X-Git-Url: https://git.gag.com/?p=debian%2Fsplat;a=blobdiff_plain;f=docs%2Fenglish%2Fman%2Fsplat.man;fp=docs%2Fenglish%2Fman%2Fsplat.man;h=88ef6f19a6c8912b00349490bf203cd935c2daf2;hp=0000000000000000000000000000000000000000;hb=49350c09f112a613dc33e9a5e116a1a3c0f06997;hpb=2b83ee9944726f29b3f6679fba24a902bcd33c56 diff --git a/docs/english/man/splat.man b/docs/english/man/splat.man new file mode 100644 index 0000000..88ef6f1 --- /dev/null +++ b/docs/english/man/splat.man @@ -0,0 +1,1129 @@ +.TH SPLAT! 1 "16 September 2007" "KD2BD Software" "KD2BD Software" +.SH NAME +splat \- An RF \fBS\fPignal \fBP\fPropagation, \fBL\fPoss, \fBA\fPnd \fBT\fPerrain analysis tool +.SH SYNOPSIS +splat [-t \fItransmitter_site.qth\fP] +[-r \fIreceiver_site.qth\fP] +[-c \fIrx antenna height for LOS coverage analysis (feet/meters) (float)\fP] +[-L \fIrx antenna height for Longley-Rice coverage analysis (feet/meters) (float)\fP] +[-p \fIterrain_profile.ext\fP] +[-e \fIelevation_profile.ext\fP] +[-h \fIheight_profile.ext\fP] +[-H \fInormalized_height_profile.ext\fP] +[-l \fILongley-Rice_profile.ext\fP] +[-o \fItopographic_map_filename.ppm\fP] +[-b \fIcartographic_boundary_filename.dat\fP] +[-s \fIsite/city_database.dat\fP] +[-d \fIsdf_directory_path\fP] +[-m \fIearth radius multiplier (float)\fP] +[-f \fIfrequency (MHz) for Fresnel zone calculations (float)\fP] +[-R \fImaximum coverage radius (miles/kilometers) (float)\fP] +[-dB \fImaximum attenuation contour to display on path loss maps (80-230 dB)\fP] +[-fz \fIFresnel zone clearance percentage (default = 60)\fP] +[-plo \fIpath_loss_output_file.txt\fP] +[-pli \fIpath_loss_input_file.txt\fP] +[-udt \fIuser_defined_terrain_file.dat\fP] +[-n] +[-N] +[-nf] +[-ngs] +[-geo] +[-kml] +[-metric] +.SH DESCRIPTION +\fBSPLAT!\fP is a powerful terrestrial RF propagation and terrain +analysis tool for the spectrum between 20 MHz and 20 GHz. +\fBSPLAT!\fP is free software, and is designed for operation 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 \fBSPLAT!\fP +source code in proprietary or closed-source applications is a violation +of this license and is \fBstrictly\fP forbidden. + +\fBSPLAT!\fP is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY, without even the implied warranty of MERCHANTABILITY +or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License +for more details. +.SH INTRODUCTION +Applications of \fBSPLAT!\fP 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. + +\fBSPLAT!\fP provides RF site engineering data such as great circle +distances and bearings between sites, antenna elevation 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. + +\fBSPLAT!\fP produces reports, graphs, and high resolution topographic +maps that depict line-of-sight paths, and regional path loss and signal +strength contours through which expected coverage areas of transmitters +and repeater systems can be obtained. When performing line-of-sight +and Longley-Rice analyses in situations where multiple transmitter or +repeater sites are employed, \fBSPLAT!\fP determines individual and +mutual areas of coverage within the network specified. + +Simply typing \fCsplat\fR on the command line will return a summary +of \fBSPLAT!\fP's command line options: +\fC + + --==[ 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/kilometers) + -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 +\fR +.SH INPUT FILES +\fBSPLAT!\fP 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. +.SH SPLAT DATA FILES +\fBSPLAT!\fP 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 \fBusgs2sdf\fP +utility included with \fBSPLAT!\fP. USGS Digital Elevation Models +compatible with this utility may be downloaded from: +\fIhttp://edcftp.cr.usgs.gov/pub/data/DEM/250/\fP. + +Significantly better resolution and accuracy can be obtained through +the use of SRTM-3 Version 2 digital elevation 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 \fBsrtm2sdf\fP utility. +SRTM-3 Version 2 data may be obtained through anonymous FTP from: +\fIftp://e0srp01u.ecs.nasa.gov:21/srtm/version2/\fP + +The \fBstrm2sdf\fP utility may also be used to convert 3-arc second SRTM +data in Band Interleaved by Line (.BIL) format for use with \fBSPLAT!\fP. +This data is available via the web at: +\fIhttp://seamless.usgs.gov/website/seamless/\fP + +Band Interleaved by Line data must be downloaded in a very specific manner +to be compatible with \fBsrtm2sdf\fP and \fBSPLAT!