1 .TH SPLAT! 1 "16 September 2007" "KD2BD Software" "KD2BD Software"
3 splat \- An RF \fBS\fPignal \fBP\fPropagation, \fBL\fPoss, \fBA\fPnd \fBT\fPerrain analysis tool
5 splat [-t \fItransmitter_site.qth\fP]
6 [-r \fIreceiver_site.qth\fP]
7 [-c \fIrx antenna height for LOS coverage analysis (feet/meters) (float)\fP]
8 [-L \fIrx antenna height for Longley-Rice coverage analysis (feet/meters) (float)\fP]
9 [-p \fIterrain_profile.ext\fP]
10 [-e \fIelevation_profile.ext\fP]
11 [-h \fIheight_profile.ext\fP]
12 [-H \fInormalized_height_profile.ext\fP]
13 [-l \fILongley-Rice_profile.ext\fP]
14 [-o \fItopographic_map_filename.ppm\fP]
15 [-b \fIcartographic_boundary_filename.dat\fP]
16 [-s \fIsite/city_database.dat\fP]
17 [-d \fIsdf_directory_path\fP]
18 [-m \fIearth radius multiplier (float)\fP]
19 [-f \fIfrequency (MHz) for Fresnel zone calculations (float)\fP]
20 [-R \fImaximum coverage radius (miles/kilometers) (float)\fP]
21 [-dB \fImaximum attenuation contour to display on path loss maps (80-230 dB)\fP]
22 [-fz \fIFresnel zone clearance percentage (default = 60)\fP]
23 [-plo \fIpath_loss_output_file.txt\fP]
24 [-pli \fIpath_loss_input_file.txt\fP]
25 [-udt \fIuser_defined_terrain_file.dat\fP]
34 \fBSPLAT!\fP is a powerful terrestrial RF propagation and terrain
35 analysis tool for the spectrum between 20 MHz and 20 GHz.
36 \fBSPLAT!\fP is free software, and is designed for operation on Unix
37 and Linux-based workstations. Redistribution and/or modification
38 is permitted under the terms of the GNU General Public License, Version 2,
39 as published by the Free Software Foundation. Adoption of \fBSPLAT!\fP
40 source code in proprietary or closed-source applications is a violation
41 of this license and is \fBstrictly\fP forbidden.
43 \fBSPLAT!\fP is distributed in the hope that it will be useful, but
44 WITHOUT ANY WARRANTY, without even the implied warranty of MERCHANTABILITY
45 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
48 Applications of \fBSPLAT!\fP include the visualization, design, and
49 link budget analysis of wireless Wide Area Networks (WANs), commercial
50 and amateur radio communication systems above 20 MHz, microwave links,
51 frequency coordination and interference studies, and the prediction
52 of analog and digital terrestrial radio and television contour regions.
54 \fBSPLAT!\fP provides RF site engineering data such as great circle
55 distances and bearings between sites, antenna elevation angles (uptilt),
56 depression angles (downtilt), antenna height above mean sea level,
57 antenna height above average terrain, bearings, distances, and elevations
58 to known obstructions, Longley-Rice path attenuation, and received signal
59 strength. In addition, the minimum antenna height requirements needed to
60 clear terrain, the first Fresnel zone, and any user-definable percentage
61 of the first Fresnel zone are also provided.
63 \fBSPLAT!\fP produces reports, graphs, and high resolution topographic
64 maps that depict line-of-sight paths, and regional path loss and signal
65 strength contours through which expected coverage areas of transmitters
66 and repeater systems can be obtained. When performing line-of-sight
67 and Longley-Rice analyses in situations where multiple transmitter or
68 repeater sites are employed, \fBSPLAT!\fP determines individual and
69 mutual areas of coverage within the network specified.
71 Simply typing \fCsplat\fR on the command line will return a summary
72 of \fBSPLAT!\fP's command line options:
75 --==[ SPLAT! v1.2.1 Available Options... ]==--
77 -t txsite(s).qth (max of 4 with -c, max of 30 with -L)
79 -c plot coverage of TX(s) with an RX antenna at X feet/meters AGL
80 -L plot path loss map of TX based on an RX at X feet/meters AGL
81 -s filename(s) of city/site file(s) to import (5 max)
82 -b filename(s) of cartographic boundary file(s) to import (5 max)
83 -p filename of terrain profile graph to plot
84 -e filename of terrain elevation graph to plot
85 -h filename of terrain height graph to plot
86 -H filename of normalized terrain height graph to plot
87 -l filename of Longley-Rice graph to plot
88 -o filename of topographic map to generate (.ppm)
89 -u filename of user-defined terrain file to import
90 -d sdf file directory path (overrides path in ~/.splat_path file)
91 -m earth radius multiplier
92 -n do not plot LOS paths in .ppm maps
93 -N do not produce unnecessary site or obstruction reports
94 -f frequency for Fresnel zone calculation (MHz)
95 -R modify default range for -c or -L (miles/kilometers)
96 -db maximum loss contour to display on path loss maps (80-230 dB)
97 -nf do not plot Fresnel zones in height plots
98 -fz Fresnel zone clearance percentage (default = 60)
99 -ngs display greyscale topography as white in .ppm files
100 -erp override ERP in .lrp file (Watts)
101 -pli filename of path-loss input file
102 -plo filename of path-loss output file
103 -udt filename of user defined terrain input file
104 -kml generate Google Earth (.kml) compatible output
105 -geo generate an Xastir .geo georeference file (with .ppm output)
106 -metric employ metric rather than imperial units for all user I/O
109 \fBSPLAT!\fP is a command-line driven application and reads input
110 data through a number of data files. Some files are mandatory for
111 successful execution of the program, while others are optional.
112 Mandatory files include 3-arc second topography models in the
113 form of SPLAT Data Files (SDF files), site location files (QTH
114 files), and Longley-Rice model parameter files (LRP files).
115 Optional files include city location files, cartographic boundary
116 files, user-defined terrain files, path-loss input files, antenna
117 radiation pattern files, and color definition files.
119 \fBSPLAT!\fP imports topographic data in the form of SPLAT Data Files
120 (SDFs). These files may be generated from a number of information sources.
121 In the United States, SPLAT Data Files can be generated through U.S.
122 Geological Survey Digital Elevation Models (DEMs) using the \fBusgs2sdf\fP
123 utility included with \fBSPLAT!\fP. USGS Digital Elevation Models
124 compatible with this utility may be downloaded from:
125 \fIhttp://edcftp.cr.usgs.gov/pub/data/DEM/250/\fP.
127 Significantly better resolution and accuracy can be obtained through
128 the use of SRTM-3 Version 2 digital elevation models. These models are
129 the product of the STS-99 Space Shuttle Radar Topography Mission, and
130 are available for most populated regions of the Earth. SPLAT Data Files
131 may be generated from SRTM data using the included \fBsrtm2sdf\fP utility.
