Hello Stefan!
The fence was just used in the first attempt for transmitting and is
meanwhile replaced by Ossi's LF-antenna. Still Ossi is using fences
around his QTH but only for receiving and to check his own signal.
The big goal was to have a signal on his grabber so that he would be
able to improve the set-up. Yesterday, for the first time after a lot of
work, we saw a clear signal there.
I built a MiniWhip for the receiving station but we had some problems
with the audio driver on the netbook he is using. No matter what
sample-rate was chosen in SpecLab, no signal above 8khz could be
received. Meanwhile we replaced this audio-driver by a new version and
now the netbook is working as expected, showing signals up to 24Khz.
This is only a fraction of the problems we had to deal with.
73
OE3GHB
Gerhard
Am Samstag, den 06.11.2010, 13:20 +0100 schrieb Stefan Schäfer:
> Wow! Congratulations to this successful start up on VLF!
>
> If i understand it correctly you have used the fence as the antenna, so
> a kind of earth antenna or ground dipole? Have you measured antenna
> currents or so? :-)
>
> Will Ossi use his LF TX antenna for VLF too? :-)
>
> It's very pleasing to see this band is coming slowly alive :-)
>
> 73 and good luck!
>
> Stefan/DK7FC
>
>
>
> Am 06.11.2010 10:23, schrieb Gerhard Hickl:
> > Dear group!
> >
> > After weeks of testing and playing around with different kind of
> > equipment and antennas, Ossi OE5ODL has managed to transmit a signal on
> > VLF which is received by his grabber www.langwelle.at
> >
> > It all started when we connected an car audio amplifier over a
> > toroid-transformer to two big fences out in the wood some weeks ago.
> > The purpose just was to see if we could transmit anything with this kind
> > of equipment. We archived about 100W of input power but nearly no signal
> > was radiated.
> >
> > Since this time, Ossi has constantly improved his setup and yesterday
> > for the first time saw his signal on his grabber about 10km away from
> > his home QTH.
> >
> > He is using his LF-antenna (20m vertical) with additional top-loads to
> > get a capacity of about 1200pf. The antenna is matched with some
> > different coils in series and for sure there is still a lot room for
> > improvements on the TX as well as on the RX setup. The power amplifier
> > is a car-audio equipment, antenna input is up to 250W.
> >
> > I think this is the first noticeable signal on VLF radiated by an
> > amateur in OE...
> >
> > Congrats to Ossi
> >
> > 73
> > OE3GHB
> > Gerhard
> >
> >
> >
> >
> >
> >
>
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