Am 11.03.2016 10:06, schrieb Domenico IZ7SLZ:
What about an VLF Ebnaut signal from you ?
73 Domenico, iz7slz
In about 2 weeks i will prepare a small transmit (air cored) coil for
VLF. Markus/DF6NM has been here in Heidelberg a few days ago. He kindly
lent me his yoghurt-cup coil which has > 1 H. I measured 820 Ohm DC
resistance but since my antenna C is about 470 pF, i can remove some of
the stacked cups.
The advantage of the coming tests is that i will be able to transmit
under all WX conditions, even in rain and storm! I will also control the
phase of the radiated signal in a feed back loop to compensate eventual
phase changes (thermal variation of L; wire movement in the wind...). So
my signal could be very stable. It is already using 1pps syncing...
The disadvantage is that i am limited to about 200 mA antenna current.
So the signal will be even 10 dB weaker than in my last experiments with
the large coil. And it is about 30 dB weaker then the kite experiments
signal. An ERP below 100 uW.
We will see if this makes any sense at all. I hope i can leave a signal
on my 3.5 km distant VLF remote grabber then ;-)
Are YOU prepared to monitor traces in 47 uHz FFT BW ("DFCW-60000") ?
This will likely be the mode we can try. In EbNaut it will be most
difficult, maybe when using 100s symbols??
Did you try to monitor the Alpha signals for some days, without seeing
phase glitches except one per day on 0' clock Moscow time?
I'm still struggling to get my VLF remote grabber running on its best
performance using the 0.8m diameter loop.
http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html
73, Stefan
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