1 .TH SPLAT! 1 "15 November 2008" "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 \fIthreshold beyond which contours will not be displayed\fP]
22 [-gc \fIground clutter height (feet/meters) (float)\fP]
23 [-fz \fIFresnel zone clearance percentage (default = 60)\fP]
24 [-ano \fIalphanumeric output file name\fP]
25 [-ani \fIalphanumeric input file name\fP]
26 [-udt \fIuser_defined_terrain_file.dat\fP]
37 \fBSPLAT!\fP is a powerful terrestrial RF propagation and terrain
38 analysis tool for the spectrum between 20 MHz and 20 GHz.
39 \fBSPLAT!\fP is free software, and is designed for operation on Unix
40 and Linux-based workstations. Redistribution and/or modification
41 is permitted under the terms of the GNU General Public License, Version 2,
42 as published by the Free Software Foundation. Adoption of \fBSPLAT!\fP
43 source code in proprietary or closed-source applications is a violation
44 of this license and is \fBstrictly\fP forbidden.
46 \fBSPLAT!\fP is distributed in the hope that it will be useful, but
47 WITHOUT ANY WARRANTY, without even the implied warranty of MERCHANTABILITY
48 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
51 Applications of \fBSPLAT!\fP include the visualization, design, and
52 link budget analysis of wireless Wide Area Networks (WANs), commercial
53 and amateur radio communication systems above 20 MHz, microwave links,
54 frequency coordination and interference studies, and the prediction
55 of analog and digital terrestrial radio and television contour regions.
57 \fBSPLAT!\fP provides RF site engineering data such as great circle
58 distances and bearings between sites, antenna elevation angles (uptilt),
59 depression angles (downtilt), antenna height above mean sea level,
60 antenna height above average terrain, bearings, distances, and elevations
61 to known obstructions, Longley-Rice path attenuation, and received signal
62 strength. In addition, the minimum antenna height requirements needed to
63 clear terrain, the first Fresnel zone, and any user-definable percentage
64 of the first Fresnel zone are also provided.
66 \fBSPLAT!\fP produces reports, graphs, and high resolution topographic
67 maps that depict line-of-sight paths, and regional path loss and signal
68 strength contours through which expected coverage areas of transmitters
69 and repeater systems can be obtained. When performing line-of-sight
70 and Longley-Rice analyses in situations where multiple transmitter or
71 repeater sites are employed, \fBSPLAT!\fP determines individual and
72 mutual areas of coverage within the network specified.
74 \fBSPLAT!\fP is a command-line driven application and reads input
75 data through a number of data files. Some files are mandatory for
76 successful execution of the program, while others are optional.
77 Mandatory files include digital elevation topography models in the
78 form of SPLAT Data Files (SDF files), site location files (QTH
79 files), and Longley-Rice model parameter files (LRP files).
80 Optional files include city location files, cartographic boundary
81 files, user-defined terrain files, path loss input files, antenna
82 radiation pattern files, and color definition files.
84 \fBSPLAT!\fP imports topographic data in the form of SPLAT Data Files
85 (SDFs). These files may be generated from a number of information sources.
86 In the United States, SPLAT Data Files can be generated through U.S.
87 Geological Survey Digital Elevation Models (DEMs) using the
88 \fBpostdownload\fP and \fBusgs2sdf\fP utilities included with \fBSPLAT!\fP.
89 USGS Digital Elevation Models compatible with these utilities may be
91 \fIhttp://edcftp.cr.usgs.gov/pub/data/DEM/250/\fP.
93 Significantly better resolution and accuracy can be obtained through
94 the use of SRTM Version 2 digital elevation models, especially when
95 supplemented by USGS-derived SDF data. These one-degree by
96 one-degree models are the product of the Space Shuttle STS-99
97 Radar Topography Mission, and are available for most populated
98 regions of the Earth. SPLAT Data Files may be generated from
99 3 arc-second SRTM-3 data using the included \fBsrtm2sdf\fP utility.
100 SRTM-3 Version 2 data may be obtained through anonymous FTP from:
101 \fIftp://e0srp01u.ecs.nasa.gov:21/srtm/version2/SRTM3/\fP
103 Note that SRTM filenames refer to the latitude and longitude of the
104 southwest corner of the topographic dataset contained within the file.
105 Therefore, the region of interest must lie north and east of the latitude
106 and longitude provided in the SRTM filename.
108 The \fBsrtm2sdf\fP utility may also be used to convert 3-arc second SRTM
109 data in Band Interleaved by Line (.BIL) format for use with \fBSPLAT!\fP.
110 This data is available via the web at:
111 \fIhttp://seamless.usgs.gov/website/seamless/\fP
113 Band Interleaved by Line data must be downloaded in a very specific manner
114 to be compatible with \fBsrtm2sdf\fP and \fBSPLAT!\fP. Please consult
115 \fBsrtm2sdf\fP's documentation for instructions on downloading .BIL
116 topographic data through the USGS's Seamless Web Site.
118 Even greater resolution and accuracy can be obtained by using 1 arc-second
119 SRTM-1 Version 2 topography data. This data is available for the United
120 States and its territories and possessions, and may be downloaded from:
121 \fIftp://e0srp01u.ecs.nasa.gov:21/srtm/version2/SRTM1/\fP
123 High resolution SDF files for use with \fBSPLAT! HD\fP may be generated
124 from data in this format using the \fBsrtm2sdf-hd\fP utility.
126 Despite the higher accuracy that SRTM data has to offer, some voids
127 in the data sets exist. When voids are detected, the \fBsrtm2sdf\fP
128 and \fBsrtm2sdf-hd\fP utilities replace them with corresponding data
129 found in \fBusgs2sdf\fP generated SDF files. If USGS-derived SDF data
130 is not available, voids are handled through adjacent pixel averaging,
131 or direct replacement.
133 SPLAT Data Files contain integer value topographic elevations in meters
134 referenced to mean sea level for 1-degree by 1-degree regions of the
135 Earth. SDF files can be read by \fBSPLAT!\fP in either standard format
136 (\fI.sdf\fP) as generated directly by the \fBusgs2sdf\fP, \fBsrtm2sdf\fP,
137 and \fBsrtm2sdf-hd\fP utilities, or in bzip2 compressed format
138 (\fI.sdf.bz2\fP). Since uncompressed files can be read slightly faster
139 than files that have been compressed, \fBSPLAT!\fP searches for needed
140 SDF data in uncompressed format first. If uncompressed data cannot be
141 located, \fBSPLAT!\fP then searches for data in bzip2 compressed format.
142 If no compressed SDF files can be found for the region requested,
143 \fBSPLAT!\fP assumes the region is over water, and will assign an
144 elevation of sea-level to these areas.
146 This feature of \fBSPLAT!\fP makes it possible to perform path analysis
147 not only over land, but also between coastal areas not represented by
148 Digital Elevation Model data. However, this behavior of \fBSPLAT!\fP
149 underscores the importance of having all the SDF files required for
150 the region being analyzed if meaningful results are to be expected.
151 .SH SITE LOCATION (QTH) FILES
152 \fBSPLAT!\fP imports site location information of transmitter and receiver
153 sites analyzed by the program from ASCII files having a \fI.qth\fP extension.
