Re: VLF: EbNaut transmissions on lower frequencies?, pre-tests: 6.47kHz

[DK7FC <selberdenken@posteo.de>]

Hello Paul,

Excellent! I'm happy :-)
The error map correlates with the QRN strength, see 
https://dl.dropboxusercontent.com/u/19882028/VLF/wald5.jpg
It's almost June and it works anyway...

The antenna current was quite stable at 220 mA. I'm planning to rise it 
up to 240 mA and will run the very long message (19 chars) again.
For 240 mA i need to be quite close to the resonance, so i need the 
transductor circuit to hold the resonance automatically. If some rain 
starts to fall, the total C will rise a bit, then the DC current in the 
transductor coil will rise, the transductor L will fall and the 
resonance will be hold on the spot!
So far we got 3 chars, 5 chars and now 6 chars on 6470 Hz, each one at 
100s symbols.
73, Stefan

Am 15.05.2016 18:50, schrieb Paul Nicholson:
> Stefan wrote:
>
> > f = 6470.00000 Hz
> > Start time: 14.05.2016   21:40:02 UTC
> > Symbol length: 100 s
> > Characters: 6
> > CRC 16
> > Coding 8K19A
>
> An easy decode of 'JN49IK' with Eb/N0 = +3.8 dB.
>
> Phase pattern: 30   30    0    0
>
> Carrier S/N: 16.96 dB in 17.9 uHz
>
> Symbol errors: http://abelian.org/vlf/tmp/160514a.gif
>
> >  the same message
>
> Now I know the message I can reverse the modulation of
> the previous attempt to see why it didn't decode.
>
> --
> Paul Nicholson
> --