What is SignalServer?

'Splat!" is a simulation, originally created by John Magliacane (KD2BD) that can be used to model or predict the coverage that might be obtained from a radio transmitter given a set of parameters which describe that transmitter, the intended receiver, and their respective antenna characteristics. It creates a prediction that takes such variables as terrain features, propagation characteristics, power levels, receiver sensitivities, and other factors into account.

Please see John's Splat! Website for a lot more information.

SignalServer is a 'fork' of 'Splat!' which is capable of taking advantage of modern multi-core machines. The version of SignalServer used by this website is offered by Aaron A. Collins, N9OZB and can be downloaded from here.

The W5GFE SignalServer Site

SignalServer is a command line program with a host of options and may be confusing to persons who are trying to use it for the first time. This website site uses several Perl scripts to offer a web interface to SignalServer. It is a personal effort, undertaken by Bill Walker, W5GFE, who can be reached via w5gfe@arrl.net. (GPG Public Key)

Some additional reading can be found at

SignalServer command line options if you already have SignalServer installed
Downloadable SignalServer Source Code by Aaron A. Collins, N9OZB - used on this website
Individual HGT Files in a downloadable format
ARRL article here
ARRL article here
QEX Article This article is outdated - the user interface has changed and the engine is now SignalServer
Download DragonOS (a Linux distribution) from Sourceforge By Aaron (cemaxecuter@protonmail.com)
Video HowTo use SignalServer on DragonOS By Aaron (cemaxecuter@protonmail.com). DragonOS contains a SignalServer WebSite
Video DEFCON talk including SignalServer on DragonOS By Aaron (cemaxecuter@protonmail.com). DEFCON 29
Video SCARS (Norman Okla) Presentation By Bill W5GFE (w5gfe@arrl.net) April 16, 2022
Some version of this website should always be available here

Using This WebSite

In order to use this website you must 'enroll' your station in the database before you can create plots. This lets you enter boilerplate information only once. As you develop plots you are afforded opportunity to manipulate some of the many parameters which can affect propagation. Reasonable default values are provided, which can be changed as you develop your model.

Why use a database ?

Using a database allows us to capture location information for transmitters across the world, particularly latitude, longitude, and antenna AGL data. We use that information to create an "RF Map of the World", which you are able to download as an option on some of the plots. We also log IP numbers and some other data to help prevent and mitigate abuse of this website.

Can I duplicate this site ?

See this video HowTo By Aaron (cemaxecuter@protonmail.com) for a Linux distribution featuring SignalServer called 'DragonOS Focal', as well as a collection of Software Defined Radio (SDR) programs.

You can also contact Bill W5GFE@arrl.net (GPG Public Key) and ask about obtaining a (free) copy of the Perl scripts used on this website. The site uses Linux, Apache, Perl, ImageMagick, gnuplot, gplot.pl, and MariaDB. It would require a lot of effort to port it to something other than Linux.

Caveat !

SignalServer, like all simulation programs, is at best an approximation of reality. A great many things can disturb the accuracy of the results. Even an inaccurate simulation may be able to provide some guidance to a real world situation, but there is no guarantee that the output is useful for anything. Results provided by this website may or may not be applicable to the 'real world', and should always be interpreted with a large measure of skepticism, so use them at your own risk!