\fP. Please consult +\fBsrtm2sdf\fP'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 \fBsrtm2sdf\fP +utility replaces them with corresponding data found in existing SDF +files (that were presumably created from earlier USGS data through the +\fBusgs2sdf\fP utility). If USGS-derived SDF data is not available, voids +are handled through adjacent pixel averaging, or direct replacement. + +SPLAT Data Files contain integer value topographic elevations (in meters) +referenced to 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 (\fI.sdf\fP) as generated by the \fBusgs2sdf\fP +and \fBsrtm2sdf\fP utilities, or in bzip2 compressed format +(\fI.sdf.bz2\fP). Since uncompressed files can be read slightly +faster than files that have been compressed, \fBSPLAT!\fP searches for +needed SDF data in uncompressed format first. If uncompressed data +cannot be located, \fBSPLAT!\fP then searches for data in bzip2 compressed +format. If no compressed SDF files can be found for the region requested, +\fBSPLAT!\fP assumes the region is over water, and will assign an +elevation of sea-level to these areas. + +This feature of \fBSPLAT!\fP 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 \fBSPLAT!\fP +underscores the importance of having all the SDF files required for +the region being analyzed if meaningful results are to be expected. +.SH SITE LOCATION (QTH) FILES +\fBSPLAT!\fP imports site location information of transmitter and receiver +sites analyzed by the program from ASCII files having a \fI.qth\fP 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 \fIm\fP or the word \fImeters\fP in +either upper or lower case. Latitude and longitude information 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 (\fIwnjt-dt.qth\fP) might read as follows: +\fC + WNJT-DT + 40.2828 + 74.6864 + 990.00 +\fR +Each transmitter and receiver site analyzed by \fBSPLAT!\fP must be +represented by its own site location (QTH) file. +.SH LONGLEY-RICE PARAMETER (LRP) FILES +Longley-Rice parameter data files are required for \fBSPLAT!\fP 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 transmitter site QTH file, but with a +\fI.lrp\fP extension. \fBSPLAT!\fP LRP files share the following +format (\fIwnjt-dt.lrp\fP): +\fC + 15.000 ; Earth Dielectric Constant (Relative permittivity) + 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 Temperate) + 0 ; Polarization (0 = Horizontal, 1 = Vertical) + 0.50 ; Fraction of situations (50% of locations) + 0.90 ; Fraction of time (90% of the time) + 46000.0 ; ERP in Watts (optional) +\fR +If an LRP file corresponding to the tx_site QTH file cannot +be found, \fBSPLAT!\fP scans the current working directory for +the file "splat.lrp". If this file cannot be found, then default +parameters will be assigned by \fBSPLAT!\fP and a corresponding +"splat.lrp" file containing these default parameters will be written +to the current working directory. The generated "splat.lrp" file can +then be edited by the user as needed. + +Typical Earth dielectric constants and conductivity values are as +follows: +\fC + Dielectric Constant Conductivity + 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 +\fR +Radio climate codes used by \fBSPLAT!\fP are as follows: +\fC + 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 +\fR +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 \fI.lrp\fP file correspond to the +statistical analysis provided by the Longley-Rice model. In this example, +\fBSPLAT!\fP will return the maximum 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: +\fIhttp://flattop.its.bldrdoc.gov/itm.html\fP and +\fIhttp://www.softwright.com/faq/engineering/prop_longley_rice.html\fP + +The final parameter in the \fI.lrp\fP file corresponds to the transmitter's +effective radiated power, and is optional. If it is included in the +\fI.lrp\fP file, then \fBSPLAT!\fP will compute received signal strength +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 \fI.lrp\fP file can be overridden by using +\fBSPLAT!\fP's \fI-erp\fP command-line switch. If the \fI.lrp\fP file +contains 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 \fI-erp\fP switch without having to edit the \fI.lrp\fP file +to accomplish the same result. +.SH CITY LOCATION FILES +The names and locations of cities, tower sites, or other points of interest +may be imported and plotted on topographic maps generated by \fBSPLAT!