LF: Unusual QRN

[MarkusVester@aol.com]

Dear LF group, 

tonight the band seems to be plagued by a high level of background QRN. Not the usual  distinct static crashes, but rather a continous static crackling reminiscent of old 78-rpm shellack records. This type of noise has been present during some nights, but not often. Its southerly angle of arrival went along well with the usual explanation of very distant lightning activity.

But I was stunned when I observed today that it commenced fairly suddenly, within a few seconds around 17:22 UT. Then this would have to be related to some abrupt change of ionospheric properties...?

There is a directional spectrogram at http://members.aol.com/DF6NM/crackle.jpg (66kB). The bright blue vertical strips are "normal" crashes, coming in from west and with slowly decreasing activity. The crackling noises appear at 17:22 as a continuous green haze in the 5s averaging. The audio sample http://members.aol.com/DF6NM/crackle.wav (44kB) was taken later at 19:58 UT.

73 de Markus, DF6NM