154 QTH files contain the site's name, the site's latitude (positive if North
155 of the equator, negative if South), the site's longitude (in degrees West,
156 0 to 360 degrees, or degrees East 0 to -360 degrees), and the site's
157 antenna height above ground level (AGL), each separated by a single
158 line-feed character. The antenna height is assumed to be specified in
159 feet unless followed by the letter \fIm\fP or the word \fImeters\fP in
160 either upper or lower case. Latitude and longitude information may be
161 expressed in either decimal format (74.6864) or degree, minute, second
162 (DMS) format (74 41 11.0).
164 For example, a site location file describing television station WNJT-DT,
165 Trenton, NJ (\fIwnjt-dt.qth\fP) might read as follows:
174 Each transmitter and receiver site analyzed by \fBSPLAT!\fP must be
175 represented by its own site location (QTH) file.
176 .SH LONGLEY-RICE PARAMETER (LRP) FILES
177 Longley-Rice parameter data files are required for \fBSPLAT!\fP to
178 determine RF path loss, field strength, or received signal power
179 level in either point-to-point or area prediction mode. Longley-Rice
180 model parameter data is read from files having the same base name
181 as the transmitter site QTH file, but with a \fI.lrp\fP extension.
182 \fBSPLAT!\fP LRP files share the following format (\fIwnjt-dt.lrp\fP):
185 15.000 ; Earth Dielectric Constant (Relative permittivity)
186 0.005 ; Earth Conductivity (Siemens per meter)
187 301.000 ; Atmospheric Bending Constant (N-units)
188 647.000 ; Frequency in MHz (20 MHz to 20 GHz)
189 5 ; Radio Climate (5 = Continental Temperate)
190 0 ; Polarization (0 = Horizontal, 1 = Vertical)
191 0.50 ; Fraction of situations (50% of locations)
192 0.90 ; Fraction of time (90% of the time)
193 46000.0 ; ERP in Watts (optional)
196 If an LRP file corresponding to the tx_site QTH file cannot
197 be found, \fBSPLAT!\fP scans the current working directory for
198 the file "splat.lrp". If this file cannot be found, then default
199 parameters will be assigned by \fBSPLAT!\fP and a corresponding
200 "splat.lrp" file containing these default parameters will be written
201 to the current working directory. The generated "splat.lrp" file can
202 then be edited by the user as needed.
204 Typical Earth dielectric constants and conductivity values are as
207 Dielectric Constant Conductivity
208 Salt water : 80 5.000
209 Good ground : 25 0.020
210 Fresh water : 80 0.010
211 Marshy land : 12 0.007
212 Farmland, forest : 15 0.005
213 Average ground : 15 0.005
214 Mountain, sand : 13 0.002
216 Poor ground : 4 0.001
219 Radio climate codes used by \fBSPLAT!\fP are as follows:
222 1: Equatorial (Congo)
223 2: Continental Subtropical (Sudan)
224 3: Maritime Subtropical (West coast of Africa)
226 5: Continental Temperate
227 6: Maritime Temperate, over land (UK and west coasts of US & EU)
228 7: Maritime Temperate, over sea
231 The Continental Temperate climate is common to large land masses in
232 the temperate zone, such as the United States. For paths shorter than
233 100 km, there is little difference between Continental and Maritime
236 The seventh and eighth parameters in the \fI.lrp\fP file correspond to the
237 statistical analysis provided by the Longley-Rice model. In this example,
238 \fBSPLAT!\fP will return the maximum path loss occurring 50% of the time
239 (fraction of time) in 90% of situations (fraction of situations). This is
240 often denoted as F(50,90) in Longley-Rice studies. In the United States,
241 an F(50,90) criteria is typically used for digital television (8-level
242 VSB modulation), while F(50,50) is used for analog (VSB-AM+NTSC) broadcasts.
244 For further information on these parameters, see:
245 \fIhttp://flattop.its.bldrdoc.gov/itm.html\fP and
246 \fIhttp://www.softwright.com/faq/engineering/prop_longley_rice.html\fP
248 The final parameter in the \fI.lrp\fP file corresponds to the transmitter's
249 effective radiated power, and is optional. If it is included in the
250 \fI.lrp\fP file, then \fBSPLAT!\fP will compute received signal strength
251 levels and field strength level contours when performing Longley-Rice
252 studies. If the parameter is omitted, path loss is computed instead.
253 The ERP provided in the \fI.lrp\fP file can be overridden by using
254 \fBSPLAT!\fP's \fI-erp\fP command-line switch. If the \fI.lrp\fP file
255 contains an ERP parameter and the generation of path loss rather than
256 field strength contours is desired, the ERP can be assigned to zero
257 using the \fI-erp\fP switch without having to edit the \fI.lrp\fP file
258 to accomplish the same result.
259 .SH CITY LOCATION FILES
260 The names and locations of cities, tower sites, or other points of interest
261 may be imported and plotted on topographic maps generated by \fBSPLAT!\fP.
262 \fBSPLAT!\fP imports the names of cities and locations from ASCII files
263 containing the location of interest's name, latitude, and longitude.
264 Each field is separated by a comma. Each record is separated by a
265 single line feed character. As was the case with the \fI.qth\fP
266 files, latitude and longitude information may be entered in either
267 decimal or degree, minute, second (DMS) format.
269 For example (\fIcities.dat\fP):
272 Teaneck, 40.891973, 74.014506
273 Tenafly, 40.919212, 73.955892
274 Teterboro, 40.859511, 74.058908
275 Tinton Falls, 40.279966, 74.093924
276 Toms River, 39.977777, 74.183580
277 Totowa, 40.906160, 74.223310
278 Trenton, 40.219922, 74.754665
281 A total of five separate city data files may be imported at a time,
282 and there is no limit to the size of these files. \fBSPLAT!\fP reads
283 city data on a "first come/first served" basis, and plots only those
284 locations whose annotations do not conflict with annotations of
285 locations read earlier in the current city data file, or in previous
286 files. This behavior minimizes clutter in \fBSPLAT!\fP generated
287 topographic maps, but also mandates that important locations be placed
288 toward the beginning of the first city data file, and locations less
289 important be positioned further down the list or in subsequent data
292 City data files may be generated manually using any text editor,
293 imported from other sources, or derived from data available from the
294 U.S. Census Bureau using the \fBcitydecoder\fP utility included with
295 \fBSPLAT!\fP. Such data is available free of charge via the Internet
296 at: \fIhttp://www.census.gov/geo/www/cob/bdy_files.html\fP, and must
298 .SH CARTOGRAPHIC BOUNDARY DATA FILES
299 Cartographic boundary data may also be imported to plot the boundaries of
300 cities, counties, or states on topographic maps generated by \fBSPLAT!\fP.
301 Such data must be of the form of ARC/INFO Ungenerate (ASCII Format)
302 Metadata Cartographic Boundary Files, and are available from the U.S.
303 Census Bureau via the Internet at:
304 \fIhttp://www.census.gov/geo/www/cob/co2000.html#ascii\fP and
305 \fIhttp://www.census.gov/geo/www/cob/pl2000.html#ascii\fP. A total of
306 five separate cartographic boundary files may be imported at a time.
307 It is not necessary to import state boundaries if county boundaries
308 have already been imported.