\fP. +\fBSPLAT!\fP 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 separated by a +single line feed character. As was the case with the \fI.qth\fP +files, latitude and longitude information may be entered in either +decimal or degree, minute, second (DMS) format. + +For example (\fIcities.dat\fP): +\fC + 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 +\fR +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. \fBSPLAT!\fP reads +city data on a "first come/first served" basis, and plots only those +locations whose annotations do not conflict with annotations of +locations read earlier in the current city data file, or in previous +files. This behavior minimizes clutter in \fBSPLAT!\fP generated +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 further down the list or in subsequent data +files. + +City data files may be generated manually using any text editor, +imported from other sources, or derived from data available from the +U.S. Census Bureau using the \fBcitydecoder\fP utility included with +\fBSPLAT!\fP. Such data is available free of charge via the Internet +at: \fIhttp://www.census.gov/geo/www/cob/bdy_files.html\fP, and must +be in ASCII format. +.SH CARTOGRAPHIC BOUNDARY DATA FILES +Cartographic boundary data may also be imported to plot the boundaries of +cities, counties, or states on topographic maps generated by \fBSPLAT!\fP. +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: +\fIhttp://www.census.gov/geo/www/cob/co2000.html#ascii\fP and +\fIhttp://www.census.gov/geo/www/cob/pl2000.html#ascii\fP. 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. +.SH PROGRAM OPERATION +\fBSPLAT!\fP is invoked via the command-line using a series of switches +and arguments. Since \fBSPLAT!\fP is a CPU and memory intensive application, +this type of interface minimizes overhead and lends itself well to +scripted (batch) operations. \fBSPLAT!\fP's CPU and memory scheduling +priority may be modified through the use of the Unix \fBnice\fP command. + +The number and type of switches passed to \fBSPLAT!\fP determine its +mode of operation and method of output data generation. Nearly all +of \fBSPLAT!\fP's switches may be cascaded in any order on the command +line when invoking the program. + +\fBSPLAT!\fP operates in two distinct modes: \fIpoint-to-point mode\fP, +and \fIarea prediction mode\fP. 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 +specified when performing line-of-sight analysis. +.SH POINT-TO-POINT ANALYSIS +\fBSPLAT!\fP may be used to perform line-of-sight terrain analysis +between two specified site locations. For example: + +\fCsplat -t tx_site.qth -r rx_site.qth\fR + +invokes a line-of-sight terrain analysis between the transmitter +specified in \fItx_site.qth\fP and receiver specified in \fIrx_site.qth\fP +using a True Earth radius model, and writes a \fBSPLAT!\fP Path Analysis +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, +\fBSPLAT!\fP 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 \fI-metric\fP switch is added to \fBSPLAT!\fP's command line options: + +\fCsplat -t tx_site.qth -r rx_site.qth -metric\fR + +If the antenna must be raised a significant amount, this determination +may take a few moments. Note that the results provided are the \fIminimum\fP +necessary for a line-of-sight path to exist, and in the case of this +simple example, do not take Fresnel zone clearance requirements into +consideration. + +\fIqth\fP extensions are assumed by \fBSPLAT!\fP for QTH files, and +are optional when specifying -t and -r arguments on the command-line. +\fBSPLAT!\fP automatically reads all SPLAT Data Files necessary to +conduct the terrain analysis between the sites specified. \fBSPLAT!\fP +searches for the required SDF files in the current working directory +first. If the needed files are not found, \fBSPLAT!\fP then searches +in the path specified by the \fI-d\fP command-line switch: + +\fCsplat -t tx_site -r rx_site -d /cdrom/sdf/\fR + +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 +\fI$HOME/.splat_path\fP file must be of the form of a single line of +ASCII text: + +\fC/opt/splat/sdf/\fR + +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 \fI-p\fP switch: + +\fCsplat -t tx_site -r rx_site -p terrain_profile.png\fR + +\fBSPLAT!