NAME
- splat - A Signal Propagation, Loss, And Terrain analysis
- tool
+ 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)
- (float)] [-L rx_antenna_height_for_Longley-Rice_cover-
- age_analysis (feet) (float)] [-p terrain_profile.ext] [-e
- elevation_profile.ext] [-h height_profile.ext] [-l Long-
- ley-Rice_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)] [-R maximum_cover-
- age_range (for -c or -L) (miles) (float)] [-n] [-N]
+ splat [-t transmitter_site.qth] [-r receiver_site.qth]
+ [-c rx antenna height for LOS coverage analysis
+ (feet/meters) (float)] [-L rx antenna height for Longley-
+ Rice coverage analysis (feet/meters) (float)] [-p ter-
+ rain_profile.ext] [-e elevation_profile.ext] [-h
+ height_profile.ext] [-H normalized_height_profile.ext] [-l
+ Longley-Rice_profile.ext] [-o topographic_map_file-
+ name.ppm] [-b cartographic_boundary_filename.dat] [-s
+ site/city_database.dat] [-d sdf_directory_path] [-m earth
+ radius multiplier (float)] [-f frequency (MHz) for Fresnel
+ zone calculations (float)] [-R maximum coverage radius
+ (miles/kilometers) (float)] [-dB maximum attenuation con-
+ tour to display on path loss maps (80-230 dB)] [-nf do not
+ plot Fresnel zones in height plots] [-plo path_loss_out-
+ put_file.txt] [-pli path_loss_input_file.txt] [-udt
+ user_defined_terrain_file.dat] [-n] [-N] [-geo] [-kml]
+ [-metric]
DESCRIPTION
- SPLAT! is a simple, yet powerful terrain analysis tool
- written for Unix and Linux-based workstations. SPLAT! is
- free software. Redistribution and/or modification is per-
- mitted under the terms of the GNU General Public License
- as published by the Free Software Foundation, either ver-
- sion 2 of the License or any later version. Adoption of
- SPLAT! source code in proprietary or closed-source appli-
- cations is a violation of this license, and is strictly
- forbidden.
+ SPLAT! is a powerful terrestrial RF propagation and ter-
+ rain analysis tool covering the spectrum between 20 MHz
+ and 20 GHz. SPLAT! is free software, and is designed for
+ operation on Unix and Linux-based workstations. Redistri-
+ bution and/or modification is permitted under the terms of
+ the GNU General Public License as published by the Free
+ Software Foundation, either version 2 of the License or
+ any later version. Adoption of SPLAT! source code in pro-
+ prietary or closed-source applications is a violation of
+ this license, and is strictly forbidden.
SPLAT! is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY, without even the implied war-
POSE. See the GNU General Public License for more details.
INTRODUCTION
- SPLAT! is a terrestrial RF propagation analysis tool for
- the spectrum between 20 MHz and 20 GHz, and provides
- information of interest to communication system designers
- and site engineers. SPLAT! determines great circle dis-
- tances and bearings between sites, antenna elevation
- angles (uptilt), depression angles (downtilt), antenna
- height above mean sea level, antenna height above average
- terrain, bearings and distances to known obstructions,
- Longley-Rice path loss, and minimum antenna height
- requirements needed to establish line-of-sight communica-
- tion paths absent of obstructions due to terrain. SPLAT!
- produces reports, graphs, and highly detailed and care-
- fully annotated topographic maps depicting line-of-sight
- paths, path loss, and expected coverage areas of transmit-
- ters and repeater systems. When performing line-of-sight
- analysis in situations where multiple transmitter or
- repeater sites are employed, SPLAT! determines individual
- and mutual areas of coverage within the network specified.
-
- SPLAT! operates in two modes: point-to-point mode, and
- area prediction mode. These modes may be invoked using
- either line-of-sight (LOS) or Irregular Terrain (ITM)
- propagation models. True Earth, four-thirds Earth, or any
- other Earth radius may be specified by the user when per-
- forming line-of-sight analysis.
+ Applications of SPLAT! include the visualization, design,
+ and link budget analysis of wireless Wide Area Networks
+ (WANs), commercial and amateur radio communication systems
+ above 20 MHz, microwave links, frequency coordination and
+ interference studies, and the determination of analog and
+ digital terrestrial radio and television contour regions.
+
+ SPLAT! provides RF site engineering data such as great
+ circle distances and bearings between sites, antenna ele-
+ vation angles (uptilt), depression angles (downtilt),
+ antenna height above mean sea level, antenna height above
+ average terrain, bearings and distances to known obstruc-
+ tions, and Longley-Rice path attenuation. In addition,
+ the minimum antenna height requirements needed to clear
+ terrain, the first Fresnel zone, and 60% of the first
+ Fresnel zone are also provided.
+
+ SPLAT! produces reports, graphs, and high resolution topo-
+ graphic maps that depict line-of-sight paths, and regional
+ path loss contours through which expected coverage areas
+ of transmitters and repeater systems can be obtained.
+ When performing line-of-sight analysis in situations where
+ multiple transmitter or repeater sites are employed,
+ SPLAT! determines individual and mutual areas of coverage
+ within the network specified.
+
+ Simply typing splat on the command line will return a sum-
+ mary of SPLAT!'s command line options:
+
+ --==[ SPLAT! v1.2.0 Available Options...
