Not trying to resurrect an old thread, but if you are still looking for other methods this is for HF specific information.
VOACAP (HF Propagation Prediction and Ionospheric Communications Analysis )
http://www.voacap.com/
http://www.voacap.com/overview.html
This package is free and you can download a suite of programs or use part of it online. If anyone is familiar with a program called ITSHF (ITS HF) this is the package where it comes from.
The website has a plethora of tools and knowledge available for learning and predicting wave propagation and planning which freqs to use in a ton of different environments/ time of day/ freqs/ etc....