...another thing about phase stability on the 46km band. Take a look at
http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html
At night you can see the "local effects", frequency dependent minima
and maxima of the strength of the QRN. Arround 5:30 UTC (sunrise) these
effects disappear. The effects could cause strong phase instabilities.
Out best result was 10 characters 8K19A with 100s symbols, i.e. 21
hours for the transmission. So it must have been during the night as
well. But this was May, 20th, so the night was short!
We'll see...
73, Stefan
Am 14.10.2016 15:23, schrieb DK7FC:
Hi Paul,
Hmmmm, wellll, maybe there are some propagation behaviours on the band
that we don't know yet. Could summer work better than winter, despite
the higher average QRN levels? Who has the privilege to do
private-research on a 'new' band? We!
So, i started a new message:
f = 6470.00000 Hz
Start time: 14.10.2016 13:15:00 UTC
Symbol length: 60 s
Characters: 3
CRC 16
Coding 8K19A
Duration: 6h, 56m, 0s
Antenna current: 290 mA (ish)
The QRN is very high now on VLF. But maybe this just indicates that
propagation is better??? The QRN looks like as coming from far away, no
local effects (yet).
Any news from the previous tests?
73, Stefan
Am 12.10.2016 21:35, schrieb Paul Nicholson:
> f = 6470.00000 Hz
> Start time: 12.10.2016 14:30:00 UTC
> Symbol length: 40 s
> Characters: 3
> CRC 16
> Coding 8K19A
No decode, just a false hit ' WV' at Eb/N0 = -0.7.
Strange. According to carrier measurements this should
be an easy decode at around +3db.
More carrier measurements: night signal phase lags daytime
by 60 degrees. Night amplitude is about 0.1 fT.
The 16K25A 15 char 140 second message should decode at
about Eb/N0 +6dB. So far no improvement on the partial
decodes, next to try is correcting for that 60 deg diurnal.
--
Paul Nicholson
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