LF group, tuning at 128.930 kHz, the frequency of the German power utility station, in USB mode, I can hear what is possible to listen to in this 30 sec. MP3 file : http://www.sdradio.eu/audio/luxmbr
Yes Alberto, it sounds like the Luxembourg effect. I have a heard a similar effect many times on DCF39's carrier. The high tones of the modulation are attenuated, probably because of some "thermal in