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--------------070705060202030601000203--

... 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

---------------------------------------------

foundDREAMER

list rank 0

reference phase 30 0 0 -30

carrier RMS 3.106e-005 noise RMS 4.463e-006

carrierS/N 16.85 dB in 26.7 uHz

carrier Es/N0 -14.11 dB

carrierEb/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