VLF: New world record distance by W4DEX and IK1QFK

[Paul Nicholson <vlf0403@abelian.org>]

W4DEX wrote:

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

Success!

Decoded 'QRZ' at Cumiana (IK1QFK) with
Eb/N0 = +0.4 dB, BER 41.6%;

S/N -31.7 dB in 1Hz, -65.7 dB in 2.5kHz
(after sferic blanking);

List rank 5689, constant reference phase;

Distance is 7173.4 km which is a new world record for
VLF message decode and a record distance for EbNaut
at all bands.

Predicted Eb/N0 was +0.6 dB.

Decoded via the live VLF stream from Renato's E-field
receiver.

These two stations already hold the record distance for
carrier detection at VLF.  This result extends that to
a message decode.

Signal data available in vlfrx-tools format:

 http://78.46.38.217/w4dex-171226-vlf15.vt

Decode with

 vtraw -oa w4dex-171226-vlf15.vt |
   ebnaut -dp16K21A -r1 -S30 -k20 -N3 -v -PU -L500000

Congratulations to both stations for a great result.

--
Paul Nicholson
--