SPLAT! RF Signal Propagation, Loss, And Terrain Analysis Tool

November 14, 2010 – SPLAT! Version 1.3.1 and GUI Version 1.1.2 Available

SPLAT map I’ve spent quite a bit of time on this program by John A. Magliacane – KD2BD, so it gets its own section. In addition to the program link, I’ve included some of the Canada/Ontario overlays since they were difficult to obtain. A Windows/Linux GUI is also available – there are a few finishing touches and some debugging to be done, but a beta version 1.1.2 is now posted as of November 14, 2010.

This Windows interface will generate most combinations of command lines to operate SPLAT, and also includes file conversion utilities. A function to import an azimuth pattern from antennas modeled in 4NEC2 is now implemented, and parameters can be saved for later recall. A choice of maximum pages and resolution modes is made by selecting the desired option. This program is built around Version 1.3.1 of SPLAT, and it’s all made freely available. Download it below.

SPLAT with Windows GUI – BETA – This is an updated version 1.1.2. All previous bugfixes are included. Release 1.0.2 fixed a bug where multiple transmitter sites were ignored. Thanks to Ben Myers for beta testing the program and catching that error. Version 1.0.2 also repairs the disappearing “Radius to Plot” box, caught by John McInnes.

New to this version, support for 4NEC2 antenna azimuth plots is added, and all parameters can be saved and loaded now. A bug with the -t switch on some configurations has been fixed. The GUI now uses my updated port of SPLAT 1.3.1 with many bugfixes, which is included in the package.

This software is BETA! There may be errors and bugs. There is no guarantee it will do what you want. It is released, probably prematurely, in the hope it will be useful. Some parts don’t do anything yet. Screen shot.


Run the setup program. All the SPLAT executables are included. You don’t need to download these separately. If you already have SPLAT, you can install the update right over top of the existing version. Check the README file for more details and version information.

Warning – I know that SPLAT isn’t going to like the Windows default “Program Files” location due to the space in the file name. If you can, install SPLAT directly to “C:\SPLAT” from the setup program. Make sure that all file names and folders used with SPLAT do not use spaces. If you can’t install there directly, MOVE everything there later to keep the DOS applications happy. Update any menu shortcuts to the new location.

Run Splat.exe. It will create sub folders and copy conversion programs the first time it runs. If you already have the proper SDF files someplace, copy them into the correct folder that the program created. Do not mix up SD and HD .sdf files.

For new installations, download the required HGT files at http://dds.cr.usgs.gov/srtm/version2_1/SRTM3/ and unzip them to the “sdf-sd” folder.

If using HD terrain data, available for the United States only, download these from http://dds.cr.usgs.gov/srtm/version2_1/SRTM1/ and unzip them into the “sdf-hd” folder.

Convert them to proper .sdf files using the utility on the “Tools” menu. You can and should select multiple files at a time – hit CTRL+A to select them all. The SD and HD folders must be processed separately, using the right tool.

Now you are ready to try SPLAT. Select the type of analysis you want to perform, and set the options. Unavailable options are hidden.

All the rules for transmitter and receiver files must be observed according to the SPLAT documentation. You can edit QTH and LRP files by clicking the appropriate button. A crude text version of SPLAT documentation is included on the Help menu.

You’ll need to find or make city files and boundary files following the instructions in SPLAT documentation. Some samples are now included.

This Windows GUI is mainly a wrapper to provide SPLAT with the proper command line. A copy of the command line generated is saved as a text file. It can be modified later to add command line arguments and switches not accommodated by the GUI, and this can be run by invoking the proper SPLAT executable from a DOS console. Refer to the SPLAT documentation for further information. If SPLAT itself becomes hung, you’ll need to kill the DOS program in the task manager, not the Windows GUI. This should release the console window in the GUI. Remember that an analysis could take hours, using full CPU, but there should be some activity in the console window to verify proper operation. HD files are very memory and CPU intensive.

There is no warranty or support for this program. It’s a work in progress and may be updated or revised without notice. Check below for revised versions.

It may be freely used and distributed, although the VB source code is copyright. Comments or suggestions are welcome.

SPLAT! is an RF Signal Propagation, Loss, And Terrain analysis tool for the spectrum between 20 MHz and 20 GHz, by John A. Magliacane, KD2BD. SPLAT! provides site engineering data such as the great circle distances and bearings between sites, antenna elevation angles (uptilt), depression angles (downtilt), antenna height above mean sea level, antenna height above average terrain, bearings and distances to known obstructions, path loss and field strength based on the Longley-Rice Irregular Terrain Model, and minimum antenna height requirements needed to establish line-of-sight communication paths and Fresnel Zone clearances absent of obstructions due to terrain. This is a Linux command line program that requires multiple supplementary files for complete functionality. It works, and produces great maps. See below for Windows ports. Visit Doug Lung’s site for more links and articles.
SPLAT! 1.3.1 for Windows – This is my own Windows port of SPLAT v-1.3.1, building on the previous work by John McMellen and my earlier ports. See the official SPLAT documentation for program instructions. This zip file contains executables for all the MAXPAGES combinations for 3 arc-second details, and versions for up to MAXPAGES=36 for 1 arc-second details. Commented source code is included. John McMellen’s ported conversion utilities are updated where needed and included. See the README-FIRST.txt file for more details about operation under Windows. A new port of the srtm2sdf utility is included to handle HD terrain data.

