These are recordings from VLF stations received with LA8AK active antenna (4C) and a homebrew upconverter.

DCF77 77.5 KHz

75.0 KHz

60.0 KHz

66.66 KHz

18.1 KHz

11.9 KHz

12.65 KHz

14.88 KHz

18.1 KHz

18.1 KHz

18.3 KHz

18.9 KHz

19.6 KHz

20.2 KHz

20.9 KHz

22.1kHz

24.0kHz

26.7kHz

37.5kHz

40.75kHz

45.9kHz