I am getting fond of QGIS but I am unable to find tools for frequency plannig and other stuff. Are there any alternative to MIPT and Discover of Mapinfo in QGIS?
It seems that this tool http://www.qrap.org.za/ should do what is required. The source is available (is a C++ plugin for QGIS) but a binary is available only for Linux. Try contact the author and see if they provide support for Windows.