Hello Eike,
I recommend to prepare a BIG ferrite core to up-transform the voltage
coming from the PA to get some more current into the earth! You will
probably have an impedance of a few 100 Ohm, mostly resistive. So you
will need a few 100V to apply the power. If you can find a big ferrite
core with a high µr, you can build the transformer. I used one with 100
primary turns and > 300 turns secondary. The wire can be small, e.g.
0.4mm diameter.
I can recommend e.g. that one:
https://www.buerklin.com/default.asp?event=ShowArtikel(84D258)&context=SE:Epcos+ringkern&l=d&jump=ArtNr_84D258&ch=39944
or that one:
https://www.buerklin.com/default.asp?event=ShowArtikel(84D2601)&context=SE:Epcos+ringkern&l=d&jump=ArtNr_84D2601&ch=88922
73, Stefan/DK7FC
Am 18.07.2013 10:08, schrieb Eike Katzera:
Hi,
we will use spectrum lap to generate the test signals and
synchronise to knowen VLF-Stations.
The capability of the transmitter ist ~ 92V/25A, but the outut
power depends on the erth resistance / impedance wich we dont know. We
also dont know the local possibilities and conditions so we have to
wait and see, what is possible.
We plan to use a local ground as one pole an some erth
electrodes at a near small river as the oposite pole. Maybe the
distance between the electrodes reach more than 100m.
73s
Eike DL3IKE
Hello Eike,
Who is we? And what is the electrode spacing, earth rod length? And how
do you stabilize your signal generator? Are there any local watching
stations so you start with a few km distance? Will you transmit a
single long dash or do you plan some kind of modulation? What is the TX
power?
Some more informations would be useful..
My grabber is watching 24/7: http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber.html
73, Stefan/DK7FC
Am 17.07.2013 21:59, schrieb Eike Katzera:
Hello Group,
we are planing some VLF-activity at 8970Hz during a Meeting of
electronic hobbyists nearby Kassel / Germany (JO40vr) on this Weekend.
The Plan is to run a VLF-PA between some ground electrodes.
Due to other activities we have no exact time plan, when to start.
Depending on internet access i will inform you about the
details.
Thanks for looking for our signal in advance.
73s
Eike DL3IKE
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