Hi Torben I have also heard this sound many times. I think it is some kind of "Burst systems"
See if you can find something similar to it here: http://signals.taunus.de/TABLES/PSK.HTML 73 de LA5VNA Steinar oz1...@oz1tmk.dk wrote: > > Hello > > Am i the the only operator having this QRM on 80mtrs right now (17:42 > UTC) ? > > Please look at DM780 screen dump, and listen MP3 file here: > > http://www.oz1tmk. dk/80m-qrm/ <http://www.oz1tmk.dk/80m-qrm/> > > I walked downwards and upwards in frequency (you can hear it on the MP3 > file) down > to 3.568 MHz and up to 3.585 MHz to find the span of this QRM. > > Signal levels are around S9 + 10 to 20 > > I >