Strange “stairs” received from a lot of european stations over 13kHz Some idea about this? #VLF #hamradio #hamr #swl https://t.co/6mOqNnJrRJ
Strange “stairs” received from a lot of european stations over 13kHz Some idea about this? #VLF #hamradio #hamr #swl https://t.co/6mOqNnJrRJ