132 SRTM-3 Version 2 data may be obtained through anonymous FTP from:
133 \fIftp://e0srp01u.ecs.nasa.gov:21/srtm/version2/\fP
135 The \fBstrm2sdf\fP utility may also be used to convert 3-arc second SRTM
136 data in Band Interleaved by Line (.BIL) format for use with \fBSPLAT!\fP.
137 This data is available via the web at:
138 \fIhttp://seamless.usgs.gov/website/seamless/\fP
140 Band Interleaved by Line data must be downloaded in a very specific manner
141 to be compatible with \fBsrtm2sdf\fP and \fBSPLAT!\fP. Please consult
142 \fBsrtm2sdf\fP's documentation for instructions on downloading .BIL
143 topographic data through the USGS's Seamless Web Site.
145 Despite the higher accuracy that SRTM data has to offer, some voids
146 in the data sets exist. When voids are detected, the \fBsrtm2sdf\fP
147 utility replaces them with corresponding data found in existing SDF
148 files (that were presumably created from earlier USGS data through the
149 \fBusgs2sdf\fP utility). If USGS-derived SDF data is not available, voids
150 are handled through adjacent pixel averaging, or direct replacement.
152 SPLAT Data Files contain integer value topographic elevations (in meters)
153 referenced to mean sea level for 1-degree by 1-degree regions of the
154 earth with a resolution of 3-arc seconds. SDF files can be read in
155 either standard format (\fI.sdf\fP) as generated by the \fBusgs2sdf\fP
156 and \fBsrtm2sdf\fP utilities, or in bzip2 compressed format
157 (\fI.sdf.bz2\fP). Since uncompressed files can be read slightly
158 faster than files that have been compressed, \fBSPLAT!\fP searches for
159 needed SDF data in uncompressed format first. If uncompressed data
160 cannot be located, \fBSPLAT!\fP then searches for data in bzip2 compressed
161 format. If no compressed SDF files can be found for the region requested,
162 \fBSPLAT!\fP assumes the region is over water, and will assign an
163 elevation of sea-level to these areas.
165 This feature of \fBSPLAT!\fP makes it possible to perform path analysis
166 not only over land, but also between coastal areas not represented by
167 Digital Elevation Model data. However, this behavior of \fBSPLAT!\fP
168 underscores the importance of having all the SDF files required for
169 the region being analyzed if meaningful results are to be expected.
170 .SH SITE LOCATION (QTH) FILES
171 \fBSPLAT!\fP imports site location information of transmitter and receiver
172 sites analyzed by the program from ASCII files having a \fI.qth\fP extension.
173 QTH files contain the site's name, the site's latitude (positive if North
174 of the equator, negative if South), the site's longitude (in degrees West,
175 0 to 360 degrees, or degrees East 0 to -360 degrees), and the site's
176 antenna height above ground level (AGL), each separated by a single
177 line-feed character. The antenna height is assumed to be specified in
178 feet unless followed by the letter \fIm\fP or the word \fImeters\fP in
179 either upper or lower case. Latitude and longitude information may be
180 expressed in either decimal format (74.6864) or degree, minute, second
181 (DMS) format (74 41 11.0).
183 For example, a site location file describing television station WNJT-DT,
184 Trenton, NJ (\fIwnjt-dt.qth\fP) might read as follows:
191 Each transmitter and receiver site analyzed by \fBSPLAT!\fP must be
192 represented by its own site location (QTH) file.
193 .SH LONGLEY-RICE PARAMETER (LRP) FILES
194 Longley-Rice parameter data files are required for \fBSPLAT!\fP to
195 determine RF path loss in either point-to-point or area prediction
196 mode. Longley-Rice model parameter data is read from files having
197 the same base name as the transmitter site QTH file, but with a
198 \fI.lrp\fP extension. \fBSPLAT!\fP LRP files share the following
199 format (\fIwnjt-dt.lrp\fP):
201 15.000 ; Earth Dielectric Constant (Relative permittivity)
202 0.005 ; Earth Conductivity (Siemens per meter)
203 301.000 ; Atmospheric Bending Constant (N-units)
204 647.000 ; Frequency in MHz (20 MHz to 20 GHz)
205 5 ; Radio Climate (5 = Continental Temperate)
206 0 ; Polarization (0 = Horizontal, 1 = Vertical)
207 0.50 ; Fraction of situations (50% of locations)
208 0.90 ; Fraction of time (90% of the time)
209 46000.0 ; ERP in Watts (optional)
211 If an LRP file corresponding to the tx_site QTH file cannot
212 be found, \fBSPLAT!\fP scans the current working directory for
213 the file "splat.lrp". If this file cannot be found, then default
214 parameters will be assigned by \fBSPLAT!\fP and a corresponding
215 "splat.lrp" file containing these default parameters will be written
216 to the current working directory. The generated "splat.lrp" file can
217 then be edited by the user as needed.
219 Typical Earth dielectric constants and conductivity values are as
222 Dielectric Constant Conductivity
223 Salt water : 80 5.000
224 Good ground : 25 0.020
225 Fresh water : 80 0.010
226 Marshy land : 12 0.007
227 Farmland, forest : 15 0.005
228 Average ground : 15 0.005
229 Mountain, sand : 13 0.002
231 Poor ground : 4 0.001
233 Radio climate codes used by \fBSPLAT!\fP are as follows:
235 1: Equatorial (Congo)
236 2: Continental Subtropical (Sudan)
237 3: Maritime Subtropical (West coast of Africa)
239 5: Continental Temperate
240 6: Maritime Temperate, over land (UK and west coasts of US & EU)
241 7: Maritime Temperate, over sea
243 The Continental Temperate climate is common to large land masses in
244 the temperate zone, such as the United States. For paths shorter than
245 100 km, there is little difference between Continental and Maritime
248 The seventh and eighth parameters in the \fI.lrp\fP file correspond to the
249 statistical analysis provided by the Longley-Rice model. In this example,
250 \fBSPLAT!\fP will return the maximum path loss occurring 50% of the time
251 (fraction of time) in 90% of situations (fraction of situations). This is
252 often denoted as F(50,90) in Longley-Rice studies. In the United States,
253 an F(50,90) criteria is typically used for digital television (8-level
254 VSB modulation), while F(50,50) is used for analog (VSB-AM+NTSC) broadcasts.
256 For further information on these parameters, see:
257 \fIhttp://flattop.its.bldrdoc.gov/itm.html\fP and
258 \fIhttp://www.softwright.com/faq/engineering/prop_longley_rice.html\fP
260 The final parameter in the \fI.lrp\fP file corresponds to the transmitter's
261 effective radiated power, and is optional. If it is included in the
262 \fI.lrp\fP file, then \fBSPLAT!\fP will compute received signal strength
263 levels and field strength level contours when performing Longley-Rice
264 studies. If the parameter is omitted, path loss is computed instead.
