Re: VLF: 300 mA on 6470 Hz

[DK7FC <selberdenken@posteo.de>]

Hello Alex,

What a surprise! This is most amazing. You got the message correctly over a 1985 km distant land path and even with Eb/N0 = 6.1 dB :-) 4 characters would have been possible as well :-) I'm very happy with that result. And i bet, we will make it on 5170 Hz too!!
My congrats to your excellent RX setup!

Also thanks Jacek and Paul for the decode and permanent monitoring. It will stay exciting here and when we go lower in frequency.

Well it looks like we can learn more about the behavior of the 46 km wave, daily phase and amplitude variations. I'd like to focus on night transmissions since this less critical here.
Markus has built a tool for stacking the txt files generated by SpecLab:  http://df6nm.bplaced.net/VLF/fec_tests/add.zip I tried it yesterday and it works easy, even easier than expected. So there is a way for Windows users to stack daily receptions.
So let's try a longer message. I hope that Alex will get it too, by stacking a few daily receptions:

f = 6470.100000 Hz
Start time: 05.October.2017  17:00:00 UTC (daily)
Symbol period: 40 s
Characters: 16
CRC bits: 21
Coding 8K19
Duration: 12h
Antenna current: 300 mA

I'm transmitting as long as Alex and Jecek will get the message. Paul will get a daily decode i think, and daily SNR and phase informations.

73, Stefan




Am 05.10.2017 10:07, schrieb Alex K:

Hello Stefan,

I have two free days and my old VLF grabber in ko85ha is now running for 2-3 weeks! 6470 and 5170 Speclab-ebnaut instances are active. I will periodically visit my grabber (as in February 2017).

And I have first result (see attachment for confirmation).
73 de Rn3aus 

OK, so i'm changing to:

f = 6470.005000 Hz
Start time: 04.October.2017  17:00:00 UTC
Symbol period: 240 s
Characters: 1
CRC bits: 0
Coding 8K19A
Duration: 12h48min
Antenna current: 300 mA