Thanks to Rick for the permission to publish his data here. Signals marked with mb- are checked By Marco Bruno, IK1ODO, from Torino, Italy. Signals marked with DG4BAS are checked By Manfred Kerckhoff, DG4BAS, from Bremen, Germany. The list is very tentative. Any addition or correction is welcome.
Data come from different sources and cross-checking is sometimes confusing.
The frequency colours in a list represent the band, as shown below. Hz 30 Hz 21.4 kHz NPM Lualualei in Hawaii - USN station. 21.1 kHz 3SB, Datong, Peoples Republic of China. 2208, CW heard up to -80, about 10 wpm. 20.6 kHz 3SB, see also 19.5 KHz.