309 .SH PROGRAM OPERATION
310 \fBSPLAT!\fP is invoked via the command-line using a series of switches
311 and arguments. Since \fBSPLAT!\fP is a CPU and memory intensive application,
312 this type of interface minimizes overhead and lends itself well to
313 scripted (batch) operations. \fBSPLAT!\fP's CPU and memory scheduling
314 priority may be modified through the use of the Unix \fBnice\fP command.
316 The number and type of switches passed to \fBSPLAT!\fP determine its
317 mode of operation and method of output data generation. Nearly all
318 of \fBSPLAT!\fP's switches may be cascaded in any order on the command
319 line when invoking the program.
321 Simply typing \fCsplat\fR on the command line will return a summary
322 of \fBSPLAT!\fP's command line options:
325 --==[ SPLAT! v1.3.0 Available Options... ]==--
327 -t txsite(s).qth (max of 4 with -c, max of 30 with -L)
329 -c plot coverage of TX(s) with an RX antenna at X feet/meters AGL
330 -L plot path loss map of TX based on an RX at X feet/meters AGL
331 -s filename(s) of city/site file(s) to import (5 max)
332 -b filename(s) of cartographic boundary file(s) to import (5 max)
333 -p filename of terrain profile graph to plot
334 -e filename of terrain elevation graph to plot
335 -h filename of terrain height graph to plot
336 -H filename of normalized terrain height graph to plot
337 -l filename of path loss graph to plot
338 -o filename of topographic map to generate (.ppm)
339 -u filename of user-defined terrain file to import
340 -d sdf file directory path (overrides path in ~/.splat_path file)
341 -m earth radius multiplier
342 -n do not plot LOS paths in .ppm maps
343 -N do not produce unnecessary site or obstruction reports
344 -f frequency for Fresnel zone calculation (MHz)
345 -R modify default range for -c or -L (miles/kilometers)
346 -db threshold beyond which contours will not be displayed
347 -nf do not plot Fresnel zones in height plots
348 -fz Fresnel zone clearance percentage (default = 60)
349 -gc ground clutter height (feet/meters)
350 -ngs display greyscale topography as white in .ppm files
351 -erp override ERP in .lrp file (Watts)
352 -ano name of alphanumeric output file
353 -ani name of alphanumeric input file
354 -udt filename of user defined terrain input file
355 -kml generate Google Earth (.kml) compatible output
356 -geo generate an Xastir .geo georeference file (with .ppm output)
357 -dbm plot signal power level contours rather than field strength
358 -gpsav preserve gnuplot temporary working files after SPLAT! execution
359 -metric employ metric rather than imperial units for all user I/O
362 The command-line options for \fCsplat\fR and \fCsplat-hd\fR are identical.
364 \fBSPLAT!\fP operates in two distinct modes: \fIpoint-to-point mode\fP,
365 and \fIarea prediction mode\fP. Either a line-of-sight (LOS) or Longley-Rice
366 Irregular Terrain (ITM) propagation model may be invoked by the user. True
367 Earth, four-thirds Earth, or any other user-defined Earth radius may be
368 specified when performing line-of-sight analysis.
369 .SH POINT-TO-POINT ANALYSIS
370 \fBSPLAT!\fP may be used to perform line-of-sight terrain analysis
371 between two specified site locations. For example:
373 \fCsplat -t tx_site.qth -r rx_site.qth\fR
375 invokes a line-of-sight terrain analysis between the transmitter
376 specified in \fItx_site.qth\fP and receiver specified in \fIrx_site.qth\fP
377 using a True Earth radius model, and writes a \fBSPLAT!\fP Path Analysis
378 Report to the current working directory. The report contains details of
379 the transmitter and receiver sites, and identifies the location of any
380 obstructions detected along the line-of-sight path. If an obstruction
381 can be cleared by raising the receive antenna to a greater altitude,
382 \fBSPLAT!\fP will indicate the minimum antenna height required for a
383 line-of-sight path to exist between the transmitter and receiver locations
384 specified. Note that imperial units (miles, feet) are specified unless
385 the \fI-metric\fP switch is added to \fBSPLAT!\fP's command line options:
387 \fCsplat -t tx_site.qth -r rx_site.qth -metric\fR
389 If the antenna must be raised a significant amount, this determination
390 may take a few moments. Note that the results provided are the \fIminimum\fP
391 necessary for a line-of-sight path to exist, and in the case of this
392 simple example, do not take Fresnel zone clearance requirements into
395 \fIqth\fP extensions are assumed by \fBSPLAT!\fP for QTH files, and
396 are optional when specifying -t and -r arguments on the command-line.
397 \fBSPLAT!\fP automatically reads all SPLAT Data Files necessary to
398 conduct the terrain analysis between the sites specified. \fBSPLAT!\fP
399 searches for the required SDF files in the current working directory
400 first. If the needed files are not found, \fBSPLAT!\fP then searches
401 in the path specified by the \fI-d\fP command-line switch:
403 \fCsplat -t tx_site -r rx_site -d /cdrom/sdf/\fR
405 An external directory path may be specified by placing a ".splat_path"
406 file under the user's home directory. This file must contain the full
407 directory path of last resort to all the SDF files. The path in the
408 \fI$HOME/.splat_path\fP file must be of the form of a single line of
411 \fC/opt/splat/sdf/\fR
413 and can be generated using any text editor.
415 A graph of the terrain profile between the receiver and transmitter
416 locations as a function of distance from the receiver can be generated
417 by adding the \fI-p\fP switch:
419 \fCsplat -t tx_site -r rx_site -p terrain_profile.png\fR
421 \fBSPLAT!\fP invokes \fBgnuplot\fP when generating graphs. The filename
422 extension specified to \fBSPLAT!\fP determines the format of the graph
423 produced. \fI.png\fP will produce a 640x480 color PNG graphic file,
424 while \fI.ps\fP or \fI.postscript\fP will produce postscript output.
425 Output in formats such as GIF, Adobe Illustrator, AutoCAD dxf,
426 LaTeX, and many others are available. Please consult \fBgnuplot\fP,
427 and \fBgnuplot\fP's documentation for details on all the supported
430 A graph of elevations subtended by the terrain between the receiver and
431 transmitter as a function of distance from the receiver can be generated
432 by using the \fI-e\fP switch:
434 \fCsplat -t tx_site -r rx_site -e elevation_profile.png\fR
436 The graph produced using this switch illustrates the elevation and
437 depression angles resulting from the terrain between the receiver's
438 location and the transmitter site from the perspective of the receiver's
439 location. A second trace is plotted between the left side of the graph
440 (receiver's location) and the location of the transmitting antenna on
441 the right. This trace illustrates the elevation angle required for a
442 line-of-sight path to exist between the receiver and transmitter
443 locations. If the trace intersects the elevation profile at any point
444 on the graph, then this is an indication that a line-of-sight path
445 does not exist under the conditions given, and the obstructions can
446 be clearly identified on the graph at the point(s) of intersection.
