Re: VLF: EbNaut at 8270.003

[DK7FC <selberdenken@posteo.de>]

Hi Riccardo,

I continued to work out more decodes of the recent 2 character messages.
The new results:

Date	Carrier Eb/N0 [dB]	2 characters
09.May_08:00	-1.3
09.May_16:01	+0.4	decoded
10.May_00:00	-4.9
10.May_08:00	-6.8
10.May_16:00	+0.9	decoded
11.May_00:00	+6.9	decoded
11.May_08:00	+3.0	decoded
11.May_16:00	+4.8	decoded
12.May_00:00	+7.0	decoded
12.May_08:00	+3.0	decoded

And for the 6 character messages i got:

Date	Carrier Eb/N0 [dB]	6 characters	rank
12.May_16:00	-6.9
13.May_00:00	-0.1	decoded	1087
13.May_08:00	-
13.May_16:00	-13.5
14.May_00:00	-16.9
14.May_08:00	-9.2
14.May_17:30	-2.1
15.May_02:00	+0.4	decoded	51
15.May_10:00	-9.0
15.May_18:00	-3.2

Are you continuing to transmit the message at 18 / 02 / 10 UTC? THere is a phase jump at 0 UTC (only in SpecLab?) when TXing on 8270.003 Hz. 8270.0025 or 8270.005 Hz for example would avoid this phase jump.

It could be useful to transmit just 2 messages per day, a long one during daylight (4...18 UTC) and a short one at night (19...3 UTC). You never know who's trying to decode you. The shorter messages at night would promise better chances. Just a thought.

73, Stefan

 

Am 16.05.2018 00:31, schrieb Riccardo Zoli:

Hi VLF.

Completed transmissions:

started at [UTC (DD)]

        

1.  1730 (14) 

2.  0200 (15)

3.  1000 (15)

4.  1800 (15) now running

Reports are welcome :-)

All the best

73 de Riccardo IW4DXW

Il Lun 14 Mag 2018, 19:56 Riccardo Zoli <riccardozoli80@gmail.com> ha scritto:

Hi VLF,

I retry with some consecutive transmissions.

Session started at 17:30 UTC, every 8h, same parameters.

QRG: 8270.003 Hz

6 ch.

25 sec./sym

coding 16K21A

CRC 15

duration 7h 53' 20"

antenna current about 600mA

GE all, 73 de Riccardo IW4DXW

Il Dom 13 Mag 2018, 20:57 Riccardo Zoli <riccardozoli80@gmail.com> ha scritto:

Hi, Stefan! Thanks again for trying to decode my vy weeeak sig. :-)

Unfortunately my TX goes off at 1733 UTC.

Here the WX turned to stormy suddenly: too much wind and rain to mantain a normal antenna current and the WX forecast does not bode well :-/

I hope to come back soon on air....

GE all

73 de Riccardo IW4DXW

Il Dom 13 Mag 2018, 20:23 DK7FC <selberdenken@posteo.de> ha scritto:

RR. Thanks for the transmissions. I'd like playing with EbNaut daily.

This night was very noisy with local thunderstorms again. But with all tricks including Paul's iqnorm2 script, i decoded the message. Without that, the Eb/N0 is several dB below the decode limit. Using the -a normalisation feature i improved the Eb/N0 even more. The final result is:
sr@vlf:~/vlf/iw4dxw$ vtwavex 13.wav | vtcat -T2018-05-13_00:00,+8h | vtraw -oa | ./iqnorm2 | ebnaut -dp16K21A -N6 -S25 -r1.1574 -c4 -k15 -PS -f9 -T3 -F-0.097 -L1500 -v -a25
skipped 2.592017 seconds to start
initial reference phase 84.4 amplitude 7.287e+00
found rank 1087 ber 4.0581e-01 Eb/N0 -0.2 M -1.957628479e+02 ph 96 0,30,30,60 [IW4DXW]
carrier phase: 4.1 deg
carrier Eb/N0: -0.1 dB
carrier Es/N0: -15.29 dB
carrier S/N: 15.26 dB in 35.2 uHz, -29.27 dB in 1Hz, -63.25 dB in 2.5kHz
elapsed 1502

73, Stefan


Am 13.05.2018 18:07, schrieb Riccardo Zoli:

Restarted at 1600 UTC (13 May), 610mA.

