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
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