Hello Stefan,

> About 16 kHz: Sometimes there appear traces at 16 kHz as well as on 8 
> kHz but these may be signals caused by some alias effects in the 
> soundcard, sampling at 48 or 96 kS/s and/or caused by NAA/24 kHz. I am 

I use Perseus as the rx, not a soundcard :-)
So that rules out those problems.

> BTW, it would be interesting to see a 0...24 kHz capture of your RX 
> antenna, covering one day.

How about 2 min samples 30 min apart for 24 hours?
I'm recording every 30 minutes for 2 minutes 0-100kHz
Those recordings I later can play back and make waterfalls for specific 
frequencies. That allows me to zoom in on particular events afterwards.
However I don't see what happens within the 28 minutes waiting period. I don't 
want to record 24h as it would take another 24h to produce waterfalls


> I am receiving these traces too, see the lower capture on 
> http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber.html and 
> ignore the 600 Hz spaced QRM lines, caused by the Heidelbergs's tram SMPS...

I had a look there earlier, but the QRM lines made it hard to read.
In your case you could create a SpecLab plug-in that removes these lines before 
they are painted. I did a similar thing for a different purpose. That would 
make your grabber image easier to read.



Jurgen Bartels  Suellwarden, N. Germany
hor. Antennas: 11-ele 45-87MHz 13-ele Band-III, 48-ele UHF, FM: 15.11 
TV: Winradio G305 / Fly2000 + video noise filter & variable IF BW
FM: Downconverter + Perseus + Speclab as WFM demod.
MW: staggered 300m Beverage 320°,  30 x 4m EWE 320°, Winradio & Perseus
http://dx.3sdesign.de/tv_offset_list.htm
http://dx.3sdesign.de/station_list.htm

http://fewo.3sdesign.de  - Vacation home: DX right at the Northsea coast