splat-scripts

Scripts to run the Splat! radio terrain mapping tool.

Dependencies

This was built and tested on Debian Jessie (8.0) with the following versions:

ii  splat          1.4.0-2       amd64        analyze point-to-point terrestria
ii  bc             1.06.95-9     amd64        GNU bc arbitrary precision calcul
ii  coreutils      8.23-4        amd64        GNU core utilities
ii  imagemagick    8:6.8.9.9-5   amd64        image manipulation programs -- bi
ii  optipng        0.7.5-1       amd64        advanced PNG (Portable Network Gr
ii  sed            4.2.2-4+b1    amd64        The GNU sed stream editor
ii  wget           1.16-1        amd64        retrieves files from the web
ii  unzip          6.0-16+deb8u2 amd64        De-archiver for .zip files
ii  time           1.7-25        amd64        The GNU time program for measuring cpu resource usage

Success was also reported on Ubuntu, FreeBSD, and OpenBSD.

Configuration

Edit the shell scripts to set the paths for the SDF elevation files and the political borders file.

To download and convert the SRTM data use the get-datafiles*.sh scripts. Go get some coffee while this runs, it will take a while. After it is completed, you should be able to run the example profile as below.

If interrupted, the retrieval of the SRTM *hgt.zip files over the network can be restarted and will resume where it left off.

Note the following disk space requirements to complete the data conversion:

• Africa: 5.4 GB
• Australia: 1.2 GB
• Eurasia: 9.0 GB
• Islands: 92 MB
• North America: 3.6 GB
• South America: 3.3 GB
• All: 23 GB

The *hgt.zip files are not required after conversion, but they are not removed by the script. They are retained so that a new run may commence without downloading all the files again from the server. This happens via the wget -N option.

After removing the *hgt.zip files, disk space required for operations comes down to:

• Africa: 2.1 GB
• Australia: 434 MB
• Eurasia 3.4 GB
• Islands: 36 MB
• North America: 1.4 GB
• South America: 1.3 GB
• All: 8.5 GB

Usage

$ ./splat-radio.sh example.cfg

$ cat example.cfg
NAME="example"
CALL="KQ2H"
LAT="40.7484931946"
LON="-73.9856567383"
HTAGL="373m"
ERP="250"
FREQMHZ="449.2250"

Parameters are as follows:

• NAME: used to uniquely name files
• CALL: will be labeled onto the map
• LAT: latitude, decimal degrees
• LON: longitude, decimal degrees (East is positive)
• HTAGL: height above ground level -- without units the default is in feet; use a "m" suffix for meters (e.g. "30" means 30 feet; "10m" means 10 meters)
• ERP: effective radiated power in Watts -- be sure you take feedline loss and antenna gain into account; enter ERP="0" to produce path loss plots
• FREQMHZ: frequency in MHz

Output

Full resolution here

Height above average terrain, in feet

Prediction and propagation notes

These predictions are configured to estimate a simplex contact, with a receiver station at 2 meters (6 feet), similar to a mobile station. This is not a valid prediction for access to repeater stations on towers. This of course can be changed by editing the splat-radio.sh script.

The model does not take reflections and multipath into account.

Defaults were chosen for things like ground permeativity and other parameters. Adjust as needed if your situation warrants it.

To do

• More error checking.