Ciao, Antonio, IK8XFV has developed an APP for Android to calculate QO-100 NB Transponder Link budget. Here is the link at the Google Play store: https://play.google.com/store/apps/details?id=com.antmodstudios.eshail2linkbudget Please, let us know if results match your experience. . Best 73 de Fabio, IZ5XRC