448 A graph illustrating terrain height referenced to a line-of-sight
449 path between the transmitter and receiver may be generated using
452 \fCsplat -t tx_site -r rx_site -h height_profile.png\fR
454 A terrain height plot normalized to the transmitter and receiver
455 antenna heights can be obtained using the \fI-H\fP switch:
457 \fCsplat -t tx_site -r rx_site -H normalized_height_profile.png\fR
459 A contour of the Earth's curvature is also plotted in this mode.
461 The first Fresnel Zone, and 60% of the first Fresnel Zone can be
462 added to height profile graphs by adding the \fI-f\fP switch, and
463 specifying a frequency (in MHz) at which the Fresnel Zone should be
466 \fCsplat -t tx_site -r rx_site -f 439.250 -H normalized_height_profile.png\fR
468 Fresnel Zone clearances other 60% can be specified using the \fI-fz\fP
471 \fCsplat -t tx_site -r rx_site -f 439.250 -fz 75 -H height_profile2.png\fR
473 A graph showing Longley-Rice path loss may be plotted using the
476 \fCsplat -t tx_site -r rx_site -l path_loss_profile.png\fR
478 As before, adding the \fI-metric\fP switch forces the graphs to
479 be plotted using metric units of measure. The \fI-gpsav\fP switch
480 instructs \fBSPLAT!\fP to preserve (rather than delete) the \fBgnuplot\fP
481 working files generated during \fBSPLAT!\fP execution, allowing the user
482 to edit these files and re-run \fBgnuplot\fP if desired.
484 When performing a point-to-point analysis, a \fBSPLAT!\fP Path Analysis
485 Report is generated in the form of a text file with a \fI.txt\fP filename
486 extension. The report contains bearings and distances between the
487 transmitter and receiver, as well as the free-space and Longley-Rice
488 path loss for the path being analyzed. The mode of propagation for
489 the path is given as \fILine-of-Sight\fP, \fISingle Horizon\fP,
490 \fIDouble Horizon\fP, \fIDiffraction Dominant\fP, or \fITroposcatter
493 Distances and locations to known obstructions along the path
494 between transmitter and receiver are also provided. If the
495 transmitter's effective radiated power is specified in the
496 transmitter's corresponding \fI.lrp\fP file, then predicted
497 signal strength and antenna voltage at the receiving location
498 is also provided in the Path Analysis Report.
500 To determine the signal-to-noise (SNR) ratio at remote location
501 where random Johnson (thermal) noise is the primary limiting
505 SNR = T - NJ - L + G - NF
508 where \fBT\fP is the ERP of the transmitter in dBW in the direction
509 of the receiver, \fBNJ\fP is Johnson Noise in dBW (-136 dBW for a 6 MHz
510 television channel), \fBL\fP is the path loss provided by \fBSPLAT!\fP
511 in dB (as a \fIpositive\fP number), \fBG\fP is the receive antenna gain
512 in dB over isotropic, and \fBNF\fP is the receiver noise figure in dB.
514 \fBT\fP may be computed as follows:
520 where \fBTI\fP is actual amount of RF power delivered to the transmitting
521 antenna in dBW, \fBGT\fP is the transmitting antenna gain (over isotropic)
522 in the direction of the receiver (or the horizon if the receiver is over
525 To compute how much more signal is available over the minimum to
526 necessary to achieve a specific signal-to-noise ratio:
529 Signal_Margin = SNR - S
532 where \fBS\fP is the minimum required SNR ratio (15.5 dB for
533 ATSC (8-level VSB) DTV, 42 dB for analog NTSC television).
535 A topographic map may be generated by \fBSPLAT!\fP to visualize the
536 path between the transmitter and receiver sites from yet another
537 perspective. Topographic maps generated by \fBSPLAT!\fP display
538 elevations using a logarithmic grayscale, with higher elevations
539 represented through brighter shades of gray. The dynamic range of
540 the image is scaled between the highest and lowest elevations present
541 in the map. The only exception to this is sea-level, which is
542 represented using the color blue.
544 Topographic output is invoked using the \fI-o\fP switch:
546 \fCsplat -t tx_site -r rx_site -o topo_map.ppm\fR
548 The \fI.ppm\fP extension on the output filename is assumed by
549 \fBSPLAT!\fP, and is optional.
551 In this example, \fItopo_map.ppm\fP will illustrate the locations of the
552 transmitter and receiver sites specified. In addition, the great circle
553 path between the two sites will be drawn over locations for which an
554 unobstructed path exists to the transmitter at a receiving antenna
555 height equal to that of the receiver site (specified in \fIrx_site.qth\fP).
557 It may desirable to populate the topographic map with names and locations
558 of cities, tower sites, or other important locations. A city file may be
559 passed to \fBSPLAT!\fP using the \fI-s\fP switch:
561 \fCsplat -t tx_site -r rx_site -s cities.dat -o topo_map\fR
563 Up to five separate city files may be passed to \fBSPLAT!\fP at a time
564 following the \fI-s\fP switch.
566 County and state boundaries may be added to the map by specifying up
567 to five U.S. Census Bureau cartographic boundary files using the \fI-b\fP
570 \fCsplat -t tx_site -r rx_site -b co34_d00.dat -o topo_map\fR
572 In situations where multiple transmitter sites are in use, as many as
573 four site locations may be passed to \fBSPLAT!\fP at a time for analysis:
575 \fCsplat -t tx_site1 tx_site2 tx_site3 tx_site4 -r rx_site -p profile.png\fR
577 In this example, four separate terrain profiles and obstruction reports
578 will be generated by \fBSPLAT!\fP. A single topographic map can be
579 specified using the \fI-o\fP switch, and line-of-sight paths between
580 each transmitter and the receiver site indicated will be produced on
581 the map, each in its own color. The path between the first transmitter
582 specified to the receiver will be in green, the path between the
583 second transmitter and the receiver will be in cyan, the path between
584 the third transmitter and the receiver will be in violet, and the
585 path between the fourth transmitter and the receiver will be in sienna.
587 \fBSPLAT!\fP generated topographic maps are 24-bit TrueColor Portable
588 PixMap (PPM) images. They may be viewed, edited, or converted to other
589 graphic formats by popular image viewing applications such as \fBxv\fP,
590 \fBThe GIMP\fP, \fBImageMagick\fP, and \fBXPaint\fP. PNG format is
591 highly recommended for lossless compressed storage of \fBSPLAT!\fP
592 generated topographic output files. \fBImageMagick\fP's command-line
593 utility easily converts \fBSPLAT!\fP's PPM files to PNG format:
595 \fCconvert splat_map.ppm splat_map.png\fR
597 Another excellent PPM to PNG command-line utility is available
598 at: \fIhttp://www.libpng.org/pub/png/book/sources.html\fP. As a last
599 resort, PPM files may be compressed using the bzip2 utility, and read
600 directly by \fBThe GIMP\fP in this format.
602 The \fI-ngs\fP option assigns all terrain to the color white, and can be
603 used when it is desirable to generate a map that is devoid of terrain:
605 \fCsplat -t tx_site -r rx_site -b co34_d00.dat -ngs -o white_map\fR
607 The resulting .ppm image file can be converted to .png format with a
608 transparent background using \fBImageMagick\fP's \fBconvert\fP utility:
610 \fCconvert -transparent "#FFFFFF" white_map.ppm transparent_map.png\fR
611 .SH REGIONAL COVERAGE ANALYSIS
612 \fBSPLAT!\fP can analyze a transmitter or repeater site, or network
613 of sites, and predict the regional coverage for each site specified.
