VO1NA on 8270Hz received in Warsaw

Since a few days one can see a faint line on 8270.0075Hz. This is transmitted by Joe VO1NA from Canada. The distance to Warsaw is 5100km!

Spectrogram with normalized amplitude:

I have received Joe VO1NA in 2017 when he transmitted ebnaut:



You can also see a very strong signal from Stefan DK7FC on 8270.0Hz