X-Git-Url: https://git.gag.com/?p=debian%2Fsplat;a=blobdiff_plain;f=docs%2Fenglish%2Ftext%2Fsplat.txt;fp=docs%2Fenglish%2Ftext%2Fsplat.txt;h=43f3653247122586d0bc6576f00053d9a00ebf09;hp=0000000000000000000000000000000000000000;hb=dcc481697c227c3b265d1e68a8a82910c818332c;hpb=3504a1ce545f764f4e96a31fa53dbf498e0bd9f9 diff --git a/docs/english/text/splat.txt b/docs/english/text/splat.txt new file mode 100644 index 0000000..43f3653 --- /dev/null +++ b/docs/english/text/splat.txt @@ -0,0 +1,1289 @@ +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 + Creator, Lead Developer + + Doug McDonald + Original Longley-Rice Model integration + + Ron Bentley + Fresnel Zone plotting and clearance determination + + + + +KD2BD Software 16 September 2007 SPLAT!(1)