+ ]==--
+
+ -t txsite(s).qth (max of 4)
+ -r rxsite.qth
+ -c plot coverage of TX(s) with an RX antenna at X
+ feet/meters AGL
+ -L plot path loss map of TX based on an RX at X
+ feet/meters AGL
+ -s filename(s) of city/site file(s) to import (max
+ of 5)
+ -b filename(s) of cartographic boundary file(s) to
+ import (5 max)
+ -p filename of terrain profile graph to plot
+ -e filename of terrain elevation graph to plot
+ -h filename of terrain height graph to plot
+ -H filename of normalized terrain height graph to
+ plot
+ -l filename of Longley-Rice graph to plot
+ -o filename of topographic map to generate (.ppm)
+ -u filename of user-defined terrain file to import
+ -d sdf file directory path (overrides path in
+ ~/.splat_path file)
+ -n no analysis, brief report
+ -N no analysis, no report
+ -m earth radius multiplier
+ -f frequency for Fresnel zone calculation (MHz)
+ -R modify default range for -c or -L (miles/kilome-
+ ters)
+ -db maximum loss contour to display on path loss maps
+ (80-230 dB)
+ -nf do not plot Fresnel zones in height plots
+ -plo filename of path-loss output file
+ -pli filename of path-loss input file
+ -udt filename of user defined terrain input file
+ -geo generate a .geo georeference file (with .ppm out-
+ put)
+ -kml generate a Google Earth .kml file (for point-to-
+ point links)
+ -metric employ metric rather than imperial units for all
+ user I/O
+
INPUT FILES
- SPLAT! is a command-line driven application, and reads
- input data through a number of data files. Each has its
- own format. Some files are mandatory for successful exe-
- cution of the program, while others are optional. Manda-
- tory files include SPLAT Data Files (SDF files), site
- location files (QTH files), and Longley-Rice model parame-
- ter files (LRP files). Optional files include city/site
- location files, and cartographic boundary files.
+ SPLAT! is a command-line driven application, and reads
+ input data through a number of data files. Some files are
+ mandatory for successful execution of the program, while
+ others are optional. Mandatory files include 3-arc second
+ topography models in the form of SPLAT Data Files (SDF
+ files), site location files (QTH files), and Longley-Rice
+ model parameter files (LRP files). Optional files include
+ city location files, cartographic boundary files, user-
+ defined terrain files, path-loss input files, and antenna
+ radiation pattern files.
SPLAT DATA FILES
- SPLAT! imports topographic data in the form of SPLAT Data
- Files (SDFs) that may be generated from a number of infor-
- mation sources. In the United States, SPLAT Data Files
- are most often derived from U.S. Geological Survey Digi-
- tal Elevation Models (DEMs) using the usgs2sdf utility
- included with SPLAT!. USGS Digital Elevation Models com-
- patible with this utility are available at no cost via the
- Internet at: http://edc-
- sgs9.cr.usgs.gov/glis/hyper/guide/1_dgr_dem-
- fig/index1m.html.
-
- SPLAT Data Files contain topographic elevations to the
- nearest meter above mean sea level for 1-degree by
- 1-degree regions of the earth with a resolution of 3-arc
- seconds. SDF files can be read in either standard format
- (.sdf) as generated by the usgs2sdf utility, or in bzip2
- compressed format (.sdf.bz2). Since uncompressed files
- can be slightly faster to load than compressed files,
- SPLAT! searches for the needed SDF data in uncompressed
- format first. If such data cannot located, then SPLAT!
- tries to read the data in bzip2 compressed format. If no
- compressed SDF files can be found for the region
- requested, SPLAT! assumes the region is over water or out-
- side the United States, 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 USGS Digital
- Elevation Model Data since they are devoid of any land
- masses. However, this behavior of SPLAT! underscores the
- importance of having all the SDF files required for the
- region being analyzed if meaningful results are to be
- expected.
+ SPLAT! imports topographic data in the form of SPLAT Data
+ Files (SDFs). These files may be generated from a number
+ of information sources. In the United States, SPLAT Data
+ Files can be generated through U.S. Geological Survey
+ Digital Elevation Models (DEMs) using the usgs2sdf utility
+ included with SPLAT!. USGS Digital Elevation Models com-
+ patible with this utility may be downloaded from:
+ http://edcftp.cr.usgs.gov/pub/data/DEM/250/.
+
+ Significantly better resolution and accuracy can be
+ obtained through the use of SRTM-3 Version 2 digital ele-
+ vation models. These models are the product of the STS-99
+ Space Shuttle Radar Topography Mission, and are available
+ for most populated regions of the Earth. SPLAT Data Files
+ may be generated from SRTM data using the included
+ srtm2sdf utility. SRTM-3 Version 2 data may be obtained
+ through anonymous FTP from:
+ ftp://e0srp01u.ecs.nasa.gov:21/srtm/version2/
+
+ Despite the higher accuracy that SRTM data has to offer,
+ some voids in the data sets exist. When voids are
+ detected, the srtm2sdf utility replaces them with corre-
+ sponding data found in existing SDF files (that were pre-
+ sumably created from earlier USGS data through the
+ usgs2sdf utility). If USGS-derived SDF data is not avail-
+ able, voids are handled through adjacent pixel averaging,
+ or direct replacement.
+
+ SPLAT Data Files contain integer value topographic eleva-
+ tions (in meters) referenced to mean sea level for
+ 1-degree by 1-degree regions of the earth with a resolu-
+ tion of 3-arc seconds. SDF files can be read in either
+ standard format (.sdf) as generated by the usgs2sdf and
+ srtm2sdf utilities, or in bzip2 compressed format
+ (.sdf.bz2). Since uncompressed files can be processed
+ slightly faster than files that have been compressed,
+ SPLAT! searches for needed SDF data in uncompressed format
+ first. If uncompressed data cannot be located, SPLAT!
