Re: VLF: New world record distance by W4DEX and IK1QFK

[Markus Vester <markusvester@aol.com>]

Well done again!

Knowing the message, I looked for the W4DEX signal in Amberg. As a compromise between 8270.0 and 8270.1, the recorded band from the DL0AO cardioid currently covers 8270.05 +-0.171 Hz. Fortunately this contains at least the full main lobe of Dex' PSK spectrum. After unspreading, there appeared a small peak with 5.1 dB SNR in 35.9 uHz, equivalent to -7.2 dB Eb/N0.

Best 73,
Markus



-----Ursprüngliche Mitteilung-----
Von: Paul Nicholson <vlf0403@abelian.org>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Mi, 27. Dez 2017 9:36
Betreff: Re: VLF: New world record distance by W4DEX and IK1QFK

Dex wrote:

> 3 chars 16K21A CRC20
> 30 second symbols
> Start 22:30 UT

At Bielefeld (6917.7 km): Eb/N0 -3.3 dB;

At Warsaw (7681.3 km): Eb/N0 -6.5 dB;

At Hawley TX (1816.2 km): Eb/N0 +5.7 dB *Decoded*;

The decode at Hawley is a new USA record distance
for VLF message decode.

If Alex can supply a WAV file, I will analyse it to
measure Dex's signal. Frequency is 8269.9 Hz
and the message ran from 2017-12-26 22:30 to
2017-12-27 06:14 UT.

The intention was to use 16K23A but I had forgotten
that code is not yet in the Windows version.

--
Paul Nicholson
--

w4dex_dl0ao_unspread_spectrum_171226-27.png
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