614 In this mode, \fBSPLAT!\fP can generate a topographic map displaying
615 the geometric line-of-sight coverage area of the sites based on the
616 location of each site and the height of receive antenna wishing to
617 communicate with the site in question. A regional analysis may be
618 performed by \fBSPLAT!\fP using the \fI-c\fP switch as follows:
620 \fCsplat -t tx_site -c 30.0 -s cities.dat -b co34_d00.dat -o tx_coverage\fR
622 In this example, \fBSPLAT!\fP generates a topographic map called
623 \fItx_coverage.ppm\fP that illustrates the predicted line-of-sight
624 regional coverage of \fItx_site\fP to receiving locations having
625 antennas 30.0 feet above ground level (AGL). If the \fI-metric\fP
626 switch is used, the argument following the \fI-c\fP switch is
627 interpreted as being in meters rather than in feet. The contents
628 of \fIcities.dat\fP are plotted on the map, as are the cartographic
629 boundaries contained in the file \fIco34_d00.dat\fP.
631 When plotting line-of-sight paths and areas of regional coverage,
632 \fBSPLAT!\fP by default does not account for the effects of
633 atmospheric bending. However, this behavior may be modified
634 by using the Earth radius multiplier (\fI-m\fP) switch:
636 \fCsplat -t wnjt-dt -c 30.0 -m 1.333 -s cities.dat -b counties.dat -o map.ppm\fR
638 An earth radius multiplier of 1.333 instructs \fBSPLAT!\fP to use
639 the "four-thirds earth" model for line-of-sight propagation analysis.
640 Any appropriate earth radius multiplier may be selected by the user.
642 When performing a regional analysis, \fBSPLAT!\fP generates a
643 site report for each station analyzed. \fBSPLAT!\fP site reports
644 contain details of the site's geographic location, its height above
645 mean sea level, the antenna's height above mean sea level, the
646 antenna's height above average terrain, and the height of the
647 average terrain calculated toward the bearings of 0, 45, 90, 135,
648 180, 225, 270, and 315 degrees azimuth.
649 .SH DETERMINING MULTIPLE REGIONS OF LOS COVERAGE
650 \fBSPLAT!\fP can also display line-of-sight coverage areas for as
651 many as four separate transmitter sites on a common topographic map.
654 \fCsplat -t site1 site2 site3 site4 -c 10.0 -metric -o network.ppm\fR
656 plots the regional line-of-sight coverage of site1, site2, site3,
657 and site4 based on a receive antenna located 10.0 meters above ground
658 level. A topographic map is then written to the file \fInetwork.ppm\fP.
659 The line-of-sight coverage area of the transmitters are plotted as
660 follows in the colors indicated (along with their corresponding RGB
664 site1: Green (0,255,0)
665 site2: Cyan (0,255,255)
666 site3: Medium Violet (147,112,219)
667 site4: Sienna 1 (255,130,71)
669 site1 + site2: Yellow (255,255,0)
670 site1 + site3: Pink (255,192,203)
671 site1 + site4: Green Yellow (173,255,47)
672 site2 + site3: Orange (255,165,0)
673 site2 + site4: Dark Sea Green 1 (193,255,193)
674 site3 + site4: Dark Turquoise (0,206,209)
676 site1 + site2 + site3: Dark Green (0,100,0)
677 site1 + site2 + site4: Blanched Almond (255,235,205)
678 site1 + site3 + site4: Medium Spring Green (0,250,154)
679 site2 + site3 + site4: Tan (210,180,140)
681 site1 + site2 + site3 + site4: Gold2 (238,201,0)
684 If separate \fI.qth\fP files are generated, each representing a common
685 site location but a different antenna height, a single topographic map
686 illustrating the regional coverage from as many as four separate
687 locations on a single tower may be generated by \fBSPLAT!\fP.
688 .SH PATH LOSS ANALYSIS
689 If the \fI-c\fP switch is replaced by a \fI-L\fP switch, a
690 Longley-Rice path loss map for a transmitter site may be generated:
692 \fCsplat -t wnjt -L 30.0 -s cities.dat -b co34_d00.dat -o path_loss_map\fR
694 In this mode, \fBSPLAT!\fP generates a multi-color map illustrating
695 expected signal levels in areas surrounding the transmitter site. A
696 legend at the bottom of the map correlates each color with a specific
697 path loss range in decibels.
699 The \fI-db\fP switch allows a threshold to be set beyond which contours
700 will not be plotted on the map. For example, if a path loss beyond -140 dB
701 is irrelevant to the survey being conducted, \fBSPLAT!\fP's path loss plot
702 can be constrained to the region bounded by the 140 dB attenuation contour
705 \fCsplat -t wnjt-dt -L 30.0 -s cities.dat -b co34_d00.dat -db 140 -o plot.ppm\fR
707 The path loss contour threshold may be expressed as either a positive or
710 The path loss analysis range may be modified to a user-specific
711 distance using the \fI-R\fP switch. The argument must be given in miles
712 (or kilometers if the \fI-metric\fP switch is used). If a range wider
713 than the generated topographic map is specified, \fBSPLAT!\fP will
714 perform Longley-Rice path loss calculations between all four corners
715 of the area prediction map.
717 The colors used to illustrate contour regions in \fBSPLAT!\fP generated
718 coverage maps may be tailored by the user by creating or modifying
719 \fBSPLAT!\fP's color definition files. \fBSPLAT!\fP color definition
720 files have the same base name as the transmitter's \fI.qth\fP file,
721 but carry \fI.lcf\fP, \fI.scf\fP, and \fI.dcf\fP extensions. If the
722 necessary file does not exist in the current working when \fBSPLAT!\fP
723 is run, a file containing default color definition parameters that
724 is suitable for manual editing by the user is written into the current
727 When a regional Longley-Rice analysis is performed and the transmitter's
728 ERP is not specified or is zero, a \fI.lcf\fP path loss color
729 definition file corresponding to the transmitter site (\fI.qth\fP) is
730 read by \fBSPLAT!\fP from the current working directory. If a \fI.lcf\fP
731 file corresponding to the transmitter site is not found, then a default
732 file suitable for manual editing by the user is automatically generated
735 A path loss color definition file possesses the following structure
739 ; SPLAT! Auto-generated Path-Loss Color Definition ("wnjt-dt.lcf") File
741 ; Format for the parameters held in this file is as follows:
743 ; dB: red, green, blue
745 ; ...where "dB" is the path loss (in dB) and
746 ; "red", "green", and "blue" are the corresponding RGB color
747 ; definitions ranging from 0 to 255 for the region specified.
749 ; The following parameters may be edited and/or expanded
750 ; for future runs of SPLAT! A total of 32 contour regions
751 ; may be defined in this file.