+ then searches for data in bzip2 compressed format. If no
+ compressed SDF files can be found for the region
+ requested, SPLAT! assumes the region is over water, and
+ will assign an elevation of sea-level to these areas.
+
+ This feature of SPLAT! makes it possible to perform path
+ analysis not only over land, but also between coastal
+ areas not represented by Digital Elevation Model data.
+ However, this behavior of SPLAT! underscores the impor-
+ tance of having all the SDF files required for the region
+ being analyzed if meaningful results are to be expected.
SITE LOCATION (QTH) FILES
SPLAT! imports site location information of transmitter
and receiver sites analyzed by the program from ASCII
files having a .qth extension. QTH files contain the
- site's name, the site's latitude (in degrees North), the
- site's longitude (in degrees West), and the site's antenna
- height above ground level (AGL). A single line-feed char-
- acter separates each field. 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
+ site's name, the site's latitude (positive if North of the
+ equator, negative if South), the site's longitude (in
+ degrees West, 0 to 360 degrees), and the site's antenna
+ height above ground level (AGL), each separated by a sin-
+ gle line-feed character. The antenna height is assumed to
+ be specified in feet unless followed by the letter m or
+ the word meters in either upper or lower case. Latitude
and longitude information may be expressed in either deci-
- mal format (74.6889) or degree, minute, second (DMS) for-
+ mal format (74.6889) or degree, minute, second (DMS) for-
mat (74 41 20.0).
- For example, a site location file describing television
- station WNJT, Trenton, NJ (wnjt.qth) might read as fol-
+ For example, a site location file describing television
+ station WNJT, Trenton, NJ (wnjt.qth) might read as fol-
lows:
WNJT
be represented by its own site location (QTH) file.
LONGLEY-RICE PARAMETER (LRP) FILES
- SPLAT! imports Longley-Rice model parameter data from
- files having the same base name as the transmitter site
- QTH file, but carrying a .lrp extension, thus providing
- simple and accurate correlation between these associated
- data sets. The format for the Longley-Rice model parame-
- ter files is as follows (wnjt.lrp):
+ Longley-Rice parameter data files are required for SPLAT!
+ to determine RF path loss in either point-to-point or area
+ prediction mode. Longley-Rice model parameter data is
+ read from files having the same base name as the transmit-
+ ter site QTH file, but with a format (wnjt.lrp):
15.000 ; Earth Dielectric Constant (Relative per-
mittivity)
then the default parameters listed above will be assigned
by SPLAT! and a corresponding "splat.lrp" file containing
this data will be written to the current working direc-
- tory.
+ tory. "splat.lrp" can then be edited by the user as
+ needed.
Typical Earth dielectric constants and conductivity values
are as follows:
3: Maritime Subtropical (West coast of Africa)
4: Desert (Sahara)
5: Continental Temperate
- 6: Maritime Temperate, over land (UK and west
+ 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
+ The Continental Temperate climate is common to large land
+ masses in the temperate zone, such as the United States.
+ For paths shorter than 100 km, there is little difference
between Continental and Maritime Temperate climates.
- The final two parameters in the .lrp file correspond to
- the statistical analysis provided by the Longley-Rice
- model. In this example, SPLAT! will return the maximum
- path loss occurring 50% of the time (fraction of time) in
- 50% of situations (fraction of situations). Use a
- fraction of time parameter of 0.97 for digital television,
- 0.50 for analog in the United States. Isotropic antennas
- are assumed.
-
- For further information on these parameters, see:
- http://elbert.its.bldrdoc.gov/itm.html and
+ The final two parameters in the .lrp file correspond to
+ the statistical analysis provided by the Longley-Rice
+ model. In this example, SPLAT! will return the maximum
+ path loss occurring 50% of the time (fraction of time) in
+ 50% of situations (fraction of situations). In the United
+ States, use a fraction of time parameter of 0.97 for digi-
+ tal television (8VSB modulation), or 0.50 for analog (VSB-
+ AM+NTSC) transmissions.
+
+ For further information on these parameters, see:
+ http://flattop.its.bldrdoc.gov/itm.html and
http://www.softwright.com/faq/engineering/prop_long-
ley_rice.html
CITY LOCATION FILES
- The names and locations of cities, tower sites, or other
- points of interest may imported and be plotted on topo-
- graphic maps generated by SPLAT!. SPLAT! imports the
- names of cities and locations from ASCII files containing
- the location's name, the location's latitude, and the
- location's longitude. 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 longi-
- tude information may be entered in either decimal or
- degree, minute, second (DMS) format.
+ 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):
Totowa, 40.906160, 74.223310
Trenton, 40.219922, 74.754665
- A total of five separate city data files may be imported
- at a time. There is no limit to the size of these files.
- SPLAT! reads city data sequentially, and plots only those
- locations whose positions do not conflict with previously
- plotted locations when generating topographic maps.
-
- 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
+ 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.
+ Cartographic boundary data may also be imported to plot
+ the boundaries of cities, counties, or states on topo-
+ graphic maps generated by SPLAT!. Such data must be of
+ the form of ARC/INFO Ungenerate (ASCII Format) Metadata
+ Cartographic Boundary Files, and are available from the
+ U.S. Census Bureau via the Internet at:
+ http://www.census.gov/geo/www/cob/co2000.html#ascii and
+ http://www.census.gov/geo/www/cob/pl2000.html#ascii. A
+ total of five separate cartographic boundary files may be
+ imported at a time. It is not necessary to import state
+ boundaries if county boundaries have already been
+ imported.
