Re: LF: LF EbNaut TX Announcement

[Markus Vester <markusvester@aol.com>]

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 <markusvester@aol.com>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
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 <k3rwr@md.metrocast.net>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
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 <iz7slz.domenico@gmail.com> 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.

www.qsl.net/iz7slz

73, Domenico IZ7SLZ

Putignano (APULIA) JN80nu

On Sat, 15 Sep 2018 at 15:51, Rob Renoud <k3rwr@md.metrocast.net> 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 <markusvester@aol.com> 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 <k3rwr@md.metrocast.net>
An: RSGG_LF <rsgb_lf_group@blacksheep.org>
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

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