Hi Paul,
Am 15.11.2016 08:18, schrieb Paul Nicholson:
Carrier (after phase modulation reversed) in 6uHz bandwidth
http://abelian.org/vlf/tmp/161115a.gif
Very nice indeed! :-) I like the very long transmissions. Hopefully the
phase between day and night is more equal on 5170 Hz and 2970 Hz.
http://abelian.org/vlf/tmp/161115c.gif
Most impressing. This is something i would call "DFCW-20000", a FFT
resolution for that mode. But the 15 characters would take several weeks
in that mode and probably wouldn't even be identifiable during a day
with high QRN.
Am 14.11.2016 20:09, schrieb Paul Nicholson:
Start tomorrow with 50 chars?
Currently i would like to continue with the ongoing daily repetition
experiment. We are getting most interesting data of the daily path
stability. So far 4 'events'. For a better statistical certainty i would
like to get, say, 7 days, one week of coherent adding. We are in the
comfortable situation to get a daily decode, so we can continue to write
that table. Some day we may try an attempt to transfer a message that
will not decode after days, so it would be a better feeling to know from
our own experiments that we can stay optimistic. An experiment like that
has not been done (that way) before. So it is good to see what happens
for a few more days i think.
The recent developed optimism leads us to the imagination that we can
pass every message length on 46km, as long as the path is stable. We
will show it!
Currently, RN3AUS is running his setup on VLF, 8270 and 6470. He is
running a 10 uHz spectrogram. I think i am to weak for that path in that
BW. Also the path must be stable over the FFT time. But i should give it
a try! It is also a try to leave a trace at Renato Romero / IK1QFK.
So the plan is to run the experiment (daily repetition) until the 17th,
15:44 UTC (7 events). Then i will run a carrier for about 2 days without
an interruption. Then i would start an attempt for the 20 character
message, which was the mail goal defined in May 2016. And then finally i
could start the 50 character message to complete the experiments on 6470
Hz. That is the idea.
BTW it is raining today here. The antenna is detuned a bit and the
antenna current drops, see
http://www.iup.uni-heidelberg.de/schaefer_vlf/VLF/TX.png (this link
always works if i am on air). So the SNR will be lower today. Anyway the
result will be interesting! Looking forward to that.
73, Stefan
PS: That is an issue for itselfe: If we can assume a LONG path is stable
in its phase during a certain time, would it be possible to transfer an
EbNaut message over > 10000 km? We need more stations in higher distances!
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