PROGRAM OPERATION
SPLAT! is invoked via the command-line using a series of
switches and arguments. Since SPLAT! is a CPU and memory
intensive application, this type of interface minimizes
- overhead, and also lends itself well to scripted opera-
+ overhead and lends itself well to scripted (batch) opera-
tions. SPLAT!'s CPU and memory scheduling priority may be
- adjusted through the use of the Unix nice command.
+ 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 to
- include all the features described by those switches when
- performing an analysis.
+ 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-
splat -t tx_site.qth -r rx_site.qth
- invokes a terrain analysis between the transmitter speci-
- fied in tx_site.qth and receiver specified in rx_site.qth,
- and writes a SPLAT! Obstruction Report to the current
- working directory. The report contains details of the
- transmitter and receiver sites, and identifies the loca-
- tion of any obstructions detected during the analysis. 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. If the antenna must be raised a significant
- amount, this determination may take some time.
-
- are optional when invoking the program. SPLAT! automati-
- cally reads all SPLAT Data Files necessary to conduct the
- terrain analysis between the sites specified. By default,
- the location of SDF files is assumed to be in the current
- working directory unless a ".splat_path" file is present
- under the user's home directory. If this file is present,
- it must contain the full directory path to the location of
- all the SDF files required by SPLAT! to perform its analy-
- sis for the region containing the transmitter and receiver
- sites specified. The path in this file must be of the
- form of a single line of ASCII text:
+ invokes a line-of-sight terrain analysis between the
+ transmitter specified in tx_site.qth and receiver speci-
+ fied in rx_site.qth using a True Earth radius model, and
+ writes a SPLAT! Obstruction Report to the current working
+ directory. The report contains details of the transmitter
+ and receiver sites, and identifies the location of any
+ obstructions detected along the line-of-sight path. If an
+ obstruction can be cleared by raising the receive antenna
+ to a greater altitude, SPLAT! will indicate the minimum
+ antenna height required for a line-of-sight path to exist
+ between the transmitter and receiver locations specified.
+ Note that imperial units (miles, feet) are specified
+ unless the -metric switch is added to SPLAT!'s command
+ line options:
+
+ splat -t tx_site.qth -r rx_site.qth -metric
+
+ If the antenna must be raised a significant amount, this
+ determination may take a few moments. Note that the
+ results provided are the minimum necessary for a line-of-
+ sight path to exist, and in the case of this simple exam-
+ ple, do not take Fresnel zone clearance requirements into
+ consideration.
+
+ qth extensions are assumed by SPLAT! for QTH files, and
+ are optional when specifying -t and -r arguments on the
+ command-line. SPLAT! automatically reads all SPLAT Data
+ Files necessary to conduct the terrain analysis between
+ the sites specified. SPLAT! searches for the required
+ SDF files in the current working directory first. If the
+ needed files are not found, SPLAT! then searches in the
+ path specified by the -d command-line switch:
- /opt/splat/sdf/
+ splat -t tx_site -r rx_site -d /cdrom/sdf/
- and may be generated with any text editor. The default
- path specified in the $HOME/.splat_path file may be over-
- ridden at any time using the -d switch:
+ 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:
- splat -t tx_site -r rx_site -d /cdrom/sdf/
+ /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
+ 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.gif
+ 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. .gif will produce a 640x480 color
- GIF graphic file, while .ps or .postscript will produce
- postscript output. Output in formats such as PNG, Adobe
- Illustrator, AutoCAD dxf, LaTeX, and many others are
+ 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
+ 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.gif
+ 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
+ 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
+ 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
+ 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
+ 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
+ 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.gif
+ splat -t tx_site -r rx_site -h height_profile.png
- The Earth's curvature is clearly evident when plotting
- height profiles.
+ A terrain height plot normalized to the transmitter and
+ receiver antenna heights can be obtained using the -H
+ switch:
+
+ splat -t tx_site -r rx_site -H normalized_height_pro-
+ file.png
+
+ A contour of the Earth's curvature is also plotted in this
+ mode.
+
+ The first Fresnel Zone, and 60% of the first Fresnel Zone
+ can be added to height profile graphs by adding the -f
+ switch, and specifying a frequency (in MHz) at which the
+ Fresnel Zone should be modeled:
+
+ splat -t tx_site -r rx_site -f 439.250 -H normal-
+ ized_height_profile.png
A graph showing Longley-Rice path loss may be plotted
using the -l switch:
- splat -t tx_site -r rx_site -l path_loss_profile.gif
+ splat -t tx_site -r rx_site -l path_loss_profile.png
+
+ As before, adding the -metric switch forces the graphs to
+ be plotted using metric units of measure.
- When performing path loss profiles, a Longley-Rice Model
- Path Loss Report is generated by SPLAT! in the form of a
+ When performing path loss profiles, a Longley-Rice Model
+ Path Loss Report is generated by SPLAT! in the form of a
text file with a .lro filename extension. The report con-
- tains bearings and distances between the transmitter and
- receiver, as well as the Longley-Rice path loss for vari-
- ous distances between the transmitter and receiver loca-
- tions. The mode of propagation for points along the path
- are given as Line-of-Sight, Single Horizon, Double Hori-
+ tains bearings and distances between the transmitter and
+ receiver, as well as the Longley-Rice path loss for vari-
+ ous distances between the transmitter and receiver loca-
+ tions. The mode of propagation for points along the path
+ are given as Line-of-Sight, Single Horizon, Double Hori-
zon, Diffraction Dominant, and Troposcatter Dominant.
