Hi Roger,
That's what i'm trying right now. But the frequency is not really
stable, you know. So there is an optimum bandwidth. At 3.8 mHz it looks
to blurry.
Attached is a spectrogram in 15 mHz, covering 1 hour. It looks not much
more convincing :-)
My E field antenna still lacks of sensitivity in the ELF/SLF range but
i already have plans to improve it in the near future.
For the Schumann resonances it is about the same. Something between
20...200 mHz FFT BW should be the optimum.
73, Stefan
Am 21.11.2018 15:21, schrieb Roger Lapthorn:
Yes, I can see it faintly.It would be good to look at 60Hz in a
much narrower bandwidth?
73s
Roger G3XBM
Hi
SLF friends,
Take a look at
http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html
There, on the 4th image from the top you can see a faint but
concentrated trace at 60 Hz. This should be the 60 Hz grid frequency as
used in NA and SA. It has been detected in a smaller bandwidth in the
past, but from this location on the tree, it is the first time that i
see it in 45 mHz FFT bin width.
The QRN is very low these days, in that range!
73, Stefan
PS: At 16 2/3 Hz you can see the German railway power grid changing its
colour, depending on where trains are currently driving.
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