There was this radio propagation mapping software that would show you how far a wireless signal could go if you placed the antenna somewhere in the world and ga

There was this radio propagation mapping software that would show you how far a wireless signal could go if you placed the antenna somewhere in the world and gave it some parameters. You purchased preset 'lots' of about a square mile containing accurate terrain data to run the simulations, and if you were interested in an area that saddled two patches, you had to buy both (iirc you couldn't just specify arbitrary coordinates). I had to spend some time figuring out how few patches we needed to make it 'worth it', but I don't remember the final figure; it must have been in the 5 digits all said and done?