When I designed the downconverter Convertino, I wanted to test it with a concrete application. The ADS-B airplan trasponders send signal at 1090 MHz so this frequency perfectly fit to test this kind of downconverter. After I set the local oscillator of Convertino to 1175 MHz, I could see the ADS-B signal downconverted to 85 MHz (1175-1090=85). The only thing I needed was an ADS-B software decoder with settable carrier frequency. ADSB# is a well knew ADS-B decoder but it doesn’t allow to set the carrier frequency because it is supposed to be always 1090 MHz. I was lucky to find the source code of an old version of ADSB# so using Visual Studio, I modified the program adding a textbox to set the carrier frequency as needed. The source code and the exe file of the modified ADSB# is available here, the exe file is in the ADSBSharp\bin\Debug folder. Using adsbSCOPE with the modded version of ADSB# tuned on 85 MHz, I could see some airplane positions. With this experiment I took the concrete demostration Convertino really work and I got the first data about its RF input sesitivity.
Luigi Findanno Makes 