772 If the path loss is less than 80 dB, the color Red (RGB = 255, 0, 0) is
773 assigned to the region. If the path loss is greater than or equal to
774 80 dB, but less than 90 db, then Dark Orange (255, 128, 0) is assigned
775 to the region. Orange (255, 165, 0) is assigned to regions having a
776 path loss greater than or equal to 90 dB, but less than 100 dB, and
777 so on. Greyscale terrain is displayed beyond the 230 dB path loss
779 .SH FIELD STRENGTH ANALYSIS
780 If the transmitter's effective radiated power (ERP) is specified in
781 the transmitter's \fI.lrp\fP file, or expressed on the command-line using
782 the \fI-erp\fP switch, field strength contours referenced to decibels
783 over one microvolt per meter (dBuV/m) rather than path loss are produced:
785 \fCsplat -t wnjt-dt -L 30.0 -erp 46000 -db 30 -o plot.ppm\fR
787 The \fI-db\fP switch can be used in this mode as before to limit the
788 extent to which field strength contours are plotted. When plotting
789 field strength contours, however, the argument given is interpreted
790 as being expressed in dBuV/m.
792 \fBSPLAT!\fP field strength color definition files share a very
793 similar structure to \fI.lcf\fP files used for plotting path loss:
796 ; SPLAT! Auto-generated Signal Color Definition ("wnjt-dt.scf") File
798 ; Format for the parameters held in this file is as follows:
800 ; dBuV/m: red, green, blue
802 ; ...where "dBuV/m" is the signal strength (in dBuV/m) and
803 ; "red", "green", and "blue" are the corresponding RGB color
804 ; definitions ranging from 0 to 255 for the region specified.
806 ; The following parameters may be edited and/or expanded
807 ; for future runs of SPLAT! A total of 32 contour regions
808 ; may be defined in this file.
826 If the signal strength is greater than or equal to 128 dB over 1 microvolt
827 per meter (dBuV/m), the color Red (255, 0, 0) is displayed for the region.
828 If the signal strength is greater than or equal to 118 dBuV/m, but less than
829 128 dBuV/m, then the color Orange (255, 165, 0) is displayed, and so on.
830 Greyscale terrain is displayed for regions with signal strengths less than
833 Signal strength contours for some common VHF and UHF broadcasting services
834 in the United States are as follows:
840 Analog Television Broadcasting
841 ------------------------------
842 Channels 2-6: City Grade: >= 74 dBuV/m
843 Grade A: >= 68 dBuV/m
844 Grade B: >= 47 dBuV/m
845 --------------------------------------------
846 Channels 7-13: City Grade: >= 77 dBuV/m
847 Grade A: >= 71 dBuV/m
848 Grade B: >= 56 dBuV/m
849 --------------------------------------------
850 Channels 14-69: Indoor Grade: >= 94 dBuV/m
851 City Grade: >= 80 dBuV/m
852 Grade A: >= 74 dBuV/m
853 Grade B: >= 64 dBuV/m
855 Digital Television Broadcasting
856 -------------------------------
857 Channels 2-6: City Grade: >= 35 dBuV/m
858 Service Threshold: >= 28 dBuV/m
859 --------------------------------------------
860 Channels 7-13: City Grade: >= 43 dBuV/m
861 Service Threshold: >= 36 dBuV/m
862 --------------------------------------------
863 Channels 14-69: City Grade: >= 48 dBuV/m
864 Service Threshold: >= 41 dBuV/m
866 NOAA Weather Radio (162.400 - 162.550 MHz)
867 ------------------------------------------
868 Reliable: >= 18 dBuV/m
869 Not reliable: < 18 dBuV/m
870 Unlikely to receive: < 0 dBuV/m
872 FM Radio Broadcasting (88.1 - 107.9 MHz)
873 ----------------------------------------
874 Analog Service Contour: 60 dBuV/m
875 Digital Service Contour: 65 dBuV/m
878 .SH RECEIVED POWER LEVEL ANALYSIS
879 If the transmitter's effective radiated power (ERP) is specified in
880 the transmitter's \fI.lrp\fP file, or expressed on the command-line using
881 the \fI-erp\fP switch, and the \fI-dbm\fP switch is invoked, received
882 power level contours referenced to decibels over one milliwatt (dBm)
885 \fCsplat -t wnjt-dt -L 30.0 -erp 46000 -dbm -db -100 -o plot.ppm\fR
887 The \fI-db\fP switch can be used to limit the extent to which received
888 power level contours are plotted. When plotting power level contours,
889 the argument given is interpreted as being expressed in dBm.
891 \fBSPLAT!\fP received power level color definition files share a very
892 similar structure to the color definition files described earlier,
893 except that the power levels in dBm may be either positive or negative,
894 and are limited to a range between +40 dBm and -200 dBm:
897 ; SPLAT! Auto-generated DBM Signal Level Color Definition ("wnjt-dt.dcf") File
899 ; Format for the parameters held in this file is as follows:
901 ; dBm: red, green, blue
903 ; ...where "dBm" is the received signal power level between +40 dBm
904 ; and -200 dBm, and "red", "green", and "blue" are the corresponding
905 ; RGB color definitions ranging from 0 to 255 for the region specified.
907 ; The following parameters may be edited and/or expanded
908 ; for future runs of SPLAT! A total of 32 contour regions
909 ; may be defined in this file.
930 .SH ANTENNA RADIATION PATTERN PARAMETERS
931 Normalized field voltage patterns for a transmitting antenna's horizontal
932 and vertical planes are imported automatically into \fBSPLAT!\fP when a
933 path loss, field strength, or received power level coverage analysis is
934 performed. Antenna pattern data is read from a pair of files having
935 the same base name as the transmitter and LRP files, but with \fI.az\fP
936 and \fI.el\fP extensions for azimuth and elevation pattern files,
937 respectively. Specifications regarding pattern rotation (if any) and
938 mechanical beam tilt and tilt direction (if any) are also contained
939 within \fBSPLAT!\fP antenna pattern files.
941 For example, the first few lines of a \fBSPLAT!\fP azimuth pattern file
942 might appear as follows (\fIkvea.az\fP):
957 The first line of the \fI.az\fP file specifies the amount of azimuthal
958 pattern rotation (measured clockwise in degrees from True North) to be
959 applied by \fBSPLAT!\fP to the data contained in the \fI.az\fP file.
960 This is followed by azimuth headings (0 to 360 degrees) and their associated
961 normalized field patterns (0.000 to 1.000) separated by whitespace.
963 The structure of \fBSPLAT!\fP elevation pattern files is slightly different.
964 The first line of the \fI.el\fP file specifies the amount of mechanical
965 beam tilt applied to the antenna. Note that a \fIdownward tilt\fP
966 (below the horizon) is expressed as a \fIpositive angle\fP, while an
967 \fIupward tilt\fP (above the horizon) is expressed as a \fInegative angle\fP.
968 This data is followed by the azimuthal direction of the tilt, separated by
971 The remainder of the file consists of elevation angles and their
972 corresponding normalized voltage radiation pattern (0.000 to 1.000)
973 values separated by whitespace. Elevation angles must be specified
974 over a -10.0 to +90.0 degree range. As was the convention with mechanical
975 beamtilt, \fInegative elevation angles\fP are used to represent elevations
976 \fIabove the horizon\fP, while \fIpositive angles\fP represents elevations
977 \fIbelow the horizon\fP.
979 For example, the first few lines a \fBSPLAT!\fP elevation pattern file
980 might appear as follows (\fIkvea.el\fP):
995 In this example, the antenna is mechanically tilted downward 1.1 degrees
996 towards an azimuth of 130.0 degrees.