\fP invokes \fBgnuplot\fP when generating graphs. The filename +extension specified to \fBSPLAT!\fP determines the format of the graph +produced. \fI.png\fP will produce a 640x480 color PNG graphic file, +while \fI.ps\fP or \fI.postscript\fP will produce postscript output. +Output in formats such as GIF, Adobe Illustrator, AutoCAD dxf, +LaTeX, and many others are available. Please consult \fBgnuplot\fP, +and \fBgnuplot\fP's documentation 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 \fI-e\fP switch: + +\fCsplat -t tx_site -r rx_site -e elevation_profile.png\fR + +The graph produced using this switch illustrates the elevation and +depression angles resulting from the terrain between the receiver's +location and the transmitter site from the 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 elevation 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 \fI-h\fP switch: + +\fCsplat -t tx_site -r rx_site -h height_profile.png\fR + +A terrain height plot normalized to the transmitter and receiver +antenna heights can be obtained using the \fI-H\fP switch: + +\fCsplat -t tx_site -r rx_site -H normalized_height_profile.png\fR + +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 \fI-f\fP switch, and +specifying a frequency (in MHz) at which the Fresnel Zone should be +modeled: + +\fCsplat -t tx_site -r rx_site -f 439.250 -H normalized_height_profile.png\fR + +Fresnel Zone clearances other 60% can be specified using the \fI-fz\fP +switch as follows: + +\fCsplat -t tx_site -r rx_site -f 439.250 -fz 75 -H height_profile2.png\fR + +A graph showing Longley-Rice path loss may be plotted using the +\fI-l\fP switch: + +\fCsplat -t tx_site -r rx_site -l path_loss_profile.png\fR + +As before, adding the \fI-metric\fP switch forces the graphs to +be plotted using metric units of measure. + +When performing a point-to-point analysis, a \fBSPLAT!\fP Path Analysis +Report is generated in the form of a text file with a \fI.txt\fP filename +extension. The report contains bearings 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 \fILine-of-Sight\fP, \fISingle Horizon\fP, +\fIDouble Horizon\fP, \fIDiffraction Dominant\fP, or \fITroposcatter +Dominant\fP. + +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 \fI.lrp\fP file, then predicted +signal strength and antenna voltage at the receiving 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 primary limiting +factor in reception: + +.EQ +SNR = T - NJ - L + G - NF +.EN + +where \fBT\fP is the ERP of the transmitter in dBW in the direction +of the receiver, \fBNJ\fP is Johnson Noise in dBW (-136 dBW for a 6 MHz +television channel), \fBL\fP is the path loss provided by \fBSPLAT!\fP +in dB (as a \fIpositive\fP number), \fBG\fP is the receive antenna gain +in dB over isotropic, and \fBNF\fP is the receiver noise figure in dB. + +\fBT\fP may be computed as follows: + +.EQ +T = TI + GT +.EN + +where \fBTI\fP is actual amount of RF power delivered to the transmitting +antenna in dBW, \fBGT\fP is the transmitting antenna gain (over isotropic) +in the direction of the receiver (or the horizon if the receiver is over +the horizon). + +To compute how much more signal is available over the minimum to +necessary to achieve a specific signal-to-noise ratio: + +.EQ +Signal_Margin = SNR - S +.EN + +where \fBS\fP 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 \fBSPLAT!\fP to visualize the +path between the transmitter and receiver sites from yet another +perspective. Topographic maps generated by \fBSPLAT!\fP 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 \fI-o\fP switch: + +\fCsplat -t tx_site -r rx_site -o topo_map.ppm\fR + +The \fI.ppm\fP extension on the output filename is assumed by +\fBSPLAT!\fP, and is optional. + +In this example, \fItopo_map.ppm\fP will illustrate the locations 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 \fIrx_site.qth\fP). + +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 \fBSPLAT!\fP using the \fI-s\fP switch: + +\fCsplat -t tx_site -r rx_site -s cities.dat -o topo_map\fR + +Up to five separate city files may be passed to \fBSPLAT!