265 The ERP provided in the \fI.lrp\fP file can be overridden by using
266 \fBSPLAT!\fP's \fI-erp\fP command-line switch. If the \fI.lrp\fP file
267 contains an ERP parameter and the generation of path-loss rather than
268 signal strength contours is desired, the ERP can be assigned to zero
269 using the \fI-erp\fP switch without having to edit the \fI.lrp\fP file
270 to accomplish the same result.
271 .SH CITY LOCATION FILES
272 The names and locations of cities, tower sites, or other points of interest
273 may be imported and plotted on topographic maps generated by \fBSPLAT!\fP.
274 \fBSPLAT!\fP imports the names of cities and locations from ASCII files
275 containing the location of interest's name, latitude, and longitude.
276 Each field is separated by a comma. Each record is separated by a
277 single line feed character. As was the case with the \fI.qth\fP
278 files, latitude and longitude information may be entered in either
279 decimal or degree, minute, second (DMS) format.
281 For example (\fIcities.dat\fP):
283 Teaneck, 40.891973, 74.014506
284 Tenafly, 40.919212, 73.955892
285 Teterboro, 40.859511, 74.058908
286 Tinton Falls, 40.279966, 74.093924
287 Toms River, 39.977777, 74.183580
288 Totowa, 40.906160, 74.223310
289 Trenton, 40.219922, 74.754665
291 A total of five separate city data files may be imported at a time,
292 and there is no limit to the size of these files. \fBSPLAT!\fP reads
293 city data on a "first come/first served" basis, and plots only those
294 locations whose annotations do not conflict with annotations of
295 locations read earlier in the current city data file, or in previous
296 files. This behavior minimizes clutter in \fBSPLAT!\fP generated
297 topographic maps, but also mandates that important locations be placed
298 toward the beginning of the first city data file, and locations less
299 important be positioned further down the list or in subsequent data
302 City data files may be generated manually using any text editor,
303 imported from other sources, or derived from data available from the
304 U.S. Census Bureau using the \fBcitydecoder\fP utility included with
305 \fBSPLAT!\fP. Such data is available free of charge via the Internet
306 at: \fIhttp://www.census.gov/geo/www/cob/bdy_files.html\fP, and must
308 .SH CARTOGRAPHIC BOUNDARY DATA FILES
309 Cartographic boundary data may also be imported to plot the boundaries of
310 cities, counties, or states on topographic maps generated by \fBSPLAT!\fP.
311 Such data must be of the form of ARC/INFO Ungenerate (ASCII Format)
312 Metadata Cartographic Boundary Files, and are available from the U.S.
313 Census Bureau via the Internet at:
314 \fIhttp://www.census.gov/geo/www/cob/co2000.html#ascii\fP and
315 \fIhttp://www.census.gov/geo/www/cob/pl2000.html#ascii\fP. A total of
316 five separate cartographic boundary files may be imported at a time.
317 It is not necessary to import state boundaries if county boundaries
318 have already been imported.
319 .SH PROGRAM OPERATION
320 \fBSPLAT!\fP is invoked via the command-line using a series of switches
321 and arguments. Since \fBSPLAT!\fP is a CPU and memory intensive application,
322 this type of interface minimizes overhead and lends itself well to
323 scripted (batch) operations. \fBSPLAT!\fP's CPU and memory scheduling
324 priority may be modified through the use of the Unix \fBnice\fP command.
326 The number and type of switches passed to \fBSPLAT!\fP determine its
327 mode of operation and method of output data generation. Nearly all
328 of \fBSPLAT!\fP's switches may be cascaded in any order on the command
329 line when invoking the program.
331 \fBSPLAT!\fP operates in two distinct modes: \fIpoint-to-point mode\fP,
332 and \fIarea prediction mode\fP. Either a line-of-sight (LOS) or Longley-Rice
333 Irregular Terrain (ITM) propagation model may be invoked by the user. True
334 Earth, four-thirds Earth, or any other user-defined Earth radius may be
335 specified when performing line-of-sight analysis.
336 .SH POINT-TO-POINT ANALYSIS
337 \fBSPLAT!\fP may be used to perform line-of-sight terrain analysis
338 between two specified site locations. For example:
340 \fCsplat -t tx_site.qth -r rx_site.qth\fR
342 invokes a line-of-sight terrain analysis between the transmitter
343 specified in \fItx_site.qth\fP and receiver specified in \fIrx_site.qth\fP
344 using a True Earth radius model, and writes a \fBSPLAT!\fP Path Analysis
345 Report to the current working directory. The report contains details of
346 the transmitter and receiver sites, and identifies the location of any
347 obstructions detected along the line-of-sight path. If an obstruction
348 can be cleared by raising the receive antenna to a greater altitude,
349 \fBSPLAT!\fP will indicate the minimum antenna height required for a
350 line-of-sight path to exist between the transmitter and receiver locations
351 specified. Note that imperial units (miles, feet) are specified unless
352 the \fI-metric\fP switch is added to \fBSPLAT!\fP's command line options:
354 \fCsplat -t tx_site.qth -r rx_site.qth -metric\fR
356 If the antenna must be raised a significant amount, this determination
357 may take a few moments. Note that the results provided are the \fIminimum\fP
358 necessary for a line-of-sight path to exist, and in the case of this
359 simple example, do not take Fresnel zone clearance requirements into
362 \fIqth\fP extensions are assumed by \fBSPLAT!\fP for QTH files, and
363 are optional when specifying -t and -r arguments on the command-line.
364 \fBSPLAT!\fP automatically reads all SPLAT Data Files necessary to
365 conduct the terrain analysis between the sites specified. \fBSPLAT!\fP
366 searches for the required SDF files in the current working directory
367 first. If the needed files are not found, \fBSPLAT!\fP then searches
368 in the path specified by the \fI-d\fP command-line switch:
370 \fCsplat -t tx_site -r rx_site -d /cdrom/sdf/\fR
372 An external directory path may be specified by placing a ".splat_path"
373 file under the user's home directory. This file must contain the full
374 directory path of last resort to all the SDF files. The path in the
375 \fI$HOME/.splat_path\fP file must be of the form of a single line of
378 \fC/opt/splat/sdf/\fR
380 and can be generated using any text editor.
382 A graph of the terrain profile between the receiver and transmitter
383 locations as a function of distance from the receiver can be generated
384 by adding the \fI-p\fP switch:
386 \fCsplat -t tx_site -r rx_site -p terrain_profile.png\fR
388 \fBSPLAT!\fP invokes \fBgnuplot\fP when generating graphs. The filename
389 extension specified to \fBSPLAT!\fP determines the format of the graph
390 produced. \fI.png\fP will produce a 640x480 color PNG graphic file,
391 while \fI.ps\fP or \fI.postscript\fP will produce postscript output.
