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Re: LF: 2200M EbNaut Beacon

To: [email protected]
Subject: Re: LF: 2200M EbNaut Beacon
From: DK7FC <[email protected]>
Date: Tue, 02 Oct 2018 08:38:39 +0200
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Hello Domenico,

Very well! Your EbNaut grabber is the only one world wide and performs very well.

I should do the same, but my Linux PC is nearly overloaded with the VLF stuff.
A Raspi could do the job but does not have enough memory i assume...

73, Stefan

Am 02.10.2018 01:15, schrieb Domenico IZ7SLZ:
LF EbNauters,

thanks to Markus and Stefan for the comments and to Rob for putting on air a very good signal.
I was also surprised to see the decode achieved by the auto-decoder without any time and frequency offset !
Propagation conditions are becoming better, but noise here is still high.
I tried a deep investigation: no further decode,  but with an offset of -0.0001 Hz and +0.005s (ooops !) i have improved the 2018-09-30_03:00 UT decode:

initial reference phase -62.3 amplitude 2.049e-01
phase   0    0    0    0    0
carrier phase: -6.9 deg
carrier Eb/N0: 0.5 dB
carrier Es/N0: -10.10 dB
carrier S/N: 19.87 dB in 672.0 uHz, -11.86 dB in 1Hz, -45.84 dB in 2.5kHz
elapsed 58
found rank 43 ber 3.4980e-01 Eb/N0 -0.6 M -7.389708042e+00 ph 0 0,0,0,0 [K3RWR_FM18QI_73]

Looking on the October 1st recordings, with these offsets,  i got another decode at 02:30 UT:

initial reference phase -6.6 amplitude 2.356e-01
phase   0    0    0    0    0
carrier phase: -1.2 deg
carrier Eb/N0: 0.4 dB
carrier Es/N0: -10.23 dB
carrier S/N: 19.74 dB in 672.0 uHz, -11.99 dB in 1Hz, -45.97 dB in 2.5kHz
elapsed 58
found rank 84 ber 3.6694e-01 Eb/N0 -1.7 M -7.504411221e+00 ph 0 0,0,0,0 [K3RWR_FM18QI_73]

QRB  is about 7600 km.

Working conditions here, (vintage 😀) as usual:
- miniwhip (a modified ex-Navtex antenna from Furuno ; see attachment)
- receiver JRC NRD-92M with external 10 MHz reference signal steered by  GPS
- a modest PC (Intel P4 CPU 3.50GHz x2) from scrap with Ubuntu 14.04LTS
- software vlfrx-tool from Paul Nicholson.

I have attached also the latest version of  the bash './autoebnaut' i.e. the list of the commands that recall vlfrx-tool programs to start the decoder each 30 minutes.
Other linux programs are running in background:
- vtcard and vttime to manage and calibrate the audio card
- vtwrite to store audio coming from receiver
- gpsd and chrony to manage the nmea and 1pps from neo8 gps (connected at serial COM1) and adjusting the PC clock.

73, Domenico IZ7SLZ

On Mon, 1 Oct 2018 at 03:24, Markus Vester <[email protected]> wrote:
Just happened to see this on Domenico's auto-Decoder:

2018-09-30_03:00:00 137470.000Hz N=15 T=1.5s 8K19A CRC=16 list=1000 sym=992 Duration=1488.0s
found rank 29 ber 3.5081e-01 Eb/N0 -0.7 M -8.147493362e+00 ph 13 -150,-150,180,180 [K3RWR_FM18QI_73]
found rank 9 ber 3.5988e-01 Eb/N0 -1.3 M -8.275846004e+00 ph 49 -120,-150,-150,180 [K3RWR_FM18QI_73]

Cool, well done both!

73, Markus (DF6NM)

-----Ursprüngliche Mitteilung-----
Von: Rob Renoud <[email protected]>
An: RSGG_LF <[email protected]>
Verschickt: Fr, 28. Sept 2018 15:49
Betreff: LF: 2200M EbNaut Beacon

Hello 2200 Meters EbNaut,

I will run the EbNaut beacon on 28, 29 and 30 September from 2300 UTC to 1100 UTC this coming weekend as follows:

Code: 8K19A
Symbol Period: 1.5 sec
CRC: 16
Number of Char: 15 (K3RWR_FM18QI_73)
Signal Bits: 992
Duration: 1488 sec (00:24:48.00)
Frequency: 137470.000 Hz
TX Sequence: 2 X per hour starting on minutes 00 and 30
Power: 1 Watt EIRP

Reports and comments welcome :-)

Rob - K3RWR
“Practicing the Art of Radio”

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