GE, 73 de Riccardo IW4DXW

Il Dom 13 Mag 2018, 12:26 Riccardo Zoli <riccardozoli80@gmail.com> ha scritto:

Hi VLF.

TX stopped at 0800 UTC.

More info soon.

Thanks!

All the best

73 de Riccardo IW4DXW

Il 12 Mag 2018 18:29, "Riccardo Zoli" <riccardozoli80@gmail.com> ha scritto:

Hi VLF,

Thanks Stefan and Markus for your detailed reports.

Ok Stefan, I'm agree, we can try: a new message started at 1600 UTC, same scheduling for the following transmissions.

QRG: 8270.003 Hz

6 ch.

25 sec./sym

coding 16K21A

CRC 15

duration 7h 53' 20"

antenna current about 600mA

GL and thanks again for your patience :-)

P.S.: now there are some thunderstorms nearby, I hope I won't have to stop the TX :-/

All the best

73 de Riccardo IW4DXW

Il Sab 12 Mag 2018, 12:34 DK7FC <selberdenken@posteo.de> ha scritto:

Here is a corrected and continued list of the results of your transmissions:

Date	Carrier Eb/N0 [dB]
09.May_08:00	-1.3
09.May_16:01	-6.1
10.May_00:00	-4.9
10.May_08:00	-6.8
10.May_16:00	+0.9	decoded
11.May_00:00	+6.9	decoded
11.May_08:00	-2.7
11.May_16:00	+4.8	decoded
12.May_00:00	+7.0	decoded

73, Stefan

PS: You could try to transmit your full callsign for example. It would work here. A higher challenge.



Am 11.05.2018 17:01, schrieb DK7FC:

Hi Riccardo,

Now i finally got your message, see attachment. The transmission of tonite 0 UTC was very strong, as i would usually expect.
It must have been the QRN. And now since know the message i can look for the S/N or Eb/N0 of each of your transmissions:

Date	Eb/N0 [dB]
09.May_08:00	-1.3
09.May_16:01	-6.1
10.May_00:00	-4.9
10.May_08:00	-6.8
10.May_16:00	+0.9	decoded
11.May_00:00	+7.9	decoded

73, Stefan



Am 10.05.2018 02:19, schrieb Riccardo Zoli:

Hi VLF,

I have only reduced the CRC.

Start time: 00:00 UTC (May 10) every 8 hours.

QRG: 8270.003

2 chars

30 sec/sym.

coding 16K21A

CRC 27

duration: 7h 52'

antenna current: 580 mA

Thanks for reports, as usual...

All the best

73 de Riccardo IW4DXW

Il Sab 12 Mag 2018, 12:34 DK7FC <selberdenken@posteo.de> ha scritto:

Here is a corrected and continued list of the results of your transmissions:

Date	Carrier Eb/N0 [dB]
09.May_08:00	-1.3
09.May_16:01	-6.1
10.May_00:00	-4.9
10.May_08:00	-6.8
10.May_16:00	+0.9	decoded
11.May_00:00	+6.9	decoded
11.May_08:00	-2.7
11.May_16:00	+4.8	decoded
12.May_00:00	+7.0	decoded

73, Stefan

PS: You could try to transmit your full callsign for example. It would work here. A higher challenge.



Am 11.05.2018 17:01, schrieb DK7FC:

Hi Riccardo,

Now i finally got your message, see attachment. The transmission of tonite 0 UTC was very strong, as i would usually expect.
It must have been the QRN. And now since know the message i can look for the S/N or Eb/N0 of each of your transmissions:

Date	Eb/N0 [dB]
09.May_08:00	-1.3
09.May_16:01	-6.1
10.May_00:00	-4.9
10.May_08:00	-6.8
10.May_16:00	+0.9	decoded
11.May_00:00	+7.9	decoded

73, Stefan



Am 10.05.2018 02:19, schrieb Riccardo Zoli:

Hi VLF,

I have only reduced the CRC.

Start time: 00:00 UTC (May 10) every 8 hours.

QRG: 8270.003

2 chars

30 sec/sym.

coding 16K21A

CRC 27

duration: 7h 52'

antenna current: 580 mA

Thanks for reports, as usual...

All the best

73 de Riccardo IW4DXW