Remember, this is a console application that requires a properly formatted command line, with support files in the appropriate locations. The version posted July 11, 2009 fixed a couple of bugs, and the November 14, 2010 update includes several changes.

Notably, the new itm.cpp file is used, which fixes problems in the Longley-Rice calculations – this was coded by Sid Shumate, and Allen Schultz kindly forwarded it to me for inclusion in my port of SPLAT. Doug Lung has written about the fix at TV Technology, and there is a detailed article in the IEEE Spring 2010 Newsletter. The original ITM (Irregular Terrain Model) was released by NTIA.

My update also handles antenna azimuth files properly now without adding garbage radials. Better feedback to the console was added.

Feedback would be appreciated. This is GNU software that I hope will be useful, but it comes AS IS without any warranty or guarantee.

SRTM2SDF 1.3.0 for Windows – This is my own Windows port of the newest srtm2sdf utility. It can convert the terrain data files from .hgt format to the .sdf format required by SPLAT. This port will handle either standard 3 arc-second files, or the new 1 arc-second files used by SPLAT v-1.3.0. All of John McMellen’s other SPLAT utilities ported for Windows are included in the archive. See the README-FIRST.txt file for more details and usage instructions. It is also included in the Windows version of SPLAT above, and the Windows GUI, so you should download those instead. This is GNU software that I hope will be useful, but it comes AS IS without any warranty or guarantee.
SPLAT! for Win32 – This is my own Windows port of SPLAT v-1.2.3, building on the work by John McMellen . The main improvements are MAXPAGES=16, giving larger maps, and more informative console feedback was added (to make sure SPLAT is running calculations on the files you think). It also fixes calculation of the 0 and 180 degree average height. Commented source code is included, and John McMellen’s port of the conversion utilities is also in the .zip file, along with the documentation. See the README-FIRST.txt file for more details. Run SPLAT-win32.exe for MAXPAGES=16 or SPLAT-win32x.exe for MAXPAGES=25. Remember, this is a console application that requires a properly formatted command line. Feedback would be appreciated. This is GNU software that I hope will be useful, but it comes AS IS without any warranty or guarantee.
SDF helper script – I wrote this simple Linux bash script to quickly batch convert the downloaded .hgt files to the .sdf files required by SPLAT. Follow the instructions in the remarks. Requires the Space Shuttle Radar Topology files – see SPLAT documentation for link. Provided AS IS under the GNU General Public Licence. (Remove the .txt extension and chmod to make executable. Make sure none of the .sdf files in the series are missing.) Note: to use the files in Windows, the “:” must be changed to “x” in the filenames. The Windows GUI (released in beta) will batch convert any files.
Canadian ARC/INFO files SPLAT requires ARC/INFO files in ASCII format to plot boundaries. The SPLAT site links to the American files in .dat format, which work great if the propagation study includes US land. I couldn’t find Canadian files in that format, but this site has ARC/INFO .E00 files. They are available for every region of Canada, in various resolutions, including lakes, rivers, railroads, highways, cities, and counties. Some of these files are huge, and can cause significant clutter on the maps, but I’ve got them to work with SPLAT. First they need to be converted to a format SPLAT recognizes. (I wrote a quick and dirty program to translate the files, contact me if you need it.) There are still a few bugs, like missing closing segments and incomplete overlays, and I’m not sure if the fault lies with SPLAT, my conversion, or the source file. See next for my converted Ontario files.
Ontario ARC/INFO files that I converted for SPLAT from E00 format (beta). The archive includes lakes, rivers, railroads, highways, cities, and counties. The “drainage” file produces the most useful plots. “CK-cities.dat” plots many southern Ontario towns and cities – it’s easy to add your own using coordinates from Google Earth. Also included is a sample command line to plot the VE3KCR repeater. There are still a few bugs in these files, like missing closing segments and incomplete overlays, but my files are currently the only thing I found to work. Put them in your SPLAT directory and include the desired filenames in the command line. They are offered here without guarantee, and are known to have mild defects. US boundaries can be obtained as listed in SPLAT documentation (I included a combined Michigan and Ohio file).

See the rest of my links – my new software pages are here:

Last Updated: Saturday, November 14, 2010, at 23:55