392 Output in formats such as GIF, Adobe Illustrator, AutoCAD dxf,
393 LaTeX, and many others are available. Please consult \fBgnuplot\fP,
394 and \fBgnuplot\fP's documentation for details on all the supported
397 A graph of elevations subtended by the terrain between the receiver and
398 transmitter as a function of distance from the receiver can be generated
399 by using the \fI-e\fP switch:
401 \fCsplat -t tx_site -r rx_site -e elevation_profile.png\fR
403 The graph produced using this switch illustrates the elevation and
404 depression angles resulting from the terrain between the receiver's
405 location and the transmitter site from the perspective of the receiver's
406 location. A second trace is plotted between the left side of the graph
407 (receiver's location) and the location of the transmitting antenna on
408 the right. This trace illustrates the elevation angle required for a
409 line-of-sight path to exist between the receiver and transmitter
410 locations. If the trace intersects the elevation profile at any point
411 on the graph, then this is an indication that a line-of-sight path
412 does not exist under the conditions given, and the obstructions can
413 be clearly identified on the graph at the point(s) of intersection.
415 A graph illustrating terrain height referenced to a line-of-sight
416 path between the transmitter and receiver may be generated using
419 \fCsplat -t tx_site -r rx_site -h height_profile.png\fR
421 A terrain height plot normalized to the transmitter and receiver
422 antenna heights can be obtained using the \fI-H\fP switch:
424 \fCsplat -t tx_site -r rx_site -H normalized_height_profile.png\fR
426 A contour of the Earth's curvature is also plotted in this mode.
428 The first Fresnel Zone, and 60% of the first Fresnel Zone can be
429 added to height profile graphs by adding the \fI-f\fP switch, and
430 specifying a frequency (in MHz) at which the Fresnel Zone should be
433 \fCsplat -t tx_site -r rx_site -f 439.250 -H normalized_height_profile.png\fR
435 Fresnel Zone clearances other 60% can be specified using the \fI-fz\fP
438 \fCsplat -t tx_site -r rx_site -f 439.250 -fz 75 -H height_profile2.png\fR
440 A graph showing Longley-Rice path loss may be plotted using the
443 \fCsplat -t tx_site -r rx_site -l path_loss_profile.png\fR
445 As before, adding the \fI-metric\fP switch forces the graphs to
446 be plotted using metric units of measure.
448 When performing a point-to-point analysis, a \fBSPLAT!\fP Path Analysis
449 Report is generated in the form of a text file with a \fI.txt\fP filename
450 extension. The report contains bearings and distances between the
451 transmitter and receiver, as well as the free-space and Longley-Rice
452 path loss for the path being analyzed. The mode of propagation for
453 the path is given as \fILine-of-Sight\fP, \fISingle Horizon\fP,
454 \fIDouble Horizon\fP, \fIDiffraction Dominant\fP, or \fITroposcatter
457 Distances and locations to known obstructions along the path
458 between transmitter and receiver are also provided. If the
459 transmitter's effective radiated power is specified in the
460 transmitter's corresponding \fI.lrp\fP file, then predicted
461 signal strength and antenna voltage at the receiving location
462 is also provided in the Path Analysis Report.
464 To determine the signal-to-noise (SNR) ratio at remote location
465 where random Johnson (thermal) noise is the primary limiting
469 SNR = T - NJ - L + G - NF
472 where \fBT\fP is the ERP of the transmitter in dBW in the direction
473 of the receiver, \fBNJ\fP is Johnson Noise in dBW (-136 dBW for a 6 MHz
474 television channel), \fBL\fP is the path loss provided by \fBSPLAT!\fP
475 in dB (as a \fIpositive\fP number), \fBG\fP is the receive antenna gain
476 in dB over isotropic, and \fBNF\fP is the receiver noise figure in dB.
478 \fBT\fP may be computed as follows:
484 where \fBTI\fP is actual amount of RF power delivered to the transmitting
485 antenna in dBW, \fBGT\fP is the transmitting antenna gain (over isotropic)
486 in the direction of the receiver (or the horizon if the receiver is over
489 To compute how much more signal is available over the minimum to
490 necessary to achieve a specific signal-to-noise ratio:
493 Signal_Margin = SNR - S
496 where \fBS\fP is the minimum required SNR ratio (15.5 dB for
497 ATSC (8-level VSB) DTV, 42 dB for analog NTSC television).
499 A topographic map may be generated by \fBSPLAT!\fP to visualize the
500 path between the transmitter and receiver sites from yet another
501 perspective. Topographic maps generated by \fBSPLAT!\fP display
502 elevations using a logarithmic grayscale, with higher elevations
503 represented through brighter shades of gray. The dynamic range of
504 the image is scaled between the highest and lowest elevations present
505 in the map. The only exception to this is sea-level, which is
506 represented using the color blue.
508 Topographic output is invoked using the \fI-o\fP switch:
510 \fCsplat -t tx_site -r rx_site -o topo_map.ppm\fR
512 The \fI.ppm\fP extension on the output filename is assumed by
513 \fBSPLAT!\fP, and is optional.
515 In this example, \fItopo_map.ppm\fP will illustrate the locations of the
516 transmitter and receiver sites specified. In addition, the great circle
517 path between the two sites will be drawn over locations for which an
518 unobstructed path exists to the transmitter at a receiving antenna
519 height equal to that of the receiver site (specified in \fIrx_site.qth\fP).
521 It may desirable to populate the topographic map with names and locations
522 of cities, tower sites, or other important locations. A city file may be
523 passed to \fBSPLAT!\fP using the \fI-s\fP switch:
525 \fCsplat -t tx_site -r rx_site -s cities.dat -o topo_map\fR
527 Up to five separate city files may be passed to \fBSPLAT!\fP at a time
528 following the \fI-s\fP switch.
530 County and state boundaries may be added to the map by specifying up
531 to five U.S. Census Bureau cartographic boundary files using the \fI-b\fP
534 \fCsplat -t tx_site -r rx_site -b co34_d00.dat -o topo_map\fR
536 In situations where multiple transmitter sites are in use, as many as
537 four site locations may be passed to \fBSPLAT!\fP at a time for analysis:
539 \fCsplat -t tx_site1 tx_site2 tx_site3 tx_site4 -r rx_site -p profile.png\fR
541 In this example, four separate terrain profiles and obstruction reports
542 will be generated by \fBSPLAT!\fP. A single topographic map can be
543 specified using the \fI-o\fP switch, and line-of-sight paths between
544 each transmitter and the receiver site indicated will be produced on
545 the map, each in its own color. The path between the first transmitter
546 specified to the receiver will be in green, the path between the
547 second transmitter and the receiver will be in cyan, the path between
548 the third transmitter and the receiver will be in violet, and the
549 path between the fourth transmitter and the receiver will be in sienna.
