Re: VLF: Uwe on the air!

[DK7FC <selberdenken@posteo.de>]

Hi Uwe,

800 mA, that would be +6 dB! Fine fine fine!
We need more RX stations. Any why are all TX stns from DL these days?

Isn't it possible to ground the neighbors fences? Otherwise you can at least run 800 mA at night, when they are sleeping.

I can recommend to use that ALC technique i added into my scheduled/conditional actions.
Then you can:
- plot and monitor your antenna current
- keep the target antenna current constant (delta i < +- 1 mA)
- run different antenna current profiles automatically (e.g. 800 mA from 21...6 UTC and 400 mA from 6...21 UTC)
- add a safety function which stops the transmission automatically when the current drops below a certain limit over a certain time period

It is just some lines into SLs scheduled/conditional actions. You already have the hardware available (capacitive probe feeding a signal back into the microphone input).

73, Stefan



Am 02.02.2017 12:55, schrieb dj8wx@t-online.de:

Stefan, Paul, Markus,

thanks fort he reports and the hints.

 

yes,Stefan, the reason for malfunction was a too weak driver output signal. Now the antenna current could be up to 800mA. but the induction into fences etc does allow max 500mA to avoid neighbors yell when toutching his railings.

 

today I will try to finish the new rx 10m-circumference-loop. so the TX will be switched off.

Any EbNaut transmission later.

 

Uwe/dj8wx

 

 

 

 

-----Original-Nachricht-----

Betreff: Re: VLF: Uwe on the air!

Datum: 2017-02-02T12:39:19+0100

Von: "Markus Vester" <markusvester@aol.com>

An: "rsgb_lf_group@blacksheep.org" <rsgb_lf_group@blacksheep.org>

 

 

 

There's also a peak and a trace on 8269.995 Hz in the bottom window of my VLF grabber (~ 10 dB SNR in 63 uHz). Uwe, I'm glad to see your signal again! Unfortunately my receiver seems to be many dB worse that Stefan's...

Best 73,
Markus (DF6NM)

-----Ursprüngliche Mitteilung-----
Von: DK7FC <selberdenken@posteo.de>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Do, 2. Feb 2017 11:19
Betreff: VLF: Uwe on the air!

Hi Uwe, VLF,

Your signal is very strong today, currently 15 dB SNR in 424 uHz!
http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html

I bet you are trying to run more antenna current to leave a trace at
RN3AUS in the next session!? :-)

It would be interesting to see another EbNaut message from you. Maybe
Markus can decode it as well. Or you can try to use a message longer
than 5 characters, which is the longest message between us so far.

Use Paul's calculator. With the information 15 dB in 424 uHz you can
fill the upper two fields on the page and then vary the message length
and symbol length. For example:
http://abelian.org/ebnaut/calc.php?sndb=15&snbws=0.000424&snmps=&code=8K19&sp=30&crc=16&nc=12&submit=Calculate
Theoretically this should give a decode even if the SNR falls by 6 dB.
With 12 characters you could send your callsign and the locator!

Meanwhile i'm transmitting since 35 hours a stable carrier on
2970.000000 Hz :-)

73, Stefan



 

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