Hello Markus, ULF,
Thanks for the files covering 5x 30 hours (overlapping). As usual i've
built a weighted stack out of them and put them through my script
producing the set of data plotted in the attachment. The plot starts at
15 UTC and covers the following ~ 30 hours.
The best S/N so far is 9.16 dB in 17.4 uHz if you analyse a 16 hour
long carrier starting 15:40 UTC. I will determine this in detail later
because the optimum seems to lie between 14h and 16h or maybe even at
18h? That would mean the day/night phase change is not so high.
One obtaines 9.15 dB in 19.8 uHz for a 14 hour carrier starting 17:20
UTC.
There seems to be a short "night optimum", 7.86 dB in 69.4 uHz for a 4
hour carrier starting 3:20 UTC. That is strange and not so proof due to
the weak S/N. We'll see in the next days if that builds up and
disappears.
What do you think about that data, does it agree with your
expectations? I did expect better results for the daytime because the
QRN is quite high at night and low during the short time arround 11 UTC.
Thanks to the DL0AO crew for running the VLF/ULF/SLF grabber service.
With some more days we will reach a proof carrier detection on that 191
km band. It will be the first time that radio amateurs cross a distance
of > 1 lambda on that band!
A spectrum peak from this 9.16 dB carrier is in the 2nd attachment. But
you see it is not the strongest peak ( in 2000 bins) and not high
enough, so far!
Just for fun a tried to decode a '*' message from that peak, which
worked well:
sr@vlf:~/vlf/dl0ao$ vtwavex sum2630.wav | vtcat -T2018-04-29_15:40,+16h
| vtraw -oa | ebnaut -dp16K21A -S80 -k19 -c4 -r0.1524125 -N1 -PS
-L133712
found rank 11582 ber 4.5972e-01 Eb/N0 -1.9 M -6.131338887e-04 ph 3
-150,-150,-150,-150 [*]
found rank 2403 ber 4.5556e-01 Eb/N0 -1.0 M -6.794492947e-04 ph 7
-120,-120,-120,-120 [*]
found rank 3051 ber 4.5833e-01 Eb/N0 -1.6 M -6.850516656e-04 ph 63
-120,-150,-90,-120 [*]
sr@vlf:~/vlf/dl0ao$ vtwavex sum2630.wav | vtcat -T2018-04-29_15:40,+16h
| vtraw -oa | ebnaut -dp16K21A -S80 -k19 -c4 -r0.1524125 -N1 -v -f15
-f16 -M'*'
carrier phase: -171.8
carrier Eb/N0: 1.6 dB
carrier S/N: 9.14 dB in 17.4 uHz, -38.46 dB in 1Hz, -72.44 dB in 2.5kHz
Looking forward to the next days...
73, Stefan
PS: What about your own analysis?
Am 30.04.2018 23:20, schrieb Markus Vester:
> Nun mit Anhang...
>
> Anbei fünf überlappende Datensätze der letzten Tage. Ich will auch
selbst mal hineingucken aber heute Abend bin ich einfach zu müde.
>
> Viele Grüße,
> Markus
Am 25.04.2018 22:05, schrieb DK7FC:
ULF,
The system changes have been done now. The carrier was off again
between 17:43...19:00 UTC.
>From now on there will be no significant ( > 1 min) interruptions
any more.
The carrier can run up to 3 weeks, depending on the feedback. Possible
known RX stations are DL0AO, DL4YHF, Paul and Renato(vlf.it).
73, Stefan
Am 25.04.2018 13:56, schrieb DK7FC:
ULF,
Unfortunately i forgot to remove the stop command from the last day, so
the carrier stopped again at 10:30 UTC. It is back since 11:50 UTC.
Just a note for those few who try to watch out for the signal.
73, Stefan
Am 25.04.2018 11:04, schrieb DK7FC:
ULF,
After 9 hours of work the carrier is now back since 01:00 UTC. I'm now
running the actual target level of 56 mA, so the signal should
be 6.3 dB stronger now.
Eventually i'll have to do some worke work tomorrow but maybe not.
The carrier will stay on the air for a few days without interruptions
if all works well!
Reports welcome :-)
73, Stefan
PS: Forgot to send the message last night (morning actually), must have
been tired ;-)
Am 24.04.2018 10:49, schrieb DK7FC:
Hello ULF friends,
I just opened up a new band by starting some activity on 1570 Hz
! It is the 191 km band! :-)
Since 8 UTC a carrier is running at 1570.01 Hz. Soon the first trace
will appear on a spectrogram from my tree which is in 3.5 km distance
from the transmitter.
See the developing trace at http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html
The spectrogram scrolls with 10 minutes/pixel.
The carrier will stay on the air for 2.5 hours. It is just a first
test. So far the antenna current is just 27 mA but tonite i'll try to
reach the target level of 58 mA which means 12 kV again acros the
special iron cored coil. This will mean about 120 nW ERP then.
DL0AO is already watching the band. I hope to be received by Paul and
at the reomte site of DL4YHF. I'm not planning to do /p RX experiments
on that band, just focusing on these 3 RX stations.
73, Stefan
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DL0AO_1570_5days.png
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