551 \fBSPLAT!\fP generated topographic maps are 24-bit TrueColor Portable
552 PixMap (PPM) images. They may be viewed, edited, or converted to other
553 graphic formats by popular image viewing applications such as \fBxv\fP,
554 \fBThe GIMP\fP, \fBImageMagick\fP, and \fBXPaint\fP. PNG format is
555 highly recommended for lossless compressed storage of \fBSPLAT!\fP
556 generated topographic output files. \fBImageMagick\fP's command-line
557 utility easily converts \fBSPLAT!\fP's PPM files to PNG format:
559 \fCconvert splat_map.ppm splat_map.png\fR
561 Another excellent PPM to PNG command-line utility is available
562 at: \fIhttp://www.libpng.org/pub/png/book/sources.html\fP. As a last
563 resort, PPM files may be compressed using the bzip2 utility, and read
564 directly by \fBThe GIMP\fP in this format.
566 The \fI-ngs\fP option assigns all terrain to the color white, and can be
567 used when it is desirable to generate a map that is devoid of terrain:
569 \fCsplat -t tx_site -r rx_site -b co34_d00.dat -ngs -o white_map\fR
571 The resulting .ppm image file can be converted to .png format with a
572 transparent background using \fBImageMagick\fP's \fBconvert\fP utility:
574 \fCconvert -transparent "#FFFFFF" white_map.ppm transparent_map.png\fR
575 .SH REGIONAL COVERAGE ANALYSIS
576 \fBSPLAT!\fP can analyze a transmitter or repeater site, or network
577 of sites, and predict the regional coverage for each site specified.
578 In this mode, \fBSPLAT!\fP can generate a topographic map displaying
579 the geometric line-of-sight coverage area of the sites based on the
580 location of each site and the height of receive antenna wishing to
581 communicate with the site in question. A regional analysis may be
582 performed by \fBSPLAT!\fP using the \fI-c\fP switch as follows:
584 \fCsplat -t tx_site -c 30.0 -s cities.dat -b co34_d00.dat -o tx_coverage\fR
586 In this example, \fBSPLAT!\fP generates a topographic map called
587 \fItx_coverage.ppm\fP that illustrates the predicted line-of-sight
588 regional coverage of \fItx_site\fP to receiving locations having
589 antennas 30.0 feet above ground level (AGL). If the \fI-metric\fP
590 switch is used, the argument following the \fI-c\fP switch is
591 interpreted as being in meters rather than in feet. The contents
592 of \fIcities.dat\fP are plotted on the map, as are the cartographic
593 boundaries contained in the file \fIco34_d00.dat\fP.
595 When plotting line-of-sight paths and areas of regional coverage,
596 \fBSPLAT!\fP by default does not account for the effects of
597 atmospheric bending. However, this behavior may be modified
598 by using the Earth radius multiplier (\fI-m\fP) switch:
600 \fCsplat -t wnjt-dt -c 30.0 -m 1.333 -s cities.dat -b counties.dat -o map.ppm\fR
602 An earth radius multiplier of 1.333 instructs \fBSPLAT!\fP to use
603 the "four-thirds earth" model for line-of-sight propagation analysis.
604 Any appropriate earth radius multiplier may be selected by the user.
606 When performing a regional analysis, \fBSPLAT!\fP generates a
607 site report for each station analyzed. \fBSPLAT!\fP site reports
608 contain details of the site's geographic location, its height above
609 mean sea level, the antenna's height above mean sea level, the
610 antenna's height above average terrain, and the height of the
611 average terrain calculated toward the bearings of 0, 45, 90, 135,
612 180, 225, 270, and 315 degrees azimuth.
613 .SH DETERMINING MULTIPLE REGIONS OF LOS COVERAGE
614 \fBSPLAT!\fP can also display line-of-sight coverage areas for as
615 many as four separate transmitter sites on a common topographic map.
618 \fCsplat -t site1 site2 site3 site4 -c 10.0 -metric -o network.ppm\fR
620 plots the regional line-of-sight coverage of site1, site2, site3,
621 and site4 based on a receive antenna located 10.0 meters above ground
622 level. A topographic map is then written to the file \fInetwork.ppm\fP.
623 The line-of-sight coverage area of the transmitters are plotted as
624 follows in the colors indicated (along with their corresponding RGB
627 site1: Green (0,255,0)
628 site2: Cyan (0,255,255)
629 site3: Medium Violet (147,112,219)
630 site4: Sienna 1 (255,130,71)
632 site1 + site2: Yellow (255,255,0)
633 site1 + site3: Pink (255,192,203)
634 site1 + site4: Green Yellow (173,255,47)
635 site2 + site3: Orange (255,165,0)
636 site2 + site4: Dark Sea Green 1 (193,255,193)
637 site3 + site4: Dark Turquoise (0,206,209)
639 site1 + site2 + site3: Dark Green (0,100,0)
640 site1 + site2 + site4: Blanched Almond (255,235,205)
641 site1 + site3 + site4: Medium Spring Green (0,250,154)
642 site2 + site3 + site4: Tan (210,180,140)
644 site1 + site2 + site3 + site4: Gold2 (238,201,0)
646 If separate \fI.qth\fP files are generated, each representing a common
647 site location but a different antenna height, a single topographic map
648 illustrating the regional coverage from as many as four separate locations
649 on a single tower may be generated by \fBSPLAT!\fP.
650 .SH LONGLEY-RICE PATH LOSS ANALYSIS
651 If the \fI-c\fP switch is replaced by a \fI-L\fP switch, a
652 Longley-Rice path loss map for a transmitter site may be generated:
654 \fCsplat -t wnjt -L 30.0 -s cities.dat -b co34_d00.dat -o path_loss_map\fR
656 In this mode, \fBSPLAT!\fP generates a multi-color map illustrating
657 expected signal levels in areas surrounding the transmitter site. A
658 legend at the bottom of the map correlates each color with a specific
659 path loss range in decibels or signal strength in decibels over one
660 microvolt per meter (dBuV/m).
662 The Longley-Rice analysis range may be modified to a user-specific
663 value using the \fI-R\fP switch. The argument must be given in miles
664 (or kilometers if the \fI-metric\fP switch is used). If a range wider
665 than the generated topographic map is specified, \fBSPLAT!\fP will
666 perform Longley-Rice path loss calculations between all four corners
667 of the area prediction map.
669 The \fI-db\fP switch allows a constraint to be placed on the maximum
670 path loss region plotted on the map. A maximum path loss between 80
671 and 230 dB may be specified using this switch. For example, if a path
672 loss beyond -140 dB is irrelevant to the survey being conducted,
673 \fBSPLAT!\fP's path loss plot can be constrained to the region
674 bounded by the 140 dB attenuation contour as follows:
676 \fCsplat -t wnjt-dt -L 30.0 -s cities.dat -b co34_d00.dat -db 140 -o plot.ppm\fR
678 .SH SIGNAL CONTOUR COLOR DEFINITION PARAMETERS
679 The colors used to illustrate signal strength and path loss contours
680 in \fBSPLAT!\fP generated coverage maps may be tailored by the user
681 by creating or modifying \fBSPLAT!\fP's color definition files.
