Jim posted a while back - 
http://lists.allstarlink.org/pipermail/app_rpt-users/2013-September/008322.html

About plotting simulcast plots using Splat!. This is the only post I can see about this. Looking in the svn, I can see the simul.c file and various READMES and docos, but no real information on how to compile Splat! for this functionality. I'm also not a Linux buff, but I had a quick go at compiling and I got errors on a test Debian machine I had.

Has anyone gotten this working, or do you use an alternate like Radio Mobile? I've used Radio Mobile's online plotter, but this doesn't include simulcast support.

http://radiomobile.pe1mew.nl/?How_to:Combined_Cartesian:Simulcast&q=simulcast