998 For best results, the resolution of azimuth pattern data should be
999 specified to the nearest degree azimuth, and elevation pattern data
1000 resolution should be specified to the nearest 0.01 degrees. If the
1001 pattern data specified does not reach this level of resolution,
1002 \fBSPLAT!\fP will interpolate the values provided to determine the
1003 data at the required resolution, although this may result in a loss
1005 .SH EXPORTING AND IMPORTING REGIONAL CONTOUR DATA
1006 Performing a regional coverage analysis based on a Longley-Rice
1007 path analysis can be a very time consuming process, especially if
1008 the analysis is performed repeatedly to discover what effects changes
1009 to a transmitter's antenna radiation pattern make to the predicted
1012 This process can be expedited by exporting the contour data produced
1013 by \fBSPLAT!\fP to an alphanumeric output \fI(.ano)\fP file. The data
1014 contained in this file can then be modified to incorporate antenna
1015 pattern effects, and imported back into \fBSPLAT!\fP to quickly
1016 produce a revised contour map. Depending on the way in which
1017 \fBSPLAT!\fP is invoked, alphanumeric output files can describe
1018 regional path loss, signal strength, or received signal power levels.
1020 For example, an alphanumeric output file containing path loss information
1021 can be generated by \fBSPLAT!\fP for a receive site 30 feet above ground
1022 level over a 50 mile radius surrounding a transmitter site to a maximum
1023 path loss of 140 dB (assuming ERP is not specified in the transmitter's
1024 \fI.lrp \fPfile) using the following syntax:
1026 \fCsplat -t kvea -L 30.0 -R 50.0 -db 140 -ano pathloss.dat\fR
1028 If ERP is specified in the \fI.lrp\fP file or on the command line through
1029 the \fI-erp\fP switch, the alphanumeric output file will instead contain
1030 predicted field values in dBuV/m. If the \fI-dBm\fP command line switch
1031 is used, then the alphanumeric output file will contain receive signal
1032 power levels in dBm.
1034 \fBSPLAT!\fP alphanumeric output files can exceed many hundreds of
1035 megabytes in size. They contain information relating to the boundaries
1036 of the region they describe followed by latitudes (degrees North),
1037 longitudes (degrees West), azimuths (referenced to True North),
1038 elevations (to the first obstruction), followed by either path loss
1039 (in dB), received field strength (in dBuV/m), or received signal
1040 power level (in dBm) \fBwithout regard to the transmitting antenna's
1041 radiation pattern\fP.
1043 The first few lines of a \fBSPLAT!\fP alphanumeric output file could
1044 take on the following appearance (\fIpathloss.dat\fP):
1047 119, 117 ; max_west, min_west
1048 35, 34 ; max_north, min_north
1049 34.2265424, 118.0631096, 48.199, -32.747, 67.70
1050 34.2270358, 118.0624421, 48.199, -19.161, 73.72
1051 34.2275292, 118.0617747, 48.199, -13.714, 77.24
1052 34.2280226, 118.0611072, 48.199, -10.508, 79.74
1053 34.2290094, 118.0597723, 48.199, -11.806, 83.26 *
1054 34.2295028, 118.0591048, 48.199, -11.806, 135.47 *
1055 34.2299962, 118.0584373, 48.199, -15.358, 137.06 *
1056 34.2304896, 118.0577698, 48.199, -15.358, 149.87 *
1057 34.2314763, 118.0564348, 48.199, -15.358, 154.16 *
1058 34.2319697, 118.0557673, 48.199, -11.806, 153.42 *
1059 34.2324631, 118.0550997, 48.199, -11.806, 137.63 *
1060 34.2329564, 118.0544322, 48.199, -11.806, 139.23 *
1061 34.2339432, 118.0530971, 48.199, -11.806, 139.75 *
1062 34.2344365, 118.0524295, 48.199, -11.806, 151.01 *
1063 34.2349299, 118.0517620, 48.199, -11.806, 147.71 *
1064 34.2354232, 118.0510944, 48.199, -15.358, 159.49 *
1065 34.2364099, 118.0497592, 48.199, -15.358, 151.67 *
1068 Comments can be placed in the file if they are proceeded by a semicolon
1069 character. The \fBvim\fP text editor has proven capable of editing
1072 Note as was the case in the antenna pattern files, negative elevation
1073 angles refer to upward tilt (above the horizon), while positive angles
1074 refer to downward tilt (below the horizon). These angles refer to the
1075 elevation to the receiving antenna at the height above ground level
1076 specified using the \fI-L\fP switch \fIif\fP the path between transmitter
1077 and receiver is unobstructed. If the path between the transmitter
1078 and receiver is obstructed, an asterisk (*) is placed on the end of
1079 the line, and the elevation angle returned by \fBSPLAT!\fP refers the
1080 elevation angle to the first obstruction rather than the geographic
1081 location specified on the line. This is done in response to the fact
1082 that the Longley-Rice model considers the energy reaching a distant point
1083 over an obstructed path to be the result of the energy scattered over
1084 the top of the first obstruction along the path. Since energy cannot
1085 reach the obstructed location directly, the actual elevation angle to
1086 the destination over such a path becomes irrelevant.
1088 When modifying \fBSPLAT!\fP path loss files to reflect antenna
1089 pattern data, \fIonly the last numeric column\fP should be amended
1090 to reflect the antenna's normalized gain at the azimuth and elevation
1091 angles specified in the file. Programs and scripts capable of
1092 performing this task are left as an exercise for the user.
1094 Modified alphanumeric output files can be imported back into \fBSPLAT!\fP
1095 for generating revised coverage maps provided that the ERP and -dBm options
1096 are used as they were when the alphanumeric output file was originally
1099 \fCsplat -t kvea -ani pathloss.dat -s city.dat -b county.dat -o map.ppm\fR
1101 Note that alphanumeric output files generated by \fCsplat\fR cannot
1102 be used with \fCsplat-hd\fR, or vice-versa due to the resolution
1103 incompatibility between the two versions of the program. Also, each of
1104 the three types of alphanumeric output files are incompatible with one
1105 another, so a file containing path loss data cannot be imported into
1106 \fBSPLAT!\fR to produce signal strength or received power level contours, etc.
1107 .SH USER-DEFINED TERRAIN INPUT FILES
1108 A user-defined terrain file is a user-generated text file containing
1109 latitudes, longitudes, and heights above ground level of specific terrain
1110 features believed to be of importance to the \fBSPLAT!\fP analysis
1111 being conducted, but noticeably absent from the SDF files being used.
