Hello Riccardo, VLF!

Looks like I have something!

After weighted stacking of 3 nights of 3 char transmissions EbNaut software produce decode :

ebnaut-rx V0.7a
input file C:\EbNaut\IW4DXW\sum3charweighted.wav
sample rate 0.342935 per second
rx frequency 8270.1
file start time 2017-12-16 20:32:19.690
polynomial 16K21A
crc size 24
number of chars 3
block size 42
symbol period 30.000
number of symbols 992
list length 20000000
start offset 3472.274
freq offset -0.096681
cores 1
skipped 3472.961348 seconds to start
initial reference phase 28.1
---------------------------------------------
found QSY
list rank 14946658
reference phase -150 -150 -150 -150
carrier S/N 10.41 dB in 33.6 uHz, -34.33 dB in 1Hz, -68.31 dB in 2.5kHz
carrier Es/N0 -19.56 dB
carrier Eb/N0 -1.92 dB
info bit period 1740.35 seconds
symbol error rate 428/992 = 43.145 %
Es/N0 from symbol errors -18.2 dB
Eb/N0 from symbol errors -0.6 dB
Shannon capacity 1.9 bits/hour
Shannon efficiency 108.5 %
symbols file C:\EbNaut\IW4DXW\sum3charweighted-symbols.csv
elapsed 1396 seconds
-------------------

Maybe this decode is true? 

Files for reprocessing: http://rn3aus.narod.ru/IW4DXW-3char.zip

PS: stacking of 2-char transmissions give me decode "JA".  And also many other decodes like "46", "2+"... 

73 de Rn3aus / Alex 

Воскресенье, 17 декабря 2017, 0:31 +03:00 от Riccardo Zoli <[email protected]>:

Hi VLF,

I'm ready for another transmission:

f = 8270.00332 Hz
Start time: 21:30:00 UTC
Symbol period: 30 s
Characters: 3 (repeated)
CRC bits: 24
Coding 16K21A
Duration: 8h,16min
Antenna current: 395 mA

...thanks again for reports.

All the best

73 de Riccardo IW4DXW