- To determine the signal-to-noise (SNR) ratio at remote
- location where random Johnson (thermal) noise is the pri-
+ 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, NJ is John-
- son Noise in dBW (-136 dBW for a 6 MHz TV channel), L is
- the path loss provided by SPLAT! in dB (as a positive num-
- ber), G is the receive antenna gain in dB over isotropic,
- and NF is the receiver noise figure in dB.
+ 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:
Signal_Margin=SNR-S
- where S is the minimum desired SNR ratio (15.5 dB for ATSC
- DTV, 42 dB for analog NTSC television).
+ where S is the minimum required SNR ratio (15.5 dB for
+ ATSC (8-VSB) DTV, 42 dB for analog NTSC television).
A topographic map may be generated by SPLAT! to visualize
the path between the transmitter and receiver sites from
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
- in blue.
+ using the color blue.
- SPLAT! generated topographic maps are 24-bit TrueColor
- Portable PixMap (PPM) images, and 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. An excellent command-line utility capable of con-
- verting SPLAT! PPM graphic files to PNG files is wpng, and
- 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.
- Topographic output is specified using the -o switch:
+ Topographic output is invoked using the -o switch:
splat -t tx_site -r rx_site -o topo_map.ppm
a time for analysis:
splat -t tx_site1 tx_site2 tx_site3 tx_site4 -r rx_site -p
- profile.gif
+ profile.png
In this example, four separate terrain profiles and
obstruction reports will be generated by SPLAT!. A single
receiver will be in violet, and the path between the
fourth transmitter and the receiver will be in sienna.
-DETERMINING REGIONAL COVERAGE
+ SPLAT! generated topographic maps are 24-bit TrueColor
+ Portable PixMap (PPM) images. They may be viewed, edited,
+ or converted to other graphic formats by popular image
+ viewing applications such as xv, The GIMP, ImageMagick,
+ and XPaint. PNG format is highly recommended for lossless
+ compressed storage of SPLAT! generated topographic output
+ files. ImageMagick's command-line utility easily converts
+ SPLAT!'s PPM files to PNG format:
+
+ convert splat_map.ppm splat_map.png
+
+ Another excellent PPM to PNG command-line utility is
+ available at:
+ http://www.libpng.org/pub/png/book/sources.html. As a
+ last resort, PPM files may be compressed using the bzip2
+ utility, and read directly by The GIMP in this format.
+
+REGIONAL COVERAGE ANALYSIS
SPLAT! can analyze a transmitter or repeater site, or net-
- work of sites, and predict the regional coverage for each
+ 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
+ graphic map displaying the geometric line-of-sight cover-
+ age area of the sites based on the location of each site
+ and the height of receive antenna wishing to communicate
with the site in question. SPLAT! switches from point-to-
- point analysis mode to area prediction mode when the -c
+ point analysis mode to area prediction mode when the -c
switch is invoked as follows:
- splat -t tx_site -c 30.0 -s cities.dat -b co34_d00.dat -o
+ 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). The
- contents of cities.dat are plotted on the map, as are the
- cartographic boundaries contained in the file
+ 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)
+ When plotting line-of-sight paths and areas of regional
+ coverage, SPLAT! by default does not account for the
+ effects of atmospheric bending. However, this behavior
+ may be modified by using the Earth radius multiplier (-m)
switch:
- splat -t wnjt -c 30.0 -m 1.333 -s cities.dat -b coun-
+ splat -t wnjt -c 30.0 -m 1.333 -s cities.dat -b coun-
ties.dat -o map.ppm
- An earth radius multiplier of 1.333 instructs SPLAT! to
+ 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
+ gation analysis. Any appropriate earth radius multiplier
may be selected by the user.
- When invoked in area prediction mode, SPLAT! generates a
+ When invoked in area prediction mode, SPLAT! generates a
site report for each station analyzed. SPLAT! site
reports contain details of the site's geographic location,
- its height above mean sea level, the antenna's height
- above mean sea level, the antenna's height above average
- terrain, and the height of the average terrain calculated
- in the directions of 0, 45, 90, 135, 180, 225, 270, and
+ its height above mean sea level, the antenna's height
+ above mean sea level, the antenna's height above average
+ terrain, and the height of the average terrain calculated
+ in the directions of 0, 45, 90, 135, 180, 225, 270, and
315 degrees azimuth.
- 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 tx_site -L 30.0 -s cities.dat -b co34_d00.dat -o
- path_loss_map
-
- In this mode, SPLAT! generates a multi-color map illus-
- trating expected signal levels (path loss) in areas sur-
- rounding the transmitter site. A legend at the bottom of
- the map correlates each color with a specific path loss
- level in decibels. Since Longley-Rice area prediction map
- generation is quite CPU intensive, provision for limiting
- the analysis range is provided by the -R switch. The
- argument must be given in miles. 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.
-
-DETERMINING MULTIPLE REGIONS OF COVERAGE
+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 30.0 -o network.ppm
+ 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 30.0
- feet above ground level. A topographic map is then writ-
- ten to the file network.ppm. The line-of-sight coverage
- area of the transmitters are plotted as follows in the
- colors indicated (along with their corresponding RGB val-
+ 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)
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
+ 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!.
-TOPOGRAPHIC MAP GENERATION
- In certain situations, it may be desirable to generate a
+LONGLEY-RICE PATH LOSS ANALYSIS
+ If the -c switch is replaced by a -L switch, a Longley-
+ Rice path loss map for a transmitter site may be gener-
+ ated:
+
+ splat -t wnjt -L 30.0 -s cities.dat -b co34_d00.dat -o
+ path_loss_map
+
+ In this mode, SPLAT! generates a multi-color map illus-
+ trating expected signal levels (path loss) in areas sur-
+ rounding the transmitter site. A legend at the bottom of
+ the map correlates each color with a specific path loss
+ range in decibels.