\fP at a time +following the \fI-s\fP 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 \fI-b\fP +switch: + +\fCsplat -t tx_site -r rx_site -b co34_d00.dat -o topo_map\fR + +In situations where multiple transmitter sites are in use, as many as +four site locations may be passed to \fBSPLAT!\fP at a time for analysis: + +\fCsplat -t tx_site1 tx_site2 tx_site3 tx_site4 -r rx_site -p profile.png\fR + +In this example, four separate terrain profiles and obstruction reports +will be generated by \fBSPLAT!\fP. A single topographic map can be +specified using the \fI-o\fP 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. + +\fBSPLAT!\fP 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 \fBxv\fP, +\fBThe GIMP\fP, \fBImageMagick\fP, and \fBXPaint\fP. PNG format is +highly recommended for lossless compressed storage of \fBSPLAT!\fP +generated topographic output files. \fBImageMagick\fP's command-line +utility easily converts \fBSPLAT!\fP's PPM files to PNG format: + +\fCconvert splat_map.ppm splat_map.png\fR + +Another excellent PPM to PNG command-line utility is available +at: \fIhttp://www.libpng.org/pub/png/book/sources.html\fP. As a last +resort, PPM files may be compressed using the bzip2 utility, and read +directly by \fBThe GIMP\fP in this format. + +The \fI-ngs\fP 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: + +\fCsplat -t tx_site -r rx_site -b co34_d00.dat -ngs -o white_map\fR + +The resulting .ppm image file can be converted to .png format with a +transparent background using \fBImageMagick\fP's \fBconvert\fP utility: + +\fCconvert -transparent "#FFFFFF" white_map.ppm transparent_map.png\fR +.SH REGIONAL COVERAGE ANALYSIS +\fBSPLAT!\fP can analyze a transmitter or repeater site, or network +of sites, and predict the regional coverage for each site specified. +In this mode, \fBSPLAT!\fP can generate a topographic map displaying +the geometric line-of-sight coverage 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 \fBSPLAT!\fP using the \fI-c\fP switch as follows: + +\fCsplat -t tx_site -c 30.0 -s cities.dat -b co34_d00.dat -o tx_coverage\fR + +In this example, \fBSPLAT!\fP generates a topographic map called +\fItx_coverage.ppm\fP that illustrates the predicted line-of-sight +regional coverage of \fItx_site\fP to receiving locations having +antennas 30.0 feet above ground level (AGL). If the \fI-metric\fP +switch is used, the argument following the \fI-c\fP switch is +interpreted as being in meters rather than in feet. The contents +of \fIcities.dat\fP are plotted on the map, as are the cartographic +boundaries contained in the file \fIco34_d00.dat\fP. + +When plotting line-of-sight paths and areas of regional coverage, +\fBSPLAT!\fP by default does not account for the effects of +atmospheric bending. However, this behavior may be modified +by using the Earth radius multiplier (\fI-m\fP) switch: + +\fCsplat -t wnjt-dt -c 30.0 -m 1.333 -s cities.dat -b counties.dat -o map.ppm\fR + +An earth radius multiplier of 1.333 instructs \fBSPLAT!\fP to use +the "four-thirds earth" model for line-of-sight propagation analysis. +Any appropriate earth radius multiplier may be selected by the user. + +When performing a regional analysis, \fBSPLAT!\fP generates a +site report for each station analyzed. \fBSPLAT!\fP 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. +.SH DETERMINING MULTIPLE REGIONS OF LOS COVERAGE +\fBSPLAT!\fP can also display line-of-sight coverage areas for as +many as four separate transmitter sites on a common topographic map. +For example: + +\fCsplat -t site1 site2 site3 site4 -c 10.0 -metric -o network.ppm\fR + +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 \fInetwork.ppm\fP. +The line-of-sight coverage area of the transmitters are plotted as +follows in the colors indicated (along with their corresponding RGB +values in decimal): +\fC + 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) +\fR +If separate \fI.qth\fP 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 \fBSPLAT!\fP. +.SH LONGLEY-RICE PATH LOSS ANALYSIS +If the \fI-c\fP switch is replaced by a \fI-L\fP switch, a +Longley-Rice path loss map for a transmitter site may be generated: + +\fCsplat -t wnjt -L 30.0 -s cities.dat -b co34_d00.dat -o path_loss_map\fR + +In this mode, \fBSPLAT!