Hi Stefan, the screenshot generally looks good. There are some 50 Hz harmonics as well as modulated 33 Hz harmonics but neither seems to contaminate the desired frequency range around 9.70 hectoHz. H
Hi Markus, Thanks. I can follow your complex and interesting answer :-) Oh oh i hope the effect you are discribing didn't happen during the recording. It took about 4 m wire for the probe, then there
Hi Jim, Thanks for your feedback. Strong local lightnings, < 200 km, oh yes! My loops on the tree saw the resonance effects from them. See https://www.dropbox.com/s/0p5cxdw89kljok1/Strong%20QRN%20see