1112 A user-defined terrain file is imported into a \fBSPLAT!\fP analysis
1113 using the \fI-udt\fP switch:
1115 \fC splat -t tx_site -r rx_site -udt udt_file.txt -o map.ppm\fR
1117 A user-defined terrain file has the following appearance and structure:
1120 40.32180556, 74.1325, 100.0 meters
1121 40.321805, 74.1315, 300.0
1122 40.3218055, 74.1305, 100.0 meters
1125 Terrain height is interpreted as being described in feet above ground
1126 level unless followed by the word \fImeters\fP, and is added \fIon top of\fP
1127 the terrain specified in the SDF data for the locations specified. Be
1128 aware that each user-defined terrain feature specified will be interpreted
1129 as being 3-arc seconds in both latitude and longitude in \fCsplat\fR and
1130 1 arc-second in latitude and longitude in \fCsplat-hd\fR. Features
1131 described in the user-defined terrain file that overlap previously
1132 defined features in the file are ignored by \fBSPLAT!\fP to avoid
1135 The height of ground clutter can be specified using the \fI-gc\fP switch:
1138 splat -t wnjt-dt -r kd2bd -gc 30.0 -H wnjt-dt_path.png
1141 The \fI-gc\fP switch as the effect of raising the overall terrain by the
1142 specified amount in feet (or meters if the \fI-metric\fP switch is invoked),
1143 except over areas at sea-level and at the transmitting and receiving
1144 antenna locations. Note that the addition of ground clutter does not
1145 necessarily modify the Longley-Rice path loss results unless the additional
1146 clutter height results in a switch in the propagation mode from a less
1147 obstructed path to a more obstructed path (from Line Of Sight to Single
1148 Horizon Diffraction Dominant, for example). It does, however, affect
1149 Fresnel zone clearances and line of sight determinations.
1150 .SH SIMPLE TOPOGRAPHIC MAP GENERATION
1151 In certain situations it may be desirable to generate a topographic map
1152 of a region without plotting coverage areas, line-of-sight paths, or
1153 generating obstruction reports. There are several ways of doing this.
1154 If one wishes to generate a topographic map illustrating the location
1155 of a transmitter and receiver site along with a brief text report
1156 describing the locations and distances between the sites, the \fI-n\fP
1157 switch should be invoked as follows:
1159 \fCsplat -t tx_site -r rx_site -n -o topo_map.ppm\fR
1161 If no text report is desired, then the \fI-N\fP switch is used:
1163 \fCsplat -t tx_site -r rx_site -N -o topo_map.ppm\fR
1165 If a topographic map centered about a single site out to a minimum
1166 specified radius is desired instead, a command similar to the following
1169 \fCsplat -t tx_site -R 50.0 -s NJ_Cities -b NJ_Counties -o topo_map.ppm\fR
1171 where -R specifies the minimum radius of the map in miles (or kilometers
1172 if the \fI-metric\fP switch is used). Note that the tx_site name and
1173 location are not displayed in this example. If display of this information
1174 is desired, simply create a \fBSPLAT!\fP city file (\fI-s\fP option) and
1175 append it to the list of command-line options illustrated above.
1177 If the \fI-o\fP switch and output filename are omitted in these
1178 operations, topographic output is written to a file named \fItx_site.ppm\fP
1179 in the current working directory by default.
1180 .SH GEOREFERENCE FILE GENERATION
1181 Topographic, coverage (\fI-c\fP), and path loss contour (\fI-L\fP) maps
1182 generated by \fBSPLAT!\fP may be imported into \fBXastir\fP (X Amateur
1183 Station Tracking and Information Reporting) software by generating a
1184 georeference file using \fBSPLAT!\fP's \fI-geo\fP switch:
1186 \fCsplat -t kd2bd -R 50.0 -s NJ_Cities -b NJ_Counties -geo -o map.ppm\fR
1188 The georeference file generated will have the same base name as the
1189 \fI-o\fP file specified, but have a \fI .geo\fP extension, and permit
1190 proper interpretation and display of \fBSPLAT!\fP's .ppm graphics in
1191 \fBXastir\fP software.
1192 .SH GOOGLE MAP KML FILE GENERATION
1193 Keyhole Markup Language files compatible with \fBGoogle Earth\fP may
1194 be generated by \fBSPLAT!\fP when performing point-to-point or regional
1195 coverage analyses by invoking the \fI-kml\fP switch:
1197 \fCsplat -t wnjt-dt -r kd2bd -kml\fR
1199 The KML file generated will have the same filename structure as a
1200 Path Analysis Report for the transmitter and receiver site names given,
1201 except it will carry a \fI .kml\fP extension.
1203 Once loaded into \fBGoogle Earth\fP (File --> Open), the KML file
1204 will annotate the map display with the names of the transmitter and
1205 receiver site locations. The viewpoint of the image will be from the
1206 position of the transmitter site looking towards the location of the
1207 receiver. The point-to-point path between the sites will be displayed
1208 as a white line while the RF line-of-sight path will be displayed in
1209 green. \fBGoogle Earth\fP's navigation tools allow the user to
1210 "fly" around the path, identify landmarks, roads, and other
1213 When performing regional coverage analysis, the \fI .kml\fP file
1214 generated by \fBSPLAT!\fP will permit path loss or signal strength contours
1215 to be layered on top of \fBGoogle Earth\fP's display in a semi-transparent
1216 manner. The generated \fI.kml\fP file will have the same basename as
1217 that of the \fI.ppm\fP file normally generated.
1218 .SH DETERMINATION OF ANTENNA HEIGHT ABOVE AVERAGE TERRAIN
1219 \fBSPLAT!\fP determines antenna height above average terrain (HAAT)
1220 according to the procedure defined by Federal Communications Commission
1221 Part 73.313(d). According to this definition, terrain elevations along
1222 eight radials between 2 and 10 miles (3 and 16 kilometers) from the site
1223 being analyzed are sampled and averaged for each 45 degrees of azimuth
1224 starting with True North. If one or more radials lie entirely over water
1225 or over land outside the United States (areas for which no USGS topography
1226 data is available), then those radials are omitted from the calculation
1229 Note that SRTM-3 elevation data, unlike older USGS data, extends beyond
1230 the borders of the United States. Therefore, HAAT results may not be
1231 in full compliance with FCC Part 73.313(d) in areas along the borders
1232 of the United States if the SDF files used by \fBSPLAT!\fP are SRTM-derived.
1234 When performing point-to-point terrain analysis, \fBSPLAT!\fP determines
1235 the antenna height above average terrain only if enough topographic
1236 data has already been loaded by the program to perform the point-to-point
1237 analysis. In most cases, this will be true, unless the site in question
1238 does not lie within 10 miles of the boundary of the topography data in
1241 When performing area prediction analysis, enough topography data is
1242 normally loaded by \fBSPLAT!\fP to perform average terrain calculations.
1243 Under such conditions, \fBSPLAT!\fP will provide the antenna height
1244 above average terrain as well as the average terrain above mean sea
1245 level for azimuths of 0, 45, 90, 135, 180, 225, 270, and 315 degrees,
1246 and include such information in the generated site report. If one or
1247 more of the eight radials surveyed fall over water, or over regions
1248 for which no SDF data is available, \fBSPLAT!\fP reports \fINo Terrain\fP
1249 for the radial paths affected.
1250 .SH ADDITIONAL INFORMATION
1251 The latest news and information regarding \fBSPLAT!\fP software is
1252 available through the official \fBSPLAT!\fP software web page located
1253 at: \fIhttp://www.qsl.net/kd2bd/splat.html\fP.
1256 John A. Magliacane, KD2BD <\fIkd2bd@amsat.org\fP>
1257 Creator, Lead Developer
1259 Doug McDonald <\fImcdonald@scs.uiuc.edu\fP>
1260 Original Longley-Rice Model integration
1262 Ron Bentley <\fIronbentley@embarqmail.com\fP>
1263 Fresnel Zone plotting and clearance determination