\fP generates a multi-color map illustrating +expected signal levels in areas surrounding the transmitter site. A +legend at the bottom of the map correlates 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 \fI-R\fP switch. The argument must be given in miles +(or kilometers if the \fI-metric\fP switch is used). If a range wider +than the generated topographic map is specified, \fBSPLAT!\fP will +perform Longley-Rice path loss calculations between all four corners +of the area prediction map. + +The \fI-db\fP 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, +\fBSPLAT!\fP's path loss plot can be constrained to the region +bounded by the 140 dB attenuation contour as follows: + +\fCsplat -t wnjt-dt -L 30.0 -s cities.dat -b co34_d00.dat -db 140 -o plot.ppm\fR + +.SH SIGNAL CONTOUR COLOR DEFINITION PARAMETERS +The colors used to illustrate signal strength and path loss contours +in \fBSPLAT!\fP generated coverage maps may be tailored by the user +by creating or modifying \fBSPLAT!\fP's color definition files. +\fBSPLAT!\fP color definition files have the same base name as the +transmitter's \fI.qth\fP file, but carry \fI.lcf\fP and \fI.scf\fP +extensions. + +When a regional Longley-Rice analysis is performed and the transmitter's +ERP is not specified or is zero, a \fI.lcf\fP path loss color +definition file corresponding to the transmitter site (\fI.qth\fP) is +read by \fBSPLAT!\fP from the current working directory. If a \fI.lcf\fP +file corresponding to the transmitter site is not found, then a default +file suitable for manual editing by the user is automatically generated +by \fBSPLAT!\fP. If the transmitter's ERP is specified, then a signal +strength map is generated and a signal strength color definition file +(\fI.scf\fP) is read, or generated if one is not available in the current +working directory. + +A path-loss color definition file possesses the following structure +(\fIwnjt-dt.lcf\fP): +\fC + ; SPLAT! Auto-generated Path-Loss Color Definition ("wnjt-dt.lcf") File + ; + ; Format for the parameters held in this file is as follows: + ; + ; 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 specified. + ; + ; 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 +\fR + +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. + +\fBSPLAT!\fP signal strength color definition files share a very similar +structure (\fIwnjt-dt.scf\fP): +\fC + ; SPLAT! Auto-generated Signal Color Definition ("wnjt-dt.scf") File + ; + ; Format for the parameters held in this file is as follows: + ; + ; 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 specified. + ; + ; 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 +\fR + +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: +\fC + 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 +\fR + +.SH ANTENNA RADIATION PATTERN PARAMETERS +Normalized field voltage patterns for a transmitting antenna's horizontal +and vertical planes are imported automatically into \fBSPLAT!\fP 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 transmitter +and LRP files, but with \fI.az\fP and \fI.el\fP extensions for azimuth +and elevation pattern files, respectively. Specifications regarding +pattern rotation (if any) and mechanical beam tilt and tilt direction +(if any) are also contained within \fBSPLAT!\fP antenna pattern files. + +For example, the first few lines of a \fBSPLAT!\fP azimuth pattern file +might appear as follows (\fIkvea.az\fP): +\fC + 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 +\fR +The first line of the \fI.az\fP file specifies the amount of azimuthal +pattern rotation (measured clockwise in degrees from True North) to be +applied by \fBSPLAT!\fP to the data contained in the \fI.az\fP file. +This is followed by azimuth headings (0 to 360 degrees) and their associated +normalized field patterns (0.000 to 1.000) separated by whitespace. + +The structure of \fBSPLAT!\fP elevation pattern files is slightly different. +The first line of the \fI.el\fP file specifies the amount of mechanical +beam tilt applied to the antenna. Note that a \fIdownward tilt\fP +(below the horizon) is expressed as a \fIpositive angle\fP, while an +\fIupward tilt\fP (above the horizon) is expressed as a \fInegative angle\fP. +This data is followed by the azimuthal direction of the tilt, separated by +whitespace. + +The remainder of the file consists of elevation angles and their +corresponding normalized voltage radiation pattern (0.000 to 1.000) +values separated by whitespace. Elevation angles must be specified +over a -10.0 to +90.0 degree range. As was the convention with mechanical +beamtilt, \fInegative elevation angles\fP are used to represent elevations +\fIabove the horizon\fP, while \fIpositive angles\fP represents elevations +\fIbelow the horizon\fP. + +For example, the first few lines a \fBSPLAT!