FWIW, that program does work and is worth the donation to
@vma (Vitor) who developed and then progressively improved it
(with a little help from me to clarify and improve the instruction manual!).
HOWEVER it does require careful configuration, and some extra components in the RF feed from the LNB to avoid blowing up either the spec analyser module, or possibly even your PC. Also, the spec analyser module is available in various forms from a number of suppliers and so do take Vitor's advice on what to buy and from where.
Therefore I suggest that you download and carefully study the instruction manual before going any further!