Hello Alex,
Wow, what a perfect result again! Congrats Alex!! And still 0.84 dB
(and more) spare! We could risk some more again :-) In a few days.
I like the 30 0 0 -30 reference phase. It seems to tell us
something, maybe i'm starting to transmit when it's still not
completely nighttime on the path and stopping when it's already daytime
again?
Somehow the resonance frequency of the antenna rises! I measured 8285
Hz a few days ago. Thus my antenna current dropped, i was unable to
hold 700 mA, it dropped to 665 mA. Maybe the winding is slowly gliding
downwards, so that the coil length becomes higher? That would at least
explain the effect. So now i added another 30 turns on the coil which
should correct for that. There is no sign of HV stress on the
arrangement. So far i'm very satisfied with the coil design. Now, if i
can run 700 mA again in the next transmission, this would lead to a
0.45 dB stronger signal relative to the 7 character message, not much
but still a lot!
Do you have any plans to improve things on your side?
How many characters is your PC able to decode, in 16K21A and a list
length of 200000?
I would try 8 characters in 16K21A soon, still at 30s symbols.
Thanks for all, and i'm following the Russian VLF thread on 136.su :-)
73, Stefan
Am 20.02.2017 17:05, schrieb Alex K:
Hello
Stefan, VLF
... and new decode again!
ebnaut-rx V0.5
input file
C:\EbNaut\ebnaut19_FEB_0026_8270-1pps.wav
sample rate 0.342935 per second
rx frequency 8270.1
file start time 2017-02-18 17:48:44.690
polynomial 16K21A
crc size 16
number of chars 7
block size 58
symbol period 30.000
number of symbols 1248
list length 20000
start offset 1587.274
freq offset 0.000000
cores 1
skipped 1586.306443 seconds to start
initial reference phase 8.5
---------------------------------------------
found DREAMER
list rank 5
reference phase 0 0 0 0
carrier RMS 3.002e-005 noise RMS
4.463e-006
carrier S/N 16.56 dB in 26.7 uHz
carrier Es/N0 -14.41 dB
carrier Eb/N0 0.55 dB
info bit period 938.35 seconds
symbol error rate 508/1248 = 40.705 %
Es/N0 from symbol errors -15.5 dB
Eb/N0 from symbol errors -0.5 dB
Shannon capacity 6.2 bits/hour
Shannon efficiency 62.2 %
symbols file
C:\EbNaut\ebnaut19_FEB_0026_8270-1pps-symbols.csv
elapsed 10 seconds
---------------------------------------------
found DREAMER
list rank 9
reference phase 30 30 0 0
carrier RMS 3.106e-005 noise RMS
4.463e-006
carrier S/N 16.85 dB in 26.7 uHz
carrier Es/N0 -14.11 dB
carrier Eb/N0 0.84 dB
info bit period 938.35 seconds
symbol error rate 495/1248 = 39.663 %
Es/N0 from symbol errors -14.6 dB
Eb/N0 from symbol errors 0.4 dB
Shannon capacity 6.6 bits/hour
Shannon efficiency 58.2 %
symbols file
C:\EbNaut\ebnaut19_FEB_0026_8270-1pps-symbols.csv
elapsed 128 seconds
---------------------------------------------
found DREAMER
list rank 0
reference phase 30 0 0 -30
carrier RMS 3.106e-005 noise RMS
4.463e-006
carrier
S/N 16.85 dB in 26.7 uHz
carrier Es/N0 -14.11 dB
carrier Eb/N0
0.84 dB
info bit period 938.35 seconds
symbol error rate 493/1248 = 39.503 %
Es/N0 from symbol errors -14.5 dB
Eb/N0 from symbol errors 0.5 dB
Shannon capacity 6.6 bits/hour
Shannon efficiency 58.2 %
symbols file
C:\EbNaut\ebnaut19_FEB_0026_8270-1pps-symbols.csv
elapsed 531 seconds
Let's risk something more
again and try:
f = 8270.100000 Hz
Start time: Saturday 18.Feb.2017 18:00:00 UTC
Symbol period: 30 s
Characters: 7
CRC bits: 16
Coding 16K21A
Duration: 10h, 24m, 0s
Antenna current: 700 mA
73, Stefan
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