\fP elevation pattern file +might appear as follows (\fIkvea.el\fP): +\fC + 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 +\fR +In this example, the antenna is mechanically tilted downward 1.1 degrees +towards an azimuth of 130.0 degrees. + +For best results, the resolution of azimuth pattern data should be +specified to the nearest degree azimuth, and elevation pattern data +resolution should be specified to the nearest 0.01 degrees. If the +pattern data specified does not reach this level of resolution, +\fBSPLAT!\fP will interpolate the values provided to determine the +data at the required resolution, although this may result in a loss +in accuracy. + +.SH 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 coverage 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 \fBSPLAT!\fP +to rapidly produce a revised path loss map. + +For example, a path loss output file can be generated by \fBSPLAT!\fP +for a receive site 30 feet above ground level over a 50 mile radius +surrounding a transmitter site to a maximum path loss of 140 dB using +the following syntax: + +\fCsplat -t kvea -L 30.0 -R 50.0 -db 140 -plo pathloss.dat\fR + +\fBSPLAT!\fP path loss output files often exceed 100 megabytes in size. +They contain information relating to the boundaries of region they describe +followed by latitudes (degrees North), longitudes (degrees West), azimuths, +elevations (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 \fBSPLAT!\fP path loss +output file take on the following appearance (\fIpathloss.dat\fP): +\fC + 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 +\fR +It is not uncommon for \fBSPLAT!\fP 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 \fBvim\fP +text editor has proven capable of editing files of this size. + +Note as was the case in the antenna pattern files, negative 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 \fI-L\fP switch \fIif\fP the path between transmitter +and receiver is unobstructed. If the path between the transmitter +and receiver is obstructed, then the elevation angle to the first +obstruction is returned by \fBSPLAT!\fP. 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 \fBSPLAT!\fP path loss files to reflect antenna +pattern data, \fIonly the last column (path loss)\fP 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 \fBSPLAT!\fP for +generating revised coverage maps: + +\fCsplat -t kvea -pli pathloss.dat -s city.dat -b county.dat -o map.ppm\fR + +\fBSPLAT!\fP path loss files can also be used for conducting coverage or +interference studies outside of \fBSPLAT!\fP. +.SH 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 \fBSPLAT!\fP analysis being conducted, but noticeably +absent from the SDF files being used. A user-defined terrain file is imported +into a \fBSPLAT!\fP analysis using the \fI-udt\fP switch: + +\fC splat -t tx_site -r rx_site -udt udt_file.txt -o map.ppm\fR + +A user-defined terrain file has the following appearance and structure: +\fC + 40.32180556, 74.1325, 100.0 meters + 40.321805, 74.1315, 300.0 + 40.3218055, 74.1305, 100.0 meters +\fR +Terrain height is interpreted as being described in feet above ground +level unless followed by the word \fImeters\fP, and is added \fIon top of\fP +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. Features described +in the user-defined terrain file that overlap previously defined features +in the file are ignored by \fBSPLAT!\fP. +.SH 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 \fI-n\fP +switch should be invoked as follows: + +\fCsplat -t tx_site -r rx_site -n -o topo_map.ppm\fR + +If no text report is desired, then the \fI-N\fP switch is used: + +\fCsplat -t tx_site -r rx_site -N -o topo_map.ppm\fR + +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: + +\fCsplat -t tx_site -R 50.0 -s NJ_Cities -b NJ_Counties -o topo_map.ppm\fR + +where -R specifies the minimum radius of the map in miles (or kilometers +if the \fI-metric\fP switch is used). Note that the tx_site name and +location are not displayed in this example. If display of this information +is desired, simply create a \fBSPLAT!