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Date: Tue, 04 Oct 2011 21:20:45 +0200
From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= <schaefer@iup.uni-heidelberg.de>
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Subject: Re: LF: A test of cmsk on "the dreamers band"
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Hello Steinar and welcome to the group!

Good to hear there is interest on VLF by norwegian radio amateurs. There 
is not much coming from LA in the last time, unfortunately. So i'm happy 
to read of your interest and experiments.

Well, much has been done on VLF in the last year(s). I expect you know 
about Roger/G3XBM's VLF pages at https://sites.google.com/site/sub9khz/ ??
If not, i would strongly recommend to take a look on that and read all 
that is written there ;-)

Many of us have done similar local tests and SpecLab is THE most useful 
software here, without any doubts. Even more: Without SpecLab, most of 
the VLF receptions were not have been possible, due to its band limiting 
and noise reduction technics.

Please, what is your locator?

What about your RX performance on VLF, i.e. how well can you receive the 
Alphas and other MSK military transmitters, such as JXN ;-) ?

In a short time i will come back, TXing on VLF with several 100 watts on 
a 300m vertical antenna. I would like to invite you to make the first 
official DL-LA VLF reception (by amateurs).

If you have any questions about VLF settings on SpecLab, don't hesitate 
to ask here.

Best 73, Stefan/DK7FC


Am 02.10.2011 13:23, schrieb Steinar Aanesland:
> Hi all,
>
> I am new to the group and on top of that Norwegian so please be nice to
> me,  my English is not the best.
>
> The last few days I've been doing some digi mode testing at 8.97 khz;
> "dreamers band", mostly with use of the QRSS mode.
>
> On the transmitter side, I have been using a 5 turn 10 x 10 m antenna
> and an audio amplifier 100W. The system is feeded with a signal from the
> program "Spectrum Lab".
>
> On the receiver side, I have been using a 70 x 70 cm 60 turns loop,
> tuned with a capacitor. The loop was connected to the microphone input
> on my laptop and decoded with "Spectrum Lab".
>
> The result has been interesting . With this simple arrangement, I have
> reach a distance of 2.5 km.
>
> Yesterday I tried out CMSK8 made by ZL1BPU  Murray. I had to make some
> changes in the ini-file to get the CMSK work om 8.97khz. The sampling
> rate was adjusted with the program CheckSR and the transmitting
> frequency was set to 8970Hz.  Waterfall has a 2000Hz limit so this was
> black and useless on 8790Hz.
>
> It would makes it easier to track the signal if the developer could
> extend waterfall to 10 kHz. I am aware that one can get the view of the
> waterfall by going down in frequency, but 8.97khz has become a de facto
> water hole of VLF .
>
> The result was exciting. A clean copy of the signal was received at
> about 2 km.
>
> I would also try to test out some of the VLF mode in multipsk ,
> especially  PSK10 and PSKAM10,  but I have not find a way to fool the
> program to work on 8.97Khz yet.
>
> 73 and good dx the VLF Steinar la5vna
>
>
>
>
>
>
>
>