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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