\fP city file (\fI-s\fP option) and +append it to the list of command-line options illustrated above. + +If the \fI-o\fP switch and output filename are omitted in these +operations, topographic output is written to a file named \fItx_site.ppm\fP +in the current working directory by default. +.SH GEOREFERENCE FILE GENERATION +Topographic, coverage (\fI-c\fP), and path loss contour (\fI-L\fP) maps +generated by \fBSPLAT!\fP may be imported into \fBXastir\fP (X Amateur +Station Tracking and Information Reporting) software by generating a +georeference file using \fBSPLAT!\fP's \fI-geo\fP switch: + +\fCsplat -t kd2bd -R 50.0 -s NJ_Cities -b NJ_Counties -geo -o map.ppm\fR + +The georeference file generated will have the same base name as the +\fI-o\fP file specified, but have a \fI .geo\fP extension, and permit +proper interpretation and display of \fBSPLAT!\fP's .ppm graphics in +\fBXastir\fP software. +.SH GOOGLE MAP KML FILE GENERATION +Keyhole Markup Language files compatible with \fBGoogle Earth\fP may +be generated by \fBSPLAT!\fP when performing point-to-point or regional +coverage analyses by invoking the \fI-kml\fP switch: + +\fCsplat -t wnjt-dt -r kd2bd -kml\fR + +The KML file generated will have the same filename structure as a +Path Analysis Report for the transmitter and receiver site names given, +except it will carry a \fI .kml\fP extension. + +Once loaded into \fBGoogle Earth\fP (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 displayed in +green. \fBGoogle Earth\fP's navigation tools allow the user to +"fly" around the path, identify landmarks, roads, and other +featured content. + +When performing regional coverage analysis, the \fI .kml\fP file +generated by \fBSPLAT!\fP will permit path loss or signal strength contours +to be layered on top of \fBGoogle Earth\fP's display in a semi-transparent +manner. The generated \fI.kml\fP file will have the same basename as +that of the \fI.ppm\fP file normally generated. +.SH DETERMINATION OF ANTENNA HEIGHT ABOVE AVERAGE TERRAIN +\fBSPLAT!\fP determines antenna height above average terrain (HAAT) +according to the procedure defined by Federal Communications Commission +Part 73.313(d). According to this definition, terrain 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 available), 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 compliance with FCC Part 73.313(d) +in areas along the borders of the United States if the SDF files +used by \fBSPLAT!\fP are SRTM-derived. + +When performing point-to-point terrain analysis, \fBSPLAT!\fP 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 topography data is +normally loaded by \fBSPLAT!\fP to perform average terrain calculations. +Under such conditions, \fBSPLAT!\fP 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, \fBSPLAT!\fP reports \fINo Terrain\fP +for the radial paths affected. +.SH RESTRICTING THE MAXIMUM SIZE OF AN ANALYSIS REGION +\fBSPLAT!\fP 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 \fI#define MAXPAGES\fP statement in the first several lines of +\fIsplat.cpp\fP sets the maximum number of "pages" available for holding +topography data. It also sets the maximum size of the topographic maps +generated by \fBSPLAT!\fP. MAXPAGES is set to 9 by default. If \fBSPLAT!\fP +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 \fBSPLAT!\fP with the number of MAXPAGES specified. In situations where +available memory is low, MAXPAGES may be reduced to 4 with the understanding +that this will greatly limit the maximum region \fBSPLAT!\fP will be able +to analyze. If 118 megabytes or more of total memory (swap space plus +RAM) is available, 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 distances of over 1000 miles. +.SH ADDITIONAL INFORMATION +The latest news and information regarding \fBSPLAT!\fP software is +available through the official \fBSPLAT!\fP software web page located +at: \fIhttp://www.qsl.net/kd2bd/splat.html\fP. +.SH AUTHORS +.TP +John A. Magliacane, KD2BD <\fIkd2bd@amsat.org\fP> +Creator, Lead Developer +.TP +Doug McDonald <\fImcdonald@scs.uiuc.edu\fP> +Original Longley-Rice Model integration +.TP +Ron Bentley <\fIronbentley@earthlink.net\fP> +Fresnel Zone plotting and clearance determination +