+
+ The Longley-Rice analysis range may be modified to a user-
+ specific value using the -R switch. The argument must be
+ given in miles (or kilometers if the -metric switch is
+ used). If a range wider than the generated topographic
+ map is specified, SPLAT! will perform Longley-Rice path
+ loss calculations between all four corners of the area
+ prediction map.
+
+ The -db switch allows a constraint to be placed on the
+ maximum path loss region plotted on the map. A maximum
+ path loss between 80 and 230 dB may be specified using
+ this switch. For example, if a path loss beyond -140 dB
+ is irrelevant to the survey being conducted, SPLAT!'s path
+ loss plot can be constrained to the region bounded by the
+ 140 dB attenuation contour as follows:
+
+ splat -t wnjt -L 30.0 -s cities.dat -b co34_d00.dat -db
+ 140 -o plot.ppm
+
+
+ANTENNA RADIATION PATTERN PARAMETERS
+ Normalized field voltage patterns for a transmitting
+ antenna's horizontal and vertical planes are imported
+ automatically into SPLAT! when a Longley-Rice coverage
+ analysis is performed. Antenna pattern data is read from
+ a pair of files having the same base name as the transmit-
+ ter and LRP files, but with .az and .el extensions for
+ azimuth and elevation pattern files, respectively. Speci-
+ fications regarding pattern rotation (if any) and
+ mechanical beam tilt and tilt direction (if any) are also
+ contained within SPLAT! antenna pattern files.
+
+ For example, the first few lines of a SPLAT! azimuth pat-
+ tern file might appear as follows (kvea.az):
+
+ 183.0
+ 0 0.8950590
+ 1 0.8966406
+ 2 0.8981447
+ 3 0.8995795
+ 4 0.9009535
+ 5 0.9022749
+ 6 0.9035517
+ 7 0.9047923
+ 8 0.9060051
+
+ The first line of the .az file specifies the amount of
+ azimuthal pattern rotation (measured clockwise in degrees
+ from True North) to be applied by SPLAT! to the data con-
+ tained in the .az file. This is followed by azimuth head-
+ ings (0 to 360 degrees) and their associated normalized
+ field patterns (0.000 to 1.000) separated by whitespace.
+
+ The structure of SPLAT! elevation pattern files is
+ slightly different. The first line of the .el file speci-
+ fies the amount of mechanical beam tilt applied to the
+ antenna. Note that a downward tilt (below the horizon) is
+ expressed as a positive angle, while an upward tilt (above
+ the horizon) is expressed as a negative angle. This data
+ is followed by the azimuthal direction of the tilt, sepa-
+ rated by whitespace.
+
+ The remainder of the file consists of elevation angles and
+ their corresponding normalized voltage radiation pattern
+ (0.000 to 1.000) values separated by whitespace. Eleva-
+ tion angles must be specified over a -10.0 to +90.0 degree
+ range. As was the convention with mechanical beamtilt,
+ negative elevation angles are used to represent elevations
+ above the horizon, while positive angles represents eleva-
+ tions below the horizon.
+
+ For example, the first few lines a SPLAT! elevation pat-
+ tern file might appear as follows (kvea.el):
+
+ 1.1 130.0
+ -10.0 0.172
+ -9.5 0.109
+ -9.0 0.115
+ -8.5 0.155
+ -8.0 0.157
+ -7.5 0.104
+ -7.0 0.029
+ -6.5 0.109
+ -6.0 0.185
+
+ In this example, the antenna is mechanically tilted down-
+ ward 1.1 degrees towards an azimuth of 130.0 degrees.
+
+ For best results, the resolution of azimuth pattern data
+ should be specified to the nearest degree azimuth, and
+ elevation pattern data resolution should be specified to
+ the nearest 0.01 degrees. If the pattern data specified
+ does not reach this level of resolution, SPLAT! will
+ interpolate the values provided to determine the data at
+ the required resolution, although this may result in a
+ loss in accuracy.
+
+
+IMPORTING AND EXPORTING REGIONAL PATH LOSS CONTOUR DATA
+ Performing a Longley-Rice coverage analysis can be a very
+ time consuming process, especially if the analysis is
+ repeated repeatedly to discover what effects changes to
+ the antenna radiation patterns make to the predicted cov-
+ erage area.
+
+ This process can be expedited by exporting the Longley-
+ Rice regional path loss contour data to an output file,
+ modifying the path loss data externally to incorporate
+ antenna pattern effects, and then importing the modified
+ path loss data back into SPLAT! to rapidly produce a
+ revised path loss map.
