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Re: LF: LF EbNaut TX Announcement

To: [email protected]
Subject: Re: LF: LF EbNaut TX Announcement
From: Markus Vester <[email protected]>
Date: Wed, 19 Sep 2018 09:55:30 -0400
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In-reply-to: <[email protected]>
Reply-to: [email protected]
Sender: [email protected]
Using the known message I searched Time-Doppler-space in the DL0AO 4 UT file. The peak occured at 1.1 s time delay (presumably due to latency of the virtual audio cable between cascaded SpecLab instances), and -0.3 mHz shift caused by propagational variations, as indicated by the ragged peak in the unspread spectrum. Running the decoder with those extra offsets produced a correct decode from DL0AO.
Regarding future message formats: I understand that longer messages will be needed for real two-way QSO's once the quality of a propagation path has been established. However in the current experimental stage, where we still need to tweak our tools and learn propagation patterns, I would favour shorter messages with simple codes (or even straight carriers), which require less frequency and time accuracy, and can be processed quickly even on modest computers. 

Best 73,
Markus


-----Ursprüngliche Mitteilung-----
Von: Markus Vester <[email protected]>
An: rsgb_lf_group <[email protected]>
Verschickt: Di, 18. Sept 2018 22:19
Betreff: Re: LF: LF EbNaut TX Announcement

Another belated report: Three decodes in Nürnberg in the morning of Sep 16:

start  EbN0  rank
  UT     dB
03:00   1.0   89
03:30   0.7   17
04:00   3.9   0

At DL0AO in Amberg, we picked up pieces of carrier before and after the 4:00 transmission, indicating favourable SNR. But for some yet unidentified reason we didn't manage to achieve a decode.

Best 73,
Markus (DF6NM)

-----Ursprüngliche Mitteilung-----
Von: Rob Renoud <[email protected]>
An: rsgb_lf_group <[email protected]>
Verschickt: So, 16. Sept 2018 21:52
Betreff: Re: LF: LF EbNaut TX Announcement

Domenico and EbNaut:

Thanks to all for the comments and decode info from 16 September EbNaut Beacon Transmissions

I will run the EbNaut Beacon again this evening from 2300 UTC 16 September to 1100 UTC 17 September.  I am using EbNaut Sender V0.8 for generating the code and employ GPS-based time and frequency references for all station equipment and computers.

EbNaut Transmission Details:
Freq:  137470 Hz
Coding:  8K19A
CRC 16
Symbol Period:  3 sec
Message length:  5 characters
Number of Signal Bits:  512
Duration:  00:25:36.00
Message repeated 2x per hour at minutes 00 and 30
1 Watt EIRP

73,
Rob - K3RWR
FM18qi


On Sep 16, 2018, at 12:20, Domenico IZ7SLZ <[email protected]> wrote:

Hello Rob and EbNauters,

With pleasure, i  got one T/A decode at 04:00 UTC of today  :
2018-09-16_04:00:00 137470.000Hz N=5 T=3s 8K19A CRC=16 list=5000 sym=512 Duration=1536s
found rank 650 ber 3.5742e-01 Eb/N0 0.8 M -8.017886162e+00 ph 0 0,0,0,0 [K3RWR]
found rank 245 ber 3.4375e-01 Eb/N0 1.6 M -8.088760853e+00 ph 16 0,0,-30,-30 [K3RWR]
--------------------------------------------------------------------------------------------

Strange thing is that the decode comes only using nominal offsets (time and frequency).
Thank you very much Robert for the signal and for the activity. Hope to have a 2-way contact soon !
I'm out of home for some days; When returned, i will try to deep search  your signal in other timeslots using the recordered audio of the LF op32  band.

The receiver will continue to record the band for this week.

I have programmed my auto-decode utility with the transmit parameters of Luis EA5DOM . Unfortunatly i have discovered a bug so decoding work of last 3 days is invalid. 
Same for you, Luis, i will try a deep search your recent transmissions at next week-end.
But now bug in auto-decoder routine  is fixed so, you can try further transmission anytime. Thanks in advance for testing my grabber.


73, Domenico IZ7SLZ
Putignano (APULIA) JN80nu





On Sat, 15 Sep 2018 at 15:51, Rob Renoud <[email protected]> wrote:
Markus and EbNaut,

I will activate my 2200m EbNaut Beacon from 2300 UTC - 1100 UTC for the next two days, weather permitting (2300 UTC 15 Sep - 1100 UTC 16 Sep and 2300 UTC 16 Sep - 1100 UTC 17 Sep).

Tnx to all for reports and comments!

73,
Rob - K3RWR
FM18qi

On Sep 15, 2018, at 07:41, Markus Vester <[email protected]> wrote:

Sorry I missed the action last night, but will activate filesaves and try again tonight Sat/Sun. Best times to Europe have usually occured between 1 and 5 UT. Would it perhaps be possible to transmit a few hours longer?

Best 73,
Markus (DF6NM)

-----Ursprüngliche Mitteilung-----
Von: Rob Renoud <[email protected]>
An: RSGG_LF <[email protected]>
Verschickt: Sa, 15. Sept 2018 0:39
Betreff: LF: LF EbNaut TX Announcement

Hi EbNaut,

For the next 24 hours will be transmitting an EbNaut Beacon (weather permitting) on 2200m

Freq: 137470.00 Hz
Code: 8K19A
Symbol Period: 3 sec
CRC: 16
Characters: 5
Duration: 00:25:36.0
Start Time: 23:30 UTC 14 September 2018
Repeated on minutes 00 and 30

Reports and comments welcome :-)

Rob - K3RWR
FM18qi


Attachment: dl0ao_09160411_spectrum_-0.3mHz.png
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Attachment: dl0ao_09160411a_result.png
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Attachment: dl0ao_09160411a_sym.png
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