thanks for your grabber very much! I use it every day.
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> Date: Fri, 15 Apr 2011 21:25:46 +0200
> From:
[email protected]> To:
[email protected]> Subject: LF: VLF grabber at DK7FC
>
> Dear group,
>
> Today, my VLF grabber at
> http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber.html
> becomes 1 year old :-)
>
> I've never thought that it will be so sensible and will see so many
> stations, even with usual LF home antennas and moderate power. The
> circuit of the active antenna was modified several times. Also Spectrum
> Lab by DL4YHF plays a dominant role here. By improving the noise
> reduction settings, we won another 2 dB (about).
>
> First it was a idea of Paul Nicholson to choose a compromise of a long
> (enough) "carrier" and sending informations. So i came to the good old
> "DFCW-600". Since my signal was strong out of 40km distance i wanted to
> add a DFCW-60 and DFCW-3 window, to monitor my own signal in faster
> modes. For test purposes i arranged a DFCW-6000 window. The idea was
> that someone who prepares to be visible in 600 could see his signal in
> 6000 and then knowns how many dBs are still missed. OE5ODL for example
> showed often that he is visible in 6000 but just sometimes, with the
> balloon, in 600.
> Now we arrived at even 60000 (= 47 uHz). Stations like DJ8WX became
> regularly visible. But there seems to be a limit, given by the VFO
> accuracy, time and phase instabilities at higher distances.
> The Alpha stations are a perfect reference and since having a stable RX
> is essential and there were often questions about the availability of
> RSDN-20, i added the Alpha window, not only to check if my GPS module is
> still locked.
> The wideband window gives a good overview of the current QRN situation,
> solar activities and the presence or absence of military MSK stations or
> fauls of the rig, that shows in a sudden loss of sensitivity.
>
> Thank you for the interest of 7314 visitors out of 60 countries (34 of
> 51 US states) and 198665 pageviews so far :-) I'll keep the service
> running as long as possible, and this may be a looong time!
> Stations who appeared there so far were: DF6NM, OE5ODL, OE3GHB, DJ8WX,
> OK2BVG, DK7FC and a small sign of PA3CPM
> I hope to see more stations soon!
>
>
> 73, Stefan/DK7FC
>