682 \fBSPLAT!\fP color definition files have the same base name as the
683 transmitter's \fI.qth\fP file, but carry \fI.lcf\fP and \fI.scf\fP
686 When a regional Longley-Rice analysis is performed and the transmitter's
687 ERP is not specified or is zero, a \fI.lcf\fP path loss color
688 definition file corresponding to the transmitter site (\fI.qth\fP) is
689 read by \fBSPLAT!\fP from the current working directory. If a \fI.lcf\fP
690 file corresponding to the transmitter site is not found, then a default
691 file suitable for manual editing by the user is automatically generated
692 by \fBSPLAT!\fP. If the transmitter's ERP is specified, then a signal
693 strength map is generated and a signal strength color definition file
694 (\fI.scf\fP) is read, or generated if one is not available in the current
697 A path-loss color definition file possesses the following structure
700 ; SPLAT! Auto-generated Path-Loss Color Definition ("wnjt-dt.lcf") File
702 ; Format for the parameters held in this file is as follows:
704 ; dB: red, green, blue
706 ; ...where "dB" is the path loss (in dB) and
707 ; "red", "green", and "blue" are the corresponding RGB color
708 ; definitions ranging from 0 to 255 for the region specified.
710 ; The following parameters may be edited and/or expanded
711 ; for future runs of SPLAT! A total of 32 contour regions
712 ; may be defined in this file.
733 If the path loss is less than 80 dB, the color Red (RGB = 255, 0, 0) is
734 assigned to the region. If the path-loss is greater than or equal to
735 80 dB, but less than 90 db, then Dark Orange (255, 128, 0) is assigned
736 to the region. Orange (255, 165, 0) is assigned to regions having a
737 path loss greater than or equal to 90 dB, but less than 100 dB, and
738 so on. Greyscale terrain is displayed beyond the 230 dB path loss
741 \fBSPLAT!\fP signal strength color definition files share a very similar
742 structure (\fIwnjt-dt.scf\fP):
744 ; SPLAT! Auto-generated Signal Color Definition ("wnjt-dt.scf") File
746 ; Format for the parameters held in this file is as follows:
748 ; dBuV/m: red, green, blue
750 ; ...where "dBuV/m" is the signal strength (in dBuV/m) and
751 ; "red", "green", and "blue" are the corresponding RGB color
752 ; definitions ranging from 0 to 255 for the region specified.
754 ; The following parameters may be edited and/or expanded
755 ; for future runs of SPLAT! A total of 32 contour regions
756 ; may be defined in this file.
774 If the signal strength is greater than or equal to 128 db over 1 microvolt
775 per meter (dBuV/m), the color Red (255, 0, 0) is displayed for the region.
776 If the signal strength is greater than or equal to 118 dbuV/m, but less than
777 128 dbuV/m, then the color Orange (255, 165, 0) is displayed, and so on.
778 Greyscale terrain is displayed for regions with signal strengths less than
781 Signal strength contours for some common VHF and UHF broadcasting services
782 in the United States are as follows:
784 Analog Television Broadcasting
785 ------------------------------
786 Channels 2-6: City Grade: >= 74 dBuV/m
787 Grade A: >= 68 dBuV/m
788 Grade B: >= 47 dBuV/m
789 --------------------------------------------
790 Channels 7-13: City Grade: >= 77 dBuV/m
791 Grade A: >= 71 dBuV/m
792 Grade B: >= 56 dBuV/m
793 --------------------------------------------
794 Channels 14-69: Indoor Grade: >= 94 dBuV/m
795 City Grade: >= 80 dBuV/m
796 Grade A: >= 74 dBuV/m
797 Grade B: >= 64 dBuV/m
799 Digital Television Broadcasting
800 -------------------------------
801 Channels 2-6: City Grade: >= 35 dBuV/m
802 Service Threshold: >= 28 dBuV/m
803 --------------------------------------------
804 Channels 7-13: City Grade: >= 43 dBuV/m
805 Service Threshold: >= 36 dBuV/m
806 --------------------------------------------
807 Channels 14-69: City Grade: >= 48 dBuV/m
808 Service Threshold: >= 41 dBuV/m
810 NOAA Weather Radio (162.400 - 162.550 MHz)
811 ------------------------------------------
812 Reliable: >= 18 dBuV/m
813 Not reliable: < 18 dBuV/m
814 Unlikely to receive: < 0 dBuV/m
816 FM Radio Broadcasting (88.1 - 107.9 MHz)
817 ----------------------------------------
818 Analog Service Contour: 60 dBuV/m
819 Digital Service Contour: 65 dBuV/m
822 .SH ANTENNA RADIATION PATTERN PARAMETERS
823 Normalized field voltage patterns for a transmitting antenna's horizontal
824 and vertical planes are imported automatically into \fBSPLAT!\fP when a
825 Longley-Rice coverage analysis is performed. Antenna pattern data is
826 read from a pair of files having the same base name as the transmitter
827 and LRP files, but with \fI.az\fP and \fI.el\fP extensions for azimuth
828 and elevation pattern files, respectively. Specifications regarding
829 pattern rotation (if any) and mechanical beam tilt and tilt direction
830 (if any) are also contained within \fBSPLAT!\fP antenna pattern files.
832 For example, the first few lines of a \fBSPLAT!\fP azimuth pattern file
833 might appear as follows (\fIkvea.az\fP):
846 The first line of the \fI.az\fP file specifies the amount of azimuthal
847 pattern rotation (measured clockwise in degrees from True North) to be
848 applied by \fBSPLAT!\fP to the data contained in the \fI.az\fP file.
849 This is followed by azimuth headings (0 to 360 degrees) and their associated
850 normalized field patterns (0.000 to 1.000) separated by whitespace.
852 The structure of \fBSPLAT!\fP elevation pattern files is slightly different.
853 The first line of the \fI.el\fP file specifies the amount of mechanical
854 beam tilt applied to the antenna. Note that a \fIdownward tilt\fP
855 (below the horizon) is expressed as a \fIpositive angle\fP, while an
856 \fIupward tilt\fP (above the horizon) is expressed as a \fInegative angle\fP.
857 This data is followed by the azimuthal direction of the tilt, separated by
860 The remainder of the file consists of elevation angles and their
861 corresponding normalized voltage radiation pattern (0.000 to 1.000)
862 values separated by whitespace. Elevation angles must be specified
863 over a -10.0 to +90.0 degree range. As was the convention with mechanical
864 beamtilt, \fInegative elevation angles\fP are used to represent elevations
865 \fIabove the horizon\fP, while \fIpositive angles\fP represents elevations
866 \fIbelow the horizon\fP.
