
+ [-udt user_defined_terrain_file.dat] [-n] [-N] [-nf]
+ [-ngs] [-geo] [-kml] [-metric]
+
+DESCRIPTION
+ SPLAT! is a powerful terrestrial RF propagation and ter-
+ rain analysis tool for the spectrum between 20 MHz and 20
+ GHz. SPLAT! is free software, and is designed for opera-
+ tion on Unix and Linux-based workstations. Redistribution
+ and/or modification is permitted under the terms of the
+ GNU General Public License, Version 2, as published by the
+ Free Software Foundation. Adoption of SPLAT! source code
+ in proprietary or closed-source applications is a viola-
+ tion 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 prediction 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, distances, and elevations to
+ known obstructions, Longley-Rice path attenuation, 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 topo-
+ graphic maps that depict line-of-sight paths, and regional
+ path loss and signal strength contours through which
+ expected coverage areas of transmitters and repeater sys-
+ tems can be obtained. When performing line-of-sight and
+ Longley-Rice analyses in situations where multiple trans-
+ mitter 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! v1.2.1 Available Options...
+ ]==--
+
+ -t txsite(s).qth (max of 4 with -c, max of 30 with
+ -L)
+ -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 (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 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)
+ -m earth radius multiplier
+ -n do not plot LOS paths in .ppm maps
+ -N do not produce unnecessary site or obstruction
+ reports
+ -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
+ -fz Fresnel zone clearance percentage (default = 60)
+ -ngs display greyscale topography as white in .ppm
+ files
+ -erp override ERP in .lrp file (Watts)
+ -pli filename of path-loss input file
+ -plo filename of path-loss output file
+ -udt filename of user defined terrain input file
+ -kml generate Google Earth (.kml) compatible output
+ -geo generate an Xastir .geo georeference file (with
+ .ppm output) -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, antenna
+ radiation pattern 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. 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/
+
+ The strm2sdf utility may also be used to convert 3-arc
+ second SRTM data in Band Interleaved by Line (.BIL) format
+ for use with SPLAT!. This data is available via the web
+ at: http://seamless.usgs.gov/website/seamless/
+
+ Band Interleaved by Line data must be downloaded in a very
+ specific manner to be compatible with srtm2sdf and SPLAT!.
+ Please consult srtm2sdf's documentation for instructions
+ on downloading .BIL topographic data through the USGS's
+ Seamless Web Site.
+
+ 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 read 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 com-
+ pressed 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, 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 specified 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 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-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 ; ERP in Watts (optional)
+
+ 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 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 generated "splat.lrp" file 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 seventh and eighth parameters in the .lrp file corre-
+ spond to the statistical analysis provided by the Longley-
+ Rice model. In this example, SPLAT! will return the maxi-
+ mum path loss occurring 50% of the time (fraction of time)
+ in 90% of situations (fraction of situations). This is
+ often 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 modulation), while
+ F(50,50) is used for analog (VSB-AM+NTSC) broadcasts.
+
+ 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
+
+ The final parameter in the .lrp file corresponds to the
+ transmitter's effective radiated power, and is optional.
+ If it is included in the levels and field strength level
+ contours when performing Longley-Rice 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 con-
+ tains an ERP parameter and the generation of path-loss
+ rather than signal strength contours is desired, the ERP
+ can be assigned to zero using the -erp switch without hav-
+ ing 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 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.cen-
+ sus.gov/geo/www/cob/co2000.html#ascii and http://www.cen-
+ sus.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! Path Analysis Report to the current work-
+ ing directory. The report contains details of the trans-
+ mitter 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
+
+ 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 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 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 bear-
+ ings and distances between the transmitter and receiver,
+ as well as the free-space and Longley-Rice 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.
+
+ 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 corresponding .lrp file, then pre-
+ dicted signal strength and antenna voltage at the receiv-
+ ing location is also provided in the Path Analysis Report.
+
+ 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-level 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.
+
+ 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 utility:
+
+ 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 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. 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_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-dt -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 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 average
+ terrain, and the height of the average terrain calculated
+ toward the bearings 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 in areas surrounding the
+ transmitter site. A legend at the bottom of the map cor-
+ relates each color with a specific path loss range in
+ decibels or signal strength in decibels over one microvolt
+ per meter (dBuV/m).
+
+ 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-dt -L 30.0 -s cities.dat -b co34_d00.dat -db
+ 140 -o plot.ppm
+
+
+SIGNAL CONTOUR COLOR DEFINITION PARAMETERS
+ The colors used to illustrate signal strength and path
+ loss contours in SPLAT! generated coverage 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 and .scf extensions.
+
+ When a regional Longley-Rice analysis is performed and the
+ transmitter's ERP is not specified or is zero, a .lcf path
+ loss color definition file corresponding to the transmit-
+ ter site (.qth) is read by SPLAT! from the current 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!. If the transmitter's ERP is specified, then a
+ signal strength map is generated and a signal strength
+ color definition file (.scf) is read, or generated if one
+ is not available in the current working directory.
+
+ A path-loss color definition file possesses the following
+ 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
+ regions
+ ; 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 regions 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 contour.
+
+ SPLAT! signal strength color definition files share a very
+ similar structure (wnjt-dt.scf):
+
+ ; 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
+ regions
+ ; 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 microvolt per meter (dBuV/m), the color Red (255,
+ 0, 0) is displayed 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 displayed,
+ 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 services 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
+
+
+
+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 mechani-
+ cal beam tilt and tilt direction (if any) are also con-
+ tained 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). Note that
+ the tx_site name and location are not displayed in this
+ example. If display of this information is desired, sim-
+ ply 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 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
+ or regional 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 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.
+
+ 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 in a semi-transparent manner. 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 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" within the structure of the program. Each "page"
+ holds one SDF file representing a one degree by one degree
+ region of terrain. A #define MAXPAGES statement in the
+ first several lines of splat.cpp sets the maximum number
+ of "pages" available for holding topography data. It also
+ sets the maximum size of the topographic maps generated by
+ SPLAT!. MAXPAGES is set to 9 by default. If SPLAT! pro-
+ duces 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 MAXPAGES specified. In situations where avail-
+ able memory is low, MAXPAGES 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 avail-
+ able, then MAXPAGES 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 dis-
+ tances 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>
+ Original Longley-Rice Model integration
+
+ Ron Bentley <ronbentley@earthlink.net>
+ Fresnel Zone plotting and clearance determination
+
+
+
+
+KD2BD Software 16 September 2007 SPLAT!(1)
projects / debian / splat / blobdiff