Low pass filter 40 meters

Low pass filter 40 meters  homemade for RTLSDR to receive WSPR signals. I used a toroid and two ceramic capacitors, measured with NanoVNA at 7040Khz I get RL 43.71db. First test 7038.6 Khz in WSPR reception with RapberryPi Zero / RTLSDR V.3 and 40 meters homemade wire antenna. Special thanks to our friend Giovanni IT9TZZ.