20 Dec 2016

More ULF amateur DX

The latest ULF DX news from Stefan DK7FC:


In addition to the informations from older mails about this experiment, here are the results of the post-processing:

First, a spectrogram in 424 uHz FFT bin width (after sferic blanking) showing the whole transmission:
The SNR reached levels up to 22 dB. Even during the (relatively) strong QRN periods at night, the transmissions are still visible. Even the EbNaut transmissions were visible. All this is about 10 dB stronger than i expected. The low winter noise levels and the quiet location certainly plays a big role here. The 'short' DFCW-10800 (3h per element) message "FC" is O copy as the experts say. Inbetween the "F" and "C" there is an EbNaut message (#2) with the content "73". One more example showing the power of EbNaut.
In the last experiments i've shown reference spactrograms beeing generated in low distance (tree grabber) just to give a better overview of what was transmitted, but this is not necessary here :-)

3 EbNaut messages were transmitted. All of them have been decoded with a strong SNR:
1st message:
2nd message: https://dl.dropboxusercontent.com/u/19882028/ULF/65_EbNaut_2970Hz_Message2.png
3rd message: https://dl.dropboxusercontent.com/u/19882028/ULF/65km_EbNaut_2970Hz_Message3.png

Last but not least a spectrogram showing the recorded range from 0...12 kHz, without a noise blanker:

A new experiment in 140 km distance is in the pipeline.
The plan is to run it in 2016.

73, Stefan

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