Re: LF: EbNaut Autodecoder 137490 Hz: EA5DOM received

[Markus Vester <markusvester@aol.com>]

 Hi Luis,

> Impedance drops a lot after rain

This seems unusual. I have exactly the opposite effect here: Series resistance at 137 kHz is normally around 20 ohms (including 5 ohms for the coil). When it rains it get worse up to about 40 ohms, whereas best times are cold and dry winter days with ~15 ohms when the trees are solidly frozen. So I presume that the major contribution to my resistance are capacitively-coupled losses in vegetation and other nearfield environment. The ground connection itself (the "house earth" which is connected to electric grid PE, and also pipe systems for water supply and distict heating) seems to have a low resistance.

My only explanation for lower wet resistance would be if one were using a separate radial system in the garden, whose connection to ground might be better when the lawn is soaked. But I don't think this applies to your setup at all.

Best 73,
Markus

-----Ursprüngliche Mitteilung-----
Von: VIGILANT Luis Fernández <luis@vigilant.es>
An: rsgb_lf_group@blacksheep.org <rsgb_lf_group@blacksheep.org>
Verschickt: Sa, 27. Okt 2018 10:56
Betreff: Re: LF: EbNaut Autodecoder 137490 Hz: EA5DOM received

Hi EbNaut

Alaska is still too far away for me. Even in EbNaut :(

I'm struggling here with the antenna. Most of the time impedance rises and I hardly run 1A RF current

For long EbNaut transmissions the PA needs to work more relaxed and last night it was no more than 200mA

Domenico decoded my messages too. I tried a 30 characters message at 0.1s but didn´t work

Which are the EbNaut scripts you have configured now, Domenico ? Only for 6 characters at 3s/symbol ?

Can you run different srips at the same time to try different message lenghts and speeds ?

Rainy weekend here. Impedance drops a lot after rain. Let's see how much current can drain

Last time I could see almost 4A RF. But for short time untill a mosfet rised a white flag ;-)

73 de Luis

EA5DOM

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De: owner-rsgb_lf_group@blacksheep.org [owner-rsgb_lf_group@blacksheep.org] en nombre de Laurence KL7 L [hellozerohellozero@hotmail.com]
Enviado: sábado, 27 de octubre de 2018 0:19
Para: rsgb_lf_group@blacksheep.org
Asunto: Re: LF: EbNaut Autodecoder 137490 Hz: EA5DOM received

Im trying to quieten down my 1pps into the sound card so it doesnt bleed over....getting there slowly!

Lauence KL7L

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From: owner-rsgb_lf_group@blacksheep.org <owner-rsgb_lf_group@blacksheep.org> on behalf of Markus Vester <markusvester@aol.com>
Sent: Friday, October 26, 2018 1:51 PM
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: EbNaut Autodecoder 137490 Hz: EA5DOM received

 

Another strong decode with zero symbol errors. This can go much further! I hope someone in DX-land is observing the frequency.

Best 73,
Markus (DF6NM)


-----Ursprüngliche Mitteilung-----
Von: VIGILANT Luis Fernández <luis@vigilant.es>
An: rsgb_lf_group@blacksheep.org <rsgb_lf_group@blacksheep.org>
Verschickt: Do, 25. Okt 2018 12:36
Betreff: RE: LF: EbNaut Autodecoder 137490 Hz: EA5DOM received

Hi Domenico, LF

 

I can test again tonight. No problem. I will transmit in “second” periods at minute 30

 

Finally made an small pcb with 4013 and 4070 in SMD. It plugs directly in the 4013 shocket. Uses just one row of the shocket

So it is a very easy way to get phase modulation in Class-D G0MRF style PA’s. Just plug and play. Attached is a picture of an ugly

wired version. A new pcb is already designed using just one side, no drills, and just one wire jumper. Easy to reproduce with

big SMD components (1206)

 

Schematic and picture attached

 

73 de Luis

EA5DOM

 

De: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] En nombre de Domenico IZ7SLZ
Enviado el: miércoles, 24 de octubre de 2018 23:36
Para: rsgb_lf_group@blacksheep.org
Asunto: Re: LF: EbNaut Autodecoder 137490 Hz: EA5DOM received

 

Hi Luis, Markus and all

 

i'm sorry Luis becouse i miss your recent EbNaut transmissions.

My Linux PC was engaged in SAQ reception. After dinner i have restored the setup and now receiver on 136.490 kHz and autodecoder are again operational so i hope that you are planning to transmit again further messages tonight.

 

Good reception of SAQ here in JN80nu thanks to very low QRN and to Paul's vlfrx-tools used for acquiring, filtering and stream the audio to Windows PC.  Then i have used Spectrum Lab to convert to analog and send the audio to the speaker. Path is about 2300 km.

This is the audio recordered:

https://drive.google.com/file/d/1QzJYH8GajL2PzCngnkteNT3p5vBN-tAY/view?usp=sharing

In perfect 'vintage' marine radio officer style, i have prepared the text sent by SAQ :

https://drive.google.com/file/d/1R36BPmf5lyiAlOzDj-bj1dZuNkKleQt3/view?usp=sharing

 

a nice text about the Peace. Thanks to the SAQ staff for their activities.

 

73, Domenico IZ7SLZ

 

 

 

 

 

 

 

 

On Wed, 24 Oct 2018 at 22:43, VIGILANT Luis Fernández <luis@vigilant.es> wrote:

Thank you Markus ! :-)

 

A second message was transmited at odd (second) period. Your auto decoder is performing very good 

 

73 de Luis

EA5DOM

 

 

El 24 oct. 2018 21:38, Markus Vester <markusvester@aol.com> escribió:

Luis, you've made it! 

An error-free decode at DF6NM, and also successful at DL0AO (with lower SNR, presumably due to the RX antenna pointing in another direction).

Best 73,
Markus (DF6NM)

IZ7SLZ: https://www.qsl.net/iz7slz/EBNAUT/DECODED.TXT

DL0AO: https://vlf.u01.de/LF/LFgrabber/ebnautresults.txt
DF6NM: http://df6nm.darc.de/opds/ebnautresults.txt