+
+ For example, a path loss output file can be generated by
+ SPLAT! for a receive site 30 feet above ground level over
+ a 50 mile radius surrounding a transmitter site to a maxi-
+ mum path loss of 140 dB using the following syntax:
+
+ splat -t kvea -L 30.0 -R 50.0 -db 140 -plo pathloss.dat
+
+ SPLAT! path loss output files often exceed 100 megabytes
+ in size. They contain information relating to the bound-
+ aries of region they describe followed by latitudes
+ (degrees North), longitudes (degrees West), azimuths, ele-
+ vations (to the first obstruction), and path loss figures
+ (dB) for a series of specific points that comprise the
+ region surrounding the transmitter site. The first few
+ lines of a SPLAT! path loss output file take on the fol-
+ lowing appearance (pathloss.dat):
+
+ 119, 117 ; max_west, min_west
+ 35, 33 ; max_north, min_north
+ 34.2265434, 118.0631104, 48.171, -37.461, 67.70
+ 34.2270355, 118.0624390, 48.262, -26.212, 73.72
+ 34.2280197, 118.0611038, 48.269, -14.951, 79.74
+ 34.2285156, 118.0604401, 48.207, -11.351, 81.68
+ 34.2290077, 118.0597687, 48.240, -10.518, 83.26
+ 34.2294998, 118.0591049, 48.225, 23.201, 84.60
+ 34.2304878, 118.0577698, 48.213, 15.769, 137.84
+ 34.2309799, 118.0570984, 48.234, 15.965, 151.54
+ 34.2314720, 118.0564346, 48.224, 16.520, 149.45
+ 34.2319679, 118.0557632, 48.223, 15.588, 151.61
+ 34.2329521, 118.0544281, 48.230, 13.889, 135.45
+ 34.2334442, 118.0537643, 48.223, 11.693, 137.37
+ 34.2339401, 118.0530930, 48.222, 14.050, 126.32
+ 34.2344322, 118.0524292, 48.216, 16.274, 156.28
+ 34.2354164, 118.0510941, 48.222, 15.058, 152.65
+ 34.2359123, 118.0504227, 48.221, 16.215, 158.57
+ 34.2364044, 118.0497589, 48.216, 15.024, 157.30
+ 34.2368965, 118.0490875, 48.225, 17.184, 156.36
+
+ It is not uncommon for SPLAT! path loss files to contain
+ as many as 3 million or more lines of data. Comments can
+ be placed in the file if they are proceeded by a semicolon
+ character. The vim text editor has proven capable of
+ editing files of this size.
+
+ Note as was the case in the antenna pattern files, nega-
+ tive elevation angles refer to upward tilt (above the
+ horizon), while positive angles refer to downward tilt
+ (below the horizon). These angles refer to the elevation
+ to the receiving antenna at the height above ground level
+ specified using the -L switch if the path between trans-
+ mitter and receiver is unobstructed. If the path between
+ the transmitter and receiver is obstructed, then the ele-
+ vation angle to the first obstruction is returned by
+ SPLAT!. This is because the Longley-Rice model considers
+ the energy reaching a distant point over an obstructed
+ path as a derivative of the energy scattered from the top
+ of the first obstruction, only. Since energy cannot reach
+ the obstructed location directly, the actual elevation
+ angle to that point is irrelevant.
+
+ When modifying SPLAT! path loss files to reflect antenna
+ pattern data, only the last column (path loss) should be
+ amended to reflect the antenna's normalized gain at the
+ azimuth and elevation angles specified in the file. (At
+ this time, programs and scripts capable of performing this
+ operation are left as an exercise for the user.)
+
+ Modified path loss maps can be imported back into SPLAT!
+ for generating revised coverage maps:
+
+ splat -t kvea -pli pathloss.dat -s city.dat -b county.dat
+ -o map.ppm
+
+ SPLAT! path loss files can also be used for conducting
+ coverage or interference studies outside of SPLAT!.
+
+USER-DEFINED TERRAIN INPUT FILES
+ A user-defined terrain file is a user-generated text file
+ containing latitudes, longitudes, and heights above ground
+ level of specific terrain features believed to be of
+ importance to the SPLAT! analysis being conducted, but
+ noticeably absent from the SDF files being used. A user-
+ defined terrain file is imported into a SPLAT! analysis
+ using the -udt switch:
+
+ splat -t tx_site -r rx_site -udt udt_file.txt -o map.ppm
+
+ A user-defined terrain file has the following appearance
+ and structure:
+
+ 40.32180556, 74.1325, 100.0 meters
+ 40.321805, 74.1315, 300.0
+ 40.3218055, 74.1305, 100.0 meters
+
+ Terrain height is interpreted as being described in feet
+ above ground level unless followed by the word meters, and
+ is added on top of the terrain specified in the SDF data
+ for the locations specified. Be aware that each user-
+ defined terrain feature specified will be interpreted as
+ being 3-arc seconds in both latitude and longitude. Fea-
+ tures described in the user-defined terrain file that
+ overlap previously defined features in the file are
+ ignored by SPLAT!.
+
+SIMPLE TOPOGRAPHIC MAP GENERATION
+ In certain situations it may be desirable to generate a
topographic map of a region without plotting coverage
areas, line-of-sight paths, or generating obstruction
reports. There are several ways of doing this. If one
splat -t tx_site -r rx_site -N -o topo_map.ppm
- If the -o switch and output filename are omitted when
- using either the -n or -N switches, output is written to a
- file named map.ppm in the current working directory by
- default.
+ If a topographic map centered about a single site out to a
+ minimum specified radius is desired instead, a command
+ similar to the following can be used:
+
+ splat -t tx_site -R 50.0 -s NJ_Cities -b NJ_Counties -o
+ topo_map.ppm
+
+ where -R specifies the minimum radius of the map in miles
+ (or kilometers if the -metric switch is used).
+
+ If the -o switch and output filename are omitted in these
+ operations, topographic output is written to a file named
+ map.ppm in the current working directory by default.
+
+GEOREFERENCE FILE GENERATION
+ Topographic, coverage (-c), and path loss contour (-L)
+ maps generated by SPLAT! may be imported into Xastir (X
+ Amateur Station Tracking and Information Reporting) soft-
+ ware by generating a georeference file using SPLAT!'s -geo
+ switch:
+
+ splat -t kd2bd -R 50.0 -s NJ_Cities -b NJ_Counties -geo -o
+ map.ppm
+
+ The georeference file generated will have the same base
+ name as the -o file specified, but have a .geo extension,
+ and permit proper interpretation and display of SPLAT!'s
+ .ppm graphics in Xastir software.