868 For example, the first few lines a \fBSPLAT!\fP elevation pattern file
869 might appear as follows (\fIkvea.el\fP):
882 In this example, the antenna is mechanically tilted downward 1.1 degrees
883 towards an azimuth of 130.0 degrees.
885 For best results, the resolution of azimuth pattern data should be
886 specified to the nearest degree azimuth, and elevation pattern data
887 resolution should be specified to the nearest 0.01 degrees. If the
888 pattern data specified does not reach this level of resolution,
889 \fBSPLAT!\fP will interpolate the values provided to determine the
890 data at the required resolution, although this may result in a loss
893 .SH IMPORTING AND EXPORTING REGIONAL PATH LOSS CONTOUR DATA
894 Performing a Longley-Rice coverage analysis can be a very time
895 consuming process, especially if the analysis is repeated repeatedly
896 to discover what effects changes to the antenna radiation patterns
897 make to the predicted coverage area.
899 This process can be expedited by exporting the Longley-Rice
900 regional path loss contour data to an output file, modifying the
901 path loss data externally to incorporate antenna pattern effects,
902 and then importing the modified path loss data back into \fBSPLAT!\fP
903 to rapidly produce a revised path loss map.
905 For example, a path loss output file can be generated by \fBSPLAT!\fP
906 for a receive site 30 feet above ground level over a 50 mile radius
907 surrounding a transmitter site to a maximum path loss of 140 dB using
908 the following syntax:
910 \fCsplat -t kvea -L 30.0 -R 50.0 -db 140 -plo pathloss.dat\fR
912 \fBSPLAT!\fP path loss output files often exceed 100 megabytes in size.
913 They contain information relating to the boundaries of region they describe
914 followed by latitudes (degrees North), longitudes (degrees West), azimuths,
915 elevations (to the first obstruction), and path loss figures (dB) for a
916 series of specific points that comprise the region surrounding the
917 transmitter site. The first few lines of a \fBSPLAT!\fP path loss
918 output file take on the following appearance (\fIpathloss.dat\fP):
920 119, 117 ; max_west, min_west
921 35, 33 ; max_north, min_north
922 34.2265434, 118.0631104, 48.171, -37.461, 67.70
923 34.2270355, 118.0624390, 48.262, -26.212, 73.72
924 34.2280197, 118.0611038, 48.269, -14.951, 79.74
925 34.2285156, 118.0604401, 48.207, -11.351, 81.68
926 34.2290077, 118.0597687, 48.240, -10.518, 83.26
927 34.2294998, 118.0591049, 48.225, 23.201, 84.60
928 34.2304878, 118.0577698, 48.213, 15.769, 137.84
929 34.2309799, 118.0570984, 48.234, 15.965, 151.54
930 34.2314720, 118.0564346, 48.224, 16.520, 149.45
931 34.2319679, 118.0557632, 48.223, 15.588, 151.61
932 34.2329521, 118.0544281, 48.230, 13.889, 135.45
933 34.2334442, 118.0537643, 48.223, 11.693, 137.37
934 34.2339401, 118.0530930, 48.222, 14.050, 126.32
935 34.2344322, 118.0524292, 48.216, 16.274, 156.28
936 34.2354164, 118.0510941, 48.222, 15.058, 152.65
937 34.2359123, 118.0504227, 48.221, 16.215, 158.57
938 34.2364044, 118.0497589, 48.216, 15.024, 157.30
939 34.2368965, 118.0490875, 48.225, 17.184, 156.36
941 It is not uncommon for \fBSPLAT!\fP path loss files to contain as
942 many as 3 million or more lines of data. Comments can be placed in
943 the file if they are proceeded by a semicolon character. The \fBvim\fP
944 text editor has proven capable of editing files of this size.
946 Note as was the case in the antenna pattern files, negative elevation
947 angles refer to upward tilt (above the horizon), while positive angles
948 refer to downward tilt (below the horizon). These angles refer to the
949 elevation to the receiving antenna at the height above ground level
950 specified using the \fI-L\fP switch \fIif\fP the path between transmitter
951 and receiver is unobstructed. If the path between the transmitter
952 and receiver is obstructed, then the elevation angle to the first
953 obstruction is returned by \fBSPLAT!\fP. This is because
954 the Longley-Rice model considers the energy reaching a distant point
955 over an obstructed path as a derivative of the energy scattered from
956 the top of the first obstruction, only. Since energy cannot reach
957 the obstructed location directly, the actual elevation angle to that
960 When modifying \fBSPLAT!\fP path loss files to reflect antenna
961 pattern data, \fIonly the last column (path loss)\fP should be amended
962 to reflect the antenna's normalized gain at the azimuth and elevation
963 angles specified in the file. (At this time, programs and scripts
964 capable of performing this operation are left as an exercise for
967 Modified path loss maps can be imported back into \fBSPLAT!\fP for
968 generating revised coverage maps:
970 \fCsplat -t kvea -pli pathloss.dat -s city.dat -b county.dat -o map.ppm\fR
972 \fBSPLAT!\fP path loss files can also be used for conducting coverage or
973 interference studies outside of \fBSPLAT!\fP.
974 .SH USER-DEFINED TERRAIN INPUT FILES
975 A user-defined terrain file is a user-generated text file containing latitudes,
976 longitudes, and heights above ground level of specific terrain features believed
977 to be of importance to the \fBSPLAT!\fP analysis being conducted, but noticeably
978 absent from the SDF files being used. A user-defined terrain file is imported
979 into a \fBSPLAT!\fP analysis using the \fI-udt\fP switch:
981 \fC splat -t tx_site -r rx_site -udt udt_file.txt -o map.ppm\fR
983 A user-defined terrain file has the following appearance and structure:
985 40.32180556, 74.1325, 100.0 meters
986 40.321805, 74.1315, 300.0
987 40.3218055, 74.1305, 100.0 meters
989 Terrain height is interpreted as being described in feet above ground
990 level unless followed by the word \fImeters\fP, and is added \fIon top of\fP
991 the terrain specified in the SDF data for the locations specified. Be
992 aware that each user-defined terrain feature specified will be interpreted
993 as being 3-arc seconds in both latitude and longitude. Features described
994 in the user-defined terrain file that overlap previously defined features
995 in the file are ignored by \fBSPLAT!\fP.
996 .SH SIMPLE TOPOGRAPHIC MAP GENERATION
997 In certain situations it may be desirable to generate a topographic map
998 of a region without plotting coverage areas, line-of-sight paths, or
999 generating obstruction reports. There are several ways of doing this.
