Hi ELF,

Attached is the resulting spectrogram of the post-processing of the carrier transmission, using optimised filter and blanker parameters. The trace is something like 'O copy' in 212 uHz. It was the first goal of the transmissions on that frequency.
The time stamps are rubbish, the spectrogram covers 36 hours and scrolls at 20 min/pixel.

73, Stefan


Am 07.02.2019 17:05, schrieb DK7FC:

Hi ELF ;-)

I'm glad to announce that since 15:46 UTC i am transmitting on ELF (the real ELF, i.e. into the range of 3...30 Hz, ITU radio band 1 ) for the first time ever.

Here are the parameters:

TX frequency: 22.970 Hz
Wavelength of that frequency: 13060 km
Antenna voltage: 4.8 kV rms (+ a DC component of 7.5 kV)
Antenna current: 325 uA
ERP: 600 aW, or 6E-16 W

Call it QRP!
The goal is to detect the signal on my 3.5 km distant tree grabber, whose E field is now working again. Since the E field probe is not to far above the tree, the effective height is not as much as it should ideally be, at this frequency, so the RX is somewhat deaf. Anyway i can see the Schumann resonances and the 60 Hz power grid. So i hope it will work.

A spectrogram which is centered on the frequency of interest in now shown at http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html (3rd window). But maybe 424 uHz FFT bin width is even to optimistic! In a few minutes we'll see more :-) It takes about 40 minutes until a peak could have fully developed...

73, Stefan