+
+GOOGLE MAP KML FILE GENERATION
+ Keyhole Markup Language files compatible with Google Earth
+ may be generated by SPLAT! when performing point-to-point
+ analyses by invoking the -kml switch:
+
+ splat -t wnjt -r kd2bd -kml
+
+ The KML file generated will have the same filename struc-
+ ture as an Obstruction Report for the transmitter and
+ receiver site names given, except it will carry a .kml
+ extension.
+
+ Once loaded into Google Earth (File --> Open), the KML
+ file will annotate the map display with the names of the
+ transmitter and receiver site locations. The viewpoint of
+ the image will be from the position of the transmitter
+ site looking towards the location of the receiver. The
+ point-to-point path between the sites will be displayed as
+ a white line while the RF line-of-sight path will be dis-
+ played in green. Google Earth's navigation tools allow
+ the user to "fly" around the path, identify landmarks,
+ roads, and other featured content.
DETERMINATION OF ANTENNA HEIGHT ABOVE AVERAGE TERRAIN
- SPLAT! determines antenna height above average terrain
- (HAAT) according to the procedure defined by Federal Com-
- munications Commission Part 73.313(d). According to this
+ 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-
+ 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. If part of a radial extends over a
- body of water or over land outside the United States, then
- only that part of the radial lying over United States land
- is used in the determination of average terrain.
-
- 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
+ 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
+ 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 site report generated. If
- one or more of the eight radials surveyed fall over water
- or land outside the United States, SPLAT! reports No Ter-
- rain for those radial paths.
-
-SETTING THE MAXIMUM SIZE OF AN ANALYSIS REGION
- SPLAT! reads SDF files into a series of memory "slots" as
- required within the structure of the program. Each "slot"
- holds one SDF file. Each SDF file represents a one degree
- by one degree region of terrain. A #define MAXSLOTS
+ When performing area prediction analysis, enough topogra-
+ phy data is normally loaded by SPLAT! to perform average
+ terrain calculations. Under such conditions, SPLAT! will
+ provide the antenna height above average terrain as well
+ as the average terrain above mean sea level for azimuths
+ of 0, 45, 90, 135, 180, 225, 270, and 315 degrees, and
+ include such information in the generated site report. If
+ one or more of the eight radials surveyed fall over water,
+ or over regions for which no SDF data is available, SPLAT!
+ reports No Terrain for the radial paths affected.
+
+RESTRICTING THE MAXIMUM SIZE OF AN ANALYSIS REGION
+ SPLAT! reads SDF files as needed into a series of memory
+ pages or "slots" within the structure of the program.
+ Each "slot" holds one SDF file representing a one degree
+ by one degree region of terrain. A #define MAXSLOTS
statement in the first several lines of splat.cpp sets the
- maximum number of "slots" available for topography data.
- It also sets the maximum size of the topographic maps gen-
- erated by SPLAT!. MAXSLOTS is set to 9 by default. If
- SPLAT! produces a segmentation fault on start-up with this
- default, it is an indication that not enough RAM and/or
- virtual memory (swap space) are available to run SPLAT!
- with this number of MAXSLOTS. In this case, MAXSLOTS may
- be reduced to 4, although this will greatly limit the max-
- imum region SPLAT! will be able to analyze. If 118
- megabytes or more of total memory (swap space plus RAM) is
- available, then MAXSLOTS may be increased to 16. This
- will permit operation over a 4-degree by 4-degree region,
- which is sufficient for single antenna heights in excess
- of 10,000 feet above mean sea level, or point-to-point
- distances of over 1000 miles.
+ maximum number of "slots" available for holding topography
+ data. It also sets the maximum size of the topographic
+ maps generated by SPLAT!. MAXSLOTS is set to 9 by
+ default. If SPLAT! produces a segmentation fault on
+ start-up with this default, it is an indication that not
+ enough RAM and/or virtual memory (swap space) is available
+ to run SPLAT! with the number of MAXSLOTS specified. In
+ situations where available memory is low, MAXSLOTS may be
+ reduced to 4 with the understanding that this will greatly
+ limit the maximum region SPLAT! will be able to analyze.
+ If 118 megabytes or more of total memory (swap space plus
+ RAM) is available, then MAXSLOTS may be increased to 16.
+ This will permit operation over a 4-degree by 4-degree
+ region, which is sufficient for single antenna heights in
+ excess of 10,000 feet above mean sea level, or point-to-
+ point distances of over 1000 miles.
ADDITIONAL INFORMATION
- Invoking SPLAT! without any arguments will display all the
- command-line options available with the program along with
- a brief summary of each.
-
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.
-FILES
- $HOME/.splat_path
- User-generated file containing the default path to
- the directory containing the SDF data files.
-
- splat.lrp
- Default Longley-Rice model parameters.
-
AUTHORS
John A. Magliacane, KD2BD <kd2bd@amsat.org>
Creator, Lead Developer
Doug McDonald <mcdonald@scs.uiuc.edu>
Longley-Rice Model integration
+ Ron Bentley <ronbentley@earthlink.net>
+ Fresnel Zone plotting and clearance determination
+
+
-KD2BD Software 20 January 2004 SPLAT!(1)
+KD2BD Software 20 December 2006 SPLAT!(1)
projects / debian / splat / blobdiff