1000 If one wishes to generate a topographic map illustrating the location
1001 of a transmitter and receiver site along with a brief text report
1002 describing the locations and distances between the sites, the \fI-n\fP
1003 switch should be invoked as follows:
1005 \fCsplat -t tx_site -r rx_site -n -o topo_map.ppm\fR
1007 If no text report is desired, then the \fI-N\fP switch is used:
1009 \fCsplat -t tx_site -r rx_site -N -o topo_map.ppm\fR
1011 If a topographic map centered about a single site out to a minimum
1012 specified radius is desired instead, a command similar to the following
1015 \fCsplat -t tx_site -R 50.0 -s NJ_Cities -b NJ_Counties -o topo_map.ppm\fR
1017 where -R specifies the minimum radius of the map in miles (or kilometers
1018 if the \fI-metric\fP switch is used). Note that the tx_site name and
1019 location are not displayed in this example. If display of this information
1020 is desired, simply create a \fBSPLAT!\fP city file (\fI-s\fP option) and
1021 append it to the list of command-line options illustrated above.
1023 If the \fI-o\fP switch and output filename are omitted in these
1024 operations, topographic output is written to a file named \fItx_site.ppm\fP
1025 in the current working directory by default.
1026 .SH GEOREFERENCE FILE GENERATION
1027 Topographic, coverage (\fI-c\fP), and path loss contour (\fI-L\fP) maps
1028 generated by \fBSPLAT!\fP may be imported into \fBXastir\fP (X Amateur
1029 Station Tracking and Information Reporting) software by generating a
1030 georeference file using \fBSPLAT!\fP's \fI-geo\fP switch:
1032 \fCsplat -t kd2bd -R 50.0 -s NJ_Cities -b NJ_Counties -geo -o map.ppm\fR
1034 The georeference file generated will have the same base name as the
1035 \fI-o\fP file specified, but have a \fI .geo\fP extension, and permit
1036 proper interpretation and display of \fBSPLAT!\fP's .ppm graphics in
1037 \fBXastir\fP software.
1038 .SH GOOGLE MAP KML FILE GENERATION
1039 Keyhole Markup Language files compatible with \fBGoogle Earth\fP may
1040 be generated by \fBSPLAT!\fP when performing point-to-point or regional
1041 coverage analyses by invoking the \fI-kml\fP switch:
1043 \fCsplat -t wnjt-dt -r kd2bd -kml\fR
1045 The KML file generated will have the same filename structure as a
1046 Path Analysis Report for the transmitter and receiver site names given,
1047 except it will carry a \fI .kml\fP extension.
1049 Once loaded into \fBGoogle Earth\fP (File --> Open), the KML file
1050 will annotate the map display with the names of the transmitter and
1051 receiver site locations. The viewpoint of the image will be from the
1052 position of the transmitter site looking towards the location of the
1053 receiver. The point-to-point path between the sites will be displayed
1054 as a white line while the RF line-of-sight path will be displayed in
1055 green. \fBGoogle Earth\fP's navigation tools allow the user to
1056 "fly" around the path, identify landmarks, roads, and other
1059 When performing regional coverage analysis, the \fI .kml\fP file
1060 generated by \fBSPLAT!\fP will permit path loss or signal strength contours
1061 to be layered on top of \fBGoogle Earth\fP's display in a semi-transparent
1062 manner. The generated \fI.kml\fP file will have the same basename as
1063 that of the \fI.ppm\fP file normally generated.
1064 .SH DETERMINATION OF ANTENNA HEIGHT ABOVE AVERAGE TERRAIN
1065 \fBSPLAT!\fP determines antenna height above average terrain (HAAT)
1066 according to the procedure defined by Federal Communications Commission
1067 Part 73.313(d). According to this definition, terrain elevations along
1068 eight radials between 2 and 10 miles (3 and 16 kilometers) from the site
1069 being analyzed are sampled and averaged for each 45 degrees of azimuth
1070 starting with True North. If one or more radials lie entirely over water
1071 or over land outside the United States (areas for which no USGS topography
1072 data is available), then those radials are omitted from the calculation
1075 Note that SRTM elevation data, unlike older 3-arc second USGS data,
1076 extends beyond the borders of the United States. Therefore, HAAT
1077 results may not be in full compliance with FCC Part 73.313(d)
1078 in areas along the borders of the United States if the SDF files
1079 used by \fBSPLAT!\fP are SRTM-derived.
1081 When performing point-to-point terrain analysis, \fBSPLAT!\fP determines
1082 the antenna height above average terrain only if enough topographic
1083 data has already been loaded by the program to perform the point-to-point
1084 analysis. In most cases, this will be true, unless the site in question
1085 does not lie within 10 miles of the boundary of the topography data in
1088 When performing area prediction analysis, enough topography data is
1089 normally loaded by \fBSPLAT!\fP to perform average terrain calculations.
1090 Under such conditions, \fBSPLAT!\fP will provide the antenna height
1091 above average terrain as well as the average terrain above mean sea
1092 level for azimuths of 0, 45, 90, 135, 180, 225, 270, and 315 degrees,
1093 and include such information in the generated site report. If one or
1094 more of the eight radials surveyed fall over water, or over regions
1095 for which no SDF data is available, \fBSPLAT!\fP reports \fINo Terrain\fP
1096 for the radial paths affected.
1097 .SH RESTRICTING THE MAXIMUM SIZE OF AN ANALYSIS REGION
1098 \fBSPLAT!\fP reads SDF files as needed into a series of memory "pages"
1099 within the structure of the program. Each "page" holds one SDF file
1100 representing a one degree by one degree region of terrain.
1101 A \fI#define MAXPAGES\fP statement in the first several lines of
1102 \fIsplat.cpp\fP sets the maximum number of "pages" available for holding
1103 topography data. It also sets the maximum size of the topographic maps
1104 generated by \fBSPLAT!\fP. MAXPAGES is set to 9 by default. If \fBSPLAT!\fP
1105 produces a segmentation fault on start-up with this default, it is an indication
1106 that not enough RAM and/or virtual memory (swap space) is available to
1107 run \fBSPLAT!\fP with the number of MAXPAGES specified. In situations where
1108 available memory is low, MAXPAGES may be reduced to 4 with the understanding
1109 that this will greatly limit the maximum region \fBSPLAT!\fP will be able
1110 to analyze. If 118 megabytes or more of total memory (swap space plus
1111 RAM) is available, then MAXPAGES may be increased to 16. This will
1112 permit operation over a 4-degree by 4-degree region, which is sufficient
1113 for single antenna heights in excess of 10,000 feet above mean sea
1114 level, or point-to-point distances of over 1000 miles.
1115 .SH ADDITIONAL INFORMATION
1116 The latest news and information regarding \fBSPLAT!\fP software is
1117 available through the official \fBSPLAT!\fP software web page located
1118 at: \fIhttp://www.qsl.net/kd2bd/splat.html\fP.
1121 John A. Magliacane, KD2BD <\fIkd2bd@amsat.org\fP>
1122 Creator, Lead Developer
1124 Doug McDonald <\fImcdonald@scs.uiuc.edu\fP>
1125 Original Longley-Rice Model integration
1127 Ron Bentley <\fIronbentley@earthlink.net\fP>
1128 Fresnel Zone plotting and clearance determination